ABSTRACT

In the northern U.S. Gulf Coast, Lower Cretaceous sediments form an arcuate prism which thickens from a few hundred feet updip to more than 10.000 feet along the ancient shelf margin 100 to 300 miles downdip. This prism was divided into eleven time-stratigraphic units using hundreds of control wells with lithologic and faunal data. This information led to the recognition and mapping of major depositional facies including alluvial valley, delta, prodelta, inner shelf, middle shelf, outer shelf and basin within each time-stratigraphic unit. During continuous deposition in Early Cretaceous time these major facies units have transgressed and regressed many times across the broad subsiding shelfal areas. The transgressions in Upper Cotton Valley, Lower Hosston through James, and Mooringsport through Washita times are thought to be controlled primarily by eustatic relative rise in sea level. Regressions in Upper Hosston, Rodessa, Glen Rose, and Paluxy times are probably controlled by a decreased rate of subsidence and an increase in the supply of clastic sediments from rising uplands inland.

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