Depositional Systems in the Paluxy Formation

The Paluxy Formation is a stratigraphic unit which is composed of sandstone and shale and extends across the northern part of the East Texas embayment. Paluxy deposits were derived from sedimentary rocks to the north, and they accumulated in shoreface and coastal plain environments associated with an irregular southward regression of the shoreline. Preserved in the sedimentary mass are three major depositional systems: a centrally located delta system, a fluvial system in the north, and a strandplain system in the west. The delta system is wave dominated, composed largely of marine-influenced sediments aligned along depositional strike. Sand isolith maxima, associated with stacked coastal barrier deposits, outline the cuspate shape of the delta system. Two principal delta lobes are recognizable; these are centered in Hunt and in Wood Counties. The fluvial system consists of a broad, sandy meanderbelt facies which thins northward into discrete channel complexes separated by floodbasin deposits. The strandplain system blankets the western embayment margin with coalescent beach ridge and associated shoreface and coastal lake deposits. Strandplain sands provide small to moderate quantities of groundwater that are generally suitable for uses other than irrigation. Fluvial system deposits furnish local areas with water for irrigation and for domestic and municipal supply. Major oil and gas accumulations occur in deltaic coastal barrier and fluvial meanderbelt facies.