Compose a 1500 words essay on Define the concept of sedimentary facies and demonstrate the process of facies analysis in the interpretation of geological strata in terms of depositional environments. You should use specific examples from the geological record to illustrate your answer. Needs to be plagiarism free!
Sedimentary facies can be formed only where residues are deposited and remain undisturbed for long time in their sedimentary basins where they compress and are concreted into layers or hard beds. The size of a sedimentary facies is determined by the sedimentary basin the residue deposited themselves.
There are different types of sedimentary facies. biogenic facies that occurs through buildup of whole or split shells and other solid portions of organisms or fossils, chemical facies develop when there is mineral precipitation of materials from solvents. Terrigenous facies forms up when eroded elements from older rocks are accumulated. Each facies has a three-dimension shape, but this may change with time.
Coal facies is made up of leaves, stems and bark of plants. At upper parts, ash, carbonaceous shells may be seen. Post dispositional features may include calcareous mineralization in clear spaces and modular pyritization.
Formation of coal facies is through buildup, burial and coalification of its contents. This is manifested by the presence of organic content, and plant remains in leaves, stems, brachiopod shells, etc. despite underclay facies being at its bottom they are never genetically related (McCabe, 1984). Sandstone facies and conglomerate are coal that overly non-rooted facies that were washed away and transported from neighboring peat-forming setting are genetically related to original residues (McCabe, 1984) they come from. Coal with high sulfur content and black shale facies developed in a place with oceanic conditions. Coal with high ash developed in non-marine siliciclastic environment (McCabe, 1984). Coals of Desmoinesian developed in marginal marine mire environment raised, floating or low-lying (McCabe, 1987. 1991).
They are in three variations. phosphatic black shale, fossiliferous black