特提斯喜马拉雅双伸展复合成穹作用: 来自定日穹隆构造变形和年代学的证据  

Bivergent-extensional composite doming in the Tethys Himalaya: Evidence from tectonic deformation and chronology of the Dingri dome

作　　者：李虎[1,2] 唐菊兴 吴青松[2] 代雪健 代宏睿 刘涛 魏阳春 LI Hu;TANG JuXing;WU QingSong;DAI XueJian;DAI HongRui;LIU Tao;WEI YangChun(School of Earth and Planetary Sciences,Chengdu University of Technology,Chengdu 610059,China;Civil Military Center of Geological Survey,China Geological Survey,Chengdu 610036,China;MNR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory of Deep Earth and Mineral Exploration,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]成都理工大学地球与行星科学学院,成都610059 [2]中国地质调查局军民融合地质调查中心,成都610036 [3]中国地质科学院矿产资源研究所,自然资源部成矿作用与资源评价重点实验室,北京100037 [4]深地探测与矿产勘查全国重点实验室,中国地质科学院,北京100037

出　　处：《岩石学报》2025年第5期1797-1817,共21页Acta Petrologica Sinica

基　　金：中国地质调查局项目(DD20243148、DD20211547)资助详细信息。

摘　　要：北喜马拉雅片麻岩穹隆是喜马拉雅造山带的重要组成部分, 经历了多期构造变形和岩浆事件, 记录了印度-欧亚板块俯冲汇聚、碰撞造山历史。迄今为止, 其形成过程所经历的变形序列、动力学特征和成因机制尚存争议, 关键构造-岩浆事件和时间亟待明确。本文报道了该带中段与南北向裂谷相关的定日穹隆物质组成、构造变形、运动学和年代学特征。揭示出定日穹隆物质组成和构造变形"4+4"模式, 即由上、下主拆离断层为界, 分为上部、中部、下部岩石-构造单元和核部花岗岩体, 其上、中部单元属浅变质特提斯喜马拉雅沉积岩系, 下部单元为高喜马拉雅结晶基底拆离出露, 核部侵位淡色花岗岩。穹隆体构造变形经历了早期N-S逆冲挤压、前期近N-S向伸展、主期E-W伸展和晚期垮塌伸展变形。穹隆就位继承了中生代特提斯喜马拉雅物质组成和挤压构造变形, ~22.1Ma的N-S向伸展, 岩浆初始就位;~17.1Ma与E-W向伸展相关的岩浆主体侵位, 并于14.4~14.1Ma冷却;12.5~12.0Ma南北向裂谷开启, 穹隆持续垮塌变形。在此基础上, 本文建立了成穹作用4个阶段, 即继承期、启动期、成穹期和垮塌期。结合构造变形、年代学及前人研究成果认为, 定日穹隆是STDS向北拆离N-S伸展和浅地壳尺度由于挤压应力的水平或垂向分量作用下E-W向伸展减压-熔融, 岩浆底劈共同作用结果, 属渐进造山, 双伸展复合成穹, 是对喜马拉雅造山事件的具体响应。本文的研究成果对北喜马拉雅片麻岩穹隆体形成机制及动力学探讨起到重要作用。The Northern Himalayan gneiss domes are an important part of the Himalayan orogenic belt, which has undergone multiple phases of tectonic deformation and magmatic events, and recorded the history of subduction, convergence and collision of the Indo and Eurasian plates. The deformation sequence, dynamic characteristics and genetic mechanisms of the formation process are still controversial, and the key tectono-magmatic events and time need to be clarified. This paper reports the material composition, tectonic deformation, kinematics and chronology of the Dingri dome associated with NSTR in the middle part of the belt.The "4+4" model of material composition and tectonic deformation of Dingri dome is revealed, i.e., it is divided into upper, middle and lower rock-tectonic units and core granite bodies by the upper and lower main detachment faults, among which the upper and middle rock-tectonic units belong to the shallow metamorphosed Tethyan Himalayan sedimentary rock series, and the lower rock-tectonic unit is the Higher Himalayan Crystalline basement detachment basement outcropping, and the core intrusion is leucogranite. The dome has undergone four tectonic deformations, namely, the initial southward thrust N-S extrusion, the early near N-S extension, the main E-W extension, and the late collapse extensional deformation. The dome was in place and inherited the material composition and compressive tectonic deformation of the Mesozoic Tethyan Himalaya. Then, at ~22.1Ma, the N-S extension occurred and the initial magma emplacement took place. At ~17.1Ma, the main magma intruded due to the E-W extension, and at 14.4~14.1Ma it cooled. At 12.5~12.0Ma, the NSTR opened and the dome continued to collapse and deform. According to the above regional geological histories, four stages of dome formation were established, namely the inheritance period, the initiation period, the dome formation period and the collapse period. Combined with previous research results, tectonic deformation and chronology, it is believed that the D

关 键 词：北喜马拉雅片麻岩穹隆 定日穹隆 构造变形 年代学 双伸展复合成穹 成因机制 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]