Search results
Results From The WOW.Com Content Network
A gas main being laid in a trench. A trench is a type of excavation or depression in the ground that is generally deeper than it is wide (as opposed to a swale or a bar ditch), and narrow compared with its length (as opposed to a simple hole or pit). [1] In geology, trenches result from erosion by rivers or by geological movement of tectonic ...
A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to and about 200 km (120 mi) from a volcanic arc. Much of the fluid trapped in sediments of the subducting slab returns to the surface at the oceanic trench, producing mud volcanoes and cold seeps.
Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical , geochemical , sedimentological and paleontological investigations of the ocean floor and coastal zone .
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 ...
An oceanic trench is a type of convergent boundary at which two oceanic lithospheric slabs meet; the older (and therefore denser) of these slabs flexes and subducts beneath the other slab. Oceanic lithosphere moves into trenches at a global rate of about a tenth of a square meter per second.
Sketch of trench wall Sandsheet thought to have resulted from the tsunami caused by an earthquake on January 26, 1700, river bank Oregon Seismite formed by liquefaction of sediments during a Late Ordovician earthquake (northern Kentucky, USA) Paleoseismology looks at geologic sediments and rocks, for signs of ancient earthquakes.
Graben is a loan word from German, meaning 'ditch' or 'trench'. The first known usage of the word in the geologic context was by Eduard Suess in 1883. [ 1 ] The plural form is either graben [ 2 ] or grabens .
At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can be described according to the types of plate margin that meet at them (e.g. fault–fault–trench, ridge–ridge–ridge, or abbreviated F-F-T, R-R-R).