COMMENTS ON WIND-BLOWN SAND DEPOSITS

The Navajo Sandstone
This comes from the mid Jurassic. This formation has large-scale, high angle cross-stratification in conspicuous wedge-shaped sets, typical of aeolian sand dune formations. This is NOT typical of under-water formations. It preserves an abundant and varied vertebrate track fauna, with dinosaur tracks dominating. Fossils of theropod dinosaurs and others occasionally have been found. This in itself should convince anyone with reasonable doubts that the sandstone was deposited in air, not under water. But it is often claimed that Glen Vishner argued that it may have been deposited sub-aqueously. What is not usually mentioned is that in the following two issues of the journal he published in there were four separate responses, all of which disputed and refuted Vishner’s claims. When these facts are put together, the case for the Navajo being anything other than an aeolian formation becomes very weak, and hardly worthy of consideration. However it is vital to the “one Flood did everything” model to maintain that this formation is marine, as it is difficult to account for its existence in the middle of a global Flood.

However, on this issue, many Creationists quote Carl Froede’s article in TJ as their position. In his introductory statement he says that the Navajo was “sorted and deposited in massive sandstone layers during the Middle Flood Division of the Flood Event Timeframe.” This portion is usually attributed to the 150 days that the waters prevailed upon the earth after the rain ceased on the 40th Day to the 190th Day. This creates a problem. Dinosaurs were roaming over the Navajo sandstone right in the middle of this period of the catastrophe. Furthermore, the Morrison Formation, stratigraphically above the Navajo, and therefore deposited after it, is one of the more famous dinosaur bearing layers with many footprints, fossils and coprolites. From the Scriptural account, all the animals were dead after the 40 days of rain, but the Navajo and Morrison formations indicate that the dinosaurs were still alive. The Navajo Sandstone therefore indicates there is something very wrong with the current model of “one Flood did everything”.

The Coconino Sandstone.
The situation with this formation is just as acute for the one Flood did everything model as is the Navajo. Having a wind-blown desert deposit laid down between suggested Flood layers is extremely awkward. This sandstone dates from the Permian and has abundant cross-bedding typical of aeolian or wind-blown sands. In this case, the cross-bedding averages about 25 degrees. It has been argued that this is consistent with water deposition, not desert dune conditions. Now sand waves deposited in water possess very low angle cross-beds, rarely steeper than 10 degrees. Aeolian cross-beds range in slope from 11 to 34 degrees according to E.D. McKee in US Geological Survey Professional Paper 1052. This gives an average around 25 to 28 degrees, in good accord with the Coconino formation. Interestingly enough, though, McKee points out that the maximum slope that is attained in the Coconino does in fact reach from 30 to 34 degrees. This at once dismisses any claim to formation under water.

The Coconino also has other evidence of its wind-blown origin. It includes the extent and homogeneity of the unit, slump marks that are distinctive of dry-sand avalanching, ripple-mark orientation, rain-drop pits, sharply defined footprints, and reptilian tracks up the steep foreset slopes. If anyone chooses to look carefully at modern dunes, they would find an abundance of climbing translatent beds, with coarsening-up laminae that form only by the migration and accretion of low-amplitude wind ripples in aeolian environments. Such feds are completely absent from marine or lacustrine environments because the wind ripples that create them do not form under water. The fact that wind-ripple and distinctive bedding and laminations occur throughout the Coconino Sandstone tends to refute the marine hypothesis for their origin.

The large and small reptile tracks and invertebrates like scorpions have left footprints and trails. Yet these and the rain-drop pits have been interpreted by those holding to “one Flood did everything” as being evidence of marine formation. The rain-drop pits are suggested as being due to bubbles, for example. The pits which are found are, in fact, distinctive, since McKee points out that they illustrate the cohesion of sand grains with added moisture, and, importantly, a re-orientation of the crater axes with respect to the bedding slopes. By contrast, bubbles emerging under water will tend to be completely symmetrical.

To my mind, at least, the evidence of the high angle for the cross-bedding, the reptile and other tracks, and the raindrop pits all point to a desert dune environment for this formation, not a marine one. It is only when it is absolutely essential to maintain a marine origin because of one’s theoretical position on the issue that the data are force-fitted into that mould.

Barry Setterfield