Coconino sandstone was deposited underwater (Talk.Origins)
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- The Coconino Sandstone, the origin of which is conventionally attributed to desert sand dunes, was deposited by water. Evidence for this (in addition to the character of fossil footprints therein) includes cross-bedding angles of only 25 degrees, not the 30-34 degrees one expects from desert dunes.
- Andrew Snelling and Steven Austin, 1992. Grand Canyon: Startling evidence for Noah's Flood! Creation Ex Nihilo 15(1): 47.
Please take not that Snelling and Austin's model isn't the only creationist model to explain the Coconino sandstone. Whitmore also has propose a model that claims that it underwent "substratal liquefaction prior to lithification".
Whitmore. 2005. SANDSTONE CLAST BRECCIAS, HOMOGENIZED SAND, AND SAND INTRUSIONS: EVIDENCE OF SUBSTRATAL LIQUFACTION IN THE BASAL COCONINO SANDSTONE (PERMIAN), GRAND CANYON, ARIZONA. Geological Society of America Abstracts with Programs, Vol. 37, No. 7, p. 440
(Talk.Origins quotes in blue)
1. Eolian (wind-blown) and subaqueous dunes have superficial similarities, but they differ in particulars. There is a great deal of diverse evidence that the Coconino Sandstone originated as eolian desert dunes.
- The big problem with such conclusions is typical of uniformitarian geology, in that they assume conditions similar to day, but a Global flood such as is described in Genesis would create conditions not observed on Earth today and as such ignoring it will cause errors.
- There are several lines of positive evidence for underwater disposition and against wind-blown disposition.
Furthermore, in support of the substratal hypothesis, Whitmore cites:
|“||1) deformed and homogenized zones in the basal meter of the Coconino containing angular clasts of bedded Coconino sandstone, 2) sand-filled cracks (connected to the Coconino) which penetrate at a downward angle into the Hermit and 3) thin section analysis of the sand-filled cracks showing homogenized, non-bedded sand (typical of sand intrusions).||”|
As McKee (1979, 204) stated: The basis for considering the Coconino Sandstone to be of eolian origin involves numerous criteria, some of which are distinctive of an eolian environment and others merely compatible with but not diagnostic of it. No single type of evidence seems entirely conclusive, but, together, the various features present very strong evidence.
- The claim some of the features are distinctive of an eolian environment is on the assumptions of uniformitarian geology, which ignores the possible affects of the Genesis Flood.
- Furthermore, Talk Origins' sources are out of date. A 1990 study by Dr Glen Visher the Professor of Geology at the University of Tulsa in Oklahoma found evidence pointing to underwater deposition and against wind-blown deposition. Such evidence includes:
- Parting lineations, which is erosion formed by short bursts of fast-flowing water. They have never been observed in desert sand dunes.
- Evidence for the process by which sand is deposited is found in the differences of grain size found in sandstone. An analysis of the Coconino Sandstone's sand grain sizes were shown be consistent with underwater deposition and not wind-blown deposition.
- 1. The extent and homogeneity of the sand body.
- The extent of the sand body is readily explained by the Genesis Flood, which was more than capable of depositing such a large body of sand.
- In terms of grain size, the degree of inhomogeneity is more consistent with underwater deposition and not wind-blown deposition.
2. The tabular-planar and wedge-planar type and large scale of cross-stratification. The common high-angle deposits are interpreted as slipfaces on the lee sides of dunes, and the relatively rare low-angle cross-strata that dip toward the opposite quadrant apparently represent deposits of windward slopes. 3. Slump marks of several varieties preserved on the steeply dipping surfaces of lee-side deposits. These are distinctive of dry sand avalanches.
These features are only being interpreted as lee sides based on uniformitarian assumptions. Such high and steep slopes are consistent with underwater disposition in 300 feet of water and a current speed of 2-3.75 miles per hour.
4. Ripple marks which are common on surfaces of high-angle crossbedding suggest eolian deposition both by their high indexes (above 15) and by their orientation with axes parallel to dip slope.
Ripple marks are also known to form in water as well as high-angle crossbedding, but the conditions needed for both to occur together violates uniformitarianism.
5. The local preservation of a distinctive type of rain pit. Such pits illustrate the cohesion of sand grains with added moisture and a reorientation of the crater axes with respect to bedding slopes.
The most this shows is that some of the sand was dry for a time, and even this assumes they are really rain pits and not air bubbles.
6. Successions of miniature rises or steps ascending dip slopes of crossbeds.
This reference is a little vague, but such steps would seem to result from fluctuations in water current.
7. The preservation in fine sand of reptile footprints and probable millipede trails with sharp definition and clear impression.
- This assumes that tracks were made during deposition.
- The fact that the tacks are well preserved shows that they were covered quickly, which would tend to support rapid disposition regardless of the mode.
- The sharp definition and clear impression of the tracks tends to support wet sand rather than dry sand, since the cohesion of wet sand holds the form of a track better and longer than dry sand.
8. The consistent orientation of reptilian tracks up (not down) the steep foreset slopes.
This actually supports the water deposition hypothesis since it is consistent with animals trying to get out of rising water. Uniformity would assume that present day processes explain the past, yet present day animal behaviour produces tracks up and down, as well as across the slopes.
Since McKee published, additional types of terrestrial trace fossils, paleosols, and other distinctive eolian sedimentary structures have been recognized in Coconino and related eolian strata.
While such features are interpreted as inconsistent with water disposition, such interpretations are based on Uniformitarianism and thereby ignore the effects of catastrophic disposition. When catastrophic underwater deposition is considered these features are not a problem for underwater deposition. Actually, the preservation of such features requires rapid burial, so even if one could prove that this sand stone was deposited by wind the process would have had to have been catastrophic. That said there are many features observed in Coconino sand stone that can only be formed underwater, showing that they were underwater.
- Reference: Paleosols: digging deeper buries ‘challenge’ to Flood geology
- Reference: Grand Canyon: Startling evidence for Noah's Flood!
If a person looks carefully at modern dunes -- for example, the Great Sand Dunes, White Sands, and Nebraska Sand Hills -- he or she will find an abundance of climbing translatent beds, with coarsening-up laminae and that form only by the migration and accretion of low-amplitude wind ripples in eolian environments. Such beds form only in terrestrial eolian environments and are completely absent from marine or lacustrine environments because the wind ripples that create them simply do not form under water and underwater analogues of these sedimentary. The fact that wind ripple and the distinctive bedding and laminations occur throughout the Coconino Sandstone and other similar strata -- for example, the Navajo and Entrada -- clearly refutes the marine hypothesis for their origin.
If a person looks carefully at modern dunes, they will see both the lee side and the windward sides preserved in the bedding planes. The assumed windward side is completely absent from the coconino sandstones. Furthermore, these features are consistent with underwater disposition. Wind ripples are just one way such bed forms can form. They can result from ripples in any flow with a high rate deposition from suspension and can occur underwater. Wind ripples are the common uniformitarian interpretation, but such structures can form underwater.
- Reference: USGS bedform sedimentology site: "Cross-Bedding, Bedforms, and Paleocurrents"
- Reference: Bedforms & Sedimentary Structures
- Reference: Startling evidence for Noah’s Flood
2. Sand waves deposited in water possess very low angle cross-beds, rarely steeper than 10 degrees. Cross-bedding in eolian dunes occurs at various angles. The general range in slope of the cross-beds is from 11 to 34 degrees. The average appears to be close to 25-28 degrees. The average slope of cross-bedding does not have to be equal to 30 to 34 degrees, which is the maximum slope of dry sand, to be from a sand dune. The maximum slope of cross-bedding within the Coconino Sandstone does get as steep as 30 to 34 degrees. The 30-34 degree slope is produced from sand avalanching down the lee slip face of the dune. The beds and laminae produced by wind ripple migration can form cross-bedding and lamination that has slopes up to 20 degrees within a sand dune. Given that this cross-bedding is present everywhere in the Coconino Sandstone, it greatly decreases the average slope of the cross-bedding within the Coconino Sandstone.
The fact that most modern sand waves do not produce cross-beds steeper than 10 degrees only shows that the coconino crossbeds were not typical sand waves. Modern sand waves are smaller than what is found in Coconino Sandstone and so do make a good comparison, however a Global flood such as is described in Genesis would have produce larger sand waves and naturally steeper angles.
- Reference: Startling evidence for Noah’s Flood
In addition, grain-fall processes produce low, inclined lamination and beds with slopes that average between 20 to 30 degrees and range from 0 to 40 degrees. The presence of grain-fall bedding and lamination within the Coconino, not only refutes the hypotheses concerning the underwater or marine origin of the Coconino Sandstone but also again greatly decreases the average slope of the cross-bedding found in the Coconino Sandstone. Thus, it is completely reasonable that the average slope of the cross-bedding in the Coconino Sandstone is less than the average slope of dry sand -- that is 30 to 34 degrees -- because the cascading of sand down the lee side of the sand dune is not the only process producing cross-beds and laminations in dune sands
This is an interesting conclusion, and a form of circular reasoning.
- They interpret bedding and laminations as resulting from grain-fall because that is how such angles would be produce by wind.
- They then use this claim of grain-fall bedding and lamination to argue against underwater disposition.