Trinity Group (geologic Formation) on:
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The Trinity Group is a group (sequence of
The Trinity Group is a group (sequence of rock strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...
) in the Lower Cretaceous lithostratigraphy of Texas, Arkansas, Mississippi, Louisiana and Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
. It is named for the Trinity River of Texas.
A stratigraphic column at the Mount Bonnell Fault location starts with the Lower Cretaceous Trinity Group overlain by the Edwards Group. Upper Cretaceous formation (geology), formations follow, starting with the Del Rio Clay, Buda Limestone, and then the Eagle Ford Group. Formations within the Trinity Group include the Hammett Formation, Cow Creek Formation, Hensel Formation, and Lower and Upper Glen Rose Formation. The Hammett and the lower portion of the Upper Glen Rose act as confining units (or aquitard) for the Middle Trinity Aquifer. The Upper Glen Rose contains the Upper Trinity Aquifer, which appears to have intra-aquifer groundwater flow with the Edwards Aquifer as water levels are at the same elevation.
Vertebrate fauna
Crocodylomorphs
Dinosaurs
Pterosaurs
References
{{coord missing, Texas Cretaceous Arkansas Lower Cretaceous Series of North America Aptian Stage Geologic groups of Texas Natural history of Texas Geologic groups of Arkansas Geologic groups of Mississippi Geologic groups of Louisiana Geologic groups of Oklahoma