| 辽东古元古代造山带花岗片麻岩穹窿:热造山带典型构造样式 |
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| 引用本文： | 张程,杨洪祥,冯嘉,刘俊来.辽东古元古代造山带花岗片麻岩穹窿:热造山带典型构造样式[J].岩石学报,2019,35(9):2926-2942. |
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| 作者姓名： | 张程 杨洪祥 冯嘉 刘俊来 |
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| 作者单位： | 中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083,中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083,中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083,中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083 |
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| 基金项目： | 本文受国家自然科学基金项目（41772201、41430211）和国家重点研发计划项目（2016YFC0600108-01）联合资助. |
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| 摘 要： | 中下地壳的底辟上升是地壳中物质运移和热传递的一种重要机制,由这种机制产生的一系列穹窿构造不仅为揭示区域构造环境和构造演化提供了重要的线索,而且还提供了一个了解地壳深部物质流动的窗口。辽东半岛的古元古代造山带内就发育有这样一套花岗片麻岩穹窿构造,为了深入理解这套花岗片麻岩穹窿的成因以及对造山带演化的影响,本文对其不同构造层次进行了详细的构造特点和变形演化研究。结果显示,典型的花岗片麻岩穹窿可分为三层结构:混合岩化的花岗岩内核、发育顺层韧性剪切带的幔部以及含大型构造透镜体的外壳。其中核部花岗岩塑性流动变形发育,并具有明显的交代现象。顺层韧性剪切带的变形环境由靠近岩体的角闪岩相到远离岩体的低绿片岩相,并且没有明显的退化变质特点,拉伸线理具有统一的NW-SE方向。根据年代学数据与区域构造分析,花岗片麻岩穹窿构造是在区域收缩体制下花岗岩底辟形成的产物,其出现标志着辽东古元古代造山带变为一个由垂向和横向对流作用为主导的热造山带。
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| 关 键 词： | 花岗片麻岩穹窿 辽吉古元古代造山带 热造山带 |
| 收稿时间： | 2017/10/22 0:00:00 |
| 修稿时间： | 2018/2/27 0:00:00 |
Granitic gneiss domes from the Paleoproterozoic orogen in eastern Liaoning: The typical structural styles in hot orogen |
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| ZHANG Cheng,YANG HongXiang,FENG Jia and LIU JunLai.Granitic gneiss domes from the Paleoproterozoic orogen in eastern Liaoning: The typical structural styles in hot orogen[J].Acta Petrologica Sinica,2019,35(9):2926-2942. |
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| Authors: | ZHANG Cheng YANG HongXiang FENG Jia and LIU JunLai |
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| Institution: | State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China,State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China,State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China and State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | Diapiric upwelling of the middle and lower crust is an important mechanism of mass transportation and thermal transmission in the crust. Gneissic domes produced by this mechanism provide not only important clues for revealing regional tectonic environment and tectonic evolution, but also a window to understand the mass flow in the deep crust. There are such a set of dome-like magmatic domes in the Paleoproterozoic orogen of Liaodong Peninsula. In order to deeply understand the origin of the granite-gneiss domes and their influence on the evolution of the orogenic belt, this paper has conducted detailed studies on structural characteristics and deformation evolution of its different tectonic levels. The results show that typical granitic gneiss domes are composed of three parts:the core of gneissic granites, the mantle of metamorphic rocks and the crust of sliding blocks. The cores are characterized by plastic flow deformation and obvious metasomatism phenomenon. The mantle of metamorphic rocks was sheared at amphibolite facies near the granite to the distal low-greenschist facies. Stretching lineations are uniformly oriented at NW-SE orientation. According to geochronology data and regional structural analyses, the granite-gneiss domes were formed by migmatitic granite diapirism under the influence of regional contraction. The occurrence of granite-gneiss domes implies that the Paleoproterozoic orogenic belt in Liaodong Peninsula was a hot orogen dominated by vertical and horizontal convection. |
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| Keywords: | Granitic gneiss dome Liao-Ji Paleoproterozoic orogen Hot orogen |
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