Internal structure of oceanic lithosphere : A perspective from tectonic Windows
Internal structure of oceanic lithosphere : A perspective from tectonic Windows
复制标题
大洋岩石圈的内部结构:构造窗的视角
DOI：
10.1029/gm106p0177
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
J. Karson
中科院分区：
文献类型：
--
作者：
J. Karson
海底的主要断崖为洋壳和上地幔提供了构造窗口。在这些背景下的直接观测显示，主要岩石单元之间的空间布置、内部结构和接触比根据地震研究和蛇绿岩类似物通常预期的要复杂得多。从这个角度来看，层状、蛇绿岩类的岩石单元序列，包括玄武岩火山岩、席状辉绿岩脉杂岩、上地幔橄榄岩上方的各向同性和层状辉长岩和超镁铁质岩石--所有这些都由大致水平的接触隔开--在大洋岩石圈中可能比通常认为的要少得多。相反，缺乏蛇绿岩类层序或包含不符合蛇绿岩模型的结构的大露头地区(直径数十公里)的有文件记录的例子使蛇绿岩杂岩的重建和解释中所做的基本假设受到质疑。历史上，层状蛇绿岩构造体一直是推断洋中脊扩张中心构造作用与岩浆作用相互作用的基础。
Major faulted escarpments on the seafloor provide tectonic windows into oceanic crust and upper mantle. Direct observations in these settings reveal that the spatial arrangement, internal structure, and contacts between major rock units are significantly more complex than commonly anticipated on the basis of seismic studies and ophiolite analogs. From this perspective, a stratiform, ophiolite-like sequence of rock units, including basaltic volcanic rocks, sheeted diabase dike complex, isotropic and layered gabbroic and ultramafic rocks over upper mantle peridotites-all separated by generally horizontal contacts, may be much less common in the oceanic lithosphere than generally thought. Conversely, documented examples of large outcrop areas (tens of kilometers across) that lack the ophiolite-like sequence or that contain structures that do not conform to the ophiolite model call into question the basic assumptions made in the reconstruction and interpretation of ophiolite complexes. Historically, the stratiform ophiolite architecture has been the basis for inferences of the interaction between tectonism and magmatism at mid-ocean ridge spreading centers.