What does sedimentary mean in geology ?
Sedimantary : definition
Sedimentary rocks are rocks formed by the deposition of materials torn from the continent by erosion, then transported over a more or less long distance before being redeposited. These materials are either solid particles (clays, sands, blocks...), or dissolved elements (Fe, Na, Cl, etc...).
Sedimentary rocks are very varied and geologically essential (5% of the volume of the earth's crust but 75% of the surface).
Their classification is complex and changing. We usually distinguish :
- detrital rocks, mainly formed of fragments torn from older rocks (conglomerates, sandstone, clay, etc...).
- biogenic (or physico-chemical) rocks, not formed from ancient rocks and resulting from the precipitation of elements dissolved in solutions or from the deposit of animal or plant organisms : limestone and dolomites, saline or evaporitic rocks (salt...), carbonaceous rocks (coals, petroleum, etc...), phosphate rocks, ferruginous rocks, etc...
Sedimentary rocks are very varied and geologically essential (5% of the volume of the earth's crust but 75% of the surface).
Their classification is complex and changing. We usually distinguish :
- detrital rocks, mainly formed of fragments torn from older rocks (conglomerates, sandstone, clay, etc...).
- biogenic (or physico-chemical) rocks, not formed from ancient rocks and resulting from the precipitation of elements dissolved in solutions or from the deposit of animal or plant organisms : limestone and dolomites, saline or evaporitic rocks (salt...), carbonaceous rocks (coals, petroleum, etc...), phosphate rocks, ferruginous rocks, etc...