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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 ...
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 ...
Basins may appear on a geologic map as roughly circular or elliptical, with concentric layers. Because the strata dip toward the center, the exposed strata in a basin are progressively younger from the outside in, with the youngest rocks in the center. Basins are often large in areal extent, often hundreds of kilometers across. Structural ...
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]
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 Paris Basin is a geological basin of sedimentary rocks. It overlies geological strata folded by the Variscan orogeny. It forms a broad shallow bowl in which marine deposits from throughout periods from the Triassic to the Pliocene were laid down. Their extent generally decreases with time.
A roof (pl.: roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temperature, and wind. [1]
Basement rock is the thick foundation of ancient, and oldest, metamorphic and igneous rock that forms the crust of continents, often in the form of granite. [2] Basement rock is contrasted to overlying sedimentary rocks which are laid down on top of the basement rocks after the continent was formed, such as sandstone and limestone.