哀牢山深变质带内两类晚渐新世花岗岩成因及其构造指示

发布时间：2018-03-14 03:41

本文选题：哀牢山构造带　切入点：花岗质岩石　出处：《中山大学学报(自然科学版)》2017年06期 　论文类型：期刊论文

【摘要】：红河-哀牢山构造带发育了广泛的、与印度欧亚板块碰撞造山作用紧密相关的新生代构造-岩浆作用,出露于云南哀牢山变质带中段的两个花岗岩样品锆石U-Pb定年结果分别为26.2±0.5 Ma和26.8±0.5 Ma,说明哀牢山变质带并不全是扬子板块结晶基底的下元古界,也存在新生代岩浆岩。花岗岩锆石ε_(Hf)(t)分别为+0.3~+6.9和-9.8~-0.7,平均为+3.4和-4.3,其二阶段模式年龄T_(DM2)分别为526~853 Ma和903~1 355 Ma。低ε_(Hf)(t)花岗岩源岩可能是元古宙哀牢山群变质杂砂岩,高ε_(Hf)(t)花岗岩源自软流圈地幔热源加热诱发的新生下地壳部分熔融。结合前人研究成果,认为晚渐新世红河剪切带剪切作用切穿了岩石圈地幔;渐新世印支地块两侧的高黎贡山和哀牢山走滑剪切系统肢解了东南亚不同的块体,为印支地块向东南方向的挤出创造了条件。
[Abstract]:The Honghe-Ailaoshan tectonic belt developed extensive Cenozoic tectonic-magmatism closely related to the collision orogeny of the Indian Eurasian plate. The zircon U-Pb dating results of two granite samples exposed in the middle segment of the Ailaoshan metamorphic belt in Yunnan Province are 26.2 卤0.5 Ma and 26.8 卤0.5 Ma, respectively, indicating that the Ailaoshan metamorphic belt is not all the Lower Proterozoic of the Yangtze plate crystalline basement. There are also Cenozoic magmatic rocks. The zircon 蔚 s of the granite are 0.3-6.9 and -9.8mg-0.7, with an average age of 3.4 and -4.3, respectively. The two-stage model age TX DM2) is 526553 Ma and 9033.35 Ma.The low 蔚 Hftt) granite source rock may be a metamorphic complex sandstone of the Proterozoic Aishan Group, and the granite source rock may be a metamorphic sandstone of the Proterozoic Aishan Group, and its two-stage model age TX DM2 is 526553 Ma and 903N 1 355 Ma.The granite source rocks may be of the Proterozoic Aishan Group. The granite originated from the partial melting of the new lower crust induced by the heat source of the asthenosphere mantle. Based on the previous research results, it is considered that the shear of the Honghe shear zone in the late Oligocene cut through the lithospheric mantle; The strike slip shear system of Goligong and Ailao mountains on both sides of the Oligocene Indosinian block dismembered different blocks in Southeast Asia, which created conditions for the extrusion of the Indosinian block to the southeast.
【作者单位】：中国科学院广州地球化学研究所同位素地球化学国家重点实验室;中山大学地球科学与工程学院;中国科学院大学;广东省地球动力作用与地质灾害重点实验室;
【基金】：国家重点研发计划项目(2016YFC0600303) 国家重点基础研究发展计划(973)项目(2014CB440901) 国家自然科学基金联合基金(U170160005) 中山大学高校基本业务费项目
【分类号】：P588.121

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