平板俯衝
平板俯衝（英語：flat slab subduction）的特點是俯衝角度有兩個折點，在淺処的震源層(seismogenic layer)與其他俯衝板塊相同，但在震源層之外的俯衝角較小（與水平面小於 30 度），並且在遠離海溝的地方恢復正常俯衝角度[1]。 平板俯衝與在墨西哥西部的下部板塊淺傾斜不同。平板俯衝可導致軟流圈的尖滅、弧形岩漿作用向內陸遷移以及導致弧形岩漿作用的最終停止[2]。 平板與被俯衝的上板之間的耦合被認為，是造成上板表面的變形改變方式，如同落基山脈一樣，是由基底核心隆起造成的[2][3].平板還可能導致大陸岩石圈下部的水化[2]，形成經濟意義礦床[4]。在俯衝過程中，平板本身可能會變形或屈曲，從而導致平板上的海洋沉積物出現沉積間斷[5]。 平板俯衝的停止和弧形火山活動的反向遷移有關[2]。關於平板俯衝成因有多種假設，由於較厚（15-20 公里）並有浮力的的洋殼俯衝[6],或由於海溝的退滾並伴隨著上板塊的快速超越的，以至於增強的海溝吸力[7]。 南美洲西海岸有兩個最大的平板俯衝帶[2]。 平板俯衝佔全球俯衝帶的10%[3]。
參考文獻
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- ^ 2.0 2.1 2.2 2.3 2.4 Humphreys, Eugene; Hessler, Erin; Dueker, Kenneth; Farmer, G. Lang; Erslev, Eric; Atwater, Tanya (2003-07-01). "How Laramide-Age Hydration of North American Lithosphere by the Farallon Slab Controlled Subsequent Activity in the Western United States". International Geology Review. 45 (7): 575–595. doi:10.2747/0020-6814.45.7.575. ISSN 0020-6814.
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- ^ Rosenbaum, Gideon; Giles, David; Saxon, Mark; Betts, Peter G.; Weinberg, Roberto F.; Duboz, Cecile (2005-10-30). "Subduction of the Nazca Ridge and the Inca Plateau: Insights into the formation of ore deposits in Peru". Earth and Planetary Science Letters. 239 (1–2): 18–32. Bibcode:2005E&PSL.239...18R. doi:10.1016/j.epsl.2005.08.003.
- ^ Li, Yong-Xiang; Zhao, Xixi; Jovane, Luigi; Petronotis, Katerina E.; Gong, Zheng; Xie, Siyi (2015-12-01). "Paleomagnetic constraints on the tectonic evolution of the Costa Rican subduction zone: New results from sedimentary successions of IODP drill sites from the Cocos Ridge". Geochemistry, Geophysics, Geosystems. 16 (12): 4479–4493. doi:10.1002/2015GC006058. ISSN 1525-2027.
- ^ Antonijevic, Sanja Knezevic; Wagner, Lara S.; Kumar, Abhash; Beck, Susan L.; Long, Maureen D.; Zandt, George; Tavera, Hernando; Condori, Cristobal (2015-08-13). "The role of ridges in the formation and longevity of flat slabs". Nature. 524 (7564): 212–215. doi:10.1038/nature14648. ISSN 0028-0836. PMID 26268192
- ^ Manea, Vlad C.; Pérez-Gussinyé, Marta; Manea, Marina (2012-01-01). "Chilean flat slab subduction controlled by overriding plate thickness and trench rollback". Geology. 40 (1): 35–38. doi:10.1130/G32543.1. ISSN 0091-7613.