| 东昆仑黑海地区早古生代过铝质花岗岩成因及对构造演化的制约 |
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| 引用本文：赵春涛,陈亮,刘泽,余冬梅,凌智永,霍世璐,韩进军,李朋,李玉刚,王建萍.2026.东昆仑黑海地区早古生代过铝质花岗岩成因及对构造演化的制约[J].地球学报,47(1):118-134. |
| DOI：10.3975/cagsb.2025.070612 |
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| 基金项目:由第二次青藏高原综合科学考察研究(编号: 2022QZKK0201)、国家自然科学基金项目(编号: U24A20598)、青海省自然科学基金项目(编号: 2024-ZJ-984)、盐湖资源绿色高值利用重点实验室开放基金项目(编号: ISL2024-07)、中国科学院特别研究助理项目 (编号: E410DZ01)和中信十大科技创新项目盐湖资源综合开发与利用(编号: 2023ZXKYA05100)联合资助。 |
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| 中文摘要:原特提斯洋在东昆仑闭合时间以及之后的碰撞造山过程一直存在争议, 东昆仑造山带黑海地区发育的晚志留世—早泥盆世两期过铝质花岗岩为研究该问题提供了天然对象。通过对加组它士和大灶火岩体的过铝质花岗岩进行元素地球化学、Hf同位素地球化学、锆石U-Pb年代学等工作, 查明加组它士黑云母花岗岩和大灶火花岗闪长岩均为高硅、高铝、富碱的碱性-高钾钙碱性I型花岗岩, 相似的地球化学特征指示它们具有相同的岩浆源区。Hf同位素数据显示两期过铝质花岗岩的源岩为古老地壳, 在形成时受到地幔物质或源于地幔新生地壳物质的混染。加组它士黑云母花岗岩和大灶火花岗闪长岩的成岩年龄分别为(421.9±2.6) Ma和(412.0±2.0) Ma。结合区域地质演化, 本研究认为黑海地区早古生代过铝质花岗岩形成于陆陆碰撞造山结束后的伸展环境, 这指示东昆仑造山带在晚志留世—早泥盆世时期可能已经完成东昆仑与柴达木陆块的俯冲碰撞, 开始进入碰撞后的伸展阶段。 |
| 中文关键词:过铝质花岗岩 Lu-Hf同位素地球化学 锆石U-Pb年代学 构造演化 东昆仑造山带 |
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| The Genesis of Early Paleozoic Peraluminous Granite in the Heihai Region of East Kunlun Orogenic Belt and Its Constraints on Tectonic Evolution |
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| Abstract:The timing of the Proto-Tethys Ocean closure in East Kunlun and the subsequent collisional orogeny remains debated. Late Silurian–Early Devonian peraluminous granites in the Heihai area of the East Kunlun orogenic belt offer critical insights, as natural objects, into this process. Our study analyzes elemental geochemistry, Hf isotope geochemistry, and zircon U-Pb chronological analyses of the Jiazutashi and Dazaohuo peraluminous granites in the Heihai area. Whole-rock geochemistry shows that both the Jiazutashi biotite granite and the Dazaohuo granodiorite are high-silica, high-alumina, alkali-rich, I-type granites, and with similar geochemical characteristics, suggesting a common magma source area. Hf isotopes indicate possible derivation of peraluminous granites from the anatexis of ancient crustal materials and mixed with mantle or juvenile crust materials. The diagenetic ages of the Jiazutashi biotite granite and the Dazaohuo granodiorite are (421.9±2.6) Ma and (412.0±2.0) Ma, respectively. The results combined with the regional geological evolution indicate that the Early Paleozoic peraluminous granites in the Heihai region probably formed in an extensional tectonic setting after the end of the collisional orogens. This indicates that the Late Silurian–Early Devonian may have completed the subduction collision between the East Kunlun and Qaidam terranes and entered the post-collision extension stage. |
| keywords:peraluminous granite Lu-Hf isotope geochemistry zircon U-Pb chronology tectonic evolution East Kunlun orogenic belt |
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