| 西准噶尔拉巴岩体的成因——来自岩石学、年代学和地球化学的证据 |
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| 引用本文：徐盛林,陈宣华,马飞宙,邵兆刚,丁伟翠,韩乐乐,王叶.2022.西准噶尔拉巴岩体的成因——来自岩石学、年代学和地球化学的证据[J].地球学报,43(6):875-894. |
| DOI：10.3975/cagsb.2022.052601 |
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| 基金项目:中国地质调查局地质调查项目(编号: DD20160083; DD20190011; DD20221643);国家重点研发计划项目(编号: 2018YFC0603700);中国地质科学院基本科研业务费项目(编号: JKY202011) |
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| 中文摘要:西准噶尔西南部的拉巴岩体形成于早二叠世(285.7~295.1 Ma), 由花岗岩、花岗闪长岩、二长花岗岩岩基和一系列花岗闪长斑岩、闪长岩、花岗岩等岩脉组成, 矿物主要包括石英、斜长石、碱性长石、角闪石和黑云母等, CaO、Na2O含量较高, Eu弱负异常, 高εNd、低(87Sr/86Sr)i, 具有中高硅、钙碱性、贫镁铁、准铝质-弱过铝质的特点, 属典型的I型花岗岩, 可进一步分为高Sr低Yb的高压型埃达克岩和低Sr高Yb的低压型岛弧花岗岩, 均形成于洋壳俯冲的岛弧环境, 西准噶尔地区在早二叠世可能仍存在未完全关闭的有限洋盆, 对完善区域大地构造演化具有重要意义。 |
| 中文关键词:地球化学 U-Pb年代学 Sr-Nd-Hf同位素 有限洋盆 西准噶尔 |
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| Petrogenesis of Laba Plutons in West Junggar, Central Asian Orogenic Belt: Evidence from Petrology, Chronology, and Geochemistry |
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| Abstract:The Laba plutons in southwest West Junggar were formed in the Early Permian (285.7~295.1 Ma). They are composed of granite, granodiorite, monzogranite batholith, and a series of granodiorite porphyry, diorite, granite, and other dikes. Minerals mainly consist of quartz, plagioclase, alkali feldspar, hornblende, and biotite. The Laba plutons are characterized by medium-high silicon, calc-alkaline, mafic, and peraluminous with high CaO and Na2O content, Eu weak negative anomaly, high εNd, and low (87Sr/86Sr)i. They are typical I-Type granites formed in the island arc environment of oceanic crust subduction, which can be further divided into high-pressure adakite with high Sr and low Yb content and low-pressure island arc granite with low Sr and high Yb content. In the Early Permian, there may still have been a limited ocean basin in West Junggar, which is of great significance to improvement of the regional tectonic evolution. |
| keywords:geochemistry U-Pb dating Sr-Nd-Hf isotopic composition limited oceanic basin West Junggar |
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