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Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [9] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor.These particles either have their origins in soil and rocks and have been transported from the land to the sea, mainly by rivers but also by dust carried by wind and by the flow of glaciers into the sea, or they are biogenic deposits from marine organisms or from ...
Chert (/ tʃ ɜːr t /) is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, [1] the mineral form of silicon dioxide (SiO 2). [2] Chert is characteristically of biological origin, but may also occur inorganically as a chemical precipitate or a diagenetic replacement, as in petrified wood.
Those rocks that contain the most silica, and on crystallizing yield free quartz, form a group generally designated the "felsic" rocks. Those again that contain the least silica and most magnesia and iron, so that quartz is absent while olivine is usually abundant, form the "mafic" group. The "intermediate" rocks include those characterized by ...
The next unit is composed of 0.3–0.7 km thick pillow basalts, formed by the quenching of basaltic magma as it erupts into ocean water. Under the pillow basalts is a basaltic sheeted dike complex, that represent cooled magma conduits. The bottom units represent the crystallized magma chamber, feeding the mid-ocean ridge at which the crust was ...
The type of rock the sediment originated from and the intensity of the environment give different compositions of sand. The most common rock to form sand is granite, where the feldspar minerals dissolve faster than the quartz, causing the rock to break apart into small pieces. In high energy environments rocks break apart much faster than in ...
SEDEX deposits form in sedimentary basins under a regional tectonic extensional environment, under the ocean where cold seawater (blue arrows) is mixed with basin water and through sinsedimentary faults flow towards the bottom of the basin, which are heated by the geothermal gradient, and later ascends by convective currents (red arrows). [42]
A cobble encrusted with halite evaporated from the Dead Sea, Israel (with Israeli ₪1 coin [diameter 18mm] for scale). An evaporite (/ ɪ ˈ v æ p ə ˌ r aɪ t /) is a water-soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. [1]