Abstract

The Canyon Group (Missourian) is a sequence of westward-dipping, carbonate and terrigenous clastic facies that crops out in a northeast trending belt across North-Central Texas. Surface and subsurface studies within thirteen counties indicate that the terrigenous clastic rocks are principally component facies of high-constructive delta systems. The Perrin delta system repeatedly prograded westward and northwestward from source areas in the Ouachita fold belt. At times, algal carbonate banks flanked the Perrin delta system to the northeast and southwest. A typical vertical Perin deltaic sequence includes (upward): (1) organic rich, unfossiliferous prodelta mudstone; (2) thin, distal delta-front sandstone and mudstone displaying graded beds, sole marks, and highly contorted beds; (3) thicker proximal delta-front sandstone exhibiting contorted beds, flow rolls, and contemporaneous faults; (4) locally contorted distributary-mouth bar sandstone; and (5) distributary channel sandstone, containing abundant trough cross stratification and local clay-chip conglomerate. All constructive delta facies contain abundant plant debris.

During delta abandonment and destruction, shallow bay-lagoon environments developed. Destructional and transgressive facies include bioturbated sandy mudstones, highly burrowed sandstones, and thin, platy argillaceous limestones with abundant invertebrate fossils. Fossiliferous shelf mudstones grade upward into shelf carbonates commonly composed of phylloid algal-crinoid biomicrudites and local intraclastic biosparite shoal facies. Carbonate accumulations include onlapping sheetlike deposits and thick elongate bank deposits, as well as massive platform and shelf-edge reef-bank accumulations.

The Henrietta fan delta system, occurring exclusively in the subsurface, is composed of thick wedges of feldspathic sandstones and conglomerates that were deposited by high-gradient fluvial systems which built south-westward into northern Texas from sources in the mountains of southern Oklahoma.

Hydrocarbons are produced primarily from thin sandstones peripheral to the major Henrietta fan delta lobe and from the carbonate systems.