Deposition and diagenesis of Caddo mud mounds, in the Breckenridge field, Stephens County, Texas.

摘要

The Pennsylvanian Caddo Limestone of north-central Texas is a carbonate sequence that is present only in the subsurface. Over the hinge of the Bend arch, carbonate mounds occur in the uppermost 30.5 m (100 ft) of the Caddo Limestone sequence. The Caddo mud mounds in the Breckenridge field, Stephens County, Texas can be subdivided into three distinct facies (substrate facies, lower mound facies, and upper mound facies), and each individual facies may contain more than one lithotype.;Diagenesis of the Caddo mud mounds began in the meteoric phreatic environment and continued into the burial diagenetic environment. Meteoric phreatic diagenesis included dissolution of Komia, coral, phylloid algae, and foraminifera fragments. Deep burial diagenesis included four events: (1) compaction, (2) cementation, (3) dissolution, and (4) dolomitization. Petroleum reservoirs in the Caddo mud mounds developed in the following lithotypes: Komia packstone-wackestone, phylloid algae packstone-wackestone, and intraclastic wackestone.