Petrology of Peridotites and Nd-Sr Isotopic Composition of Their Clinopyroxenes from the Middle Andaman Ophiolite, India
Petrology of Peridotites and Nd-Sr Isotopic Composition of Their Clinopyroxenes from the Middle Andaman Ophiolite, India
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DOI：
10.3390/min8090410
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发表时间：
2018-09
期刊：
影响因子：
2.5
通讯作者：
T. Morishita;M. Yoshikawa;A. Tamura;J. Guotana;B. Ghosh
中科院分区：
文献类型：
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作者：
T. Morishita;M. Yoshikawa;A. Tamura;J. Guotana;B. Ghosh
印度安达曼蛇绿岩位于特提斯蛇绿岩带的东南端。我们研究岩石学和矿物学的两个二辉橄榄岩和一个完全蛇纹化纯橄榄岩与二辉橄榄岩从中部安达曼岛。主成分和微量元素组成的矿物在lherzitans建议其残留的起源后，低程度的部分熔融，少通量渗透，并恢复大洋中脊的深海橄榄岩相似。橄榄岩与洋中脊玄武岩类熔体相互作用形成了具有低Cr/（Cr + Al）比值尖晶石的纯橄榄岩。两个二辉橄榄岩的单斜辉石87 Sr/86 Sr和143 Nd/144 Nd同位素组成与MORB型地幔源区一致。所研究的二辉蛇绿岩的岩石学特征和单斜辉石的轻稀土元素亏损模式与特提斯蛇绿岩西部的某些单斜辉石相同。具有轻稀土亏损模式的特提斯二辉橄榄岩单斜辉石经年龄校正的初始εNd值可能与亏损地幔演化线一致。
The Andaman Ophiolite, India, is located at the southeastern end of the Tethyan ophiolites. We examine petrology and mineralogy of two lherzolites and a completely serpentinized dunite associated with lherzolite from the middle Andaman Island. Major and trace element compositions of minerals in the lherzolites suggest their residual origin after low-degree of partial melting with less flux infiltration, and are similar to those of abyssal peridotites recovered from mid-ocean ridges. The dunite with spinels having low-Cr/(Cr + Al) ratio was formed by interaction between peridotite and mid-ocean ridge basalt-like melt. The 87Sr/86Sr and 143Nd/144Nd isotopic systematics of clinopyroxenes of the two lherzolites are consistent with MORB-type mantle source. Petrology and light rare earth element (LREE)-depleted patterns of clinopyroxene from the studied lhezolites are the same as those from some of the western Tethyan ophiolites. The age-corrected initial εNd values of the Tethyan lherzolite clinopyroxenes with LREE-depleted patterns are likely to be consistent with the depleted mantle evolution line.