Unconformities and Megasequences

Roth, Ariel A.  “Those Gaps in the Sedimentary Layers.”  Origins (Geoscience Research Institute) 15(2):75–92.  1988.  A general science article by Ariel Roth of the Geoscience Research Institute, arguing that the gaps are too flat to have taken millions of years and fit rapid deposition in the Genesis Flood.  It works through Palo Duro Canyon in Texas, where the Ogallala Formation lies very flat on the Trujillo Formation across about 150,000 km2, a gap the standard time scale puts at some 200 million years.  The article uses it as the technical statement of the flat-gap argument, which it treats as a good argument with an answer.

1. 1a.

   Page 89:  “Rarely, at these planar surfaces, there is some evidence of deeper erosion, sometimes even several hundred meters of erosion.  However, the general pattern shows little erosion.” ↩

2. 1b.

   Page 90:  “The difficulty with the extended time proposed for these gaps is that one cannot have deposition, nor can one have much erosion.  With deposition, there is no gap, because sedimentation continues.  With erosion, one would expect abundant channeling and the formation of deep gullies, canyons and valleys;  yet, the contacts are usually 'nearly planar.'” ↩ ↩

3. 1c.

   Page 84:  “Present rates of erosion for the United States average about 6.1 cm/1000 yrs (Judson & Ritter 1964), which is 61 m/Ma.  In 10 Ma one would expect 600 m of erosion, etc.  It is sometimes stated that our present rates of erosion should level the United States in 10 Ma or less.”  The figure comes from Judson, S. and D. F. Ritter, "Rates of regional denudation in the United States," Journal of Geophysical Research 69:3395-3401 (1964), which measures sediment yield from drainage basins. ↩ ↩

Sloss, L. L.  “Tectonic evolution of the craton in Phanerozoic time.”  Sedimentary Cover — North American Craton: U.S. (The Geology of North America) D-2:25–51.  Geological Society of America, Boulder.  Edited by L. L. Sloss.  1988.  A chapter in a Geological Society of America volume on the sedimentary cover of the North American craton, on the craton's tectonic evolution through Phanerozoic time, the eon of abundant animal fossils.  The article uses it for his statement that surfaces of unconformity (gaps in the rock record between layers) are rarely isochronous, meaning they do not mark one moment in time everywhere.

1. 2a.

   Page 25:  “The surfaces of unconformity are rarely isochronous in cratonic stratigraphy since such surfaces typically involve truncation and loss of record in the subjacent units and time-consuming progressive onlap of overlying strata.” ↩ ↩ ↩ ↩

Peters, Shanan E., and Robert R. Gaines.  “Formation of the 'Great Unconformity' as a trigger for the Cambrian explosion.”  Nature 484(7394):363–366.  Apr 19, 2012.  A research letter in Nature arguing that the Great Unconformity, the surface under the Cambrian sandstones, was formed by a long wearing-down of the continents and may have helped trigger the Cambrian explosion of animal life.  The authors used stratigraphic and lithologic data for 21,521 rock units from 830 regions of North America, with carbon and oxygen isotopes on 220 mudstone samples, to explore that hypothesis.  The article uses it because young-earth authors cite it for the surface's near-global extent, and it says what they say it says.  Mirror:  Strata.geology.wisc.edu

1. 3a.

   Section Abstract, page 363:  “The resultant globally occurring stratigraphic surface, which in most regions separates continental crystalline basement rock from much younger Cambrian shallow marine sedimentary deposits, is known as the Great Unconformity.” ↩ ↩

2. 3b.

   Page 363, column 2:  “Continental-scale marine transgression during the Cambrian–Early Ordovician accentuated rates of weathering on the Great Unconformity by shifting landward the position of the erosive transgressive shoreface system, often called the 'wave-base razor', as well as adjacent transitional backshore, aeolian and fluvial systems.  As a result, much of the soil and weathered basement rock (regolith) that covered low-relief continental interiors was eroded and mobilized during the transgression.” ↩

3. 3c.

   Page 363, column 2:  “The Cambrian- to Early Ordovician-aged sediments of the Sauk Sequence that overlie the Great Unconformity are time-transgressive, such that Early Cambrian sediments occur on the margins of the palaeocontinents and Late Cambrian sediments overlie the Great Unconformity in continental interiors (Fig. 1).” ↩ ↩ ↩

Dunbar, Carl O., and John Rodgers.  Principles of Stratigraphy.  New York: John Wiley & Sons.  1957.  A stratigraphy textbook in which the word paraconformity is coined.  It defines the word for a break in the rock record where the beds are parallel and the contact is a simple bedding plane, and says that spotting such a contact is commonly subjective.  The article uses it to show that the discipline named the idea before any creationist used it.

1. 4a.

   Page 119:  The passage that coins the word, in the authors' words:  “We propose to restrict the term disconformity to the third type, in which two units of stratified rocks are parallel but the surface of unconformity is an old erosion surface of appreciable relief, and to introduce a new term paraconformity for the fourth type, in which the beds are parallel and the contact is a simple bedding plane.”  “There is special need for a term for this non-evident type of unconformity in which the contact is a simple bedding plane, since its recognition is commonly subjective.” ↩

2. 4b.

   Page 126:  The eight criteria for a break, in the authors' words:  “Such evidence may be in the physical form of the surface, such as pronounced irregularities, mounds, crevices, or even caves, overlapped and filled by the materials of the overlying unit;  it may be evidence of weathering of the rock below before deposition of the rock above, such as a fire clay, an old soil profile, or a rusty, silicified, or calichified zone;  it may be the abrupt truncation of structural features such as joints, faults, or dikes in the lower beds;  or it may be the presence of pebbles from the beds below in the basal layers above.  Lag gravels and sands of any sort are suggestive of unconformity;  likewise, especially in marine deposits, concentrates of phosphate, manganese, iron, or glauconite nodules or grains (though such concentrates may be evidence only of extremely slow deposition and not of a break in the record).” ↩

Peters, Shanan E., and Jon M. Husson.  “Sediment cycling on continental and oceanic crust.”  Geology 45(4):323–326.  2017.  A research paper in the journal Geology by two University of Wisconsin geoscientists.  It counted 1,013 columns of the Macrostrat rock database, holding 22,282 sedimentary rock units in North America and the circum-Caribbean, and found that shallow-marine sediment on continental crust, about 75% of the surviving volume, shows no steady decline with age.  The article uses it against the claim that most Phanerozoic rock was eroded away, and for its estimate of about 110 million cubic kilometres of Phanerozoic sediment on North America.

1. 5a.

   Page 323, section Abstract:  “Most of the surviving volume of sedimentary rock (~75%) was deposited in and adjacent to shallow seas on continental crust and does not exhibit any steady decrease in quantity with increasing age.  Instead, shallow marine sediments exhibit large fluctuations in quantity that were driven by shifting global tectonic boundary conditions, such as those that occur during the breakup and coalescence of supercontinents.” ↩ ↩ ↩

2. 5b.

   Page 323, section Results:  “Chronostratigraphically above this surface there is a large volume of Phanerozoic sedimentary rock (~110 × 10⁶ km³) that exhibits little temporal trend in quantity from ca. 10 to 500 Ma;  below this surface there is a comparatively small amount of Proterozoic sedimentary rock (~30 × 10⁶ km³)”.  The data set behind it:  “A total of 1013 Macrostrat columns containing 22,282 sedimentary rock units and covering 26 × 10⁶ km² in North America and the circum-Caribbean region (Fig. DR2) were used to estimate surface and subsurface sedimentary rock quantities”. ↩ ↩ ↩

Sharp, Robert P.  “Ep-Archean and Ep-Algonkian erosion surfaces, Grand Canyon, Arizona.”  Geological Society of America Bulletin 51(8):1235–1270.  Aug 1, 1940.  A study of two ancient erosion surfaces in the Grand Canyon, Arizona, and the weathered rock beneath them.  Sharp's lower "Ep-Archean" surface is what is now called the Great Nonconformity, and his upper "Ep-Algonkian" surface is the Great Unconformity proper.  The article uses it for Sharp's mapping, his estimate of the time the upper surface took to form, and his own warning that the estimate is only an approximation.

1. 6a.

   Page 1261:  “By no means should the inference be drawn that 100 million years of erosion are required to produce a peneplain, for it is well known that many peneplains have been formed in a small fraction of that time.” ↩

2. 6b.

   Page 1251:  Sharp gives his reasons that the weathering is ancient rather than modern, numbered 3 to 5:  “(3) The beds overlying the Ep-Archean surface contain fragments of gossanlike material derived from the underlying weathered zone.  (4) Residual quartz fragments on hillocks and surficial creep indicate ancient weathering on at least the Ep-Algonkian surface.  (5) Recent weathering has developed caves and alcoves along the weathered zone, it has not produced that zone.”  His reason (2), on the same page, is that the weathered mantle was.  “reworked and incorporated in the overlying sedimentary deposits, hence it must have been in existence prior to encroachment of the seas in which those deposits were formed.” ↩ ↩ ↩

3. 6c.

   Page 1264:  “Both surfaces show evidence of subaerial weathering, and this weathered mantle has been studied in considerable detail.  The greatest depth of weathering is 10 feet beneath the Ep-Archean surface;  it is 50 feet beneath the Ep-Algonkian surface, but only the uppermost 5 to 10 feet is greatly altered. …  Biotite changes first to a green chlorite and then to a colorless chloritelike material in which are dispersed small grains of iron oxide.  Eventually, biotite is entirely eliminated, leaving hydrated iron oxide.  Feldspars show some kaolinization even at considerable depth, and plagioclase is almost entirely decomposed in an early stage of the weathering. …  Quartz and muscovite with hydrated iron oxides and clay constitute most of the residual regolith produced by extended weathering;  the amount of iron oxides ranges from 0.9 to 12.8 per cent. …  Insoluble residues constitute an average of 88 per cent of the most maturely weathered material.  The evidence of chemical weathering on these surfaces is far greater than the evidence of mechanical weathering.” ↩ ↩ ↩

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:  The abstract says:  “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 paper by four geologists that studies the Pikes Peak granite in Colorado and the sandstone that was injected into it.  It argues that there are several Great Unconformities, formed at different times as regional tectonic features rather than one global event.  The article sets it against Keller and colleagues, who attribute the same surface to Neoproterozoic glaciation. ↩

1. 7a.

   Section Constraints on the Great Unconformity in Colorado:  “Locally, the basal Cambrian beds above the Great Unconformity drape over relief induced by variably resistant, meter-scale core stones in an ∼100-m-thick weathered zone of the Pikes Peak granite (Fig. 3A).  This is clear evidence that a Pikes granite regolith was also present in the Cambrian.” ↩ ↩ ↩

Corsetti, Frank A., and James W. Hagadorn.  “Precambrian-Cambrian transition: Death Valley, United States.”  Geology 28(4):299–302.  Apr 2000.  A research paper that places the Precambrian-Cambrian boundary in the Death Valley rocks of California, using the trace fossil Treptichnus pedum and a carbon-isotope profile.  The article uses it because the boundary falls inside the lower member of the Wood Canyon Formation, an ordinary succession with no Great Unconformity.

1. 8a.

   Page 300:  “Interbedded siltstone and sandstone units of the third parasequence, overlying the second major carbonate unit at most sections, contain an easily recognizable suite of bed-parallel trace fossils, as well as several forms demonstrating a vertical burrowing component, including T. pedum (Fig. 2D).  Thus, the Precambrian-Cambrian boundary can be correlated to the basal siliciclastic units of the third parasequence in the lower member of the Wood Canyon Formation.” ↩ ↩ ↩ ↩

Clarey, Timothy L., and Davis J. Werner.  “The Sedimentary Record Demonstrates Minimal Flooding of the Continents During Sauk Deposition.”  Answers Research Journal 10:271–283.  2017.  A research paper by Timothy Clarey and Davis Werner of the Institute for Creation Research, built on about 1,500 stratigraphic columns, which tabulates the area, volume and average thickness of all six megasequences on North America, South America and Africa.  It finds the first package, the Sauk, thin and uneven between continents, and argues against large erosion between packages.  This overview uses its Table 1 for the Great Unconformity's mass balance and for the North American volume total, and its text for Clarey's own view of erosion at the boundaries.

1. 9a.

   Page 275:  “The areal extent of the Sauk megasequence across North America is quite impressive, covering over 12 million km² (Table 1 and Fig. 4). … It averages only about 275 m across the North American continent where present (Table 1).”  “In stark contrast to North America, the sedimentary rocks of the Sauk megasequence show very little extent across the South American (Fig. 5) and African continents (Fig. 6).  The areal extent of the Sauk across South America is about 1.45 million km² and the areal extent across Africa is just under 9 million km² (Table 1).”  The 2025 reply concedes that the North American figure "likely exaggerate[s] the real extent of the Sauk Megasequence in the middle of the country," by an unstated amount.  Table 1, page 282:  Table 1, on this printed page, is the earliest published version of the numbers that became Clarey and Werner 2023 Table 1.  The two agree on every North American figure except the Absaroka volume, which is 6,312,620 km³ in 2017 and 6,337,270 km³ in 2023. ↩

2. 9b.

   Page 278:  Clarey and Werner, arguing against large erosion between megasequences:  “Secondly, we do not observe significant numbers of reworked fossils and mixed fossil debris in younger, Cretaceous and Cenozoic strata.  Massive late Flood or post-Flood erosion should have transported vast amounts of fossil material and microfossils from the earlier megasequences.”  Their first argument on the same page is that.  “the consistent internal stratigraphy of each megasequence testifies against significant erosion.” ↩

3. 9c.

   Table 1, page 282:  The Sauk megasequence, summed over North America, South America and Africa: 22,594,600 km² of surface area and 10,436,090 km³ of rock.  Sauk, Tippecanoe and Kaskaskia together on the same three continents come to about 35 million km³.  The article's own mass-balance arithmetic, in Part 5, is computed from those two published figures; no number in it is disputed by the authors. ↩ ↩ ↩ ↩

Conant, Louis C., and Vernon E. Swanson.  “Chattanooga Shale and Related Rocks of Central Tennessee and Nearby Areas.”  U.S. Geological Survey Professional Paper 357.  1961.  A 91-page U.S. Geological Survey report on the Chattanooga Shale and the rocks around it in central Tennessee, reporting work done for the U.S. Atomic Energy Commission.  The article uses it for the bevel under the shale: the shale rests on 23 formations, and the beds beneath it are rarely tilted by as much as 1 degree.

1. 10a.

   Page 13:  “Throughout the area of this study the Chattanooga shale rests on a peneplain that is notable for its extent and degree of perfection.  In the Tennessee area alone the shale rests on no less than 23 different sedimentary formations (pl. 3), as mapped by Wilson (1949, pl. 2), ranging in age from Middle Ordovician to Middle Devonian.  The older beds were tilted so slightly before Chattanooga time that in most outcrops the shale appears to parallel the older rocks;  at a few places an angular discordance is visible (pl. 5A) but is rarely as much as 1°.” ↩ ↩ ↩ ↩ ↩

2. 10b.

   Page 13:  “Limestones, sandstones, and shales were beveled and planed during what must have been a time of unusual crustal stability until a wide area was reduced to an almost featureless plain barely above sea level.” ↩ ↩

Billingsley, George H., and Stanley S. Beus.  “The Surprise Canyon Formation.”  U.S. Geological Survey Bulletin 1605-A:A27–A33.  1985.  A U.S. Geological Survey bulletin that describes the Surprise Canyon Formation, a rock unit that fills valleys and caves cut into the top of the Redwall Limestone.  The paleovalleys "average about 300 m in width and 75 m in depth"; the thickest is 122 m, at Quartermaster Canyon, where the paleovalleys cut through the Horseshoe Mesa Member into the Mooney Falls Member.  The article uses it for the size of those valleys and for what fills them. ↩ ↩

1. 11a.

   Page A32:  “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.”  The fill also carries tree impressions, mud cracks, burrows and stromatolites.  Three separate erosion surfaces occur in the interval: the valley-cutting surface, an unconformity inside the fill, and one below the Watahomigi Formation. ↩

Banks, V. J., and P. F. Jones.  “Measurement of rates of surface lowering of limestone in the southern Pennines: an example in the Wye catchment, Derbyshire, UK.”  Proceedings of the Geologists' Association 125(1):20–30.  2014.  A field study of how fast limestone dissolves, measured on a railway cutting in the Wye valley, Derbyshire, where resistant chert bands stand out in relief from the limestone around them.  The authors give a rate of 0.035 millimetres per year, within the range of earlier UK measurements, and their Table 7 lists ten earlier published rates.  The article uses it as its worked example of a measured limestone dissolution rate, taken from a cut of known age.

1. 12a.

   Table 7:  Ten published limestone surface-lowering rates, in millimetres per year: Goodchild 1875 Yorkshire 0.051; Sweeting 1966 0.042; Sweeting 1972 NW Yorkshire 0.049-0.050; Goldie 2006 Yorkshire 0.003-0.013; Parry 2007 0.0037-0.0135; Wilson et al. 2012 0.018; Pitty 1966 Derbyshire 0.083; Piggott 1962 Derbyshire 0.055-0.100; Gams 1962 Slovenia 0.077-0.080; Lauritzen 1990 North Norway 0.033 ± 0.010.  These are temperate humid-climate rates with soil and vegetation present, near the high end globally, so using the fastest of them is generous to the young-earth side.  Most karst dissolution is focused at dolines and along the epikarst rather than spread evenly, so the plateau-average figure is an order-of-magnitude floor rather than a date. ↩ ↩ ↩ ↩

Portenga, Eric W., and Paul R. Bierman.  “Understanding Earth's eroding surface with 10Be.”  GSA Today 21(8):4–10.  Aug 2011.  A compilation of 1,599 published measurements of how fast rock surfaces and river basins wear away, each measured in place with beryllium-10, a rare isotope that cosmic rays make in the top few metres of rock, and recalculated with the CRONUS calculator.  Bare outcrops average 12 metres per million years, with a median of 5.4 metres per million years, and the authors warn that few studies come from South America, Africa, the Middle East or the polar regions.  The article uses the outcrop figure because a bare low-relief rock surface needs it.

1. 13a.

   Page 6:  “Outcrops (n = 450) erode at an average rate of 12 ± 1.3 m Myr−1.  The median erosion rate is 5.4 m Myr−1.”  Page 7:  “Compiled outcrop erosion rates are slow and do not exceed 140 m Myr−1.” ↩ ↩

Sloss, Laurence L. et al.  “Integrated facies analysis.”  Sedimentary Facies in Geologic History (Geological Society of America Memoir 39), 91–124.  Edited by Chester R. Longwell.  1949.  A chapter in a 1949 Geological Society of America memoir on sedimentary facies, in which three geologists defined a "sequence" as a rock unit bounded by recognizable horizons, with no specific time significance.  The article uses it as the origin of the term and of the definition quoted below.

1. 14a.

   Pages 110–111:  “The writers term the assemblages of strata separated by the above-described objective horizons 'sequences'.  Sequences should be considered as rock units, assemblages of formations and groups.  They are simply the strata which are included between objective, recognizable horizons, and are without specific”.  The sentence breaks at the foot of page 110 and finishes on page 111.  “time significance since their limits do not coincide with time lines and may include rocks of different ages in various areas.” ↩ ↩

Macrostrat.  Macrostrat API v2.  n.d.  Retrieved Sep 4, 2026.  Macrostrat is a database of rock units, and this article ran its own query of it for the North American columns.  The run returns 24,141 rock units in 949 North American stratigraphic columns covering 24.81 million km², and the article's boundary, package and lithology counts all come from it.  The article states these limitations in its body: unit ages are interpolated from assigned chronostratigraphic intervals, so a loosely dated unit smears across a boundary and can produce a negative apparent hiatus; the compilation is onshore-dominated; and the lithology classifier lumps quartzite with sandstone, which favours the "starts with sand" reading. ↩ ↩

1. 15a.

   The check is restricted to columns that hold rock in the megasequence below and in the one above each boundary.  topBelow is the age of the youngest top of the lower megasequence in that column.  Sauk/Tippecanoe: 477 columns, 10th–90th percentile 414.7–484.4 Ma, spread 69.7 Myr, median hiatus −13.1 Myr, 58 columns with the upper package on Precambrian basement.  Tippecanoe/Kaskaskia: 481, 358.9–445.2, spread 86.4, median hiatus −3.2, 71 on basement.  Kaskaskia/Absaroka: 411, 298.9–357.0, spread 58.1, median hiatus −3.1, 33 on basement.  Absaroka/Zuni: 391, 156.5–274.4, spread 117.9, median hiatus 12.3, 75 on basement.  Zuni/Tejas: 405, 58.4–98.3, spread 39.9, median hiatus 6.3, 29 on basement. ↩ ↩ ↩ ↩

2. 15b.

   The basal unit is the unit in that megasequence with the oldest bottom age in that column.  Sauk: 573 columns, 394 sand, 61 carbonate, 19 mud, 6 evaporite, 82 igneous or metamorphic, 11 other → 68.8% sand.  Tippecanoe: 573, 209 sand, 237 carbonate → 36.5%.  Kaskaskia: 593, 192 sand, 265 carbonate → 32.4%.  Absaroka: 545, 292 sand, 114 carbonate → 53.6%.  Zuni: 552, 250 sand, 43 carbonate, 88 mud → 45.3%.  Tejas: 472, 324 sand, 16 carbonate → 68.6%. ↩

3. 15c.

   Macrostrat's section_id is a gap-bound package, the same object Peters 2006 counted from the COSUNA charts.  North America holds 7,239 of them: median 7 per column, mean 7.63, maximum 25, and 506 of 949 columns (53.3%) holding more than six.  The complementary figure: merging each column's unit age ranges, the median North American column holds rock for 23.6% of Phanerozoic time (10th percentile 7.7%, 90th 49.6%, maximum 92.2%, over 908 columns). ↩ ↩ ↩

Clarey, Timothy L., and Davis J. Werner.  “A Progressive Global Flood Model Confirmed by Rock Data Across Five Continents.”  Proceedings of the Ninth International Conference on Creationism 9:412–445.  Cedarville University International Conference on Creationism.  2023.  A conference paper by Timothy Clarey and Davis Werner of the Institute for Creation Research, built on nearly 3,000 stratigraphic columns from five continents, which maps Sloss's six megasequences and assigns them to days of a Flood that rises and then falls.  It is the most data-rich young-earth model of the rock record.  This overview uses it for the Flood calendar, for its definition of a megasequence, and for its own statements that the boundaries between packages show little erosion.

1. 16a.

   Page 433:  “The earliest three megasequences (Sauk, Tippecanoe and Kaskaskia) seem to have inundated only shallow marine environments as the fossils within these megasequences are almost exclusively marine (Fig. 22).  We interpret that these megasequences were deposited in the first 40 Days of the Flood (Fig. 23).  As the water rose higher, floating the Ark (on or after Day 40) and flooding portions of the dry land, the first massive coal seams appear and the first land animal fossils appear in great numbers. … depositing the Absaroka and Zuni megasequences between Days 40-150 of the Flood, until the water covered the highest hills (Fig. 24).”  The article's block quotation leaves out the three figure references shown here. ↩ ↩

2. 16b.

   Page 414:  “Each sequence was defined as a discrete package of sedimentary rock bounded top and bottom by inter-regional unconformity surfaces across the North American craton (Sloss 1963) … Sequences supersede and include multiple geologic systems, and in many instances, can be recognized by their bounding erosional surfaces and sudden changes in rock type, independent of fossil content.” ↩

3. 16c.

   Page 423:  “the consistent internal stratigraphy of each megasequence testifies against significant erosion.  Megasequences often start out with sandstone followed by shale and then carbonate rock.  For example, the Sauk in North America still exhibits a complete cycle consisting of basal sandstone (Tapeats equivalent), followed by shale (Bright Angel equivalent) and topped by a carbonate (Muav equivalent).  Vast erosion in between each megasequence cycle would have likely destroyed this systematic signature in many locations, if not totally.  And yet we observe the complete sequence of sandstone, shale and carbonate in the Sauk megasequence across large portions of North America.” ↩ ↩

4. 16d.

   Page 435:  “Suggestions that the Flood was completely over at the K-Pg boundary also fail to explain the lack of significant erosional evidence at the K-Pg boundary.  Where are the major canyons and the planation surfaces like those that formed at the top of the Tejas (Clarey 2021b)?”  Page 436:  “There should be massive erosional features at the K-Pg, but in most places, it resembles a disconformity, where the sedimentary beds are parallel above and below the boundary surface, with little indication of any missing sediment or massive erosion.”  The authors are arguing against putting the end of the Flood at the Cretaceous-Paleogene boundary, which lies close to the base of their last megasequence, the Tejas. ↩ ↩ ↩

5. 16e.

   Page 414, section Methods:  “Nearly 3000 stratigraphic columns were compiled from 100s of published papers and available oil wells, measured sections, cross-sections and seismic data data from every major basin and uplift across North and South America, Europe, Africa and Asia.  Within each column we identified the rock type and the stratigraphic megasequence intervals.  Phanerozoic fossil-bearing rocks are divided into six packages of sedimentation based on the 'megasequences' concept of Sloss (1963).  We also kept track of a seventh 'megasequence,' called the Pre-Sauk.”  The doubled "data data" is in the original. ↩

6. 16f.

   Page 425:  “confined to nearly the same identical locations across each of the five continents, and stack uniformly one on top of the other.  This is the general rule for all five continents.  Random erosion would not leave this consistent of a megasequence pattern across five continents.”  “Our study also found that all megasequences thin toward the crystalline shield areas on all continents (Fig. 16).  In other words, the stratigraphic units do not show evidence of massive erosion and truncation.” ↩

7. 16g.

   Page 415:  “Acceptance of the validity of the geologic column does not mean we advocate for deep time nor acceptance of the geologic timescale so commonly used in conventional geology.” ↩ ↩

Baumgardner, John R., and Evan Navarro.  “The Role of Large Tsunamis in the Formation of the Flood Sediment Record.”  Proceedings of the Ninth International Conference on Creationism, 363–386.  Cedarville University.  Edited by J. H. Whitmore.  2023.  Page 373:  “we require seven episodes of sea level drop, one at the beginning, five separating the six megasequences, and one at the end ... by choosing each to result in a 700 m drop in the average sea bottom height ... We model the first six of these sea level drops to occur at 25-day intervals beginning at time zero, with each unfolding during a 24-hour period.”  Page 374:  “God's cooling of the oceanic lithosphere has been an inherent component of the catastrophic plate tectonics framework since the first paper in 1986. Not until this paper have we suggested that this cooling occurred in distinct pulses.”  A conference paper by John Baumgardner of Liberty University and Evan Navarro that extends an earlier computer model in which giant tsunamis erode the continents and spread their sediment.  It assumes that the erosional breaks between megasequences came from abrupt drops in global sea level, and it plans seven such drops of 700 m each, the first six spaced 25 days apart.  The article uses it as the source for this model and checks the model against the paper's own stated rates. ↩ ↩

This overview's own scale check, made by neither child article.  In Clarey and Werner's Table 1 the Sauk covers 22,594,600 km² over three continents and holds 10,436,090 km³, an average thickness of 0.462 km, which the table also prints.⁹  Eroding a depth d off the same footprint makes d ÷ 0.462 times the deposit, which is 6.5 at 3 km, as in The Great Unconformity.  If the true volume on that footprint were twice Clarey and Werner's figure, the average thickness would be 0.924 km, and 1, 3 and 5 km of erosion would make 1.08, 3.25 and 5.41 times the deposit.  At 3 km that is 67.8 − 20.9 = 46.9 million km³ more rock than the deposit holds.  The factor of two comes from North American totals only:  the six North American volumes in the same table sum to 53,620,170 km³, against about 110 million km³ from Peters and Husson, a ratio of 2.05.⁵  Nobody has measured the shortfall for the Sauk by itself. ↩ ↩

Grand Canyon: Monument to Catastrophe.  Institute for Creation Research, Santee, California.  Edited by Steven A. Austin.  1994.  An edited book of chapters on the geology of the Grand Canyon, published by the Institute for Creation Research.  The article uses its chapter 3 (pp. 45–47) and chapter 4 (pp. 57 and 66–70) as the young-earth side's own account of the Great Unconformity.

1. 19a.

   Figure 3.22, page 46:  The caption, which reads:  “Detail of the Great Unconformity in Grand Canyon.  At this location, Tapeats Sandstone (Cambrian) overlies Dox Sandstone (Precambrian).  Evidences of extensive chemical weathering are not obvious.  Instead, feldspar-rich pebbles of Tapeats overlie the unaltered surface of Dox Sandstone.  Does the surface of erosion represent one-half billion years?  We marvel at the fresh appearance of the contact.”  Page 45:  On the preceding page Austin sets out the dispute:  “Has evidence of 'gentle weathering' been documented at the Great Unconformity?  Geologists have been divided on this point.”  Page 46:  His witness against Sharp is N. E. A. Hinds, who.  “could not find significant evidence of chemical weathering of bedrock, or of the debris incorporated into the base of the Tapeats Sandstone”. ↩

2. 19b.

   Page 57:  “Everywhere in northern Arizona these strata occur, they are bounded above by a very conspicuous planar surface of erosion (the 'Great Unconformity'), believed to represent early erosion and the onset of Noah's Flood.”  Page 67:  He generalises:  “Most creationist geologists regard the Great Unconformity as the feature formed during the tectonic and erosive catastrophe at the onset of Noah's Flood.” ↩

Snelling, Andrew A.  “The Petrology of the Tapeats Sandstone, Tonto Group, Grand Canyon, Arizona.”  Answers Research Journal 14:159–254.  2021.  A 2021 petrology study, which is a study of rock composition and texture, by Andrew Snelling of Answers in Genesis, a young-earth creationist ministry that publishes the journal.  The paper runs 96 pages and examines 26 thin sections, which are slices of rock viewed under a microscope, from the Tapeats Sandstone, the Cambrian sandstone at the base of the Tonto Group in the Grand Canyon.  The article uses it as the most detailed young-earth treatment of this surface in print.

1. 20a.

   Page 240:  “However, before the Tapeats Sandstone was deposited there had to be a prolonged period (days or more) in which there was a significant amount of continental-scale erosion to bevel the Precambrian (pre-Flood) land surface to produce the Great Unconformity.  In the Grand Canyon region this involved intensive catastrophic erosion to remove several thousand meters of Grand Canyon Supergroup strata (which appear to only have survived in several down-faulted blocks) and then to bevel the underlying metamorphic schists and granite plutons.” ↩

Clarey, Timothy.  “Still Trying to Explain the Great Unconformity.”  Creation Science Update, Institute for Creation Research.  2020.  A short news commentary answering Flowers et al. 2020, citing Keller et al. 2019 as its reference 3.  The article uses it as the young-earth answer to Flowers and colleagues.

1. 21a.

   “To make this extensive erosional surface, a significant portion of the Precambrian surface material, and some of the pre-Flood sedimentary rocks, must have been stripped off a majority of the world's continents, simultaneously, before the deposition of the overlying Sauk megasequence (Cambrian rocks).  This may have been caused by the torrential rains that occurred in the first 40 days of the Flood and/or by the erosive action of tsunami-like waves propagating across parts of the continents.” ↩ ↩ ↩

Clarey, Timothy.  “Conventional Science Still Struggling to Exhume the Great Unconformity.”  Creation Science Update, Institute for Creation Research, article 15828.  2026.  Its references are marked.  “accessed February 27, 2026”.  The byline at the foot of the body reads:  “Dr. Clarey is the director of research at the Institute for Creation Research.”  No publication date is printed on the page, so it was posted on or after the date its references were accessed.  It is a reply to Zhan et al. 2026, and the article uses it because it moves the Flood's onset down to the Great Nonconformity, one surface below the Great Unconformity.

1. 22a.

   “But the results of this study do support an earlier beginning to the massive erosional event that likely marked the onset of the global Flood.  This earlier erosional surface is known as the Great Nonconformity at Grand Canyon, possibly marking the beginning of the Flood. …  Furthermore, this suggests that many Proterozoic (Precambrian) sediments may have also been part of the Genesis Flood.” ↩

Oard, Michael J.  “The Puzzle of Planation Surfaces (Part VII, chapters 32 and 49).”  Michael Oard's online Flood-runoff monograph.  Apr 30, 2014.  Two chapters from Oard's online book on the Flood's runoff, about the flat erosion surfaces called planation surfaces that cut across the continents.  Chapter 32 defines them, and chapter 49 summarizes the survey evidence that they are common on all continents, which Oard attributes to sheet erosion during the Flood.  The article uses it for his mechanism, sheet flow off a rising continent during the Retreating Stage of the Flood; the phrase "Great Unconformity" does not appear in either chapter.  Mirror:  Michael.oards.net

1. 23a.

   Chapter 32, page 2:  “Today, comparatively small planation surfaces (strath terraces) are formed when a river floods, overflows its banks, and planes bedrock to a horizontal or near horizontal surface.  But, present processes do not form planation surfaces of any significant size.  The large surfaces that frequent the Earth's surface are contrary to the principle of uniformitarianism.”  His chapter 49 supports the claim with mainstream geomorphologists including King, Twidale, and Ollier and Pain.  The article grants the point. ↩

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.  A National Park Service report on the ages of the rock layers in Grand Canyon National Park, with a table of numeric ages for them.  The Park Service's web version of that table was last updated on 12 March 2024.  The article uses it for the three unconformities the Park Service names in the canyon and for the revised date of the Cardenas Basalt.

1. 24a.

   Section Missing Time, page 14:  The Great Nonconformity spans this much missing record:  “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.” ↩

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 2022 study that dated basement rock under the Great Unconformity in the eastern Grand Canyon with zircon (U-Th)/He, a method that shows when a rock cooled through about 200 °C.  It used 37 single zircon grain aliquots from seven locations and modeled the cooling history, and it found the main Precambrian cooling between 1300 and 1250 Ma and canyon carving under 20 Ma.  The article uses it for the spread of missing time along one canyon, from 200 to 1300 million years. ↩ ↩

Oard, Michael J.  “Analysis of Walt Brown's Flood model.”  Creation Ministries International.  2013.  “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.”  On Brown's block-faulting of the Grand Staircase and Book Cliffs, Oard writes:  “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 commissioned critique of Walt Brown's hydroplate model of the Flood, written by Michael Oard, a full-time researcher in field geology and a board member of the Creation Research Society, at the request of Creation Ministries International.  It summarizes Brown's model, then tests its Grand Canyon and woolly mammoth claims, finding questionable starting conditions, data fitted to the model, and a dam-breach explanation of the canyon that cannot account for its long, deep tributary canyons.  The article uses it for Oard's own water-to-rock arithmetic from the Missoula floods and for his Bonneville erosion rate.

1. 26a.

   On the Bonneville flood, Oard writes:  “It is estimated that about 100 m (330 ft) of rock was eroded in about 8 weeks before the flood ended.”  He adds that although the estimate is a uniformitarian one, he believes it, because the flood landforms in the Snake River Valley are small.  The article's rate of 6.5 × 10⁵ mm/yr is its own arithmetic on this figure: 100 m in 8 weeks. ↩

2. 26b.

   “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!”  “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.” ↩

Keller, C. Brenhin et al.  “Neoproterozoic glacial origin of the Great Unconformity.”  Proceedings of the National Academy of Sciences 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 2019 paper by nine authors that combines three records: oxygen and hafnium isotope measurements in zircon crystals, the impact craters found on Earth, and how much sediment covers the continents through time.  The authors argue that Neoproterozoic glacial erosion can explain all three together, with a global average of 3-5 vertical kilometers of rock removed.  The article uses it as the strongest case for a single glacial cause. ↩

1. 27a.

   Section Neoproterozoic Glaciation and Erosion:  “Modern glacial erosion rates are highly variable, estimated to span some four orders of magnitude from ∼0.01 mm/y to ∼100 mm/y (54).  For comparison, 4 km of erosion over 64 Ma of Neoproterozoic glaciation would require an average erosion rate of only 0.0625 mm/y — nearly two orders of magnitude slower than recent direct estimates for the modern Greenland ice sheet (55).”  The same paper offers an independent test that comes out in its favour.  Impact craters are shallow features, so kilometre-scale erosion should destroy all but the largest, and the authors report that.  Section The Terrestrial Bolide Impact Record:  “only two craters matching the criteria of Fig. 3 predate the onset of Sturtian glaciation, both deeply eroded remnants of massive craters:  Sudbury and Vredefort, eroded to depths of 4.2–5.8 km and 8–11 km, respectively,”.  The paper also reports.  “an abrupt truncation of <100-km diameter craters before 700 Ma and <10-km diameter craters before 600 Ma.”  A Flood that stripped the continents in a year predicts a truncation too, but not one that arrives in size order across 100 million years. ↩ ↩ ↩

Zhan, Rong-Ruo et al.  “Tectonism rather than 'snowball Earth' glaciation is responsible for the Great Unconformity.”  PNAS 123(9):e2523891123.  Feb 23, 2026.  A 2026 study, published on 23 February 2026, that dated basement rock beneath the Great Unconformity at five North China locations, three inside the craton and two near its margin, with zircon and monazite U-Pb, biotite and muscovite Rb-Sr and zircon (U-Th)/He, and argues that plate tectonics, not snowball Earth glaciation, drove most of the exhumation below the unconformity.  Nicholas Christie-Blick, a co-author, is a long-standing critic of catastrophic snowball interpretations, so this is not a consensus restatement.  The article cites it for its finding that most of the exhumation came 2,100 to 1,600 million years ago, far earlier than any glacial model allows.

1. 28a.

   Section abstract, page 1:  “Dates from multichronometers and thermal history inversions show that the most substantial cooling of continental basement took place from ~2,100 to 1,600 Ma.  Comparison with thermal history data from Laurentia, Baltica, and Amazonia suggests that protracted plate tectonics broadly modulated by supercontinent cycles, and not 'snowball Earth' glaciation, is responsible for crustal exhumation below the unconformity.” ↩ ↩

Snelling, Andrew A.  “The Case of the 'Missing' Geologic Time.”  Creation 14(3):30–35.  1992.  A 1992 article by a creationist author, first published in the magazine Creation and later reprinted by Answers in Genesis.  It examines one contact on the North Kaibab Trail, where the Redwall Limestone sits directly on the Muav Limestone, and checks it against seven features that a long break in deposition should leave.  The article uses it as the creationist field test at a single locality.

1. 29a.

   “not even one of the seven expected features listed above can be seen at this supposed boundary … Consequently, at least 155 million years of geological time are 'missing' at this location.” ↩

Oard, Michael J.  “Much supposed geological time missing from strata.”  Journal of Creation 30(3):5–6.  Dec 2016.  A short creationist note by Michael Oard that argues the flat contacts between strata show continuous deposition, which he attributes to Noah's Flood rather than to long gaps.  It takes the Muav-Redwall contact in the Grand Canyon, which its Figure 1 labels as 160 million years of missing time, and adds Miall's 2014 missing-time study to the argument.  The article cites it with Snelling's article as the two young-earth treatments that argue the surface shows no long gap.

1. 30a.

   Section Conclusion:  “This is exactly the sort of evidence we would expect from Noah's Flood and further implies that the claimed millions of years are imaginary.” ↩ ↩

Reed, John K., and Michael J. Oard.  “The meaning of unconformities.”  Journal of Creation 32(1):92–99.  Apr 2018.  A long Journal of Creation essay by John Reed and Michael Oard arguing that most unconformities, the gaps between rock layers, formed quickly during the Flood, and that the Muav-Redwall contact, supposedly 160 million years, shows little erosion.  It answers the Redwall karst with Silvestru's degassing mechanism and reads the Surprise Canyon fill as a depositional lag within a Flood channel.  The article uses it for the young-earth reply on the Redwall karst and on paraconformities.

1. 31a.

   “Paraconformities, if real, would represent short breaks in continuous sedimentation, or possibly short time intervals between successive tsunami-like wave sets.  Disconformities and angular unconformities would have been caused by rapid erosion, often accompanied by rapid tectonic changes.” ↩ ↩ ↩

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.  A 2019 paper in the Answers Research Journal, a creationist journal, that correlates the Coconino Sandstone and surveys Permian 'Eolian' sandstones, with implications for Flood geology.  The article cites it for two points: the reading of the Hermit-Coconino cracks as sand injectites, and the argument that flat contacts between marine layers are easier to explain than flat land surfaces.

1. 32a.

   Page 294:  “While flat surfaces are uncommon in terrestrial settings, they are quite common on the seafloor.  So, it is not surprising that we see flat contacts between marine layers, which are most of the rocks in Grand Canyon, even from a conventional perspective.  There is still missing time in between many of these layers from a conventional view, sometimes in excess of 100 Ma, but at least that is easier to explain in a marine setting.” ↩ ↩

López-Quirós, A. et al.  “Glaucony authigenesis, maturity and alteration in the Weddell Sea: An indicator of paleoenvironmental conditions before the onset of Antarctic glaciation.”  Scientific Reports 9:13580.  2019.  A research paper that studied glaucony, a green iron-potassium clay that forms on the seafloor, in late Eocene sediment from one ocean drill hole in the northwestern Weddell Sea off Antarctica.  Using thin sections and mineral and chemical analyses, the authors found that the grains formed in place where sediment arrived slowly and bottom currents winnowed it.  The article uses the paper for how long a mature glaucony grain takes to form on a starved seafloor.

1. 33a.

   Page 6:  “The time required to produce an autochthonous evolved glaucony grain is considered to be higher than”.  10^3-10mall>  “years for ancient glaucony-bearing records.”  Figure 7, page 8:  The figure gives the stages:  “(1) Microbial oxidation of organic matter (~10-10^3-10rs).  (2) Neoformation of Fe(III)-smectite precursor (~10^3-104 years).  (3) Fe(III)-smectite to glauconite reaction (~10^4-106 years).” ↩

Billingsley, George H.  “Geologic Map of the Grand Canyon 30' x 60' Quadrangle, Coconino and Mohave Counties, Northwestern Arizona.”  Geologic Investigations Series (I-2688).  U.S. Geological Survey.  2000.  A U.S. Geological Survey geologic map of the central and western Grand Canyon at a scale of 1:100,000, with a 16-page pamphlet that describes each rock unit and its thickness.  This overview uses the pamphlet for where the Surprise Canyon Formation is found, which shows that the fill sits only in the old valleys and caves at the top of the Redwall.

1. 34a.

   The Surprise Canyon Formation is.  “present only in paleovalleys and karst caves eroded into top half of Redwall Limestone.” ↩ ↩

Miall, Andrew D.  “The emptiness of the stratigraphic record: A preliminary evaluation of missing time in the Mesaverde Group, Book Cliffs, Utah.”  GeoConvention 2014: FOCUS.  2014.  A preliminary study by a University of Toronto geologist of the Mesaverde Group in Utah, a 4.86-million-year pile of river, delta and shoreline rock dated by ammonite zones.  He compared the rock actually preserved with how fast modern rivers, deltas and shorelines deposit sediment, and treats the gaps between sediment packages as missing time.  The article uses it because it is the mainstream paper most cited in recent creationist writing on this topic, and its author accepts the full 4.86 million years.  This is a nine-page extended abstract; the same study was published in refereed form in the Journal of Sedimentary Research 84(6):457–469, doi 10.2110/jsr.2014.40, and the abstract carries the same numbers.

1. 35a.

   Page 7:  “When sedimentation rates for modern equivalents of the nonmarine to shallow-marine environments in which the Mesaverde Group was deposited are applied to the preserved facies successions that comprise this group, less than 10% of the 4.86 m.y. elapsed time represented by the group can be accounted for.  The remainder is 'missing' at bedding planes and other bounding surfaces of all types, a pattern predicted by Sadler (1999).”  The 4.86 million years is fixed by ammonite zones, and Miall keeps it. ↩

Silvestru, Emil.  “The riddle of paleokarst solved.”  Journal of Creation 15(3):105–114.  2001.  A 2001 paper in the Journal of Creation, then called TJ, by Emil Silvestru, who draws on more than 30 years of field experience to argue that pre-Cenozoic 'paleokarst' is really pseudokarst made by gas and fluid seeps.  He holds that buried karst could not survive for millions of years, and that gas and seeps from organic matter destroyed in the Flood made the features; the paper gives no dissolution rate at all.  The article uses it as one of two young-earth answers on the Redwall karst.

1. 36a.

   Page 109:  “It is likely that the rapidly accumulating Flood sediments periodically emerged.  The resultant degassing and dewatering of waterlogged sediments, along with the associated chemical changes, would have developed a wide range of negative relief in a matter of days.  Such features would mimic karst landforms.”  Page 105:  His thesis, from the abstract:  “In all probability 'paleokarst' does not exist because any primary morphology initially enclosed inside soluble rocks could not have been preserved for millions or even hundreds of millions of years.” ↩

Woodmorappe, John.  “Hardgrounds and the Flood: the need for a re-evaluation.”  Journal of Creation 20(3):104–110.  2006.  A technical paper by a creationist author that re-examines the evidence for hardgrounds, which are ancient seafloor surfaces that turned to rock.  It reports fieldwork on Ordovician hardgrounds in 2004 and at the Caesar Creek site in 2005, and argues that some hardgrounds were misidentified and that others were built from recycled rock during the Flood.  The article cites it as the fuller creationist answer to the hardground challenge, and for its argument on why a clean cut through a hard grain does not prove the layer was lithified.

1. 37a.

   Page 106, right column:  On the petrographic test:  “One must ask if the clean truncation of hard objects such as large carbonate grains, intraclasts or fossils at the holes' margins necessarily proves that the entire holed limestone layer was lithified at the time of the excavation of the holes or if the hardness of the object itself is a sufficient explanation for this observation.”  Page 106:  On the same page:  “it is now acknowledged that sharp margins of ichnofossils do not necessarily imply the lithified state of the penecontemporaneous surface.” ↩

Walker, Tas, and Mark A. Wilson.  “Are hardgrounds really a challenge to the global Flood?”  Creation Ministries International feedback, 2 February 2006.  Feb 2, 2006.  An exchange in which Tas Walker, replying to Mark A. Wilson of the Department of Geology at The College of Wooster, answers Wilson's argument point by point, where Wilson, who studies carbonate hardgrounds, argues that they are a problem for the global Flood.  Walker says the hardgrounds are pre-Flood seafloor debris cemented during dewatering, and that the borings are compaction moulds.  The article uses it because hardgrounds test the order of events, and Wilson himself admits there is no direct clock for how long they took to form.

1. 38a.

   Wilson's words:  “Forming a hardground probably takes years, but we do not yet have any direct way to estimate the duration of the process.”  His positive claim is the weaker one:  “Hardgrounds and their fossils show that many limestones formed over long intervals of time, at least hundreds if not thousands of years.” ↩

Clarey, Timothy L.  “Reading African Strata.”  Acts & Facts 44(9):9.  Institute for Creation Research.  Aug 31, 2015.  A one-page popular article by Timothy Clarey in the Institute for Creation Research's magazine Acts & Facts, comparing the stratigraphic columns of Africa and North America.  It argues that the two continents record the same levels of the Flood at the same time.  The article uses it for ICR's claim that water levels rose and fell at the same time on both continents.

1. 39a.

   Paragraph 8:  “Comparison of the stratigraphic columns of Africa and North America show many similarities indicative of a global flood.  Water levels seem to have risen and dropped simultaneously across both continents.” ↩

Peters, Shanan E. et al.  “Macrostratigraphy: Insights into Cyclic and Secular Evolution of the Earth-Life System.”  Annual Review of Earth and Planetary Sciences 50:419–449.  2022.  A review article that surveys how the quantity of rock changes with age in continental and oceanic crust, using the approach of macrostratigraphy.  Its central finding is that the continents show episodic growth in rock, while the ocean floor shows continual destruction.  The article uses it for its statement that the Phanerozoic rock record carries little trace of erosion.

1. 40a.

   Page 432:  “Within the Phanerozoic, macrostratigraphic quantities describing sedimentary rock quantity carry little discernible overprint of erosion and are instead dominated by a process signal that reflects changes in the extent of continental basin formation and marine flooding.”  Page 434:  The review relays a sentence of Sloss 1963, who.  “began his unconformity-based physical classification of the North American sedimentary rock record with the Sauk Sequence, the Cambrian–Early Ordovician marine succession deposited on an unconformity that 'over the greater part of the cratonic interior. . .was cut on Precambrian crystalline rocks and deformed metasedimentary rocks.'” ↩

Clarey, Timothy L.  “Grappling with Megasequences.”  Acts & Facts 44(4):18–19.  Institute for Creation Research.  Mar 31, 2015.  A short popular article by Timothy Clarey in the Institute for Creation Research's magazine Acts & Facts, reporting on the ICR Column Project's analysis of rock samples from North America.  The article uses it to show what Clarey said in 2015 about the megasequences in his own columns, before his 2023 paper.

1. 41a.

   Paragraph 4:  “Careful comparison of the rock types in each column with the sequence boundaries show very few 'ideal' uniformitarian megasequences.” ↩

2. 41b.

   Paragraph 7:  “the lowermost rocks in the Tippecanoe Megasequence that spans much of the eastern U.S. placed limestone (Figure 2) right on top of the limestone of the upper Sauk Megasequence.  This relationship suggests that the floodwaters may never have drained off these areas between the Sauk and Tippecanoe Megasequence cycles.” ↩ ↩

Dott, Robert H. Jr.  “Laurence L. Sloss and the Sequence Stratigraphy Revolution.”  GSA Today 24(3):24–26.  Mar 2014.  A profile of Sloss in GSA Today by Robert Dott, who interviewed him in 1996, the year Sloss died.  It traces how Sloss first noticed the unconformities while working in Montana, how the sequences were named, and how the 1948 symposium received them.  The article uses it for the history of the six sequences and for the early objection to them.

1. 42a.

   Page 25:  “Thus the Sauk Sequence was named for Sauk County, Wisconsin.  At first, four sequences were so named, which approximately spanned all of the Paleozoic systems.  Later, as they became more acquainted with the younger record toward the margins of the craton, two more sequences were named (Fig. 4).” ↩

Sloss, Laurence L.  “Tectonic Cycles of the North American Craton.”  Symposium on Cyclic Sedimentation (Kansas Geological Survey Bulletin 169), 449–459.  Edited by D. F. Merriam.  1964.  A symposium paper that restates Sloss's thesis that the rock record of the North American craton, from the late Precambrian to the present, divides into six sequences.  It reports that the rock associations in the sequences show no systematic repetition suggesting cycles, that four sequences fit a model of broad, slow crustal movements, and that two fit an orogenic (mountain-building) model with no apparent order.  The article uses it for the count of six, for Sloss's finding that the six show no cycle, and for his rejection of Wheeler's proposal to split two of the sequences.

1. 43a.

   Section Head-note:  Head-note added in proof, printed before the Introduction.  “It is Wheeler's thesis that the writer's Tippecanoe and Kaskaskia sequence should each be divided into two sequences.”  Sloss's answer, quoted with the two OCR typos that the KGS transcription contains:  “It is the present writer's contention that Wheeler is confusing temporary stabilization of the craton and consequent local and trivial unconformity witht he uplift anbd accompanying cratonwide erosion between sequences.”  The rival division is by Harry E. Wheeler, whose paper the head-note cites as:  “Post-Sauk and Pre-Absaroka Paleozoic Stratigraphic Patterns in North America”.  “Am, Assoc. Petroleum Geologists Bull., v. 47, p. 1497-1526, 1963”.  The comma after "Am" is one more OCR slip.  The head-note's reference to the published discussion (v. 48, p. 122-124) gives 1974, which is a mistyped year, since the discussion is from 1964. ↩

Meyers, Stephen R., and Shanan E. Peters.  “A 56 million year rhythm in North American sedimentation during the Phanerozoic.”  Earth and Planetary Science Letters 303:174–180.  2011.  Stephen Meyers and Shanan Peters of the University of Wisconsin–Madison ran a spectral analysis, a test for repeating cycles in a data series, on how much of North America was covered by sedimentary rock through the Phanerozoic, and found a 56-million-year cycle.  That cycle accounts for only about 14% of the observed variance, and the paper's longer-term pattern is statistically indistinguishable from a random background process.  The article uses it for the paper's proposal of nine units and two mega-sequences, which challenges the conventional count of six.

1. 44a.

   Page 174, section Abstract:  “The newly identified 56 Myr cycle in sedimentation delineates most of the cratonic sequences that have previously been identified qualitatively in North America, but here we propose a quantitative redefinition that includes nine distinct units and two mega-sequences.” ↩

Clarey, Timothy L., and Davis J. Werner.  “Megasequences during the Flood? Response to Oard.”  Journal of Creation 39(2).  2025.  A 2025 reply in Journal of Creation by Clarey and Werner to Michael Oard's critique of their megasequence model.  It sets out where the data come from, including the oil-industry correlation charts used for the United States, and it concedes some weak points, such as that few megasequences are ideal apart from the Sauk.  The article uses it for the source of the American columns and for those concessions.

1. 45a.

   Section Quality of COSUNA data:  “The COSUNA stratigraphic columns were created by oil industry geologists and state geologists who used oil well and outcrop data. … We ultimately used about 500 columns from the USA. … The biggest drawback is that the columns may include a bit too much. … This is why the maps across the USA likely exaggerate the real extent of the Sauk Megasequence in the middle of the country”.  For the rest of the columns, the authors write:  “Other than the use of COSUNA data for much of the USA, we compiled the other 2,700 columns in our study from actual oil wells, measured outcrops, and even seismic data through wells.” ↩

2. 45b.

   Section Missing megasequences:  On the Tippecanoe, which is absent under the Grand Canyon:  “we are not convinced that considerable sections of the rock record have been eroded … Rather, we suspect the Tippecanoe is missing here primarily due to non-deposition, with only minimal erosion marking the boundary between megasequences.  We infer that the tsunami waves of the Flood simply did not reach this point during deposition of the Tippecanoe, for some unknown reason.” ↩ ↩

3. 45c.

   Section Ideal megasequences:  “And we agree that there are few ideal megasequences (other than the Sauk) as envisioned by uniformitarian geologists.  Instead, the chaotic nature of the stratigraphic column is more the 'rule'.” ↩

Soares, Paulo Cesar et al.  “Tectonic cycles and sedimentary sequences in the Brazilian intracratonic basins.”  GSA Bulletin 89(2):181–191.  1978.  A 1978 paper in GSA Bulletin that reads the rock record of three basins on the Brazilian craton, the Paraná, Parnaiba and Amazon basins, as a series of tectonic cycles.  A craton is a stable, old core of a continent, and an intracratonic basin is one that sits inside such a core.  The authors divide the record into named sequences and find that they are synchronous with cratons on other continents.  The article cites it as one of the two papers Clarey and Werner use for the intercontinental correlation.

1. 46a.

   Section Abstract:  “Cyclic successions of erosional and depositional events are synchronous on the Brazilian craton and are correlated with cratons of other continents.”  The units are the authors' own:  “Cambrian-Ordovician sedimentary rocks … are assigned to the Alpha sequence.  The Beta (Ordovician and Silurian), Gamma (Devonian–early Carboniferous), and Delta (late Carboniferous–Late Permian sequences) and the Delta-A subsequence (Middle Triassic–Jurassic) … indicate accumulation in large subsiding basins.”  Two more follow, Epsilon (Cretaceous) and Zeta (Cenozoic).  On the intercontinental comparison:  “Marine transgression and basin subsidence increased progressively through the Devonian phase of the Gamma sequence and declined thereafter, in a pattern similar to that of the North American craton and the Russian platform.” ↩

Peters, Shanan E., and Noel A. Heim.  “Stratigraphic distribution of marine fossils in North America.”  Geology 39(3):259–262.  2011.  A research paper in the journal Geology by two University of Wisconsin geoscientists.  It crossed marine rock packages in North America, which have a mean duration of about 10 million years, with fossil collections from the Paleobiology Database, a database of fossil occurrences.  The article uses it because it is a test that a simple rising-water model should pass and does not.

1. 47a.

   Page 259, section Abstract:  “We find that fossil collections and marine genera are, when averaged over all Phanerozoic sedimentary rock packages, more abundant than expected in the top 40% of package durations, and less common than expected in the bottom ~25%.  Generic first and last appearance datums (FADs and LADs) in North America are not randomly distributed among fossil collections.  Instead, LADs are more common than expected in the top ~20% of package durations, whereas FADs are more uniformly distributed.  This result is not consistent with an unconformity-related sampling bias”. ↩

Newell, Norman D.  “Paraconformities.”  Essays in Paleontology and Stratigraphy: R. C. Moore Commemorative Volume, 349–367.  University of Kansas Department of Geology, Special Publication 2.  Edited by Curt Teichert and Ellis L. Yochelson.  1967.  An essay on paraconformities by Norman D. Newell, in the R. C. Moore Commemorative Volume.  It contains the sentence that creationist writers quote most, that paraconformities show a general lack of evidence of leaching of the rock beneath them, together with Newell's admission that their origin is uncertain.  The article uses it because Roth treats Newell as his strongest authority, and because Newell's own answer appears later in the same essay.

1. 48a.

   Page 364:  Four sentences later, the author names the hypothesis he favours:  “Some geologists may find it difficult to accept the hypothesis that I favor, namely, a concept of long protracted stillstand of relative sea level adjacent to very low land surfaces.  Yet this seems to be the most probable explanation of the prevalent absence of unequivocal evidence of leaching and oxidation at paraconformities.  This hypothesis envisages nearly static ground waters saturated with respect to calcium carbonate owing to extremely low terrestrial relief or inundation by shallow sea water.” ↩ ↩

Hessler, Angela M.  “The Incompleteness Fallacy: The Stratigraphic Record Is Not an Imperfect Archive of Earth's History.”  The Sedimentary Record 21(1):1–4.  2023.  Page 1:  “Stratigraphy is not missing anything.  It simply exists as the collective product of earth processes across time and geography.”  An editorial by Angela Hessler of the Deep Time Institute arguing that the record is not incomplete, because it is simply what Earth processes produced across time and place.  She says the word 'incompleteness' sets up a false expectation of a perfect record, and she uses the definition of completeness from Sadler and Strauss (1990).  The article uses it as one side of a debate among sedimentologists over how to describe missing time. ↩

Miall, Andrew, and Angela M. Hessler.  “Discussion on 'The Incompleteness Fallacy: The Stratigraphic Record Is Not an Imperfect Archive of Earth's History' (Hessler, 2023).”  The Sedimentary Record 22(1).  2024.  “I would suggest that 'stratigraphic incompleteness' is real, and has, in fact, bedeviled the science of stratigraphy ever since we tried to quantify it.  Incompleteness is a fact, but it is measurable, quantifiable, and explainable.”  “To conclude, there is no 'incompleteness fallacy'.  It is a concept that ignores the hard, practical science that is actually being done.”  A discussion piece by Andrew Miall, replying to Hessler's 2023 editorial, in which he argues that incompleteness is real, measurable and explainable.  He points to physical and numerical modelling work by Chris Paola and Peter Burgess as evidence that the practical science is being done.  The article uses it as the other side of the same debate:  Miall argues that the gaps are real and countable. ↩

Peters, Shanan E.  “Macrostratigraphy of North America.”  The Journal of Geology 114(4):391–412.  2006.  A 2006 study by Shanan Peters of the University of Michigan that counted the gap-bound rock packages, the rock bodies bounded by gaps in the record, in the continental United States and southern Alaska, using the AAPG COSUNA correlation charts.  It found 4,173 packages in charts assembled at a resolution of about 1–3 million years, and it found that the largest increase in erosional truncation comes at the end-Permian.  The article uses it as the database that tests Clarey, and as the source of the end-Permian point.

1. 51a.

   Section Abstract, page 391:  “the COSUNA charts were assembled at a temporal resolution of approximately 1–3 million years (m.yr.) in the Phanerozoic and contain 4173 gap-bound rock packages.”  The same abstract adds:  “The durations of gap-bound sedimentary successions are approximately exponentially distributed, with a mean duration of 25.2 m.yr. and a median duration of 16.9 m.yr.” ↩