Chapter 4 - Basin Structure, Tectonics, and Stratigraphy

Abstract

Plate tectonics has played an important role in the formation of various basins. There are nine major plates and some minor plates. Tectonically, sedimentary basins are the result of thermal doming of the crust and later subsidence. Rifting and thinning of the crust provide a floor to the basin. Mountain building is also responsible for the formation of basin structure. There were no sedimentary rocks at the time of Earth's origin (4500Ma). Initially, there were volcanic and igneous rocks. After the formation of river systems, seas, and oceans, the weathering of preexisting rocks was the initial cause of the formation of sedimentary rocks. With increasing weathering, a large quantity of sediments were produced, and the water and wind were the transport agents to move these weathering products. These weathering products were big particles (200–300mm) to very fine particles (0.005mm). Based on particle size, sedimentary rocks can be divided as very coarse-grained like breccia or conglomerate to sandstone, siltstone, and shale. Due to tectonic activity and crustal thinning, there is depression, and these weathering products get deposited over top. With increasing thickness of sedimentary deposits and overload, they subside. The major composition of the sediment is quartz, feldspar, and other minerals.