| 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 |
| 投稿时间：2025-04-29 修订日期：2025-05-23 点此下载全文 |
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| 基金项目:本文受第二次青藏高原综合科学考察研究（2022QZKK0201)、国家自然科学基金（U24A20598）、青海省自然科学基金（2024-ZJ-984）、盐湖资源绿色高值利用重点实验室开放基金（ISL2024-07）、中国科学院特别研究助理项目（E410DZ01）和盐湖资源综合开发与利用项目（2023ZXKYA05100）联合资助 |
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| 中文摘要:原特提斯洋在东昆仑造山带闭合及其之后陆块开始碰撞造山的时间一直存在争议，东昆仑昆南断裂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。通过对黑海地区加组它士和大灶火岩体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物质来源和岩浆源区。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的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，指示东昆仑造山带在晚志留世-早侏罗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 Kunnan Fault and its constraints on tectonic evolution |
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| Abstract:The timing of the closure of the Proto-Tethys Ocean in the East Kunlun orogenic belt and the subsequent onset of collisional orogeny has been controversial, and the Late Silurian-Early Devonian peraluminous granitoids developed in the Heihai region of the Kunnan fracture have provided a natural object to solve this problem. The elemental geochemistry, Hf isotope geochemistry, and zircon U-Pb chronology of the Heihai area show that the Jiazutashi and Dazaohuo peraluminous granites are both alkaline-alkaline high-potassium-calcium-alkaline type I granites with high silica, high alumina, and alkalinity, and similar geochemical characteristics indicate that they have the same material source and magma source area. The source rocks of the peraluminous granites are ancient crust, which were mixed by mantle materials or newer crustal materials originating from the mantle during their formation. The petrogenetic ages of the Kakatsugushi diorite and the Dazao sparkling granodiorite are 421.9 ± 2.6 Ma and 412.0 ± 2.0 Ma, respectively. Taking into account the geological evolution of the region, it is suggested that the Early Paleozoic peraluminous granites in the Heihai region were formed in the terrestrial-land collisional orogenic environment, and that the East Kunlun Orogenic Belt may have been in the post-collisional orogenic extensional environment in the Late Chiruruic-Early Jurassic period. |
| keywords:Peraluminous granite Lu-Hf isotope geochemistry Zircon U-Pb chronology Tectonic evolution East kunlun orogenic belt |
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