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The formation of rift basins and strain localization reflects rift maturity. At the onset of rifting, the upper part of the lithosphere starts to extend on a series of initially unconnected normal faults , leading to the development of isolated basins. [ 8 ]
Lacustrine deposits have gained more attention recently due to containing valuable source rocks of oil, coal, and uranium. Lacustrine deposits generally provide productive mining conditions but can prove challenging when underground mines are attempted due to the poor shear strength of clays and silts as well as the amount of moisture often locked in the layers due to a low permeability ...
Description and Formation Modern, Active Examples Ancient (no longer active) Examples Rift basin: Divergent: Rift basins are elongate sedimentary basins formed in depressions created by tectonically-induced thinning (stretching) of continental crust, generally bounded by normal faults that create grabens and half-grabens.
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones. There are many different views on the formation of mylonites, but it is generally agreed that crystal-plastic deformation must have occurred, and that fracturing and cataclastic flow are secondary processes in the formation of mylonites.
A rift zone is a feature of some volcanoes, especially shield volcanoes, in which a set of linear cracks (or rifts) develops in a volcanic edifice, typically forming into two or three well-defined regions along the flanks of the vent. [1]
Fractional crystallization (chemistry) – Method for refining substances based on differences in their solubility Igneous differentiation – Geologic process in formation of some igneous rocks Layered intrusion – large sill-like body of igneous rock Pages displaying wikidata descriptions as a fallback
VMS deposits have an ideal form of a conical area of highly altered volcanic or volcanogenic sedimentary rock within the feeder zone, [definition needed] which is called the stringer sulfide or stockwork zone, overlain by a mound of massive exhalites, and flanked by stratiform exhalative sulfides known as the apron.
Since ignimbrite is a deposit, its characteristics cannot completely represent the flow, and the deposit may only record the depositional process. Vertical chemical zonation in ignimbrites is interpreted as recording incremental changes in the deposition, and the zonation rarely correlates with flow unit boundaries and may occur within flow units.