Processes of Sedimenatry Rocks
Weathering- Process which acts at the earth's surface to decompose and breakdown rocks. Types of weathering are physical/mechanical and chemical. Mechanical or Physical - the breakdown of rock material into smaller and smaller pieces with no change in the chemical composition of the weathered material. Chemical - the breakdown of rocks by chemical agents. Obviously the chief chemical agent is water which carries dissociated carbonic acid.
Erosion-
The movement of weathered material from the site of weathering. Primary agent is gravity, but gravity acts in concert with running water.
Deposition-
Sediment is deposited when the energy of the transporting medium becomes too low to continue the transport process. In other words, if the velocity of the transporting medium becomes too low to transport sediment, the sediment will fall out and become deposited. The final sediment thus reflects the energy of the transporting medium.
Compaction & Cementation-
Compaction is the simplest change that sediments can undergo. Compaction occurs as the weight of accumulating sediment forces the rock and mineral grains together. This reduces pore space and eliminates some of the contained.
Cementation is a result of water circulating through the pore spaces of a sediment. Hardening and welding of clastic sediments (those formed from preexisting rock fragments) by the precipitation of mineral matter in the pore spaces. it is the last stage in the formation of a sedimentary rock.
Cementation is a result of water circulating through the pore spaces of a sediment. Hardening and welding of clastic sediments (those formed from preexisting rock fragments) by the precipitation of mineral matter in the pore spaces. it is the last stage in the formation of a sedimentary rock.
