| 金沙江造山带印支期碰撞造山作用过程——来自羊拉旭龙韧性剪切带构造变形特征和年代学证据 |
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| 引用本文：张圣超,朱政坤,江小均,黄应才,刘小青,刘凤泽,李雨健,韩 嶂,严清高.2025.金沙江造山带印支期碰撞造山作用过程——来自羊拉旭龙韧性剪切带构造变形特征和年代学证据[J].地球学报,46(4):760-776. |
| DOI：10.3975/cagsb.2025.032402 |
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| 作者 | 单位 | E-mail | | 张圣超 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093
自然资源部三江成矿作用及资源勘查利用重点实验室, 云南昆明 650051 | 1241213163@qq.com | | 朱政坤 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093；中铜矿产资源有限公司, 云南昆明 650000 | | | 江小均 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093
自然资源部三江成矿作用及资源勘查利用重点实验室, 云南昆明 650051 | cagsjiang@126.com | | 黄应才 | 中铜矿产资源有限公司, 云南昆明 650000 | | | 刘小青 | 云南迪庆矿业开发有限公司, 云南迪庆 674400 | | | 刘凤泽 | 云南迪庆矿业开发有限公司, 云南迪庆 674400 | | | 李雨健 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093
自然资源部三江成矿作用及资源勘查利用重点实验室, 云南昆明 650051 | | | 韩 嶂 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093
自然资源部三江成矿作用及资源勘查利用重点实验室, 云南昆明 650051 | | | 严清高 | 昆明理工大学国土资源工程学院地球科学系, 云南昆明 650093
自然资源部三江成矿作用及资源勘查利用重点实验室, 云南昆明 650051 | |
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| 基金项目:国家自然科学基金项目(编号: 42462011); 云南省科技厅高层次科技人才及创新团队选拔专项(编号: 202305AT350004); 校企合作项目(编号: 202404YKKC007) |
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| 中文摘要:金沙江造山带俯冲消减-碰撞造山时限研究有助于了解古特提斯东段造山演化过程, 更能为金沙江造山带印支期斑岩-矽卡岩成矿系统(诸如羊拉铜矿)提供准确的大地构造背景。本文选取金沙江缝合带中段羊拉旭龙韧性剪切带, 开展野外和显微构造几何学-运动学解析, 并利用变形花岗质片麻岩和未变形花岗闪长岩锆石LA-ICP MS U-Pb、黑云母40Ar/39Ar同位素构造-热年代学定年手段, 厘定该韧性剪切带岩浆侵位-变质变形时限。研究认为羊拉旭龙韧性剪切带走向NEE–SWW向, 产状平缓, 近S–N向剪切, 野外和显微组构指示该韧性剪切带具右行伸展性质。剪切带内变形花岗质片麻岩、茂顶弱变形花岗闪长岩和加仁未变形花岗闪长岩分别获得锆石206Pb/238U结晶年龄为285 Ma、259.5 Ma和226.4 Ma, 另外花岗质片麻岩中黑云母获得40Ar/39Ar同位素变质-变形坪年龄为(223.75±2.18) Ma, 指示羊拉旭龙韧性剪切带变形时代为晚三叠世。综合前人研究, 认为金沙江造山带中段经历了裂谷盆地(D)、洋盆扩张(C1–P1)、洋壳扩张-俯冲消减(285~279 Ma)、碰撞造山(269~259 Ma)、晚碰撞伸展造山(233~223 Ma)和碰撞后(215~200 Ma)演化过程。其中旭龙韧性剪切带活动为金沙江陆-陆碰撞造山带晚碰撞挤压-伸展构造转换阶段产物。 |
| 中文关键词:金沙江缝合带中段 旭龙韧性剪切带 印支期 黑云母40Ar/39Ar同位素测年 锆石U-Pb测年 |
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| Constraints on the Indosinian Orogeny in the Jinshajiang Orogenic Process: Evidence from the Deformation Characteristics and Geochronological Results of the Xulong Ductile Shear Zone in Yangla Town |
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| Abstract:Study of the subduction-collision orogeny timescale of the Jinshajiang Orogenic Belt is crucial for understanding the evolution of the eastern Paleo-Tethys Orogeny. It provides an accurate tectonic background and insights into the Indosinian porphyry-skarn metallogenic system (such as the Yungla copper deposit) in theorogenic belt. This study selected the Xulong hydropower station ductile shear zone of Yangla town in the middle section of the Jinsha River Suture Zone to perform a field investigation and microstructural kinematic and geometric analysis. In addition, this study utilized zircon LA-ICP MS U-Pb dating of the deformed, weakly deformed, and undeformed granodiorite and 40Ar/39Ar isotopic thermochronology on biotite to determine the magmatic emplacement and metamorphic deformation ages in the ductile shear zone. We suggest that the Xulong ductile shear zone trends in the NEE–SWW direction, has a gentle occurrence, and undergoes nearly S–N directed shearing. Field results and microstructures indicate that this ductile shear zone exhibits dextral extensional characteristics. Zircon 206Pb/238U crystallization ages of 285 Ma, 259.5 Ma, and 226.4 Ma were obtained from the deformed granitic gneiss within the shear zone, the weakly deformed Maoding granodiorite, and the undeformed Jiaren granodiorite, respectively. Additionally, biotite in the deformed granitic gneiss yielded an 40Ar/39Ar isotopic metamorphic-deformational plateau age of (223.75±2.18) Ma, indicating that the deformation age of the Xulong ductile shear zone is Late Triassic. The study concluded that the middle section of the Jinsha River Orogenic Belt underwent the evolution process of rifted basin (D), ocean basin expansion (C1–P1), oceanic crust expansion-subduction (283–279 Ma), collisional orogeny (269–259 Ma), late collisional extensional orogeny (223–231 Ma), and post-collision (215– 200 Ma). Among these, the Late Triassic metamorphic-deformation age of the Xulong ductile shear zone is the product of the late collisional extrusion-extension tectonic transition stage of the Jinsha River continent-continent collisional orogeny. |
| keywords:middle section of the Jinsha River Suture Zone Xulong ductile shear zone Indosinian Period biotite 40Ar/39Ar isotopic dating zircon U-Pb dating |
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