Episodic slab rollback fosters exhumation of HP–UHP rocks
Episodic slab rollback fosters exhumation of HP–UHP rocks
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DOI：
10.1111/j.1365-246x.2009.04372.x
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发表时间：
2009-12
影响因子：
2.8
通讯作者：
L. Husson;J. Brun;P. Yamato;C. Faccenna
中科院分区：
文献类型：
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作者：
L. Husson;J. Brun;P. Yamato;C. Faccenna
摘要俯冲带中地壳物质的埋藏-折返循环既可以由物质的浮力驱动，也可以由周围的水流驱动，或者两者兼而有之。高压和超高压岩石主要在俯冲带表现出瞬变行为的地方折返，这导致俯冲地幔楔体中的流动状况不同。具有固定海沟的俯冲带(模式I)有利于岩石单元的埋藏，而板片回滚(模式II)适度地诱导有助于折返的向上流动，当板片倾角减小时(模式III)这种机制得到加强。涉及不同岩石圈单元的幕式俯冲机制先后激活了这三种模式，从而极大地有利于岩石单元从地幔深处向地表折返，而不需要快速和持续的侵蚀。
SUMMARY The burial–exhumation cycle of crustal material in subduction zones can either be driven by the buoyancy of the material, by the surrounding flow, or by both. High pressure and ultrahigh pressure rocks are chiefly exhumed where subduction zones display transient behaviours, which lead to contrasted flow regimes in the subduction mantle wedge. Subduction zones with stationary trenches (mode I) favour the burial of rock units, whereas slab rollback (mode II) moderately induces an upward flow that contributes to the exhumation, a regime that is reinforced when slab dip decreases (mode III). Episodic regimes of subduction that involve different lithospheric units successively activate all three modes and thus greatly favour the exhumation of rock units from mantle depth to the surface without need for fast and sustained erosion.