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The Peru–Chile Trench, also known as the Atacama Trench, is an oceanic trench in the eastern Pacific Ocean, about 160 kilometres (100 mi) off the coast of Peru and Chile.〔(【引用サイトリンク】url=http://www.britannica.com/EBchecked/topic/453259/Peru-Chile-Trench )〕 It reaches a maximum depth of 8,065 metres (26,460 ft) below sea level in Richards Deep () and is approximately 5,900 kilometres (3,666 mi) long; its mean width is 64 kilometres (40 mi) and it covers an expanse of some 590,000 square kilometres (228,000 mi²). The trench delineates the boundary between the subducting Nazca Plate and the overriding South American Plate. ==Geology== The trench is a result of a convergent boundary, where the eastern edge of the oceanic Nazca Plate is being subducted beneath the continental South American Plate.〔 Two seamount ridges within the Nazca Plate enter the subduction zone along this trench: the Nazca Ridge and the Juan Fernández Ridge. From the Chile Triple Junction to Juan Fernández Ridge the trench is filled with 2.0–2.5 km of sediments, creating a flat bottom topography. Sediments are mainly turbidites interspersed with oceanic deposits of clay, volcanic ash and siliceous ooze.〔 The Peru–Chile Trench, the forearc and the western edge of the central Andean plateau (Altiplano), delineate the dramatic "Bolivian Orocline" that defines the Andean slope of southern Peru, northern Chile, and Bolivia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Peru–Chile Trench」の詳細全文を読む スポンサード リンク
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