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Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
The aim of sedimentology, studying sediments, is to derive information on the depositional conditions which acted to deposit the rock unit, and the relation of the individual rock units in a basin into a coherent understanding of the evolution of the sedimentary sequences and basins, and thus, the Earth's geological history as a whole.
A clast is a fragment of geological detritus, [1] chunks, and smaller grains of rock broken off other rocks by physical weathering. [2] Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport , whether in suspension or as bed load , and in sediment deposits.
These rocks can then in turn again be weathered and eroded to form a second generation of sediment. Detrital grains commonly weather at different rates, according to the Goldich dissolution series , which dictates that early crystallizing minerals are less stable at the Earth's surface than late crystallizing minerals.
The following is a list of rock types recognized by geologists.There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.
This figure describes the geological aspects and processes of the carbonate silicate cycle, within the long-term carbon cycle. The carbonate–silicate geochemical cycle, also known as the inorganic carbon cycle, describes the long-term transformation of silicate rocks to carbonate rocks by weathering and sedimentation, and the transformation of carbonate rocks back into silicate rocks by ...
Solidified lava flow in Hawaii Sedimentary layers in Badlands National Park, South Dakota Metamorphic rock, Nunavut, Canada. Geology (from Ancient Greek γῆ (gê) 'earth' and λoγία () 'study of, discourse') [1] [2] is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. [3]
Reverse weathering generally refers to a process of clay neoformation consuming cations and alkalinity in a way unrelated to the weathering of silicates.More specifically reverse weathering refers to the formation of authigenic clay minerals from the reaction of 1) biogenic silica with aqueous cations or cation-bearing oxides or 2) cation poor precursor clays with dissolved cations or cation ...