Indian continental crust recovered from Elan Bank, Kerguelen Plateau (ODP Leg 183, Site 1137)
Indian continental crust recovered from Elan Bank, Kerguelen Plateau (ODP Leg 183, Site 1137)
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DOI：
10.1093/petrology/43.7.1241
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发表时间：
2002-07
影响因子：
3.9
通讯作者：
S. Ingle;D. Weis;F. Frey
中科院分区：
文献类型：
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作者：
S. Ingle;D. Weis;F. Frey
在Kerguelen高原Elan银行的1137号站点，南印度洋的一个大火成岩省，河流，火山岩，多云母砾岩和河流砂岩与水下喷发的拉斑玄武岩流互层。从砾岩中回收的碎屑具有高度可变的岩性，包括碱性玄武岩，流纹岩，粗面岩，花岗岩和片麻岩，砂岩，砾岩基质和代表性碎屑的主要和微量元素丰度和全岩同位素数据被用来推断这些不同岩石类型的起源。片麻岩碎屑显示出与印度地壳岩石的相似性，特别是东高止山脉带及其可能的东南极推论雷纳杂岩。尽管长英质火山碎屑与玄武岩岩浆同时喷发，但它们与玄武岩流的成因无关。这些长英质火山碎屑可能是由演化的上陆壳部分熔融形成的。花岗岩类也可能是陆壳部分熔融形成的，可能是长英质火山岩的侵入等价物。相比之下，碱性玄武岩碎屑的同位素组成，更类似于那些拉斑玄武岩流恢复在网站1137：然而，这些碎屑是高度碱性（软玉，phonotefrite），并有一个独特的岩石成因的拉斑玄武岩流单元。
At Site 1137 on Elan Bank of the Kerguelen Plateau, a large igneous province in the southern Indian Ocean, a fluvial, volcaniclastic, polymict conglomerate and a fluvial sandstone are intercalated with subaerially erupted tholeiitic basalt flows. Clasts recovered from the conglomerate have highly variable lithologies, including alkali basalt, rhyolite, trachyte, granitoid and gneiss, Major and trace element abundances and whole-rock isotopic data for the sandstones, the conglomerate matrix and representative clasts from the conglomerate are used to infer the origin of these diverse rock types. The gneiss clasts show an affinity to crustal rocks from India, particularly those of the Eastern Ghats Belt and its possible East Antarctic corollary, the Rayner Complex. The felsic volcanic clasts an not genetically related to the intercalated basalt flows, despite being erupted contemporaneously with these basaltic magmas. These felsic volcanic clasts probably formed from partial melting of evolved upper continental crust. The granitoid also probably formed by partial melting of continental crust and could be an intrusive equivalent of the felsic volcanic rocks. In contrast, the alkali basalt clasts have isotopic compositions that are more similar to those of the tholeiitic basalt flows recovered at Site 1137: however, these clasts are highly alkalic (tephrite to phonotephrite) and have a distinct petrogenesis from the tholeiitic basalt flow units.