Mantle contamination and the Izu-Bonin-Mariana (IBM) 'high-tide mark': evidence for mantle extrusion caused by Tethyan closure
Mantle contamination and the Izu-Bonin-Mariana (IBM) 'high-tide mark': evidence for mantle extrusion caused by Tethyan closure
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DOI：
10.1016/s0040-1951(00)00264-x
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发表时间：
2001-04
期刊：
影响因子：
2.9
通讯作者：
M. Flower;R. Russo;K. Tamaki;N. Hoàng
中科院分区：
文献类型：
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作者：
M. Flower;R. Russo;K. Tamaki;N. Hoàng
西太平洋盆地具有三个显著特征：（1）与全球尺度板块相互作用相关的复杂运动学历史;（2）类似DUPAL的污染地幔;（3）中生代后封闭弧沟系统的快速回滚。板块变陡，极端的弧曲率，并与马里亚纳会聚边缘有力的盆地开口的巧合表明，回滚继续响应东向地幔“风”。在相互冲突的运动学和遗传学解释的背景下，我们探讨的概念，向东软流圈流驱动的穿时特提斯封闭导致欧亚大陆东部的拉伸和伴随的西太平洋盆地的开放。标志着后者的东部边界，伊豆-小笠原-马里亚纳前弧可以被视为岩石构造的“高潮标志”，包括连续事件的火成岩和变质产物（自公元前200年以来）。45Ma.）弧后盆地的扩张。前弧还形成了一个同位素边界分离污染的西太平洋地幔的N-MORB太平洋水库。虽然西太平洋地幔的同位素组成类似于印度洋热点和扩张系统，其时空变化和俯冲障碍的存在，南部似乎排除了印度洋地幔向北流动，并需要一个内源性的起源亚欧亚污染地幔。特提斯软流圈的挤压作用和亚亚洲板块岩石圈的混染作用是西太平洋岛弧回退和海盆开启的主要原因。该模型是一致的古地磁和地质证据支持独立的运动历史的菲律宾海和巽他板块的组成部分，虽然这些解释是推测性的。由于澳大利亚-印度尼西亚碰撞的影响，晚特提斯地幔挤压似乎产生了北方最大的DUPAL域。
Western Pacific basins are characterized by three remarkable attributes: (1) complex kinematic histories linked to global-scale plate interactions; (2) DUPAL-like contaminated mantle; and (3) rapid post-Mesozoic rollback of the confining arc-trench systems. The coincidence of slab steepening, extreme arc curvature, and vigorous basin opening associated with the Mariana convergent margin suggests that rollback continues in response to an east-directed mantle ‘wind’. Against a backdrop of conflicting kinematic and genetic interpretations we explore the notion that eastward asthenospheric flow driven by diachronous Tethyan closure caused stretching of eastern Eurasia and concomitant opening of western Pacific basins. Marking the eastern boundary of the latter, the Izu-Bonin-Mariana forearc may be regarded as a litho-tectonic ‘high-tide mark’ comprising igneous and metamorphic products from successive episodes (since ca. 45Ma.) of arc sundering and backarc basin opening. The forearc also forms an isotopic boundary separating contaminated western Pacific mantle from the N-MORB Pacific Ocean reservoir. While the isotopic composition of western Pacific mantle resembles that feeding Indian Ocean hotspot and spreading systems, its spatial–temporal variation and the presence of subduction barriers to the south appear to preclude northward flow of Indian Ocean mantle and require an endogenous origin for sub-Eurasian contaminated mantle. It is concluded that the extrusion of Tethyan asthenosphere, contaminated by sub-Asian cratonic lithosphere, was a major cause of western Pacific arc rollback and basin opening. The model is consistent with paleomagnetic and geologic evidence supporting independent kinematic histories for constituent parts of the Philippine Sea and Sunda plates although interpretation of these is speculative. Compounded by effects of the Australia–Indonesia collision, late-Tethyan mantle extrusion appears to have produced the largest DUPAL domain in the northern hemisphere.