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Two depositional units distinguished in the Permian White Rim Sandstone of the Elaterite basin indicate episodes of both eolian and marine sedimentation. The lower unit is a thick section of large-scale, high-angle, cross-bedded quartzarenite. The tabular cross-bed sets average 2.6 m (8.5 ft) in height and contain inversely graded translatent strata and small ripple trains with high ripple indices. Some exposures reveal large barchan dune forms. This lowest unit comprises most of the formation and is sharply cut and scoured by the overlying unit. The upper unit is a thin veneer that ranges from 1 to 5.3 m (3 to 17 ft) in thickness and possesses
characteristic marine structures.
An idealized vertical sequence within the veneer consists (in ascending order) of a laminated sandstone facies (in places containing chert pebbles), cross-stratified (0.3-m or 1-ft sets) sandstone facies, and an oscillation ripple sandstone facies. The upper part of the oscillation ripple sandstone facies may contain 6-sided polygonal structures filled with coarse-grained sandstone and chert pebbles, or it may be covered by a massive facies that contains abundant fluid-escape structures. Variations on the idealized veneer stratigraphy exist where some facies are absent, but the vertical sequence order is maintained.
Most of the formation is interpreted to be eolian in origin. Northerly winds deposited the large cross-bed sets in an extensive dune field. This event was followed by a period of marine transgression that reworked the uppermost part of the formation and formed the thin veneer. The abundance of fluid-escape structures and oscillation ripples in the veneer indicates rapid deposition by marine processes. The distinctive stratigraphy within the veneer reflects a deepening trend with the rising transgression.
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