What is the definition of abduction in geography?
What is the definition of abduction in geography?
ABDUCTION Abduction is the overthrusting of continental crust by oceanic crust or mantle rocks at a convergent plate boundary This process is uncommon as the denser oceanic lithosphere usually subducts underneath the less dense continental plate.
What is supra subduction?
Supra-subduction zone (SSZ) ophiolites have the geochemical characteristics of island arcs but the structure of oceanic crust and are thought to have formed by sea-floor spreading directly above subducted oceanic lithosphere. Most of the best-preserved ophiolite complexes in orogenic belts are of this type.
What are the ophiolites and how do they form?
ultramafic rocks are known as ophiolites. Many geologists believe that ophiolites formed at oceanic ridges were emplaced by tectonic forces at convergent plate boundaries and then became exposed in highly deformed orogenic (mountain) belts.
What are ophiolites made from?
Ophiolites are pieces of oceanic plate that have been thrusted (obducted) onto the edge of continental plates. They provide models for processes at mid-ocean ridges. Ophiolites are an assemblage of mafic and ultramafic lavas and hypabyssal rocks found in association with sedimentary rocks like greywackes and cherts.
What is the medical definition for abduction?
Abduction: The movement of a limb away from the midline of the body. The opposite of abduction is adduction.
What is plate tectonic Obduction?
Obduction is a geological process whereby denser oceanic crust (and even upper mantle) are scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. …
How does an ophiolite form at the subduction zone?
lithosphere, which becomes an ophiolite when incorporated into continental margins through a complex process known as ’emplacement’. A fundamental problem of ophiolite emplacement is how dense oceanic crust becomes emplaced over less dense material(s) of continental margins or subduction-accretion systems.
Why are Ophiolites important?
Since scientists have never drilled deep enough into the Earth to observe the mantle, ophiolites are important because they are places where geologists can observe large sections of mantle rocks directly. Since then, many more mantle exposures have been discovered, particularly on the ocean floor.
How do you pronounce Ophiolites?
Phonetic spelling of ophiolites
- ophi-o-lites.
- of-ee-uh-lahyt. Lawrence Van Den Berg.
- ophi-o-lites. Daniela Bayer.
- ophi-olites. Padama Parmer.
What is the meaning of adduction in medical terms?
Adduction: Movement of a limb toward the midline of the body. The opposite of adduction is abduction.
What are the characteristics of ophiolites?
Characteristic rocks. Ophiolites are an assemblage of oceanic lithosphere rocks that have been emplaced onto a continent. This assemblage consists of deep-marine sedimentary rock (chert, limestone, clastic sediments), volcanic rocks ( pillow lavas, glass, ash, sheeted dykes and gabbros) and peridotite (mantle rock).
What is an ophiolite suite?
Ophiolite suites. Since the late 1970s, the term ophiolite has been used to describe sections of oceanic crust and upper mantle, along with sedimentary rocks deposited on the sea floor, emplaced as thrust slices onto continental lithosphere .
Is ophiolite obduction caused by gravity sliding?
It is concluded that several convergent plate-margin mechanisms may be responsible for ophiolite obduction, none of which involve gravity sliding.
What is the medical term for Obduction?
Obduction. For the video game, see Obduction (video game). For the medical procedure, see autopsy. Obduction was originally defined by Coleman to mean the overthrusting of oceanic lithosphere onto continental lithosphere at a convergent plate boundary where continental lithosphere is being subducted beneath oceanic lithosphere.
