Weathering, Erosion, and Deposition ed.pdf

Texas is divided into 11 ecological regions (ecoregions) based on climate, vegetation, landforms, and ecological processes. Weathering, erosion, and deposition have significant effects in some of these regions, including the Gulf Coast Prairies and Marshes, Trans Pecos, and Edwards Plateau ecoregion...

Texas is divided into 11 ecological regions (ecoregions) based on climate, vegetation, landforms, and ecological processes. Weathering, erosion, and deposition have significant effects in some of these regions, including the Gulf Coast Prairies and Marshes, Trans Pecos, and Edwards Plateau ecoregions. The Gulf Coast Prairies and Marshes ecoregion is located along the Gulf of Mexico. It includes the cities of Corpus Christi, Houston, and Galveston. Marshes, barrier islands, estuaries, and bays are found near the coast. Inland, you see prairies and grasslands. The coast is eroding at a rate of about six feet per year, and some areas lose more than 30 feet per year. This costs Texas millions of dollars per year in beach and dune recovery projects, as well as wetland protection efforts. Frequent hurricanes cause much of the beach erosion. These challenges reduce tourism and hurt the fishing economy. Wildlife also suffer from the effects of erosion and loss of wetlands. In the Texas Hill Country near Austin, you find the Edwards Plateau ecoregion. This elevated area was covered by an ocean 100 million years ago and is made of marine deposits of sandstone, limestone, dolomite, and shale, which are types of sedimentary rock. Because of the specific geology in this area, there are many caves and caverns. The caves formed from water mixing with carbon dioxide gas and creating a weak solution called carbonic acid. Over a long period of time, this acid dissolved underground limestone deposits. Because of the many fault lines in this area, water moved into the rocks and slowly eroded cracks into large cavities, rooms, and caves. The caverns forms when caves connected to each other. Deposition and erosion played major roles in developing the geologic features of this region. Another area greatly affected by weathering, erosion, and deposition is Big Bend National Park in the western Trans Pecos ecoregion. The land here has been called a geologist’s paradise and nightmare, because while many geologic features are easy to see at the surface, millennia of complex changes are hidden underground. Ancient oceans deposited some of the earliest layers of rock present here, while the last 10 million years have been ruled mostly by erosion. Wind and water have also weathered many of the rock formations in this eerie landscape. The ecoregions of Texas are diverse, and they provide interesting examples of the effects of weathering, erosion, and deposition in the recent and distant past. © Kesler Science, 2020