Sedimentology of cross-stratified carbonate grainstone facies of the Honaker Trail formation (Permo-Pennsylvanian), southeastern Utah

Within the Honaker Trail Formation of southeastern Utah, thin beds of carbonate grainstone of marine origin are interbedded with red paleosol-bearing siltstone and lenses of eolian sandstone. The top cliff-forming grainstone beds (unit 4) are dominated by bioclastic debris and contain abundant ooids in their upper portions. Planar and trough cross-strata with sets up to 1 m thick are present throughout unit 4. Large Skolithos tubes penetrate the upper portions of the grainstone units and bedding-parallel Scolicia are abundant in foresets of trough cross-strata. Cross-strata of these subaqueous sediments dip unimodally southeastward, nearly parallel to the dip of eolian cross-strata within this formation and the overlying Cedar Mesa Sandstone. The cross-strata within the marine grainstone are interpreted to be products of the migration of bedforms that were driven across subtidal shoals by persistent trade winds. Experimental studies on wind speed and current velocity suggest that winds of approximately 10-25 m/sec are necessary to develop the bedforms in unit 4. Recent studies in the southeastern Bahamas by Wanless and his colleagues demonstrate the importance of wind-wave generated sand bodies in modern settings. The open interior of Caicos Platform in the southeastern Bahamas provides a suitable analog for the grainstone of unit 4. Tidal influence is indicated in some marine units below and above unit 4 by sigmoidal cross-bedding and other sedimentary structures such as lateral bundle thickness variation, mud drapes, and reactivation surfaces. The bundles are usually 30 to 40 cm thick and each bundle is bounded by centimeter-scale mud drapes, which are indicative of pause planes. Reactivation surfaces occur between two sets of cross-bedded strata and suggest instability of tidal currents. Medium to large scale trough cross-bedded sandstones overlie most of the marine limestone units. Individual cross-sets are less than 50 cm thick and foreset angles range from 15 to 20 degrees. Internal sedimentary structures such as climbing translatent stratification and grain flow strata, as well as inverse grading, demonstrate these units are of eolian origin. These eolian sandstones are interpreted to have been dunes along or near to the shorelines, similar to most Holocene eolian deposits in the Bahamas