The Proceedings of the Eighth International Conference on Creationism (2018)

we feel that some type of aqueous transport was primary. Eolian transport would have quickly rounded the K-feldspars and caused the micas to disappear. F. Frosting The Coconino sand grains are “frosted” (Fig. 18), but they have not been frosted by ballistic collisions of sand grains in an eolian environment as some have imagined. Our SEM work has shown that the grains have been frosted via chemical means, not mechanical (Whitmore et al. 2014). Marzolf (1976) found the same for the Navajo Sandstone. Grain size plays a large role in mechanical frosting. In modern deserts, only larger grains (> 300 µm, 1.74 ϕ) tend to be mechanically frosted (Pye and Tsoar 2009). Most Coconino grains are quite small, in the range of 90-148 µm (3.47-2.76 ϕ). Kuenen and Perdok (1962) found that frosting becomes less pronounced in a range of grain sizes from 500 to 150 µm (1.00-2.74 ϕ). Almost no grains of the smaller grain size were mechanically frosted. Thus, frosting should not be used as a definitive eolian criterion for the Coconino (or other sandstones) until SEM and grain size studies are completed to confirm whether the frosting is mechanical or chemical. G. Compaction Some have recognized that cross-bed dips in supposedly eolian cross-bedded sandstones are too low and have cited post-depositional compaction as the reason for consistent dips far less than the angle of repose (e.g., Glennie 1972, p. 1058; Hunter 1981, p. 323;Walker and Harms 1972, p. 280). As far as we know, no one has cited compaction as a reason for the low Coconino dips; most (as in Hill et al. 2016) just seem to be ignorant of data that has been in the literature for 80 years (Reiche 1938). Whether or not the Coconino has been compacted from the angle of repose down to an average dip of about 20° is fairly easy to assess in thin sections. Coconino thin sections show high porosities (Fig. 19), an abundance of unfractured grains (Fig. 19) and undeformed ooids (Fig. 13), which would not be present if the rock had been severely compacted. Some theoretical work has been done to see if compaction is a reasonable hypothesis to account for lower than expected cross-bed dips in the Coconino, and it is not (Emery et al. 2011). Compaction can probably account for only a few degrees of dip reduction at the most. 3. Sedimentology A. General appearance If the Coconino was truly an eolian sandstone, one of the missing features that should be prominently displayed are avalanche tongues. These are common in modern desert dunes of all Whitmore and Garner ◀ The Coconino Sandstone ▶ 2018 ICC 594 Figure 17 . Angular K-feldspar (orthoclase) within the Coconino Sandstone (Whitmore and Strom 2018). Some of the grains are labeled: (K) K-feldspar and (M) muscovite.