Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho
Crustal diopsidites from the northern Oman ophiolite: Evidence for hydrothermal circulation through suboceanic Moho
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DOI：
10.2465/jmps.110621b
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发表时间：
2011-10
影响因子：
0.7
通讯作者：
N. Akizawa;S. Arai;A. Tamura;Jiro Uesugi;M. Python
中科院分区：
文献类型：
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作者：
N. Akizawa;S. Arai;A. Tamura;Jiro Uesugi;M. Python
本文详细介绍了阿曼北部蛇绿岩中沿Wadi Fizh最下部地壳中新发现的含钙长岩透辉石岩。斜长透辉岩呈网状分布在辉长岩/橄榄岩界线以上50m的层状辉长岩中，主要由高镁透辉单斜辉石和斜长岩组成，并含有不同数量的紫辉长岩。它们的矿物化学特征介于地壳辉长岩和透辉岩之间，是高温富钙热液与地幔内橄榄岩相互作用的产物。斜长透辉岩可能是地幔中参与透辉岩化的流体与层状辉长岩相互作用形成的。形成钙长石透辉石岩的流体也是富钙的，并携带铬从下伏地幔段形成紫辉橄榄岩。高温热液循环在钙、铬等元素跨越海底莫霍面向下地壳的迁移过程中起着重要作用。
This paper details a new discovery of anorthite-bearing diopsidites (= anorthite diopsidites) from the lowermost crust along Wadi Fizh in the northern Oman ophiolite. The anorthite diopsidites occur as networks within layered gabbros 50 m above the gabbro/peridotite boundary, and are mainly composed of high-Mg diopsidic clinopyroxenes and anorthites with various amounts of uvarovite. They are intermediate in mineral chemical characteristics between the crustal gabbros and the diopsidites, and interpreted as an interaction product between high-temperature Ca-rich hydrothermal fluids and peridotites within the mantle section. The anorthite diopsidites were probably formed by interaction between the fluids involved in diopsidization within the mantle section and the layered gabbro. The fluids responsible for the formation of the anorthite diopsidite were also Ca-rich and carried Cr to form uvarovite from the underlying mantle section. High-temperature hydrothermal circulation plays an important role in the transportation of elements, e.g., Ca and Cr, from the upper mantle to the lower crust across the Moho in the ocean floor.