GEO 101 Study Guide - Comprehensive Final Exam Guide - List Of Rocks On Mars, Erosion, Weathering
20 Nov 2018
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Document Summary
Various external forces affect the earth"s surface, such as different climates and the amount of rainfall. Freezing, thawing, and running water all contribute to weathering and erosion, processes that break rock down into tiny particles. These particles are then transported by water, ice, or wind as sediment. The processes of erosion reduce mountains to hills, create canyons, valleys, and soils, and deposit huge amounts of sediments that either become eroded again or are preserved and lithified into sedimentary rock. Geoscientists have estimated the earth to be about 4. 5 billion years old. As the crust cooled, early geologic processes were largely volcanic, building up continental crust and a primitive atmosphere. Bacterial forms of life have been found in rocks that are billions of years old. Complex oceanic organisms such as trilobites began to appear only about. From about 66 million to 245 million years ago, dinosaurs and other reptiles flourished all over the world.
