--> ABSTRACT: Shoreline Depositional Environments of Glen Rose Formation (Lower Cretaceous) in Type Area, Somervell and Hood Counties, Texas, by Gail R. Bergan; #91036 (2010)

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Shoreline Depositional Environments of Glen Rose Formation (Lower Cretaceous) in Type Area, Somervell and Hood Counties, Texas

Gail R. Bergan

The studied interval of the Glen Rose Formation (Aptian-Albian) comprises a clastic-to-carbonate sequence, which was deposited in a seaward-fining tidal flat-salt marsh complex. Eight distinct facies were identified, including the calcareous sandstone, calcareous shale, bivalve shale, oyster shale, transitional terrigenous-carbonate, dolomite, bioclastic packstone-grainstone, and shell-fragment wackestone facies. These facies were deposited in sand flats; small fluvial creeks; an ecologically complex, mud-dominated intertidal flat; and a subtidal, nearshore lagoon. Thin bioclastic packstone-grainstones and dolomites of the high energy intertidal and supratidal environments regularly interrupt the terrigenous clastic facies. Abundant nearshore features include salt-toleran land plants, dinosaur tracks, desiccation cracks, and localized concentrations of evaporites. A warm semi-arid to arid climate is indicated.

This sequence is interpreted as being comparable to the Holocene salt marshes on Sapelo Island, Georgia, based on similar lithofacies, sedimentary structures, and biological components.

AAPG Search and Discovery Article #91036©1988 GCAGS and SEPM Gulf Coast Section Meeting; New Orleans, Louisiana, 19-21 October 1988.