The Grand Canyon

Grand Canyon: Monument to Catastrophe.  Institute for Creation Research, Santee, California.  Edited by Steven A. Austin.  1994.  A 1994 book edited by Steven Austin and published by the Institute for Creation Research.  The article uses its fifth chapter, "How Was Grand Canyon Eroded?" (pp. 83–110), for the lakes Austin proposed, for the volume of rock he says the canyon lost, and for what he says those lakes left behind.

1. 1a.

   Page 49:  “Most geologists have recognized the extraordinarily flat surface to be free of any channel erosion.  Furthermore, pebbles of lithified Hermit siltstone are not known, from the base of the Coconino.  No soil-or-weathering profile is known at the top of the Hermit Formation.  Instead, the Hermit Formation contains elongated cracks (clastic dikes) filled with white Coconino Sandstone at the uppermost surface.  It would appear that the uppermost Hermit was not lithified, when deposition of the Coconino began.” ↩

2. 1b.

   Page 83:  The chapter epigraph, quoting Earle E. Spamer.  The full quotation continues:  “Grand Canyon has held tight to her secrets of origin and age.  Every approach to this problem has been cloaked in hypothesis.”  The quotation predates the 2000 Grand Canyon Symposium and the thermochronology programme that followed. ↩

3. 1c.

   Page 83:  “277 miles long, counting the 60 miles of Marble Canyon upstream”.  The same page gives depth as 3,000-6,000 ft and rim-to-rim width as 4-18 miles. ↩

4. 1d.

   Page 83:  “A simple calculation of the volume of the Canyon shows that almost 1,000 cubic miles (4,000 cubic kilometers) of sediment have been removed from northern Arizona to produce just the topographic form of the Canyon itself.”  This one sentence is the origin of the figure Answers in Genesis, Oard and Clarey all repeat. ↩ ↩ ↩

5. 1e.

   Page 84:  “Our minds are staggered in the attempt to imagine not just 1,000 cubic miles of canyon erosion, but many times that volume.” ↩

6. 1f.

   Page 93, figure 5.8:  The caption to Figure 5.8 reads:  “The lake would occupy an area of more than 30,000 square miles, and contain 3,000 cubic miles of water.  The volume of the lake would be three times that of Lake Michigan.”  The multiple is wrong: Lake Michigan holds 1,180 cubic miles, so 3,000 is 2.5 times, and Oard's 2.5x is the correct figure.  The 3,000 cubic miles is a hypothetical modern lake computed from present topography, not a measured palaeolake volume. ↩

7. 1g.

   Page 103:  “It would appear that Hopi Lake failed, probably by piping, beneath a low point in the Kaibab Upwarp near Grand Canyon Village, in the extreme eastern Grand Canyon area.  As an underground channel enlarged, collapse occurred, and catastrophic erosion carved a notch which began to form the Canyon.” ↩

8. 1h.

   Page 103:  “Sedimentary deposits have yet to prove the existence of Canyonlands Lake.”  No deposit at all is claimed for Vernal Lake. ↩ ↩

9. 1i.

   Page 92:  Carol S. Breed, quoted by Austin:  “the Bidahochi Formation stands in relation to the postulated southeasterly ancestral upper Colorado in much the same way as the Muddy Creek Formation stands in the way of a pre-Pliocene westward flowing Colorado River.  There is a notorious lack of pre-Muddy Creek Colorado River sediments in the west; there is a similar lack of proven pre-Bidahochi upper Colorado sediments in the east.” ↩

10. 1j.

    Page 95:  Listing the model's own predictions: Pliocene lake strata east of the canyon; geomorphic evidence of increased ancient flow; relict landforms; and unusual Pliocene delta deposits near the Gulf of California. ↩

11. 1k.

    Page 95, figure 5.10:  The caption to Figure 5.10 reads:  “up to 500 cubic miles of water (half the present volume of Lake Michigan), eroding the Channeled Scabland of eastern Washington.  Fifty cubic miles of sediment and bedrock were eroded.” ↩

Oard, Michael J.  “The Origin of Grand Canyon—Part II: Fatal Problems with the Dam-Breach Hypothesis.”  Creation Research Society Quarterly 46(4):290–307.  2010.  Page 294:  His section, headed "My Journey Away from the Dam-Breach Hypothesis", records that he originally accepted Austin's model:  “In my first (generally favorable) examination of the dam-breach hypothesis (Oard, 1993), I noticed five geological problems … Over time, other research not directly connected to Grand Canyon began to raise other questions and uncover even more problems.”  A 2010 critique, in a creationist journal, of the dam-breach model that Austin and Brown championed, in which lakes dammed after the Flood burst and carved Grand Canyon.  Its author is a retired National Weather Service meteorologist with a master's in atmospheric science and a published monograph on the Missoula flood, and he records that he first accepted the model before turning against it.  The article uses it as a creationist's own case that the dam-breach model fails, on two counts: the lakes left no shorelines or deltas, and the Kanab and Havasu tributary canyons would need vast floods spread over a wide area.

1. 2a.

   Page 306:  He continues:  “Logic therefore pushes us toward a different explanation—that the canyon and its tributaries were all eroded during the closing stages of the Genesis Flood.” ↩

2. 2b.

   Section Abstract, page 290:  His full list is at p. 296 and runs to ten problems.  Page 296:  Among them, he says that.  “Austin's model requires an improbable simultaneous release of lake volumes”.  that piping.  “would have had to operate over nearly 100 miles”.  that.  “The plethora of features such as gravel bars and slackwater deposits readily observed for the Lake Missoula and Bonneville floods are not present on the southwest Colorado Plateau”.  and that.  “There is no massive gravel bar at the mouth of Grand Canyon, similar to the 200 mi² … Portland Delta at the mouth of the Columbia Gorge.” ↩

3. 2c.

   Pages 298–303:  “All lakes have shorelines, and when rivers flow into lakes they form deltas.  If a lake empties, those shorelines and deltas will remain … The Flood ended around 4,500 years ago.  The lakes breached several hundred years later.  That leaves slightly more than four millennia, which is not enough time to erase all traces of these lakes.”  His controls are Lake Missoula on Mount Sentinel and Mount Jumbo, the Bonneville shorelines north of Salt Lake City, Lake Manly in Death Valley, Lahontan, and the pluvial lakes of southeastern Oregon. ↩

4. 2d.

   Page 298:  From the figure caption, the glacial Lake Missoula bottom sediments were.  “laid in the bottom of glacial Lake Missoula, over 1,000 feet (300 m) below maximum lake level.  The catastrophic emptying of the lake failed to erode these sediments.” ↩

5. 2e.

   Page 299:  Quoting Alt 2001, p. 48:  “But the shorelines seem just as numerous on the weak clay slopes north of the Missoula Valley as on extremely stable slopes of Belt rocks.”  His conclusion:  “any appeal to absence from erosion seems unlikely.” ↩

6. 2f.

   Pages 296–297:  “geologists think that only a small part of the formation was deposited by a lake and that this lake was only a small desert lake … Most of the formation is volcanic or laid down in moving water.”  And:  “While the Bidahochi lake sediments are located near the northern and eastern 'shoreline,' there are no deposits in what would have been the deepest part of the lake—exactly where they would be most expected.” ↩

7. 2g.

   Pages 303–305:  Kanab Canyon.  “enters Grand Canyon as a narrow gorge about one mile (1.6 km) deep and a quarter mile (0.4 km) wide … Havasu Canyon is of similar dimensions.”  His inference:  “Since the tributaries reach the same depth as Grand Canyon, the most logical explanation is that they were eroded at the same time … water flowing at sufficient velocity for a sufficient time to erode a mile into indurated rock would have had to have been spread over a hundred miles of the southwest Colorado Plateau.”  He also quotes Wayne Ranney against the mainstream:  “How is it that much smaller tributaries, which have no water in their channels most of the time, can carve canyons just as deep as the Colorado River has carved the Grand Canyon?” ↩

He, Jason J. Y. et al.  “Late Miocene Colorado River arrival in the Bidahochi basin supports spillover origin of Grand Canyon.”  Science, 289–294.  Apr 16, 2026.  A research article in the journal Science, written by thirteen authors.  Its dating of volcanic ash and of 3,596 detrital zircon grains (sand-sized crystals that record the age of the rock they came from) placed Colorado River sediment in a lake basin east of the canyon by 6.6 million years ago.  He and Crow contributed equally, and the corresponding author, Crow, is at the U.S. Geological Survey in Flagstaff and is the same Crow who co-authored the 2014 thermochronology paper and led the lava-dam work.  The article uses it as the newest evidence that the river got through the Kaibab arch by lake spillover, the mechanism creationists have argued for far longer than the mainstream has. ↩

1. 3a.

   Page 289:  “we present new evidence from zircon uranium-lead geochronology for the arrival of distinctive Colorado-Green River sediment in the Bidahochi basin by 6.6 million years ago derived from the Browns Park Formation.  This is coeval with an order-of-magnitude increase in depositional rate, an increase in carbonate strontium isotope (87Sr/86Sr) ratios, the appearance of large fish species characteristic of fast-flowing waters, and other sedimentological changes.”  The measurement is 3,596 detrital zircon grains from nineteen sandstone samples, plus ion-microprobe dating of interbedded ash at 6.62, 6.53 ± 0.09, 6.46 ± 0.15 and 6.42 ± 0.08 Ma. ↩

2. 3b.

   Page 293:  “The size (as long as 75 cm), enlarged fins, and narrow tail fin base of fish specimens from the UBF suggest fast-moving fluvial habitats.” ↩

3. 3c.

   Page 294:  “Notching of the Kaibab arch post–6-Ma uplift and/or erosion can easily account for the small elevation difference between the sill and the highest strata of the UBF.  Thus, arguments that Bidahochi lake was not high enough to overtop the Kaibab arch are not supported.”  Page 293:  The highest Bidahochi beach deposits sit at 2,250 m against a reconstructed sill near 2,300 m. ↩

4. 3d.

   Page 294:  “karst piracy seems improbable given the lack of analogous linear collapse features … Headward erosion is not supported because of the lack of Colorado Plateau detritus in the Miocene deposits at the mouth of the Grand Canyon.  Groundwater sapping is likely to have contributed to drainage reorganization during integration but cannot be the sole process over the entire length of the Grand Canyon … Lake spillover … now seems to have played a critical role through the Grand Canyon reach as well.” ↩

5. 3e.

   Page 294:  “This suggests a 1.2- to 0.4-Ma lag between the arrival of the CR to the Bidahochi basin and to depocenters downstream from the Grand Canyon.  This lag is much greater than the ~±100,000 (2σ) errors on geochronologic constraints.” ↩

6. 3f.

   Page 294:  “It is notable that lake spillover would have established the route of the river, allowing the initiation of new fluvial incision, but catastrophic flooding during that process is not necessarily invoked as contributing substantially to canyon deepening.” ↩ ↩ ↩ ↩

Oard, Michael J.  Analysis of Walt Brown's Flood model.  Creation Ministries International.  2013.  Its verdict:  “There are many more specific problems that can be brought forth against Brown's version of the dam-breach hypothesis, but the above are enough to show that his hypothesis won't work.”  He notes, against Brown's block-faulting, that the Grand Staircase and Book Cliffs.  “are obviously erosional escarpments … They are not fault scarps”.  He also says the lakes did not breach at the low points of the Kaibab Plateau, an objection that hits Austin equally.  A critique that Creation Ministries International commissioned from Michael Oard, a full-time researcher known for his field geology, because it kept receiving mail about Brown's hydroplate model.  It summarizes Brown's model and then tests it, most closely on the origin of Grand Canyon and on the woolly mammoths.  The article uses it for the water-budget objection to Brown's lakes.

1. 4a.

   Section Not enough water for erosion:  “the total volume of rock eroded by sheet flow would be 8,500 km³ (2,000 mi³).  The volume of Brown's two lakes east of Grand Canyon was only about 12,000 km³ (2,930 mi³).  That is a little more than a cubic km of water to erode a cubic km of sediment, which seems like too little water, just to erode the 300 m (1,000 ft) of sediments before Grand Canyon was even carved!”  And:  “that much water only eroded about 200 km³ (50 mi³) of soft silt and hard basalt along the flood path.  That is about a 10 to 1 ratio of water to erosion.” ↩ ↩

Clarey, Timothy L.  “Grand Canyon Carved by Flood Runoff.”  Acts & Facts.  Institute for Creation Research.  Nov 30, 2018.  “I think the best solution is the one Mike Oard presented in his book on Grand Canyon.”  An article in Acts & Facts, the Institute for Creation Research's publication, by Timothy Clarey, who works for the institute Austin helped build.  Clarey rejects its founding model, citing the old-earth Kregel volume against it.  The article uses it because a writer for the same institute says plainly that the breached-dam lakes lack evidence.

1. 5a.

   “The biggest problem with the breached-dam hypothesis is the lack of physical evidence for the existence of these lakes … Neither of these 'lakes' has any mapped lake-cut terraces or strand lines as are common surrounding Lake Bonneville … Merely drawing in a vast lake based on today's topography, without strong evidence to back it, is speculation, not science.” ↩ ↩

Fenton, Cassandra R. et al.  “Peak discharge of a Pleistocene lava-dam outburst flood in Grand Canyon, Arizona, USA.”  Quaternary Research 65:324–335.  2006.  Section Abstract, page 324:  “The Hyaloclastite Dam was up to 366 m high … Failure of the Hyaloclastite Dam released a maximum 11 × 10^9 m3 of water in 31 h.  Peak discharges … ranged from 2.3 to 5.3 × 10^5 m3 s−1 … This discharge is an order of magnitude greater than the largest known discharge on the Colorado River (1.4 × 10^4 m3 s−1) … and in the top ten largest floods in North America.”  The 200 m bench height and the 53 km downstream extent widely attached to this paper are not in it.  They belong to Fenton, Poreda, Nash, Webb and Cerling's 2004 study Geochemical Discrimination of Five Pleistocene Lava-Dam Outburst-Flood Deposits, Western Grand Canyon, Arizona, in The Journal of Geology 112:91–110, and this article does not use them.  A 2006 paper that models the flood from the failure of the Hyaloclastite lava dam in the western Grand Canyon, estimating how much water came down and how fast.  The article uses it for the size of that flood, and for the authors' view that such floods may have been ineffective at cutting the western canyon. ↩ ↩

1. 6a.

   Page 334:  Fenton, Webb and Cerling write:  “Floods with large peak stream power, but of short duration and low total energy expenditure are ineffective agents of geomorphic change in alluvial or bedrock channels … lower incision rates are reported … in western Grand Canyon relative to eastern Grand Canyon for the past 630,000 yr, the time during which lava dams periodically existed in the western canyon.  The difference in incision rates may reflect the ineffective erosive power of lava-dam outburst floods in western Grand Canyon.” ↩ ↩

Bretz, J Harlen.  “The Channeled Scablands of the Columbia Plateau.”  The Journal of Geology 31(8):617–649.  1923.  The 1923 paper in which J Harlen Bretz described the Channeled Scablands of the Columbia Plateau, the landscape he argued a flood had scoured.  The article uses it for Bretz's own test for where his flood had been.

1. 7a.

   Pages 619–620:  From his numbered list of universal relations:  “11. The pattern of scabland tracts, where hills of the older topography are isolated in them, is anastomosing or 'braided.'  12. Scabland tracts invariably contain 'channels.'  These are gorges or canyons or elongated basins eroded in the basalt … in most cases, the channel pattern is anastomosing or braided.” ↩ ↩

2. 7b.

   Page 619:  Item 9(a):  “The areas surrounded by scabland invariably have the dendritic drainage pattern, mature topography and loessial soil of the plateau.”  This is the diagnostic by which Bretz mapped where his flood had not been. ↩ ↩

Cole, Kenneth L., and Larry Mayer.  “Use of packrat middens to determine rates of cliff retreat in the eastern Grand Canyon, Arizona.”  Geology 10(11):597–599.  1982.  Page 599:  “We have estimated the envelope line by applying linear regression to the data from 14 Pleistocene middens collected from small to medium caves in the Horseshoe Mesa Member of the Redwall Limestone… The estimate of the rate of cliff retreat for the Redwall Limestone is 0.45 m/10³ ¹⁴C yr.  The range in our estimates of the rate of cliff retreat, at the 95% confidence level, is from 0.18 to 0.72 m/10³ yr.”  They call it.  “a 13,000-yr average rate.”  A 1982 study that dated packrat middens, the plant-and-dung piles packrats leave in caves, to measure how fast the Redwall Limestone cliffs retreat.  The authors fit a line through 14 Pleistocene middens and get a rate of 0.45 metres per thousand radiocarbon years, with a 95% range of 0.18 to 0.72.  The article uses the rate to explain the canyon's width, and it reports the range in full. ↩ ↩

1. 8a.

   Three Comments on the paper appeared in Geology 11 in 1983, with the authors' replies.  Louise Hose attacks the assumed midden frequency distribution, and says middens.  Page 314:  “exist as far back as at least 158 m from any possible entrance”.  and that one dated 16,580 ± 460 yr B.P. sits.  “85 m from the closest cliff.”  Page 315:  Haman argues that the rate is a floor rather than a ceiling:  “the cliff retreat at embayments is four to five times more than salients.  Cole and Mayer's (1982) 14 sets of data were all taken from salients and thus represent minimum rates of cliff retreat from the Colorado River”.  and.  “At least 57% of the data Cole and Mayer used to estimate cliff retreat from the Colorado River represents retreat from major tributary canyons to it.”  Page 494:  Bernard J. Smith of Queen's University Belfast makes the catastrophist's objection directly:  “Episodes of significant erosion would appear, therefore, to be accomplished primarily by high-magnitude, low-frequency events.  It is clear that the nature of these processes cannot be understood in terms of 'average rates of erosion.'”  Cole and Mayer reply:  “An average rate does not mean a constant rate…  The collection of data from multiple sites was our best assurance that a catastrophic event at one site had minimal impact upon the outcome of the study.”  They also state that the sites are.  “all in areas well away from streams or washes”.  The figure is therefore a mass-wastage rate measured independently of stream action. ↩

Abbott, Lon D. et al.  “Rates of river incision and scarp retreat in eastern and central Grand Canyon over the past half million years: Evidence for passage of a transient knickzone.”  Geosphere 11(3):638–665.  2015.  A journal paper by three authors from the University of Colorado, the University of Illinois and Prescott College.  It dated travertine-cemented river terrace fill at Hermit Creek, in eastern Grand Canyon, by uranium-series methods, and found that the river cut down at 1 to 4 kilometres per million years between ca. 500 and 400 ka, then slowed at least fivefold, which the authors read as a transient knickzone, a wave of fast cutting moving upstream.  The article uses it as the mainstream's own measured exception to steady erosion.

1. 9a.

   Page 638:  “These data require an incision rate of 1-4 km/m.y. between ca. 500 and 400 ka followed by at least a fivefold decrease after 400 ka.”  From the abstract.  At Hermit Creek the average is 519 +55/-58 m/Myr since 506 ± 33 ka. ↩

2. 9b.

   Page 650:  “Our 600-800 m/m.y. retreat rate since 500 ka for the Redwall/Muav cliff at RM 96 is broadly similar to the upper end of Cole and Mayer's (1982) 180-720 m/m.y. since 13 ka and slightly faster than the 500-600 m/m.y. determined for the Kaibab cliff since 19 Ma (Lucchitta and Jeanne, 2001).  Our faster rate over 0.5 m.y. is to be expected because scarp retreat rates measured over short time intervals tend to be higher (Gardner et al., 1987).” ↩ ↩ ↩ ↩

Billingsley, George H., and Stanley S. Beus.  “The Surprise Canyon Formation — An Upper Mississippian and Lower Pennsylvanian(?) rock unit in the Grand Canyon, Arizona.”  U.S. Geological Survey Bulletin 1605-A, A27–A33.  1985.  A U.S. Geological Survey chapter, printed in a volume of stratigraphic notes dated 1984, that names and describes the Surprise Canyon Formation, a rock unit that fills valleys cut into the Redwall Limestone.  The 1999 monograph often cited with it is Museum of Northern Arizona Bulletin 61, not USGS Bulletin 2111.  The article uses it for the width and depth of the valleys cut into the Redwall Limestone, for the plants and erosion surfaces in the fill, and for the solution caves inside the Redwall. ↩

1. 10a.

   Page A28:  “The valleys in which the formation occurs average about 300 m in width and 75 m in depth in the western Grand Canyon … The thickest section measured is 122 m at Quartermaster Canyon.”  Page A31:  “Regional uplift allowed stream erosion to cut valleys as deep as 122 m.” ↩

2. 10b.

   Pages A30–A31:  “In the lower sandstone and siltstone beds of the formation, Lepidodendron logs and palynomorphs (spores) indicative of Upper Mississippian strata are locally abundant.  From the Granite Park section, 22 palynomorph species were identified by R. M. Kosanke.”  “Fossil plant materials in the basal units indicate that vegetation grew along the stream valleys and perhaps elsewhere on the limestone surface adjacent to the valleys.”  Also recorded on the same pages: red shaly siltstone.  “with horizontal burrows and mud cracks”.  stromatolites in the upper limestone, and.  “an erosional unconformity marks the boundary between the lower units and the upper marine sediments.” ↩ ↩

3. 10c.

   Page A27:  The formation.  “also occurs locally in caves within the Mooney Falls and Horseshoe Mesa Members of the Redwall Limestone.”  Page A29:  “These sediments are found also in solution caves within the Mooney Falls and Horseshoe Mesa Members of the Redwall.” ↩

Hodnett, John-Paul M., and David K. Elliott.  “Carboniferous chondrichthyan assemblages from the Surprise Canyon and Watahomigi formations (latest Mississippian-Early Pennsylvanian) of the western Grand Canyon, Northern Arizona.”  Journal of Paleontology 92(Memoir 77):1–33.  2018.  Pages 3–4:  Nine individually measured paleovalleys, quoted from Billingsley and Beus's 1999 monograph, given as width × depth in metres: Rampart Cave Canyon 396 × 51.2 m, Burnt Springs Canyon 425 × 89.2 m, Bat Tower Overlook 305 × 91.1 m, Quartermaster Canyon ~305 × 60.4 m, Granite Park 350 × 64.9-68.9 m, Blue Mountain Canyon 140 × 22-47.9 m, Stairway Canyon 122 × 39 m, West Stairway Canyon 140 × 19.5 m, Travertine Canyon 92 × 25.5 m.  A paleontology memoir describing the teeth and spines of ancient cartilaginous fish, relatives of sharks, from two rock formations in western Grand Canyon, and naming four new taxa.  The fossils came from a 1980s survey and from residues left by an earlier conodont study.  The article uses it for the size of the buried valley and for the estuary that flooded it. ↩ ↩

1. 11a.

   Page 3:  “Development of karst and entrenchment of the channels probably occurred in late Meramecian or early Chesterian times … In the late Chesterian/Serpukhovian a period of subsidence allowed marine waters to gradually flood the eroded valleys forming local estuaries.” ↩

Mead, Jim I., and Larry D. Agenbroad.  “Isotope Dating of Pleistocene Dung Deposits from the Colorado Plateau, Arizona and Utah.”  Radiocarbon 34(1):1–19.  1992.  Page 3:  All dates are conventional radiocarbon years using the Libby half-life, uncalibrated.  Page 12:  Rampart Cave:  “a small limestone cave at 525 m elevation with a north-facing entrance. In 1976, fire destroyed all but a small section of the deposit.”  Page 14:  Stanton's Cave:  “at 927 m elevation, is 44 m above the present river level.”  A review, by two Northern Arizona University researchers, of 20 Colorado Plateau localities where the dung of large animals was preserved in caves and alcoves and then radiocarbon dated.  The authors say identified dung and hair of large mammals is considered the most reliable material for radiocarbon dating when the question is when a local extinction happened.  The article uses it for the depth-ordered dates from Rampart Cave.

1. 12a.

   Pages 12–13:  Laboratory prefixes: A- is University of Arizona, I- is Isotopes Incorporated and L- is Lamont-Doherty.  The authors also reject one anomalously young date on physical grounds: on the 10,035 ± 250 from the trampled surface layer,  “Martin, Thompson and Long (1985) suggest Neotoma contamination of this 'young' sample”.  which is worth noting, because radiocarbon workers discard dates for stratigraphic reasons too.  At Muav Caves six surface boluses run 10,650 to 11,810, a tight cluster consistent with one horizon.  At Stanton's Cave the extinct mountain goat's pellets run 10,870 at 20-25 cm to 17,300 at 55-60 cm, and.  “No 'large pellets' were found above the 20-cm level in the stratified section”.  so the extinction is stratigraphic, not merely chronological. ↩ ↩

Kenworthy, Jason P. et al.  “An Inventory of Paleontological Resources Associated with Caves in Grand Canyon National Park.”  Proceedings of the 7th Federal Conference on Fossil Resources, 211–228.  National Park Service.  Edited by V. L. Santucci and L. McClelland.  2004.  The Park Service's own consolidated inventory of fossils found in Grand Canyon caves, compiled from the published literature, from calls and emails with park staff and outside scientists, and from comments by outside reviewers.  It lists 28 caves, including Rampart, Muav, Vulture, Bida, Kaetan and Stanton's, and it cites the primary radiocarbon papers by name for every figure.  The article uses it for the dung and packrat deposits in Rampart Cave and for the six named caves whose ages sort with depth. ↩ ↩

1. 13a.

   Page 215:  “One such deposit is a 33 cm unindurated 'seam' that separates the two major dung layers in the cave. The seam is made up of plant material such as twigs and other macrofossils that are 'perfectly preserved' … Deposited by packrats between 24,000 and 14,000 years BP, the seam may constitute the largest Pleistocene packrat deposit ever found.”  The same page records that the untrampled boluses on the deposit's original surface.  “date to around 11,200 yr BP”.  and that thirty further indurated middens have been found in and around the cave, yielding sixty plant types. ↩ ↩

Karlstrom, Karl E. et al.  “Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka.”  Geology 53(10):821–826.  2025.  Section Conclusions:  “We cannot rule out the possibility that the landslide-lake could have been triggered by random gravitational collapse or local seismicity.”  A dating study that re-dated driftwood logs in Stanton's Cave, in Marble Canyon, and dated the sand around them.  Radiocarbon on alpha-cellulose at the University of Waikato and at the Chronos laboratory of the University of New South Wales gave the driftwood 55.25 ± 2.44 ka (n = 4), and the enclosing sediment was dated by luminescence to 56.00 ± 6.39 ka (n = 2).  The authors propose that a landslide dam at Nankoweap Canyon ponded the river, and the article uses their dates, which agree with one another, to show that the Marble Canyon deposits are dated to ca. 55 ka.  The authors say the Meteor Crater trigger is only a hypothesis, and nothing in this article rests on it. ↩ ↩

1. 14a.

   Section Geochronology Results:  The two luminescence samples from the alcove at river mile 35.5, as the paper reports them:  “The lower sample … returned an age of 59.58 ± 8.67 ka (2se) that is within error of the mean 55.19 ± 2.16 ka mean wood age from the same deposit.  The upper sample … returned an IRSL age of 51.74 ± 9.45 ka (2se).”  Infrared stimulated luminescence measures trapped charge in feldspar accumulated since the grains were last exposed to light.  It shares no calibration curve and no laboratory with radiocarbon, but it does share the assumption of constant decay, because the dose rate is computed from uranium, thorium and potassium decaying in the surrounding sediment.  The article's main text says why that shared premise buys a young-earth reading little. ↩ ↩ ↩ ↩

2. 14b.

   Section Evaluating Cave Deposits in Marble Canyon:  “The largest known modern floods on the Colorado River recorded near Lees Ferry were the 5660 m3/s 1984 CE flood and the 8500 m3/s 1200−1600 yr B.P. flood … the 8500 m3/s level … would have been >50 m below the estimated 283,000 m3/sec flow needed to raise the modern river level to the entrance of Stanton's Cave.  Thus, both the heights and the ca. 55 ka age of the Stanton's and RM 35.5 deposits preclude a Holocene flood origin.” ↩

Whitmore, John H.  “Lithostratigraphic Correlation of the Coconino Sandstone and a Global Survey of Permian 'Eolian' Sandstones: Implications for Flood Geology.”  Answers Research Journal 12:275–328.  2019.  Page 275:  “Sand waves may not be an exact analogue of how the 'blanket' of the Coconino and other sandstones were deposited, but we envisage something similar.”  The same paper defends the reality of the geological column against other creationists:  “Some creationists have denied the validity of the geological column.  While a single 'blanket' sandstone is not a column, many 'blankets' stacked on top of one another, are a column”.  A long paper by a creationist that correlates the Coconino across about 2.4 million square kilometres and surveys other Permian sandstones that are called eolian, meaning wind-blown.  The article uses it for Whitmore's numbered case for a water origin, and for his defence of the geological column against other creationists.

1. 15a.

   Page 294:  “Some have suggested that the sand-filled cracks that can be found at the Hermit/Coconino contact are desiccation cracks that have been filled with sand from the Coconino, but the Hermit lacks the appropriate clays for them to be desiccation cracks and the sand-filled cracks have features of sand injectites, not desiccation cracks (Whitmore and Strom 2010).” ↩

2. 15b.

   Page 282:  His own numbered list.  Items quoted or discussed in this article:  “2. the grains of the Coconino can best be described as subangular to subrounded, 3. K-feldspar is a common accessory mineral and is often more angular than the quartz … 6. avalanche tongues, a feature common on steep slopes of eolian sand dunes, are missing in the Coconino … 7. cross-bed dips average about 20 deg and our hundreds of measurements agree with hundreds of other measurements made by Reiche (1938) and Maithel (2019) … 9. dolomite (we believe it is primary) occurs in many places … 10. the expected sedimentary details commonly found in eolian sands (as far as grainfall, grainflow and ripple structures) are for the most part absent or have been difficult to recognize in the Coconino (Maithel 2019).”  Item 6 fails on the movement's own sources: McKee figures dry-sand slump and avalanche marks by name, and Maithel's own first conference paper was on Coconino "avalanche beds."  Item 10 misstates the source it cites, which says the structures are hard to differentiate, not absent.  The measured dip means behind item 7 are in Whitmore 2019, Fig. 6, pp. 287-288 (6A-H on p. 287, 6I-O on p. 288): Bunker Trail 21.4°, Aubrey Cliffs 19.3°, Clear Creek 22.8°, Holbrook 17.3°, all-Arizona Coconino pooled 20.2°. ↩ ↩

Maithel, Sarah A. et al.  “Characterization of hard-to-differentiate dune stratification types in the Permian Coconino Sandstone (Arizona, USA).”  Sedimentology 68(1):238–265.  2021.  Section Abstract:  “Observed textures and sedimentary structures suggest that the cross-beds may consist of grainflow and grainfall deposits, but these remain difficult to differentiate at outcrop and thin-section scales.”  “Cross-beds were observed to be laterally extensive along-strike, with most dip angles ranging from the mid-teens to mid-twenties.”  The peer-reviewed version of Maithel's 2019 Loma Linda dissertation, whose advisers included Brand and Whitmore.  The article cites it as independent corroboration of the Coconino cross-bed dips, which it puts at about 20 degrees. ↩ ↩ ↩

Hill, Carol A., and Stephen O. Moshier.  “Flood Geology and the Grand Canyon: A Critique.”  Perspectives on Science and Christian Faith 61(2):99–115.  Jun 2009.  A critique in the journal Perspectives on Science and Christian Faith by two geologists, Carol A. Hill and Stephen O. Moshier, of the claims in Tom Vail's 2003 compilation Grand Canyon: A Different View.  It is not a point-by-point answer to Austin's technical work, and it does not engage the breached-dam lake volumes at all; anyone citing it as "the refutation of Austin's model" is overreading it.  The article uses it only for the specific points where the authors dispute details of Flood geology.

1. 17a.

   Page 113:  “in contrast to the unsubstantiated incision rates used in these math calculations, actual measured incision rates are too low (not too high) to explain the carving of the entire Grand Canyon over the last 6 million years.  Thus, this 'missing mass' must be accounted for by either invoking earlier canyon-erosion episodes (such as a Laramide proto-Grand Canyon) or accelerated erosion rates over the last 6 million years.” ↩

2. 17b.

   Pages 108–109:  “The cross-beds in the Coconino have been measured between 29-31 deg.”  No source is given, and the figure conflicts with every modern measurement.  The same paragraph gives the obsolete mechanical explanation of grain frosting. ↩ ↩

3. 17c.

   Page 110:  “some kind of debris-flow-type deposit”.  Page 109:  Their p. 109 also objects that the shells are.  “in excellent condition, not showing evidence of breakage or abrasion”.  an objection Austin's own paper undercuts, since Austin 2003, p. 67, says the body chamber "is usually not preserved, usually being ruptured during compaction in the sediment" and that fossils "sometimes occur as broken segments." ↩

4. 17d.

   Page 110:  Quoting John Morris in Grand Canyon: A Different View:  “The existence of the sharp, knife-edge contact between these two beds argues against the passage of long periods of time.”  The same page summarises the Hermit as containing.  “mud cracks, raindrop prints, and ripple marks indicative of shallow-water deposition”.  formed.  “on a broad, low-lying, arid coastal plain.” ↩

5. 17e.

   Page 111:  “how could slickensides (polished and smoothed striations made in hard rock by fault action), fault gouge and breccias … and the sharply offset rock layers along faults (rather than layers slumping into faults) have formed in rock that was still soft?”  The same page records.  “remnant ridges of up to 800 ft (240 m) high”.  of Shinumo Sandstone standing at the Great Unconformity. ↩

6. 17f.

   Page 111:  The sentence continues.  “—especially without any rain being involved in its deposition!”  which depends on a vapour-canopy reading of Genesis that many young-earth creationists including Snelling do not hold; that clause is dropped here and the thickness argument stands without it. ↩

Whitmore, John H. et al.  “The Petrology of the Coconino Sandstone (Permian), Arizona, USA.”  Answers Research Journal 7:499–532.  2014.  A petrology study, meaning a study of rock composition and grain shape, by a creationist team of four.  They examined the sand's thin sections, grains and frosting under the microscope and the scanning electron microscope.  The article uses it because it retires the frosting argument for wind and sets out the mica problem.

1. 18a.

   Section Conclusions:  “Mica occurs in almost every thin section studied as trace amounts, and is found throughout the formation both laterally and vertically.  It is difficult to understand how mica could survive an abrasive eolian climate, particularly when long distance transport is invoked.  K-feldspar occurs frequently throughout the formation and, even though it is softer than quartz, it is often more angular.”  The experimental basis is Anderson, Struble and Whitmore, Aeolian Research 24:33-37 (2017).  This is the creationist argument that the mainstream literature has not answered in print, and this article says so rather than pretending otherwise. ↩

2. 18b.

   Section Conclusions:  “Some have used grain frosting as an obvious indicator that the Coconino is eolian in origin.  However, the Coconino sand grains are too small to be frosted by mechanical means … Our SEM results show that the frosting is a result of chemical growth on the grains, not mechanical collisions … Thus, the frosted grains in the Coconino are not definitive evidence for eolian origin.”  The article credits the creationist team for retiring an argument the eolian side had been using. ↩ ↩

Whitmore, John H., and Raymond Strom.  “Sand injectites at the base of the Coconino Sandstone, Grand Canyon, Arizona (USA).”  Sedimentary Geology 230(1–2):46–59.  2010.  It corrects McKee (1979), whose own wording was a guess, which reads.  “probably the result of desiccation … apparently filtered down from above”.  McKee 1979, p. 197.  The paper also states a difficulty its authors do not resolve:  “A problem with no readily apparent solution is that it appears the basal Coconino was water saturated and unlithified … at the time of Laramide faulting.”  A field study of the sand-filled cracks at the base of the Coconino Sandstone, with original fieldwork at thirty locations under a Grand Canyon research permit (GRCA-2005-SCI-0011), published in a mainstream Elsevier journal.  Their field pattern: the deepest cracks, over 15 m, lie beside the Bright Angel Fault at its greatest offset of 61 m; the cracks get shorter away from the fault and disappear far from faults, their trends are oriented rather than random, and their fills are massive or vertically layered rather than horizontally laminated.  The article uses it for the claim that the cracks are sand injectites, not desiccation cracks, and for its correction of McKee. ↩ ↩

Karlstrom, Karl E. et al.  “Telling Time at Grand Canyon National Park: 2020 update.”  Natural Resource Report NPS/GRCA/NRR—2021/2246.  National Park Service, Fort Collins.  2021.  The National Park Service's own report on how old the canyon's rock layers are, written by Karl Karlstrom of the University of New Mexico and three co-authors.  The article uses it for three points: that no Paleozoic rock in the canyon has been dated directly, that more time is missing from the canyon's record than is preserved in it, and how thick the layers are. ↩

1. 20a.

   On the Redwall Limestone, the authors write:  “These fossils and the use of fossil biozones and the International Stratigraphic Chart v 2020/01 indicate that the Redwall Limestone is late Early to Middle Mississippian in age (which is about 340 million years old).”  There are no datable ash beds anywhere in the canyon's Paleozoic section, so the numbers come from detrital-zircon maximum depositional ages and from biozones correlated to dated sections elsewhere. ↩

2. 20b.

   Figure 23:  “Grand Canyon has one of the world's most complete geologic records, yet more time is missing (black = time not recorded in the column on the right) than preserved.” ↩

3. 20c.

   Page 22:  Of the Grand Canyon Supergroup strata, the report says they.  “are about 12,000 feet (3,600 m) thick”.  against.  “3,000-5,000 feet (900-1,500 m)”.  for the whole flat-lying Paleozoic section. ↩

4. 20d.

   Section Missing Time:  The Great Nonconformity spans.  “up to 500 million years of missing record”.  The Great Angular Unconformity.  “can span up to 750 million years of missing rock record”.  Powell's Great Unconformity, where Paleozoic rests directly on basement, is.  “approximately 1.2 billion years (or about 30 percent) of Earth history missing.” ↩

5. 20e.

   Page 25:  The nine-cave, fifty-midden synthesis shows.  “a gradual early Holocene change from woodland to desert faunal and floral communities, a change completed 8,500 years ago”.  The same page credits Cole and Arundel with identifying the Younger Dryas in the Grand Canyon midden record. ↩

Dorsey, Rebecca J., and Greg Lazear.  “A post-6 Ma sediment budget for the Colorado River.”  Geosphere 9(4):781–791.  2013.  A 2013 paper that builds a sediment budget for the Colorado River since 6 million years ago, comparing the rock eroded from the Colorado Plateau with the sediment buried in the Salton Trough and northern Gulf of California.  The authors estimate the erosion from the spread of Late Miocene basalt flows and new thermochronologic data, which record how fast rock cooled.  The article uses it for the volume of rock removed, and for the weak points in the mass balance that the authors admit.

1. 21a.

   Section Abstract, page 781:  “we calculate that ~3.4 ± 1.2 × 10^5 km3 of rock has been eroded from the Colorado Plateau since 10 Ma … (1) 2.8 ± 0.6 × 10^5 km3, assuming that crust between 5 and 10-12 km depth in the plate-boundary basins is young metasedimentary rock mixed with intrusions; and (2) 1.55 ± 0.35 × 10^5 km3, assuming that crust below 4-5 km is thinned pre-Cenozoic crystalline rock.” ↩ ↩

2. 21b.

   Page 786:  “There is no overlap between the maximum value in estimate 2 (1.9 × 10^5 km3) and the minimum estimate of rock eroded from the source (2.2 × 10^5 km3).” ↩

3. 21c.

   Page 786:  The implied flux is.  “~96-217 Mt/yr (156 ± 60 Mt/yr) averaged over 5.3 m.y.”  against a pre-dam gauged rate at Yuma of.  “172 ± 64 Mt/yr”.  Their own caveat, on the same page, is.  “we do not have a good explanation for the discrepancy between our value and the widely cited rate of 120-150 Mt/yr.” ↩

Billingsley, George H.  “Geologic Map of the Grand Canyon 30' x 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona.”  U.S. Geological Survey Geologic Investigations Series I-2688.  2000.  A U.S. Geological Survey map of the canyon's rock units at a scale of 1:100,000, with a 16-page pamphlet.  The pamphlet's Description of Map Units gives an east-to-west thickness range for every unit, and the map covers the central and western canyon, so the Cardenas Basalt, Nankoweap, Chuar and Sixtymile lie outside its area.  The article takes its thickness ranges from this pamphlet. ↩

1. 22a.

   Page 7:  Describes the Temple Butte Formation, which fills.  “channels eroded into the underlying Cambrian strata; channels are as much as 100 ft (30 m) deep in eastern half of map area, and about 40 ft (12 m) deep in western half of map area … Unconformity at base of unit represents major stratigraphic break in Paleozoic rock record in the Grand Canyon, spanning part of Late Cambrian, all of Ordovician and Silurian, and most of Early and Middle Devonian time, about 100 million years.”  On the same page, the base of the Redwall is.  “marked by erosion channels of low relief about 5-10 ft (2-3 m) in depth.” ↩

2. 22b.

   Page 6:  The Surprise Canyon Formation is.  “present only in paleovalleys and karst caves eroded into top half of Redwall Limestone”.  and is.  “the most fossiliferous rock unit in the Grand Canyon.”  The same pamphlet records erosion channels up to 40 m deep at the base of the Hermit in Havasu Canyon (p. 4), 24 m at the Manakacha/Wescogame contact (p. 5), and 45 m into the Woods Ranch Member below the Kaibab (p. 3). ↩

Karlstrom, Karl E. et al.  “Redefining the Tonto Group of Grand Canyon and recalibrating the Cambrian time scale.”  Geology 48(5):425–430.  2020.  A research article in Geology that redates the Cambrian Tonto Group rocks of Grand Canyon, using zircon crystals.  The authors laser-screened 100 to 300 zircon grains per sample, then ran chemical-abrasion isotope-dilution mass spectrometry on the youngest grains plucked off the mount.  The article uses it for the Cambrian ages, for the Shinumo islands under the Tapeats Sandstone, for the zircon peak in the Tapeats, and for trilobite zones that cut across the Bright Angel Formation. ↩

1. 23a.

   Page 427:  “As noted by McKee and Resser (1945), and confirmed by our work, trilobites of the Glossopleura walcotti Biozone (ca. 505 Ma) occur high in the Bright Angel Formation to the west and lower in the east.” ↩

2. 23b.

   Page 427:  “applying depositional rates of 50 m/Ma, compatible with 200 m of deposition of the Tapeats + Bright Angel Formations in ∼4 Ma, as required by the combined MDAs, biozone, and stratigraphic data.” ↩

3. 23c.

   Page 428, section Figure 3 caption:  “islands (monadnocks) of tilted Unkar Group strata (resistant Shinumo Sandstone) created up to 200 m of relief and were not covered until Bright Angel time.”  Billingsley's map records the same relationship, saying "The Tapeats fills in lowland areas and thins across or pinches out against young Proterozoic highlands," with a thickness of 0-122 m. ↩

4. 23d.

   Page 427, section Figure 2 caption:  The Tonto Group's detrital zircon spectrum shows.  “peaks at 1.7, 1.4, and 1.1 Ga that reflect unroofing of older Precambrian basement and the Grand Canyon Supergroup, and a strong Cambrian peak.” ↩

Mohr, Michael T. et al.  “High-precision U-Pb geochronology links magmatism in the Southwestern Laurentia large igneous province and Midcontinent Rift.”  Geology 52(3):193–197.  2024.  Table 1, page 195:  A granophyre pod in a sill intruding the Bass Formation and Hakatai Shale at Bass Canyon, river mile 107, gives 1098.16 ± 0.59 Ma; a second sill at river mile 132 gives 1098.09 ± 0.34 Ma; a Cardenas Basalt flow at Nankoweap Canyon, river mile 52, gives 1082.18 ± 1.25 Ma.  Bass Rapids is at about river mile 108, so the identification of MS17-107-01 with the sill RATE sampled is very likely but should be confirmed against Snelling and colleagues' own site description before being treated as certain.  A research article in Geology, a journal of the Geological Society of America, that dates the igneous rocks of the southwestern United States with a high-precision uranium-lead method on zircon crystals.  The authors dated zircon from a basalt flow and from felsic segregations in mafic sills, and they found that the sills are about 1098 million years old while the Cardenas Basalt is about 1083 million years old.  The article uses it for the ages of the Grand Canyon's Precambrian rocks and for its finding that the sills are older than the Cardenas Basalt they were long thought to feed. ↩

1. 24a.

   Page 194:  “Previously, sills in the Grand Canyon were considered coeval feeders of the Cardenas Basalt.  Our new ages indicate that sills intruding the Bass and Hakatai Formations in western Grand Canyon were emplaced at ca. 1098 Ma, while the Cardenas Basalt erupted at ca. 1083 Ma.”  And on the geochemistry that flagged it decades earlier:  “sills in Death Valley, the Grand Canyon, and western and central Arizona have εNd values of +3 to +5 … while the Cardenas Basalts have lower εNd values of +0.5 to +2.”  They also explain why the previous Cardenas age was wrong:  “apparently concordant, low-precision baddeleyite analyses … likely stem from inaccurate 206Pb/238U dates due to unmitigated Pb loss that is hidden by large analytical uncertainties.” ↩

Karlstrom, Karl E. et al.  “Formation of the Grand Canyon 5 to 6 million years ago through integration of older palaeocanyons.”  Nature Geoscience 7:239–244.  2014.  A research article in Nature Geoscience by eleven authors, who used apatite fission-track and helium dating (thermochronology) on paired samples from the canyon floor and from the rim 1,500 m above, which they modelled jointly to test when four segments of the canyon were cut.  They conclude that two of the three middle segments are old, cut 70 to 50 and 25 to 15 million years ago, while the two end segments were cut in the past 5 to 6 million years; Nature issued a correction on 18 February 2014 for errors in Supplementary Table 1.  The article uses it to show that the canyon is a composite of segments of different ages.

1. 25a.

   Page 239:  The abstract says:  “two of the three middle segments, the Hurricane segment and the Eastern Grand Canyon, formed between 70 and 50 million years ago and between 25 and 15 million years ago, respectively.  However, the two end segments, the Marble Canyon and the Westernmost Grand Canyon, are both young and were carved in the past 5-6 million years.  Thus, although parts of the canyon are old, we conclude that the integration of the Colorado River through older palaeocanyons carved the Grand Canyon, beginning 5-6 million years ago.”  Page 243:  Post-integration rates:  “semi-steady river incision over the past 4 Ma at rates of 100-200 m Ma−1.” ↩

2. 25b.

   Page 10, section Supplementary Discussion:  “Specific constraints include an alluvial fan bracketed in age between ~14 Ma and ~9 Ma that originated from the Grand Wash Cliffs at Pearce Canyon and extended southwest across the modern path of the Colorado River.  Remnants of this fan can be found on both sides of the modern Colorado River at the mouth of the Grand Canyon.  Thus, no Colorado River or major precursor river could have flowed through the modern Lake Mead region until after 6 Ma.”  Flowers and Farley offer the standard escape, that a smaller, largely carbonate drainage would leave few clastics.  The article prints both and lets the reader weigh them, because this is the one place where the young-canyon case rests on not finding something. ↩

3. 25c.

   Page 243:  “a pre-6 Ma Westernmost Grand Canyon continues to be falsified by the Muddy Creek Formation, which constrains the first arrival of Colorado River sediment to Grand Wash Trough to have been after 6 Ma.” ↩

Flowers, Rebecca M., and Kenneth A. Farley.  “Apatite 4He/3He and (U-Th)/He Evidence for an Ancient Grand Canyon.”  Science 338(6114):1616–1619.  Dec 21, 2012.  A 2012 report in Science that uses helium isotopes in apatite, a mineral, to trace how the rock cooled as the canyon was cut.  For the western canyon it finds the rock had been carved to within a few hundred metres of its present depth by about 70 million years ago, in contrast to the conventional view that the whole canyon was carved since 5 to 6 million years ago.  The article uses it as its main example of the old-canyon claim, and it states plainly that the western result depends on one sample.

1. 26a.

   Section Abstract, pages 1616, 1618:  “Statistically acceptable paths … require rapid cooling to <30°C by ~70 Ma … this result implies carving of the western Grand Canyon to within several hundred meters of modern depths (70 to 80% of total incision) by 70 Ma.”  Their goodness-of-fit values are 0.30–0.32 for the ancient path and below 0.06 for the young-canyon path, just below the conventional acceptability threshold, not annihilated.  Page 1616:  They also note that.  “the upper ~70% of the western Grand Canyon lacks any direct geochronologic constraint on when it was carved.” ↩

2. 26b.

   Page 1618:  “the 11 apatite 4He/3He spectra for sample GC863 have diverse shapes, arising from extreme U-Th zoning heterogeneity in this sample … this extreme zonation precludes the use of the GC863 4He/3He results for inverse modeling.”  They therefore used.  “the 4He/3He spectra from CP06-69 and the AHe dates from all four basement samples.” ↩

3. 26c.

   Page 1616:  “If an older canyon existed, it is possible that a smaller drainage basin in largely carbonate lithologies explains the absence of pre–6 Ma Colorado River clastics in the Grand Wash Trough (19, 21).”  Karlstrom and colleagues' reply (2014, supplementary p. 10) is that the Pearce Canyon fan physically crosses the river's path and that the Grand Wash Trough record is continuous and well exposed. ↩

Dickinson, William R.  “Rejection of the lake spillover model for initial incision of the Grand Canyon, and discussion of alternatives.”  Geosphere 9(1):1–20.  2013.  A 2013 paper by William Dickinson of the University of Arizona that tests whether a Hopi Lake spilling over the plateau could have started the canyon.  It reads the Bidahochi lakebeds and the surrounding topography, finds that Hopi Lake was a playa system that never achieved appreciable depth, and proposes an ancestral Colorado River as the alternative.  The article uses it as the full mainstream case against the spillover mechanism, a case that the 2026 detrital-zircon work has now largely reversed.

1. 27a.

   Section Abstract, page 1:  “Bidahochi paleogeography indicates that Hopi Lake was a playa system that never achieved appreciable depth.  Topographic relations in northern Arizona show that the maximum elevation of Bidahochi lakebeds is not compatible with lake spillover through the Grand Canyon.”  Page 6:  He also notes that restoring 400 m of post-6-Ma uplift would put the barrier.  “near the maximum elevation of the Bidahochi lacustrine facies”.  and would make spillover.  “feasible”.  That is the escape route the 2026 paper takes. ↩

2. 27b.

   Page 1:  The in-Bouse ash correlates with.  “the 4.83 Ma Lawlor Tuff … erupted near San Francisco Bay”.  and this.  “is compatible both with the age (5.6 Ma) of a sub-Bouse tuff … and with the age (6 Ma) of the youngest dated tuff interbedded with lacustrine Hualapai Limestone.” ↩

Dorsey, Rebecca J. et al.  “Stratigraphic record of basin development within the San Andreas fault system: Late Cenozoic Fish Creek-Vallecito basin, southern California.”  Geology 35:57–60.  2007.  The first Colorado River.  “C-suite”.  sand at Split Mountain Gorge appears nine metres above the Miocene-Pliocene boundary, about 5.3 Ma.  The paper states explicitly that its result.  “does not inform the debate over a marine-estuary versus lacustrine origin for the Bouse Formation”.  and this article makes no claim on that question.  A 2007 paper on the rock record of a basin in the San Andreas fault system of southern California.  The article uses it for the date of the first Colorado River sand there, about 5.3 Ma. ↩

Karlstrom, Karl E. et al.  “Comment on Apatite 4He/3He and (U-Th)/He Evidence for an Ancient Grand Canyon.”  Science 340(6129):143.  Apr 12, 2013.  A technical comment in Science, printed as folio 143-b, by eleven geologists, including Dickinson and Lucchitta, on a paper by Flowers and Farley that argued the Grand Canyon is about 70 million years old.  The comment says the old-canyon helium data rest on one sample and conflict with other data, and that a shallow paleocanyon carved in the eastern canyon 25 to 15 million years ago can reconcile the two models.  The article uses it for the three technical objections the comment raises against the helium data.

1. 29a.

   Page 143:  Karlstrom et al. 2013, p. 143-b, say that on the ensemble assumption the four-sample groupings.  “span several known faults and therefore may not have shared a common cooling history.”  On the single sample, the CP06-69 model.  “conflicts with the joint inversion of AFT and AHe data from nearby samples, which suggests those rocks cooled from ~60° to 40°C between ~40 and 25 Ma, compatible with ~1-km burial depth.”  On inherited helium, western samples.  “accumulated considerable radiation damage during residence in the AHe partial retention zone for >600 million years”.  and.  “may not have been heated enough during the Late Cretaceous time to fully anneal grains.” ↩

Abbott, Lon D.  “Reading the Record of Baselevel Change, River Incision, and Surface Uplift on the Colorado Plateau.”  AGU Advances 6:e2025AV001669.  2025.  A Viewpoint, a short essay in the journal AGU Advances, that summarises Tanski and colleagues' 2025 study of a knickzone, a wave of rapid cutting moving upstream along the Colorado River.  The article treats it as the best short statement of where the field stands, and uses it for the date of the river's modern course and for the statement that the puzzles of canyon cutting and plateau uplift remain unsolved.

1. 30a.

   Page 1:  “the modern course of the Colorado River wasn't established until ∼5.3 Ma, when drainage integrated across the Colorado Plateau-Basin and Range boundary at the Grand Wash Cliffs.” ↩

2. 30b.

   Page 1:  “Despite over 150 years of research, the intertwined puzzles of canyon incision and plateau uplift remain unsolved.” ↩

Karlstrom, Karl E. et al.  “Model for tectonically driven incision of the younger than 6 Ma Grand Canyon.”  Geology 36(11):835–838.  2008.  Page 835:  Their objection to reading speleothem ages as incision rates is stated as a falsification:  “the assumption that 'groundwater table decline rates are equivalent to incision rates' … is falsified by the modern hydrologic system.”  They also concede an internal problem in the same data, p. 837:  Page 837:  “caves giving similar ages occur at different heights … and caves of similar height give different ages, both of which negate the assumption of a strict incision rate significance for the dates.”  A short paper that builds a model of how the Grand Canyon has been cut in the last 6 million years, by researchers at the University of New Mexico and Los Alamos National Laboratory.  It reworks uranium-lead dates from cave mineral deposits (speleothems) that another team used to argue for a canyon older than 17 million years, and it finds steady cutting since 3–4 million years ago, at 175–250 metres per million years in the east and 50–80 in the west, which it attributes to fault block uplift.  The article uses it for the rate the authors give for the eastern canyon, which would cut the deepest part in about six million years.

1. 31a.

   Page 837:  Western canyon river-corridor speleothems give 75 m/Myr over 3.87 Myr and 55 m/Myr over 2.17 Myr, and the combined data give.  “a long-term (4 Ma) steady incision rate of 78 m/Ma”.  and the eastern canyon data.  “suggest an overall steady average bedrock incision rate of 250 m/Ma, the rate needed to carve the deepest part of the eastern Grand Canyon (1.6 km) in ~6 Ma.” ↩

Lehnigk, Karin E. et al.  “Rates of bedrock canyon incision by megafloods, Channeled Scabland, eastern Washington, USA.”  Geological Society of America Bulletin 136(9–10):4398–4410.  2024.  The authors reconstructed the pre-flood land surface by extrapolating the profiles of hanging tributaries, then subtracted it from modern topography.  The article uses it for the physics of why a confined flood cuts far more rock than a spread-out one, and for the flood counts that bound how many floods cut the coulees.

1. 32a.

   Upper Grand Coulee 67.8 km³ removed with a mean incision of 169 m, in 6 ± 1 floods; Moses Coulee 14.5 km³, 56 m, 6 ± 2 floods; Wilson Creek 1.6 km³, 10 m, 13 ± 14 floods.  Combined, 83.9 km³ from the three channels.  Against a total flood count near a hundred, the authors write:  “this would leave a maximum of 15-19 floods to predate upper Grand Coulee's incision.” ↩ ↩

2. 32b.

   Section Results:  “the shear stresses generated in the 10-km-long reach of Moses Coulee were several times higher than those generated for the equivalent section of Wilson Creek, likely because the inundation in Moses Coulee is narrower than Wilson Creek (average width of 2.1 versus 5.1 km).”  Similar discharge, nine times the eroded volume, because the flow was confined. ↩

Heaton, Timothy H.  “A Young Grand Canyon?”  Skeptical Inquirer 19(3):33–36.  1995.  “For a young-earth creationist book it has reached a new level of scholarship,”.  “For the most part Austin's research is rigorous and deserves praise”.  “I concur with this analysis, as do many geologists.”  A review in the Skeptical Inquirer of Steven Austin's guidebook Grand Canyon: Monument to Catastrophe (1994), which attributes the canyon's rock layers and erosion to recent Flood-related events.  Heaton is a professional geologist who corresponded with Austin before writing, and his review praises Austin's research while rejecting his logic.  He grants Austin's critique of uniformitarianism and says Austin cannot see long-term equilibrium in the canyon.  The article uses the reviewer's concessions, which carry weight because they come from a critic.

1. 33a.

   “The fact that overland flow would have circumvented the Kaibab Plateau, rather than penetrating it, lead Austin to postulate that the first lake failed by enlargement of an underground conduit.”  Heaton also notes that.  “Austin doesn't attribute the carving of the Grand Canyon to Noah's Flood, but he considers it a catastrophic event occurring in the Flood's aftermath.” ↩

2. 33b.

   “In equilibrium drainages the tributaries, even washes that only rarely carry water, meet the river exactly at its level, and slopes are controlled primarily by the hardness of the rock units.  Is the configuration of the Grand Canyon in equilibrium or relectual?  Unquestionably it is the former.”  The word "relectual" is a typo for "relictual" in the source and is quoted as printed.  On the Scabland analogy he adds:  “It would be hard to imagine two canyons more geomorphically dissimilar to one another.” ↩

Brown Jr., Walter T.  In the Beginning: Compelling Evidence for Creation and the Flood.  9th draft edition.  Jan 2019.  Chapter The Origin of the Grand Canyon, pages 215–257.  A book-length creationist case for a worldwide Flood, built on Walt Brown's hydroplate theory.  The article uses it because Brown, not Austin, is the published source of the claim that two lakes carved the Grand Canyon in weeks, and of the waterfall discharge figure that the article tests.

1. 34a.

   Page 215:  “we will consider two ancient, postflood lakes—Grand Lake and Hopi (HO-pee) Lake—that several centuries after the flood, breached their boundaries and carved the Grand Canyon in weeks.”  Brown, not Austin, is the published source of the claim that the canyon was carved in weeks.  Figure 119, page 214:  The Figure 119 caption gives Grand Lake as.  “almost twice that of Lake Michigan”.  and Hopi Lake as.  “roughly that in Lake Huron”.  That converts to about 3,200 cubic miles. ↩

2. 34b.

   Page 228:  The waterfall released by undercutting Hopi Lake's rim was.  “roughly thirteen times higher than Niagara Falls and, for a few weeks, discharged more than a hundred times more water each second than Niagara Falls.”  Niagara's flow over the falls is on the order of 2,400 m³/s, so this is about 240,000 m³/s.  That conversion is this article's own arithmetic from a general figure for Niagara, not a hydrological citation, so readers should not lean on it. ↩

Oard, Michael J.  “The Origin of Grand Canyon Part V: Carved by Late Flood Channelized Erosion.”  Creation Research Society Quarterly 47(4):271–282.  2011.  The fifth part of Oard's series, which proposes that channelized floodwater carved Grand Canyon late in the Flood, after a sheet-flow phase had stripped the Colorado Plateau.  Oard himself calls the attempt speculative and open to future revision, and the article uses it as the creationist model that dispenses with the lakes.

1. 35a.

   Section Abstract, page 271:  “Deep canyons, including Grand Canyon, were carved during this latter time by channelized currents flowing toward the west … The cutting through of the Kaibab Plateau was first initiated by the convergence of two currents, one from the northwest and the other from the southwest.”  Oard gives the preceding sheet-flow phase in Part IV:  Section Part IV, p. 146:  “The Great Denudation was accomplished by east to northeast flowing sheets of water, which left a cobble and boulder lag—the Rim Gravel—on the southwest Colorado Plateau.”  The model is qualitative. Where Oard demands volumes, shorelines and deltas from Austin he supplies none of his own: no discharge, no duration, no sediment budget, and no account of where the eroded rock went, which is the very objection he presses against the dam-breach model.  This article says so plainly, because it is the same defect on both sides. ↩

Oard, Michael J.  “The Origin of Grand Canyon—Part III: A Geomorphological Problem.”  Creation Research Society Quarterly 47(1):45–57.  2010.  The third part of Oard's series on the origin of Grand Canyon, arguing that the canyon is a water gap, one of more than a thousand places where a river cuts through a ridge.  Oard argues that the retreating stage of the Flood best explains water gaps, and that no dam-breach model easily explains them.  The article uses it for the water-gap argument.

1. 36a.

   Pages 45, 57:  Quoted from the abstract (p. 45) and the summary (p. 57):  “it is a water gap—one of over a thousand catalogued across the Earth … Grand Canyon is not unique; more than 1,000 water gaps have been documented across the globe.  But geomorphologists cannot credibly explain the canyon or other water gaps.”  His examples include the Shoshone gap at Cody, Hells Canyon, the Delaware Water Gap and the Nenana gap through the Alaska Range.  The mainstream explanations are antecedence, superposition, stream capture and lake overflow.  Oard's real point, that none of them predicts which ridges will be gapped, survives all four, and this article concedes it. ↩

Austin, Steven A. et al.  “Remembering Spillover Erosion of Grand Canyon.”  Answers Research Journal 13:153–188.  2020.  Pages 175–176:  Endnotes 35–42 carry the priority dispute with Walt Brown.  Austin reports that Brown.  “claims Austin repositioned pages deceptively”.  and replies that.  “Brown is establishing his priority by a 'God argument'.”  A 2020 paper in the Answers in Genesis journal Answers Research Journal, defending the spillover model, in which a lake spilled over a highland arch and eroded the canyon through it.  The paper gives no discharge, no water budget and no sediment budget.  The article uses it as Austin's current defence of the model, and for the wording changes he made since his earlier work. ↩

1. 37a.

   Page 155:  “Dr. Austin reported evidence that Grand Canyon was eroded in just a few weeks just thousands of years ago by catastrophic drainage of lakes.”  Page 166:  Edmond Holroyd writes:  “Perhaps the catastrophic release of three Great Lakes-worth of water carved the Grand Canyon in a few weeks by means of cavitation process rather than in millions of years.” ↩

2. 37b.

   Page 176:  “Austin, like the other spillover advocates, does not invoke a separate lake in Utah as being a contributing cause to the initial breaching of Kaibab Upwarp.”  Compare Austin 1994, where Canyonlands Lake cuts Marble Canyon and Vernal Lake follows. ↩

Meek, Norman, and John Douglass.  “Lake Overflow: An Alternative Hypothesis for Grand Canyon Incision and Development of the Colorado River.”  Colorado River: Origin and Evolution, 199–205.  Grand Canyon Association.  Edited by R. A. Young and E. E. Spamer.  2001.  A chapter, number 30 in its volume, that revisits Eliot Blackwelder's 1934 idea that a chain of lake overflows, not a river that always flowed to the sea, built the Colorado River's route.  The authors use the Mojave River as an analogue: after the Afton subbasin breached about 18 ka (thousands of years ago), a 120 m drop in base level produced a deeply dissected landscape, and more than 99 percent of the lake clays eroded away, so they warn against rejecting lake overflow just because no lake deposits survive upstream of Grand Canyon.  The article uses it to show that lake spillover was not a creationist invention: Blackwelder proposed it in 1934, and Meek and Douglass set out the detailed version in 2001.

1. 38a.

   Section Abstract, page 199:  “the Colorado River could have developed by the episodic downstream extension of its trunk channel from multiple lake-overflow events between ~10 and 4 Ma.”  Note episodic and multiple: their mechanism is a chain of separate spillovers spread across about six million years, each filling a basin and breaching it, not one event. ↩

2. 38b.

   Page 203:  “Just as a large lake overspilled the Manix Basin and initiated the incision of Afton Canyon, we propose that a large lake spilled westward across the Kaibab Plateau, initiating Grand Canyon incision.”  They accept the Muddy Creek constraint on the same page. ↩

3. 38c.

   Page 203:  “Because lake-outlet water flowed to a base level in the Lake Mead area that was ~1500 m lower than the spillover point … the channel slope was sufficiently steep to initiate Grand Canyon incision, which probably then created knickpoints that rapidly worked their way upstream.  The rate of incision must have been very high.”  They also argue from the Mojave analogue that upstream lake sediments are the first thing a spillover destroys, an argument creationists can fairly borrow, and one that is, precisely, unfalsifiable. ↩

Lamb, Michael P., and Mark A. Fonstad.  “Rapid formation of a modern bedrock canyon by a single flood event.”  Nature Geoscience 3:477–481.  2010.  “Most bedrock river canyons are thought to be cut slowly over millions of years (for example, Grand Canyon, USA).”  Any citation of the paper that omits that sentence is quoting it against its author.  A 2010 paper on Canyon Lake Gorge, Comal County, Texas.  The article uses it for the claim that canyons can be cut in days.  The paper's own first sentence reads:

1. 39a.

   Section Abstract, page 477:  The abstract says that the flood.  “moved metre-sized boulders, excavated ∼7 m of limestone and transformed a soil-mantled valley into a bedrock canyon in just ∼3 days.”  Total erosion about 4.6 × 10⁵ m³ over 2.2 km; peak daily-average discharge 1,461 m³/s; three residents independently estimated most of the erosion occurred in the first three to four days. ↩

2. 39b.

   Page 480:  Their closing sentence gives the mechanism's limit:  “it seems plausible that erosion of well-jointed rock by large floods might be extremely rapid, such that canyon formation is limited by the capacity of the flood to transport plucked blocks rather than by the plucking processes itself.”  The conditional matters: it applies to well-jointed rock. ↩

Austin, Steven A.  “Rapid Erosion at Mount St. Helens.”  Institute for Creation Research research pages.  n.d.  “downcut the rockslide and pyroclastic flow deposits north of the volcano”.  “A miniature 'Grand Canyon' over 100 feet deep”.  Figure 6:  The caption reads:  “The flat plain of pumice deposited on May 18, 1980, was eroded to a depth of more than 100 feet by August 1984.”  A web page by Steven Austin on the Institute for Creation Research site, describing erosion of volcanic deposits at Mount St. Helens after the 1980 eruption.  In it he says the 19 March 1982 mudflow downcut the deposits north of the volcano and produced a miniature Grand Canyon over 100 feet deep.  The article accepts his observation that a dendritic (branching) drainage network and amphitheatre-headed side canyons can form in a day, and concedes that such shapes do not date a landscape. ↩

Antón, Loreto et al.  “Exceptional river gorge formation from unexceptional floods.”  Nature Communications 6:7963.  2015.  A research paper on the Ricobayo dam spillway in northwest Spain, where an unlined spillway cut about 100 m down and 160 m across into unweathered granite over six years.  The article uses it to show that the joints and faults in the rock, not the size of the floods, set how fast a gorge forms.

1. 41a.

   From the abstract.  “The amount of erosion demonstrates no relationship with flood magnitude or bedload availability.  Instead, structural pattern of the bedrock through faults and joints appears to be the primary control on landscape change.  These discontinuities facilitate rapid erosion (>270 m headward retreat; ~100 m incision; and ~160 m widening over 6 years) principally through fluvial plucking and block topple.” ↩

Whipple, Kelin X. et al.  “River incision into bedrock: Mechanics and relative efficacy of plucking, abrasion, and cavitation.”  Geological Society of America Bulletin 112(3):490–503.  2000.  On cavitation, the mechanism Austin and Holroyd propose for the Grand Canyon, the authors are careful and this article follows them.  They allow that it is possible:  “For flow depths in excess of 10 m”.  “Direct field evidence of cavitation erosion is, however, lacking.”  Twenty-six years on, that is still true, and cavitation in natural channels carries no evidential weight for either side.  A research paper on how rivers cut into bedrock, comparing plucking (blocks breaking loose along cracks), abrasion (grinding by sand carried in the water) and cavitation (damage from collapsing vapour bubbles).  The article uses it for the finding that the spacing of cracks in the rock, called joints, decides which of these processes does the cutting, and for its caution about cavitation.

1. 42a.

   Section Abstract:  “the relative efficacy of the various processes of fluvial erosion … is a strong function of substrate lithology, and that joint spacing, fractures, and bedding planes exert the most direct control.  We find that plucking dominates wherever rocks are well jointed on a submeter scale … In more massive rocks, abrasion by suspended sand appears to be rate limiting.”  Their measured threshold:  “Minimum joint spacings observed in abrasion-dominated reaches range from 1-1.5 m in the Sierra Nevada drainages studied up to 3-5 m on the Indus River in Pakistan.” ↩ ↩

Lamb, Michael P. et al.  “Amphitheater-headed canyons formed by megaflooding at Malad Gorge, Idaho.”  PNAS 111(1):57–62.  2014.  The canyon-forming discharge is.  “approximately sevenfold the largest historic discharge of the Wood River (181 m3/s over a 98-y record).”  A study of three canyon heads cut into the same basalt at Malad Gorge, Idaho: two amphitheatre-headed and cut by a flood about 46 ka, and one with the active Wood River retreating at 2.5 cm/yr for at least 33 ka.  The article uses it because one basalt flow holds both a canyon cut by a single flood and a canyon cut slowly. ↩

O'Connor, Jim E., and Victor R. Baker.  “Magnitudes and implications of peak discharges from glacial Lake Missoula.”  Geological Society of America Bulletin 104(3):267–279.  1992.  A 1992 field and hydraulic study of how much water left glacial Lake Missoula in its floods.  The authors mapped high-water evidence at two sites, Spokane Valley and Wallula Gap, and used a step-backwater computer model to turn those marks into peak discharges.  They argue that the largest flood came from a sudden failure of the ice dam, and the article uses their figures as the best measured numbers for the Channeled Scabland floods.

1. 44a.

   Section Abstract, page 267:  “Within the Spokane Valley, near the point of release, the peak discharge probably exceeded 17 ± 3 million m³·sec⁻¹.  Downstream at Wallula Gap … peak discharge was about 10 ± 2.5 million m³·sec⁻¹.  Flow duration was on the order of several days.  These are the largest known terrestrial fresh-water flows.”  The 2020 review revises the peak to about 20 million m3/s near the outlet.  Page 276:  Lake volume available for flooding: 2,184 km³. ↩ ↩

O'Connor, Jim E. et al.  “The Missoula and Bonneville floods—A review of ice-age megafloods in the Columbia River basin.”  Earth-Science Reviews 208:103181.  2020.  A review of the ice-age floods of the Columbia River basin, from glacial Lake Missoula and from pluvial Lake Bonneville, the predecessor of Great Salt Lake.  It draws on stratigraphy, varve counts, radiocarbon and other dating, and two-dimensional flow models, and it concludes that Lake Missoula was producing floods for at least 3–4 thousand years between about 20 and 14 thousand years ago.  The article uses it for the count of the Missoula floods and for the dating of the lake.

1. 45a.

   Section How Many Floods?:  “at least 31 rhythmites overlying the tephra were counted … summing to at least 59 floods.  Adding these 31 post-Set-S beds in the Pasco Basin to the 72 preceding Set S at Manila Creek indicates at least 103 floods … at least 104, possibly 109 floods … Most or all of these records are likely incomplete so the actual flood total is likely greater.”  The lake was.  Section Abstract:  “extant and producing floods for at least 3-4 ky during 20-14 ka.”  For contrast, they note that the Bonneville flood.  Section A Singular Flood:  “was a one-time event.” ↩

Larsen, Isaac J., and Michael P. Lamb.  “Progressive incision of the Channeled Scablands by outburst floods.”  Nature 538:229–232.  2016.  Two-dimensional water-flow simulations of Moses Coulee, a channel in the Channeled Scablands, at four reconstructed stages of its own incision.  The article cites it as one of the remeasurements that made the floods smaller, because the older method assumed the water filled the finished canyon.

1. 46a.

   Section Abstract, page 229:  “accounting for erosion thresholds during canyon incision results in near-constant discharges that are five- to ten-fold smaller than full-to-the-brim estimates for Moses Coulee.”  Page 230:  Their physical idea:  “well-jointed rock that is subject to megaflooding may behave more like a bed of sediment with limited or no cohesion … Such bedrock channels cannot withstand large discharges or shear stresses that greatly exceed the threshold for plucking.”  Page 229:  On the comparison with other canyons:  “In the case of other bedrock canyons that formed over millions of years, such as the Grand Canyon, USA, water flows that were responsible for carving the canyon had depths that were always a small fraction of the canyon relief.” ↩

van der Bilt, Willem G. M. et al.  “Late Holocene canyon-carving floods in northern Iceland were smaller than previously reported.”  Communications Earth & Environment 2:66.  2021.  Section Abstract:  “we … confirm that flow peaks during these events were at most a third of previous estimates.  Nevertheless, exposure ages suggests that nearby knickpoints retreated by more than 2 km during these floods.  These findings support a growing consensus that the extent of bedrock erosion is not necessarily controlled by discharge.”  The earlier work it revises is Baynes and colleagues in PNAS in 2015, which measured a step function at Dettifoss: below about 8.1 m of water depth, some 3,250 m³/s, essentially nothing happens; above it, knickpoints run kilometres.  A research article that re-estimates the peak flows of the floods that carved canyons in northern Iceland in the late Holocene, the last few thousand years.  It finds that the flood peaks were at most a third of earlier estimates, while knickpoints (steps in a river bed) still retreated by more than 2 km.  The article uses it as one of the remeasurements that have cut earlier flood estimates. ↩

Vardiman, Larry et al.  “Summary of Evidence for a Young Earth from the RATE Project.”  Radioisotopes and the Age of the Earth, Volume II, chapter 10, 735–772.  Institute for Creation Research, El Cajon, California.  2005.  A chapter that summarises the RATE project's case, drawn from radioactive dating, that the Earth is young.  The article uses it for the team's claim that radioactive decay was sped up in past episodes, which it places in creation week and in the Flood.

1. 48a.

   The episodes are placed during creation week and during the Flood, and no post-Flood episode is proposed.  Page 766:  “Nuclear decay processes were accelerated during episodes in earth history.”  Page 759:  “nuclear decay of any sort occurring during Creation week (let alone accelerated decay)”.  Page 756:  “an episode of accelerated nuclear decay during the Flood”. ↩

Tweet, Justin S. et al.  “An inventory of packrat (Neotoma spp.) middens in National Park Service areas.”  Vertebrate Coprolites, New Mexico Museum of Natural History and Science Bulletin 57, 355–364.  2012.  Page 355:  “Plants and other items incorporated into the middens are gathered within a radius of approximately 30 to 50 m … from a den”.  “Individual middens are thought to have been active over short periods of time, up to a few years”.  “blocks of asphalt with the consistency and mass of an unfired adobe brick”.  A survey of packrat midden sites in National Park Service areas, printed in a volume on vertebrate coprolites (fossil droppings).  It describes where packrats gather the plants for a midden, how long a midden stays in use, and what a fossil midden is like.  The article uses it to explain that a dated midden records a dry alcove at a given elevation and date. ↩

Brown, Robert H.  “Correlation of C-14 Age with Real Time.”  Creation Research Society Quarterly 29(1):45–47.  Jun 1992.  A 1992 paper that turns radiocarbon ages into calendar years, with the Flood at 5,350 years before present and initial post-Flood carbon-14 at f = 0.011 ± 0.004 of the modern equilibrium level, recovering with an e-folding scale near 1,350 years.  It tests the formula on a frozen musk ox from Alaska and on the dung of ground sloths in Rampart Cave, where Table I on page 46 gives the conversion.  The article uses it as the one specific creationist attempt to explain Rampart Cave, and it grants Brown's point that the raw dung rate is unrealistic. ↩

1. 50a.

   Page 46:  “Approximately 39,000 dung pellets accumulated in the main area of this cave between 40 and 20 thousand C-14 years BP.  An average of 1.9 pellets per year … is unrealistic for a viable population of sloths in the vicinity of the cave.  Converting 40,000 and 20,000 to 5348 and 5271 years real-time gives a 77 year interval and about 1.4 dung pellets per day.” ↩

2. 50b.

   Page 46:  “Use of Equation 8 for C-14 ages greater than 34,000 is highly questionable.”  He then applies it to a 40,000-year date. ↩

McKee, Edwin D.  “Ancient Sandstones Considered to be Eolian.”  A Study of Global Sand Seas, U.S. Geological Survey Professional Paper 1052.  Edited by Edwin D. McKee.  1979.  Page 197:  “covers about 32,000 square miles (51,500 km2)”.  The Coconino is over 300 m thick near Pine, and its cross-strata curve.  “to form a tangent with the underlying bounding plane.”  A chapter in a 1979 U.S. Geological Survey volume on the world's sand seas, on ancient sandstones thought to have been deposited by wind (eolian).  Its Coconino section runs from printed pp. 197-203.  The article uses it for the Coconino's size and for the standard reading of it as wind-blown desert dunes. ↩

1. 51a.

   Pages 199–200:  “A detailed analysis made in 1945 of ripple marks in the Coconino, in which about 50 sets were examined, shows compelling evidence, on the basis of five characteristics, that the ripple marks were wind formed … 1. Large ripple index (lowest was 17; most were considerably higher).  2. Ripple crests were definitely rounded in all specimens.  3. A concentration of coarser sand grains occurred on or about the crests in most specimens.  4. All specimens in situ had crests trending up and down surfaces of sloping laminae; none was normal to dip.  5. Crests and troughs were straight and parallel.”  Whitmore and Garner independently confirm the fourth criterion, that Coconino ripples are.  “always parallel to dip”.  and do not engage the other four. ↩

2. 51b.

   Pages 202–203:  “On loose sand derived from the Coconino and deposited at high angles (25 deg -28 deg) comparable to that in crossbedding of the Coconino, a chuckwalla lizard was enticed to walk both up and down the surfaces of dry loose sand, damp (sprayed) sand with a crust, and wet sand.  Only in dry sand, uphill, could footprints be formed similar in size and clarity to those of the Coconino.”  Page 202:  The uphill statistic, from the trackways:  “'with only three exceptions out of many hundreds examined, were all leading uphill.'” ↩

3. 51c.

   Page 203:  “These animals were too light to leave trails in wet or damp sand and were unable to effectively climb slopes steeper than about 20 deg.  The similarity is strong between millipede trails formed under experimental conditions and invertebrate markings in certain low-angle beds of the Coconino.” ↩

Marchetti, Lorenzo et al.  “Paleozoic Vertebrate Ichnology of Grand Canyon National Park.”  Grand Canyon National Park Centennial Paleontological Resource Inventory, 333–379.  National Park Service Natural Resource Report.  2020.  “Tetrapod ichnotaxonomy in eolian paleoenvironments (Coconino and De Chelly formations, Arizona) and late Cisuralian (Permian) sauropsid radiation”.  Chapter 9 of a Park Service inventory of the park's fossils, on the tracks of Paleozoic vertebrates.  The chapter rests on a 2019 paper by Marchetti, Voigt, Lucas, Francischini, Dentzien-Dias, Sacchi, Mangiacotti, Scali, Gazzola, Ronchi and Millhouse, in Earth-Science Reviews 190:148–170; its author list includes three herpetologists from a Milan lizard-behaviour group, so it draws on its own live-animal work rather than on authority.  The article uses it for the revised reading of the Coconino tracks.

1. 52a.

   Pages 361–362:  The first sentence begins on p. 361 and the passage continues on p. 362.  “Trackways with closely spaced tracks were interpreted as subaerial upslope progression by McKee (1944, 1947), and trackways with very asymmetric patterns were interpreted as subaqueous current-driven lateral progression (Brand and Tang 1991).  This latter hypothesis was rejected by Loope (1992), Lockley (1992) and Marchetti et al. (2019b), also because of the clear eolian origin of the Coconino Sandstone lithofacies.”  The mechanism:  “the track morphology is strongly influenced by gravity and thus by sliding of the digits during the trackmaker's locomotion.  So, most of the previous ichnotaxonomic assignments were incorrect because they interpreted digit drag marks as actual digit impressions.”  The revision invalidated the ichnogenera Chelichnus and Laoporus, and with them the standard eolian tetrapod ichnofacies concept.  The same phenomenon is reported from the De Chelly Sandstone of Arizona and the Corncockle Sandstone of Scotland. ↩ ↩

2. 52b.

   Page 362:  Once slope effects are subtracted, the Coconino ichnoassociation comprises.  “cf. Amphisauropus isp., cf. Dromopus isp., Erpetopus isp., Ichniotherium sphaerodactylum, cf. Tambachichnium isp. and Varanopus curvidactylus”.  That is the same fauna as in contemporary non-desert assemblages.  Page 359:  The tracks alone give the Coconino an independent Kungurian (early Permian) age. ↩

Helble, Timothy K.  “Sediment Transport and the Coconino Sandstone: A Reality Check on Flood Geology.”  Perspectives on Science and Christian Faith 63(1):25–41.  Mar 2011.  A critique of flood geology in the form of a mass balance, a count of how much material moves in and out, run on Austin's own inputs to ask whether his flood could have moved the sand of the Coconino Sandstone.  The author is a retired National Weather Service hydrologist and a co-editor of the 2016 Kregel volume.  The work lists nine assumptions as favourable to the young-earth side.  The article uses it for the arithmetic that shows the flood could not have deposited the Coconino.

1. 53a.

   Page 34:  “To form the Coconino in Austin's Flood scenario, 42,000 km3 of sand would need to be transported across the 1,600 km long northern boundary in twelve days.  However, the volume just calculated — 26 km3 — is only about 1/1,600 of the required amount.”  The chain is 30 kg/sec/m × 3,600 × 24 × 1.6 × 10⁶ m × 12 days ÷ 1,900 kg/m³.  Austin's own transport rate is 3.0 kg/sec/m;  Helble multiplies it by ten. ↩

Whitmore, John H., and Paul A. Garner.  “Helble's critique of creationist research on the Coconino Sandstone fails.”  Proceedings of the 2025 New Scholars International Conference on Creationism.  Cedarville University.  Edited by John H. Whitmore.  2025.  Page 32.  A one-page abstract, not a full paper, in a conference volume that its first author edited.  It answers Timothy Helble's critique of creationist work on the Coconino.  Its real dispute is whether the sandstone was laid down by wind or under water, and on that it lists eleven lines of evidence but argues none of them; the authors promise fuller work, which has not appeared.  The article uses it as the creationist reply to Helble's arithmetic. ↩

Whitmore, John H., and Paul A. Garner.  “The Coconino Sandstone (Permian, Arizona, USA): Implications for the Origin of Ancient Cross-bedded Sandstones.”  Proceedings of the Eighth International Conference on Creationism, 581–627.  2018.  Funded by Cedarville University, the Biblical Creation Trust and the Institute for Creation Research.  How strongly they put it:  Page 581:  “new data has been collected by us and others that we believe indisputably identifies the Coconino as a subaqueous sandstone.”  A long creationist review of the Coconino Sandstone by John Whitmore of Cedarville University and Paul Garner of the Biblical Creation Trust, printed in the proceedings of an international creationist conference.  It argues that the sandstone was laid down under water rather than by wind, and it is the fullest version of the creationist case, with about 500 references.  The article uses it for the creationists' own admission that no modern sand deposit matches the Coconino.

1. 55a.

   Pages 581, 621:  “There are no modern analogs that match the precise sedimentology of the Coconino, but we believe that subaqueous sand waves may be a start in the right direction to understand how the Coconino was deposited.” ↩

Austin, Steven A.  “Nautiloid mass kill and burial event, Redwall Limestone (Lower Mississippian), Grand Canyon region, Arizona and Nevada.”  Proceedings of the Fifth International Conference on Creationism, 55–99.  Creation Science Fellowship, Pittsburgh.  2003.  A conference paper by Steven Austin of the Institute for Creation Research on a persistent bed of lime packstone within the Redwall Limestone, which he names the Whitmore Nautiloid Bed.  The paper argues that one rapid, sediment-choked flow, which it calls a hyperconcentrated flow, killed and buried the large nautiloids in the bed across the region.  The article uses it for the bed itself, for Austin's fieldwork and counts, for his claim of billions of fossils, and for the fact that it never mentions Noah. ↩

1. 56a.

   Page 55:  “This is the first documentation in the geological literature of a regionally extensive hyperconcentrated sediment gravity flow upon a marine carbonate platform.”  The paper contains no reference to Noah, Genesis or a global flood. ↩

2. 56b.

   Page 66:  “The areal distribution of the platform facies of WNB, therefore, appears to exceed 1.5 x 10^4 km^2 (1.5 x 10^10 m^2).  With a density of nautiloids approaching 1 fossil per m^2, billions of nautiloid fossils are likely to occur within WNB throughout the Grand Canyon region.”  The same page gives the facies areas and volumes, the palinspastically restored 200 km transport distance (the rocks' positions before later movement), and the count of more than a thousand fossils.

3. 56c.

   Page 66:  “Observations and measurement were made on more than one thousand nautiloid fossils within WNB.”  Page 68:  The size histogram, Figure 10, has n = 403.  Page 71:  The rose diagrams, Figure 12, which chart compass directions, total 337 orientations.  Page 87:  The locality register states that "Localities for study of Whitmore Nautiloid Bed (WNB) are numbered from 1 to 63 in Figure 1." ↩

4. 56d.

   Pages 60–62:  At Nautiloid Canyon, Austin writes:  “Eighty large orthocone nautiloids lie on a nearly coplanar surface of 320 m^2,”.  “the exposure of nautiloids is not optimum across a significant portion of the 320-m^2 surface.  Where the exposure is optimum, the average density within the bed is greater than 2 nautiloids per m^2.”  Eighty shells on 320 m^2 is 0.25 per m^2, and it is the only raw count in the paper with a measured area attached. ↩

5. 56e.

   Page 55:  “Bed area exceeds 3 x 10^4 km^2 and bed volume exceeds 100 km^3.”  Austin states in the abstract (p. 55) and in the conclusion (p. 79) that nautiloids are rare or not characteristic of the slope facies, so the nautiloid-bearing area is the platform facies alone.  Page 66:  Page 66 gives the platform facies alone as exceeding 1.5 x 10^4 km^2, about half the 3 x 10^4 km^2 that ministry literature converts to "10,500 square miles." ↩

6. 56f.

   Pages 60, 62, 73–74, 79:  A massive, poorly sorted bed with inverse grading in the lower half; syringoporoid and lithostrontionoid coral colonies over 20 cm across suspended in mid-bed, requiring a dispersion denser than the corals; and fluid-escape pipe structures matched to laboratory experiments at 25-45% solids by volume.  Page 69:  “None was observed with apical end upward”.  The vertical nautiloids stand apex-down.  Page 79:  The energy figures, sediment mass 1.9 x 10^14 kg and kinetic energy about 4 x 10^15 J, are on this page.  Austin's own weakest link is the vertical shells: he says at this page that a "rapid freeze of the dispersion is required in order to capture vertical orientations,"  Page 70:  His one published precedent, James Quinn on Rayonnoceras in the Fayetteville Shale, is misreported on this page.  Quinn attributes the upright posture to buoyancy and rules out turbulent transport by name. ↩

Snelling, Andrew A.  “What Are Some of the Best Flood Evidences?”  Answers in Genesis.  n.d.  “billions of straight-shelled, chambered nautiloids are found fossilized … in a 7 feet (2 m) thick layer within the Redwall Limestone of Grand Canyon.  This fossil graveyard stretches for 180 miles (290 km) across northern Arizona and into southern Nevada, covering an area of at least 10,500 square miles (30,000 km2).”  Three departures from the paper it cites: the 30,000 km² is Austin's platform plus slope facies, and Austin says twice that nautiloids are rare or absent in the slope facies, so the nautiloid-bearing area is about half that; the 100 km³ is likewise the two facies together, of which only 30 km³ carries nautiloids; and the 290 km is Austin's un-restored present-day map distance, whereas his own flow model runs on the 200 km palinspastic distance.  A web article on the Answers in Genesis site, a creationist ministry, that lists a bed of fossil nautiloids (shelled relatives of the squid) in the Grand Canyon among the best evidence for Noah's Flood.  The article uses it to show how the ministry presents that bed, and then tests the figures it gives. ↩ ↩

White, David.  “Flora of the Hermit Shale, Grand Canyon, Arizona.”  Carnegie Institution of Washington Publication 405.  1929.  Pages 8–9.  A 1929 report by David White, a research associate of the Carnegie Institution of Washington, on the fossil plants (the flora) of the Hermit Shale, a red rock layer in the canyon walls.  The article uses it as an early description of deep sun-cracks at the top of the Hermit, filled with Coconino sand, which were open before the sand arrived. ↩

1. 58a.

   Pages 8–9:  “In some areas this red surface, which was slightly muddy, seems to have been intensely shrunken and cracked to extraordinary depths, as though under very intense heat of the sun.  Irregular fissures or 'sun-cracks' reaching a maximum width of over 15 inches and extending downward to depths of 25 feet or more into the red rock material of the Hermit may be seen on the west side of the Bright Angel trail … They were filled with the inswept light-colored Coconino sand … That the fissures once stood open before the outspread of the Coconino sand is shown by 'inclusions' or infallen pieces of red shale, caught in the light-colored sand in the deep cracks.  The irregular branching of the fissures in different directions horizontally and their distribution in the Canyon seems to preclude their explanation by earthquake.” ↩

Roth, Ariel A.  Flat Gaps Challenge Long Geologic Ages.  Geoscience Research Institute.  2012.  A short public statement by Ariel Roth, PhD, arguing that flat gaps (paraconformities) in the Grand Canyon and elsewhere show very little or no weathering or erosion, so they formed fast during the Genesis Flood rather than over millions of years.  The technical version is a 2009 Journal of Creation paper, "'Flat Gaps' in sedimentary rock layers challenge long geologic ages," volume 23(2), pages 76–81.  The article uses it for the flat-gap argument and for its figure of two miles of erosion. ↩

1. 59a.

   Figure 1:  “At the lowest arrow, both the Ordovician and Silurian periods are missing, yet the contact is nearly flat.  Average continental rates of erosion during that time would be expected to erode down through two miles, which is twice the depth of the Grand Canyon.” ↩

McKee, Edwin D.  “Stratified Rocks of the Grand Canyon.”  The Colorado River Region and John Wesley Powell, U.S. Geological Survey Professional Paper 669.  1969.  Chapter B of a 1969 U.S. Geological Survey volume that honored John Wesley Powell on the hundredth anniversary of his 1869 exploration of the Colorado River.  The article quotes it for the flat, even surface of the pre-Mississippian unconformity and for the absence of large uplift there.

1. 60a.

   Page 44:  “A pre-Mississippian unconformity is represented by a flat, even surface between dolomite units of Devonian (locally Cambrian) age and Mississippian age in eastern Grand Canyon, but in many places it is obscure.  Farther west, the unconformity is marked by a surface of slight relief and local conglomerates … but is still not conspicuous.  Nowhere is there evidence of large uplift that would cause marked dissection of the region.”  On the same page he describes the Temple Butte channels,  “as much as 100 feet or more deep”.  mapped by Noble.  “along a 28-mile stretch of Grand Canyon walls.” ↩

Snelling, Andrew A.  “The Case of the 'Missing' Geologic Time.”  Creation 14(3):30–35.  1992.  Section In the Grand Canyon:  “Creationists do recognize significant erosion surfaces between rock strata in the Grand Canyon, but unlike evolutionary geologists have concluded that these erosion breaks do not represent large time breaks.”  Section The Redwall-Muav Contact:  He concedes on the same page that.  “there is often good evidence of erosion, such as gullies and stream channels at the boundary between the Temple Butte and the Muav”.  and elsewhere that.  “Apart from these rare exceptions, the boundary … [is] flat and featureless.”  Section On the North Kaibab Trail:  The National Park Service sign he quotes is worth having:  “Rocks of Ordovician and Silurian Periods are missing in Grand Canyon.”  A 1992 article in Creation, republished by Answers in Genesis, that argues the erosion breaks between the Grand Canyon's rock layers are not large gaps in time.  Its case rests on the Redwall-Muav contact on the North Kaibab Trail, where the Temple Butte Limestone is absent; it also rests on a 1986 Creation Research Society field survey, and it concedes that gullies and stream channels are often seen at the boundary elsewhere.  The article uses it as the creationist account of the canyon's flagship flat gap, which it then tests against the USGS map. ↩

Dehler, Carol et al.  “The Cambrian of the Grand Canyon: Refinement of a classic stratigraphic model.”  GSA Today 34(11):4–11.  2024.  Section Abstract, page 4:  “Instead of McKee's interpretation of one major transgression with only minor regressions, there are at least five stratigraphic sequences, of which the lower three are separated by disconformities.”  A review of how the Cambrian rocks of the Grand Canyon are interpreted since Edwin McKee's 1945 model.  The authors measured or updated more than 50 stratigraphic sections across the 500-km-wide Grand Canyon region, identified 169 new fossil localities and seven trilobite zones, and found at least five sequences where McKee saw one transgression.  The article uses it for the authors' statement that gaps in the rock record are expected on a flat, stable, pre-vegetated margin. ↩

1. 62a.

   Page 8:  “The majority of the Tonto Group above the Sixtymile Formation was deposited in paralic environments on a flat, stable margin of the Laurentia in a pre-vegetated, tropical setting … Given the overall low-relief topography … in combination with sea-level fluctuations, the presence of unconformities within the succession is expected.”  Their three intra-Tonto disconformities are identified.  “on the basis of missing biozone intervals, erosional features, and facies changes”.  and one is.  “locally incised with a relief of >1.5 m across a 5-m horizontal interval.”  They also state the limit of the evidence:  “The rocks of the Tonto Group are poorly fossiliferous, and no individual section contains a continuous fossiliferous succession.” ↩

Winograd, Isaac J., and William Thordarson.  “Hydrogeologic and Hydrochemical Framework, South-Central Great Basin, Nevada-California, with Special Reference to the Nevada Test Site.”  U.S. Geological Survey Professional Paper 712-C.  1975.  Table 1, page C11:  Table 1 gives the measured Paleozoic section 250 km west of the Grand Canyon: undifferentiated Devonian and Silurian dolomite 1,415 ft; Ely Springs Dolomite 305 ft; Eureka Quartzite 340 ft; Antelope Valley Limestone 1,530 ft; Ninemile Formation 335 ft; Goodwin Limestone about 900 ft.  Roughly 3,400 ft of Ordovician and 1,415 ft of Silurian–Devonian, in the interval that is a knife-edge gap in the canyon.  A U.S. Geological Survey report on the ground water beneath the Nevada Test Site, prepared for the U.S. Atomic Energy Commission, which in 1957 asked the Survey to study the ground water and the potential for its contamination.  It divides the rocks there into 10 hydrogeologic units.  The article uses it for the thickness of the Ordovician and Silurian–Devonian carbonate rock at the Nevada Test Site, about 250 km west of the canyon, where the canyon's own section has a gap. ↩

Snelling, Andrew A. et al.  “Radioisotopes in the Diabase Sill (Upper Precambrian) at Bass Rapids, Grand Canyon, Arizona: An Application and Test of the Isochron Dating Method.”  Proceedings of the Fifth International Conference on Creationism, 269–284.  2003.  Five isochrons, with two-sigma ranges: K-Ar whole rock 841.5 ± 164 (677-1006); Rb-Sr whole rock 1055 ± 46 (1009-1101); Rb-Sr minerals 1059 ± 48 (1011-1107); Pb-Pb whole rock 1249 ± 140 (1109-1389); Sm-Nd minerals 1375 ± 170 (1205-1545).  The two that bracket the 2024 zircon age of 1098.16 ± 0.59 Ma are the two they themselves describe as the best behaved.  Its abstract says that the isochron "ages".  “range from 841.5±164 Ma (whole-rock K-Ar) to 1375±170 Ma (mineral Sm-Nd) … It is therefore argued that only changing radioisotope decay rates in the past could account for these discordant isochron 'ages' for the same geologic event.”  Page 272:  Their own sample list also records neighbouring K-Ar samples two metres apart at 866 ± 24 and 728 ± 20 Ma.  A 2003 paper by three Institute for Creation Research scientists that dates the Bass Rapids diabase sill in the Grand Canyon with four radioisotope methods, on eleven whole-rock samples and six mineral separates from one of them.  Its isochron "ages" disagree widely, from 841.5 to 1375 million years, and the authors argue that only changing decay rates in the past could explain that; the Rb-Sr whole-rock and mineral ages agree best with each other.  The article uses it for the discordant isochrons and for the pattern in them that the authors read as accelerated decay. ↩

1. 64a.

   Page 282:  In a passage describing.  “contamination of the whole-rock Sm-Nd radioisotope system in the granophyre immediately adjacent to the overlying hornfels wall-rock.”  Hornfels is a baked, recrystallised contact-metamorphic rock; its presence requires that the Bass Formation and Hakatai Shale were coherent rock when the magma arrived, and it is RATE's own paper that reports it. ↩ ↩

2. 64b.

   Section Abstract, page 269:  “Furthermore, these data are consistent with alpha decay having been accelerated more than beta decay, and with the longer the present half-life the greater being the acceleration factor.”  The order at Bass Rapids is K-Ar (electron capture, 1.25-billion-year half-life) 841.5; Rb-Sr (beta, 49 billion) 1055; Pb-Pb (alpha, 0.7 and 4.5 billion) 1249; Sm-Nd (alpha, 106 billion) 1375. ↩

Tingle, Kelly E. et al.  “Organic preservation of vase-shaped microfossils from the late Tonian Chuar Group, Grand Canyon, Arizona, USA.”  Geobiology 21:389–406.  2023.  “the VSMs are preserved with original organic test material.”  A research article in Geobiology, a laboratory study of two thin sections of black shale from the Walcott Member of the Chuar Group in the eastern canyon.  The authors used microscopes, scanning electron microscopy, and X-ray and Raman spectroscopy to test whether the walls of these microfossils are original organic material, and they found that the walls are organic and sometimes replaced by pyrite.  Vase-shaped microfossils are the earliest evidence for testate amoebae, and their first appearance is dated to about 741 million years by the Chuar Group's own age model.  The article uses it as the study showing that these microfossils kept their original organic walls. ↩

Dehler, Carol et al.  “Precise U-Pb age models refine Neoproterozoic western Laurentian rift initiation, correlation, and Earth system changes.”  Precambrian Research 396:107156.  2023.  A 2023 paper that refines the dating of the Chuar Group in the Grand Canyon, using uranium-lead dates on zircon grains and a statistical age model.  Its Section 2.1 gives the Chuar Group's dates from three decay systems: uranium-lead on ash zircon 729.0 ± 0.9 million years (Rooney et al. 2018, replacing an earlier 742 ± 6 million years), rhenium-osmium 757.0 ± 6.8 million years on organic-rich carbonate and 751.0 ± 7.6 million years on marcasite nodules, and argon-argon 764 ± 8 million years on the same nodules.  The article uses these determinations as a cross-check on one another in a thirty-metre stratigraphic slice of the Chuar Group. ↩ ↩

Thurston, Olivia G. et al.  “Zircon (U-Th)/He thermochronology of Grand Canyon resolves 1250 Ma unroofing at the Great Unconformity and <20 Ma canyon carving.”  Geology 50(2):222–226.  2022.  Page 222:  “the sub-Tonto Group unconformity has between 200 and 1300 Ma of time 'missing'.”  “Fault blocks of the Grand Canyon Supergroup show that the GU is a composite erosion surface that records exhumation of Proterozoic crystalline basement during several pulses of intracratonic tectonism.”  A research article in Geology, the journal of the Geological Society of America.  The authors dated how fast the basement rock under the Great Unconformity cooled, using 37 zircon grains from seven sample sites in the eastern canyon, and fed the results into computer models of the rock's heat history.  They found that the main cooling of the basement happened 1300 to 1250 million years ago, and that the canyon itself was carved in the last 20 million years.  The article uses it because the time missing at the Great Unconformity varies from place to place. ↩

Keller, C. Brenhin et al.  “Neoproterozoic glacial origin of the Great Unconformity.”  PNAS 116(4):1136–1145.  2019.  Section Abstract:  The abstract says that the isotope excursions and the unconformity.  “can together be explained by spatially heterogeneous Neoproterozoic glacial erosion totaling a global average of 3-5 vertical kilometers.”  A research paper that ties the Great Unconformity to glacial erosion during the Neoproterozoic ice ages, the "snowball Earth" episodes.  The authors used oxygen and hafnium isotope measurements in zircon crystals and a model of the space that glacial erosion would have created.  The article cites it as the statement of one side in the dispute over how the unconformity formed. ↩

Flowers, Rebecca M. et al.  “Diachronous development of Great Unconformities before Neoproterozoic Snowball Earth.”  Proceedings of the National Academy of Sciences 117(19):10172–10180.  2020.  Section Abstract:  “Our results provide evidence that most erosion below the Great Unconformity in Colorado occurred before the first Neoproterozoic Snowball Earth and therefore cannot be a product of glacial erosion.  We propose that multiple Great Unconformities developed diachronously and represent regional tectonic features rather than a synchronous global phenomenon.”  A research article in the journal of the National Academy of Sciences.  The authors mapped the Pikes Peak granite in Colorado, dated the sandstone bodies forced into it, and used helium dates from zircon crystals to argue that the rock was at the surface before the Snowball Earth glaciation.  The article uses it as one side of a live dispute over whether the Great Unconformity was made by global glaciation or by regional tectonics. ↩

Peak, Barra A. et al.  “Zircon (U-Th)/He thermochronology reveals pre-Great Unconformity paleotopography in the Grand Canyon region, USA.”  Geology 50(3):e544.  2022.  Page e544:  “The Comment by Karlstrom et al. (2022) … makes false statements about our work and presents time-temperature (t-T) models that should not be interpreted because of invalidation by basic Grand Canyon geology … Reliable interpretations cannot be drawn from a model that is irreconcilable with geologic facts.”  The most recent synthesis, by Thurston and colleagues in the GSA Bulletin in 2024, finds "two regional basement unroofing events … A ca. 1350-1250 Ma cooling event … and a second cooling episode … between ca. 600 Ma and 500 Ma."  A Forum Reply in Geology, the authors' answer to a Forum Comment by Karlstrom, Guenthner, Thurston, Heizler, Ricketts and Timmons (Geology 50(3):e543, doi:10.1130/G49843C.1) on their 2021 paper.  The reply defends a fault-controlled model for the origin of the Great Unconformity in Grand Canyon, and it argues that the comment's thermal-history models cannot be reconciled with the geology.  The article uses it as one side of a dispute in which each team calls the other's models geologically impossible. ↩

Mitchell, Stephen, and Kennen S. Tillman.  “Tonto Depositional Processes and Rates.”  Peaceful Science.  Aug 15, 2024.  Computing from Snelling's own model:  “The Tapeats Sandstone would have averaged approximately 9-30 m/day (28-100 ft/day).  When we include the Bright Angel and Muav formations, the average increases a bit to 11-34 m/day … These rates can actually be expressed as averaging 0.5 to 1.4 m/hour (1.5-4.6 ft/hour)!”  They also raise a sediment-source problem that cuts against the Flood model from an unexpected direction: carbonate and evaporite are chemical precipitates, not eroded debris, and a bigger flood does not make more of them.  The second part of the series Examining Young Earth Creation Claims About the Grand Canyon.  It tests the Cambrian Tonto Group rocks of the Grand Canyon against Andrew Snelling's young-earth flood model, taking his own figures and turning them into rates.  The article uses the arithmetic for the rate that the Flood model implies, 0.5 to 1.4 metres per hour. ↩

Austin, Steven A., and Andrew A. Snelling.  “Discordant Potassium-Argon Model and Isochron 'Ages' for Cardenas Basalt (Middle Proterozoic) and Associated Diabase of Eastern Grand Canyon, Arizona.”  Proceedings of the Fourth International Conference on Creationism, 35–52.  1998.  Page 35:  “a new fourteen-point K-Ar isochron 'age' of 516 ± 30 Ma which is strongly discordant with the published Rb-Sr isochron 'age' of 1.07 ± 0.07 Ga for Cardenas Basalt.”  A conference paper by Steven Austin of the Institute for Creation Research and Andrew Snelling of Answers in Genesis.  It adds thirteen new potassium-argon analyses to nine published ones from Grand Canyon's Proterozoic basalt and diabase, and reports a fourteen-point isochron that gives a much younger date than the rubidium-strontium age that geologists widely accept.  The article uses it as the first of two creationist papers that date Grand Canyon rock by radioactive methods and get results far from the accepted ages. ↩

Isaac, Randy.  “Assessing the RATE Project.”  Perspectives on Science and Christian Faith 59(2):143–146.  Jun 2007.  Page 144:  “Discordances are not at all unusual and the source of discordance is not always understood but these fail to invalidate the vast amount of concordance.  Furthermore, no argument is presented why differences of 15% would justify the claim that radioisotope dating is in error by a factor of one million or more.”  An essay review, in the journal of the American Scientific Affiliation, of the second volume of Radioisotopes and the Age of the Earth (2005), the final report of the Institute for Creation Research's RATE project, an eight-year program to test radioisotope dating.  Its author is a physicist, Randy Isaac, who is executive director of the American Scientific Affiliation.  The review notes that the RATE researchers concede more than 500 million years' worth of decay, and it argues that their isochron discordances do not show that radioisotope dating is wrong.  The article uses it for the reviewer's point that no argument shows a 15 per cent difference justifies an error of a factor of one million or more. ↩

Morris, John D.  “The Channeled Scablands.”  Acts & Facts 40(10):15.  Institute for Creation Research.  2011.  Its closing question is:  “If this much damage resulted from a large but local failed lake flowing over a corner of the continent, what damage could be expected from the great Flood of Noah's day?”  An Institute for Creation Research article that treats the Channeled Scablands, the flood-carved coulees of eastern Washington, as an analogue for the Flood of Noah's day.  It is accurate about Bretz and correct that the coulees are cut in hard basalt, but it does not say why that basalt was cheap to cut or how many floods it took.  The article takes its closing question as the one its own answer has to meet. ↩

Brand, Leonard R.  “Variations in salamander trackways resulting from substrate differences.”  Journal of Paleontology 70(6):1004–1010.  1996.  Section Abstract:  “The positions and orientations of the toe marks were distorted if the animals were walking underwater or on sloped, damp sand.”  An experiment that made 230 trackways of the western newt Taricha torosa across ten combinations of sediment, slope and moisture.  The article uses it for Brand's own finding about where the distorted toe marks come from. ↩

Brand, Leonard, and Arthur Chadwick.  Faith, Reason, & Earth History: A Paradigm of Earth and Biological Origins by Intelligent Design.  Berrien Springs: Andrews University Press.  3rd edition.  2018.  A book by two authors that argues intelligent design accounts for Earth's history and the origin of living things.  The article uses it because Brand concedes in it that the sedimentary evidence seems to point to wind-blown sand, a conflict he says he cannot reconcile with the trackways.

1. 76a.

   Page 474:  “The trackways have features that seem virtually impossible to explain unless they were made with the animals completely underwater, while the sedimentary evidence, as interpreted by sedimentologists, seems to point to wind-blown sand.  This seeming contradiction indicates there are some unknown pieces of the puzzle that remain to be discovered.” ↩

Snelling, Andrew A., and Tom Vail.  “When and How Did the Grand Canyon Form?”  The New Answers Book 3, chapter 18, 175–191.  Answers in Genesis.  Dec 9, 2014.  “As creationists, we do not have all the answers.  In fact, there are many unanswered questions when it comes to the formation of the Grand Canyon … It is unclear as to why the waters would have eroded the course they appear to have taken … Some creationists attribute the formation of the canyon almost solely to the breaching of the dams, while others see the receding of the Flood waters to be the main carving mechanism.  It is suggested here that combining the strengths of both models best explains the evidence.”  The same chapter gives the Great Denudation as.  “around 100,000 cubic miles (400,000 cubic km)”.  Fifty times Brown's "at least 2,000 cubic miles" for the same erosion event, a published disagreement of fifty-fold inside young-earth geology that neither source addresses.  A chapter in a book of creationist answers, posted online by Answers in Genesis on 9 December 2014.  Its teaching is an explicit hybrid: sheet erosion, then channelised flow, then dam breach.  The admission is worth quoting in full.  The article uses it because the chapter admits in print that creationists do not have all the answers. ↩