仰冲(Obduction)是一種地質過程,指密度更大的洋殼聚合性板塊邊緣處從下降的海洋板塊上被剝離,並推覆到到鄰近板块上[1]。這鄰近的板块也可能是密度小的陸壳[2]。仰冲不如俯衝常見[3],因為密度較大的大洋岩石圈通常會在較輕的大陸板塊下方俯衝。仰冲與造山帶弧後盆地的板塊碰撞有關[4]

仰冲通常發生在俯衝帶,大洋壳中的基性和超基性岩石碎塊從地幔逆衝到大陸地殼上,成為蛇綠岩套[5]。仰冲也會發生在一個小的洋殼板塊夾在兩個較大的大陸板塊之間,當兩個大陸板塊碰撞時,夾在它們之間的洋殼被擠入到相鄰的大陸板塊之間,由此產生造山運動[6]。 大多數仰冲一般在俯衝帶上方的弧後盆地開始,在洋殼閉合或造山運動期間完成[7]

仰衝的例子有新喀里多尼亞塞浦路斯特羅多斯山

參考文獻编辑

  1. ^ Plate Tectonics > Glossary > M - R. [2021-10-10]. (原始内容存档于2021-10-10). 
  2. ^ Plate tectonics Glossary M-R https://www.geolsoc.org.uk/Plate-Tectonics/Glossary/M-R页面存档备份,存于互联网档案馆
  3. ^ Sarah J. Edwards, Wouter P. Schellart, Joao C. Duarte. Geodynamic models of continental subduction and obduction of overriding plate forearc oceanic lithosphere on top of continental crust: 1494-1515. [2021-10-10]. (原始内容存档于2022-03-06). 
  4. ^ Curved orogenic belts, back-arc basins, and obduction as consequences of collision at irregular continental margins (PDF). 
  5. ^ Dewey, J. F., 1976. Ophiolite Obduction. Tectonophysics, v. 31, p.93-120
  6. ^ Dewey, J. F. and Bird, J.M., 1971. Origin and emplacement of the ophiolite suite: Appalachian ophiolites in Newfoundland. J. Geophys. Res., 76:3179-3206
  7. ^ Church, W. R., 1972. Ophiolite: its definition, origin as oceanic crust, and mode of emplacement in orogenic belts, with special reference to the Appalachians. Dep. Energy, Mines Resource. Can., Publ., 42:71-85