平板俯冲
平板俯冲（英语：flat slab subduction）的特点是俯冲角度有两个折点，在浅処的震源层(seismogenic layer)与其他俯冲板块相同，但在震源层之外的俯冲角较小（与水平面小于 30 度），并且在远离海沟的地方恢复正常俯冲角度[1]。 平板俯冲与在墨西哥西部的下部板块浅倾斜不同。平板俯冲可导致软流圈的尖灭、弧形岩浆作用向内陆迁移以及导致弧形岩浆作用的最终停止[2]。 平板与被俯冲的上板之间的耦合被认为，是造成上板表面的变形改变方式，如同落基山脉一样，是由基底核心隆起造成的[2][3].平板还可能导致大陆岩石圈下部的水化[2]，形成经济意义矿床[4]。在俯冲过程中，平板本身可能会变形或屈曲，从而导致平板上的海洋沉积物出现沉积间断[5]。 平板俯冲的停止和弧形火山活动的反向迁移有关[2]。关于平板俯冲成因有多种假设，由于较厚（15-20 公里）并有浮力的的洋壳俯冲[6],或由于海沟的退滚并伴随着上板块的快速超越的，以至于增强的海沟吸力[7]。 南美洲西海岸有两个最大的平板俯冲带[2]。 平板俯冲占全球俯冲带的10%[3]。
参考文献
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- ^ 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.