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

happen in air. Creationists have also done some preliminary work in this area and showed that particles can also spontaneously sort in aqueous heterogeneous sand mixtures (Julien et al. 1994). This would be a productive area of continued research with the laminations of cross-bedded sandstones, called “wind ripples” by some, in mind. There are some other mechanisms that can make graded laminae in subaqueous conditions. Normally graded parallel lamination can be produced by the migration of very low relief ripples during upper flow regime flow (Paola et al. 1989). Cheel and Middleton (1986) found that very thin and extensive graded beds (both normally and reversely graded) can form under conditions of the upper flow regime. They found that “bursts” formed fining upward (FU) sequences and “sweeps” formed very thin coarsening upward (CU) sequences. The FU sequences were thicker than the CU sequences, some of which were very extensive and less than 1.0 mm thick. Sometimes ungraded layers were produced. Kleinhans (2004, p. 77) indicates sweeps are a dominant process on the lee sides of large subaqueous dunes (which form thin CU laminae). In many places, the Coconino is finely laminated with beds that resemble CU sequences on the foresets. One mechanism that could produce these fine laminae on the foresets are these sweeps. D. Planar and massive beds Planar beds, which are very unusual in the Coconino, were found at several locations. In Sedona, they were associated with large parabolic recumbent folds (discussed below) which may indicate a flow regime change if the sand was being transported and deposited subaqueously, and would also help explain the folds (Whitmore et al. 2015). Planar beds at Andrus Point were composed of pure dolomite and the cross-beds above contained dolomite ooids which would be very unexpected in an eolian setting, but would be much easier to explain in a marine setting (Whitmore et al. 2014). Planar beds in Kaibab-Buckskin Gulch area had abundant calcite and dolomite cement. Massive beds that contained bedded clasts of Coconino Sandstone were found at several locations near the base of the Coconino (Fig. 30). Whitmore and Strom (2010) proposed that these beds were a reaction to a seismic shock, likely originating from the BrightAngel Fault during Laramide events in the Grand Canyon region. They argued that the basal Coconino had to be water-saturated and only partially lithified (at most) during the faulting. This caused liquefaction of the basal Coconino which destroyed most laminations and created the massive (unbedded) layer. This layer was then able to flow horizontally and downward into the Hermit Formation, forming the sand-filled cracks (discussed below) that can sometimes be found at the base of the Coconino. This scenario has abundant evidence (Whitmore and Strom 2010) but causes a time problem for the conventional view. Conventionally, the Coconino was deposited about 275 million years ago and the displacement along the Bright Angel Fault occurred about 225 million years later during the Laramide uplift of the Grand Canyon area, about 50 million years ago. The problem for the conventional view is how the Coconino remained unlithified for such a long period. In a young-earth view, there is no problem because the timing of Coconino deposition and regional uplift was probably less than a year and the Coconino would have been still water-saturated due to being deposited during the Flood. Thus, the massive bed and the associated injectites eliminate millions of years of geological time from the strata of the Grand Canyon. E. Parting lineation features Parting lineation (also called current lineation, parting-step lineation or sand streaks) is commonly found on most cross-bed surfaces of the Coconino. These features are well known from subaqueous current deposits of various types (Allen 1970b; Cheel 2003; Corbett 1972; Picard and Hulen 1969; Stokes 1947) and have been produced experimentally in the laboratory (Mantz 1978; Weedman and Slingerland 1985). According to Stokes (1968, p. 1419) current Whitmore and Garner ◀ The Coconino Sandstone ▶ 2018 ICC 601 Figure 28. Cross-bed dips vary little on some of the longest-known foresets in the Coconino. The yellow numbers are dip angles and the black numbers show the distance between measurements. The cross-bed set has a vertical thickness of just over 15 meters. Photo and data courtesy of Sarah Maithel. Santa Cruz Quarry near Ash Fork, Arizona.