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Located in South Central Texas, the Edwards Aquifer encompasses an area of approximately 4,350 square miles (11,300 km 2) that extends into parts of 11 counties. [3] The aquifer's boundaries begin at the groundwater divide in Kinney County, East of Brackettville, and extend Eastward through the San Antonio area and then Northeast where the aquifer boundary ends at the Leon River in Bell County ...
Sea level rose even higher in this massive transgressive event, which helped form the 300–500 ft thick Austin Chalk, around ≈89-85mya. The Austin formation consists of recrystallized, fossiliferous, interbedded chalks and marls. Exposures of Austin chalk are mainly seen in quarries, roadcuts, and stream beds where the water eroded the top soil.
In the Permian geologic period, North-Central Texas was a part of the western coastal zone of equatorial Pangea, a super-continental land mass. [1] Nearby uplifts and mountainous regions, such as the Muenster Arch and Red River Uplift, the Wichita, Arbuckle, and Ouachita mountains developed by the end of the Pennsylvanian, [2] providing elevated topography to the north and east during the Permian.
The rich alluvial soil along the creek was noted by surveyor Elias R. Wightman who was one of the Old Three Hundred. His report attracted Anglo-American settlers in the 1820s. Typically, Stephen F. Austin's colonists burned the canebrake to help enrich the soil. Sugar production became so successful that soon large homes were built so that one ...
Texas is approximately bisected by a series of faults that trend southwest to northeast across the state, from the area of Uvalde to Texarkana.South and east of these faults, the surface exposures consist mostly of Cenozoic sandstone and shale strata that grow progressively younger toward the coast, indicative of a regression that has continued from the late Mesozoic to the present.
At the same time, the term "alluvium" came to mean all sediment deposits due to running water on plains. The definition gradually expanded to include deposits in estuaries, coasts, and young rock of marine and fluvial origin. [8] Alluvium and diluvium were grouped as colluvium in the late 19th century. "Colluvium" is now generally understood as ...
Texas has the dubious distinction of leading the nation in polluted waterways. A new report draws upon self disclosed data by industrial facilities provided to the EPA. The study counted 17 ...
The Ogallala Aquifer (oh-gə-LAH-lə) is a shallow water table aquifer surrounded by sand, silt, clay, and gravel located beneath the Great Plains in the United States. As one of the world's largest aquifers, it underlies an area of approximately 174,000 sq mi (450,000 km 2) in portions of eight states (South Dakota, Nebraska, Wyoming, Colorado, Kansas, Oklahoma, New Mexico, and Texas). [1]