Big Bend Term Paper Example | Topics and Well Written Essays - 1000 words

Big Bend - Term Paper Example uctural features that have been through various episodes of tectonic deformation, which is exactly the situation that is being dealt with in this case study since there is evidence of influence of Ouachita Orogeny, Laramide Orogeny and Basin and Range deformations in the overall regional structures (Bobbitt, 1994). The rocks available at big bend are Boquillas (Kbo), Buda(Kbu), Del Rio (Kdr), Old alluvium (Qoal), Regular alluvium (Qal) on the stream, and Santa Elena (Kse) (museum). The images obtained are as follows. Dagger Mountain is mainly composed of sedimentary rocks, with presence of intrusive sills. The sedimentary units are mainly carbonaceous and rich in fossils. It involves three major limestone formations, Boquillas, Buda and Sta. Elena formations and the fossils present are gastropods, echinoids, corals, bivalves, inoceramus and molusca. Foraminifera are single celled protists that sometimes construct calcareous shell. In fact, a lot of the Calcium carbonate in limestone and similar rocks comes from the shells of Foraminifera. This species is that found almost exclusively in the Del Rio Clay(Carsey 1926). Texigryphaea is a common genus of oyster found in Texas and New Mexico that lived during the Cretaceous period 105-99 million years ago. Those pictured above are from the Austin Chalk but those in The Santa Elena are practically identical. The gastropods are steinkerns that were found in the Austin chalk. Similar such fossils can be found in the area in between the Santa Elena and Buda formations and could come from either formation. The size of such fossils can vary greatly. Dagger Mountain is loaded with fossil allover. The most well-known fossils might be gastropods, bivalves and pacton-scalope. Other not so bounteous fossils like echinoid, coral, molusca, plant stems, inoceramus, ammonites and spatangoids. As notice, the range is exceptionally rich in marine creature skeletons, which straightforwardly suggests a marine the earth. For a