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Some are more resistant to weathering than the surrounding rock and stand up like walls, while others weather faster and form long narrow depressions. dip slope A geological formation often created by erosion of tilted strata. disconformity A surface that represents missing rock strata but beds above and below that surface are parallel to one ...
Chalk is so common in Cretaceous marine beds that the Cretaceous Period was named for these deposits. The name Cretaceous was derived from Latin creta, meaning chalk. [10] Some deposits of chalk were formed after the Cretaceous. [11] The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.
Residuum is weathered rock that is not transported by erosion, contributing in time to the formation of soil.It is distinguished from other types of parent material in that it is composed solely of mineral, not organic, material, and it remains in place rather than being moved by the action of wind, water, or gravity.
Cliffs are usually composed of rock that is resistant to weathering and erosion. The sedimentary rocks that are most likely to form cliffs include sandstone, limestone, chalk, and dolomite. Igneous rocks such as granite and basalt also often form cliffs.
Salt crystallization (also known as salt weathering, salt wedging or haloclasty) causes disintegration of rocks when saline solutions seep into cracks and joints in the rocks and evaporate, leaving salt crystals behind. As with ice segregation, the surfaces of the salt grains draw in additional dissolved salts through capillary action, causing ...
Large areas of clay-with-flints, derived from the weathering of material overlying the present day chalk, occur across the North Downs. One particular suite of sediments that occur in the Guildford vale is known as the Headley Formation and comprises gravel and sand on top of the chalk. These sediments contain marine fossils and were probably ...
Like several of the thin limestones of the upper Greenhorn and lower Carlile, the Fencepost bed is a shell-rich, coccolithic, chalky limestone; however, this bed is hardened by a crystalline matrix of sparry concretory calcite so that it is more resistant to weathering and erosion. Unexposed, the Fencepost is olive-gray, weathering to light ...
Soil bulk density, when determined at standardized moisture conditions, is an estimate of soil compaction. [3] Soil porosity consists of the void part of the soil volume and is occupied by gases or water. Soil consistency is the ability of soil materials to stick together. Soil temperature and colour are self-defining.