What is accretion in tectonic plates?
Accretion is the process in which material from the outer plate and trench (during the periods of discontinuous subduction) is removed and added to the outer continental margin or by other mechanisms such as imbricate thrusting or a combination of folding and thrusting (Karig, 1974; Karig and Sherman, 1975).
What is an accretionary Orogen?
Accretionary orogens comprise a range of mafic to silicic igneous rocks and their sedimentary deriva- tives that develop on oceanic (e.g. West Pacific) or continental (e.g. Andes and Japan) lithospheric substrates during continuing plate convergence.
What is continental growth by accretion?
Accretion is a process by which material is added to a tectonic plate or a landmass. This material may be sediment, volcanic arcs, seamounts or other igneous features, or blocks or pieces of continental crust split from other continental plates.
What are some examples of accretion?
An example of an accretion is the garage someone may build on his home. (geology) The gradual extension of land by natural forces, as in the addition of sand to a beach by ocean currents, or the extension of a floodplain through the deposition of sediments by repeated flooding.
How is an accretionary wedge formed?
An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Accretionary complexes are typically made up of a mix of turbidites of terrestrial material, basalts from the ocean floor, and pelagic and hemipelagic sediments.
How do accretionary prisms form?
Accretionary prisms form at the leading edge of convergent plate boundaries by skimming-off sediments and rocks of the lower plate. The rapid rate of underthrusting of the lower plate may carry rocks to great depths before they can heat up, forming a characteristic type of metamorphic rock called a blueschist.
What is the difference between orogeny and Epeirogeny?
Orogenic forces are that forces which means block making . they make Block mountains. epeirogenic forces are that forces which are continent making they make continent.
What is the difference between accretion and growth?
As nouns the difference between accretion and growth is that accretion is the act of increasing by natural growth; especially the increase of organic bodies by the internal accession of parts; organic growth while growth is an increase in size, number, value, or strength.
What is accretionary wedge in geography?
Sediments, the top layer of material on a tectonic plate, that accumulate and deform where oceanic and continental plates collide. These sediments are scraped off the top of the downgoing oceanic crustal plate and are appended to the edge of the continental plate.
What does an accretionary wedge consist of?
Accretionary wedges are chaotic deposits consisting of original rock fragments and metamorphic rock. The original igneous and sedimentary rock removed from the down-going plate is often turned into metamorphic rock due to the huge amounts of pressure they experience.
What is Epeirogenic force?
In geology, epeirogenic movement (from Greek epeiros, land, and genesis, birth) is upheavals or depressions of land exhibiting long wavelengths and little folding apart from broad undulations. Epeirogenic movements may divert rivers and create drainage divides by upwarping of the crust along axes.
What Orogeny means?
Orogeny, or mountain building, is the result of collision between two landmasses. This may occur via collision of continental crust (continent-continent collision) or when oceanic and continental crust collide (ocean-continent collision).