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The glass transition temperature of basalt is about 700 °C (1,292 °F). [4] The mechanisms controlling formation of volcanic glass are further illustrated by the two forms of basaltic glass, tachylite and sideromelane. Tachylite is opaque to transmitted light because of the abundance of tiny oxide mineral crystals suspended in the glass ...
They are geological depressions, the inverse of domes. Elongated structural basins are a type of geological trough . Some structural basins are sedimentary basins , aggregations of sediment that filled up a depression or accumulated in an area; others were formed by tectonic events long after the sedimentary layers were deposited.
The long-term preserved geologic record of a sedimentary basin is a large scale contiguous three-dimensional package of sedimentary rocks created during a particular period of geologic time, a 'stratigraphic succession', that geologists continue to refer to as a sedimentary basin even if it is no longer a bathymetric or topographic depression. [6]
The Newark Basin, an early Mesozoic half-graben. A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults.
Rock shelters form because a rock stratum such as sandstone that is resistant to erosion and weathering has formed a cliff or bluff, but a softer stratum, more subject to erosion and weathering, lies just below the resistant stratum, and thus undercuts the cliff.
In structural geology, inversion or basin inversion relates to the relative uplift of a sedimentary basin or similar structure [example needed] as a result of crustal shortening. This normally excludes uplift developed in the footwalls of later extensional faults , or uplift caused by mantle plumes .
A roof pendant is an erosional remnant that was created by the removal of the overlying country rock that formed the roof of the igneous intrusion that encloses it. If this downward protruding mass of roof rock still has a connection to the main, surrounding mass of country rock, they are known by structural geologists as either septa or screens.
Sedimentary basin analysis is a geologic method by which the formation and evolution history of a sedimentary basin is revealed, by analyzing the sediment fill and subsidence. Subsidence of sedimentary basins generates the spatial distribution of accommodation infilling sediments.