GEOS 1004 Lecture Notes - Lecture 6: Mesozoic, Maracaibo Basin, Titusville, Pennsylvania
Document Summary
Oil and natural gas form from accumulations of fine organic particles (algae, plankton, etc. ) that live and die in sedimentary basins, such as lakes or oceans. These particles must accumulate in quiet basin areas that lack oxygen, which causes material to decay before burial. The oil window refers to temperatures of 60-120o celsius occurring at 2-4 km depth; these conditions are appropriate to convert the correct organic material to liquid petroleum. *oil window depths are not simply reached by the ocean bottom sinking lower over time; the organic material must be buried by accumulating sediment while the crust slowly lowers beneath it. ****in basins of various types, sediments accumulate at rates of a few millimeters every year; to make burial depths of 2-4 km to form petroleum thus takes millions of years. Natural gas forms when the correct organic material is buried to temperatures of 100-200o celsius, generally occurring at depths of 3-6 km.
