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Such terranes were dubbed "accreted terranes" by geologists. Geologist J. N. Carney writes: It was soon determined that these exotic crustal slices had in fact originated as "suspect terranes" in regions at some considerable remove, frequently thousands of kilometers, from the orogenic belt where they had eventually
Most continents are composed of multiple accreted "terranes", pieces of low-density continental crust with different origins. For example, North America is made up of multiple accreted terranes that collided with the Laurentian proto-continent , such as the Proterozoic Yavapai , Mazatzal , and Grenville Province Terranes. [ 5 ]
It was later accreted to the continental margin of Laurasia. [ 4 ] Longitudinal sedimentary tapering of pre-orogenic sediments correlates strongly with curvature of the submarine frontal accretionary belt in the South China Sea margin, suggesting that pre-orogenic sediment thickness is the major control on the geometry of frontal structures.
Geologic map depicting the Smartville Complex (in brown) and other accreted terranes in California. [1]The Smartville Block, also called the Smartville Ophiolite, Smartville Complex, or Smartville Intrusive Complex, is a geologic terrane formed in the ocean from a volcanic island arc that was accreted onto the North American Plate during the late Jurassic (~160–150 million years ago).
During the Paleoproterozoic, island-arc terrane associated with the Colorado orogeny accreted to the Wyoming Craton along the Cheyenne belt, a 500-km-wide belt of Proterozoic rocks named for Cheyenne, Wyoming. As a result of the collision, older, Archean rocks of the Wyoming province were intensely deformed and metamorphosed for at least 75 km ...
Map showing some of the accreted terranes in present-day California. Multiple hypotheses have been proposed to explain this shallow subduction angle and resulting deformation. Some studies suggest that the faster movement of the North American plate caused the slab to flatten, resulting in slab rollback. [3]
In summary, the Brothers Fault Zone, and the related Eugene–Denio, McLoughlin, and Vale zones, appear to be deep-seated structures in accreted terranes bounded by the Klamath—Blue Mountains Lineament, which has been reactivated by Basin and Range extension, and exploited by mid-Miocene volcanism associated with the Yellowstone Hotspot.
This margin consisted of the ancient Rio de la Plata craton and a number of accreted terranes, whose boundaries have been discovered using paleomagnetic studies. [3] The Rio de la Plata Craton is believed to have been a component of southwest Gondwana since the end of the Proterozoic, likely forming a single body with other Gondwanan crustal ...