苏鲁造山带新沂地区新元古代花岗片麻岩成因及对Rodinia超大陆裂解的响应  

Genesis of Neoproterozoic Granite Gneiss in Xinyi Area of Sulu Orogenic Belt and Its Response to the Breakup of Rodinia Supercontinent

作　　者：张琪[1] 周琦忠 孙超 施建斌[1] 王博 侯琪 罗跃[1] 冯学知[1] 王国强[1] Zhang Qi;Zhou Qizhong;Sun Chao;Shi Jianbin;Wang Bo;Hou Qi;Luo Yue;Feng Xuezhi;Wang Guoqiang(No.5 Geological Team of Jiangsu Geology and Mineral Bureau,Xuzhou 221004,Jiangsu,China;School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]江苏省地质矿产局第五地质大队,江苏徐州221004 [2]中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《吉林大学学报（地球科学版）》2024年第1期140-159,共20页Journal of Jilin University：Earth Science Edition

基　　金：江苏省地质勘查基金项目(苏财资环[2021]46号);江苏省地质矿产勘查局科研项目(2021KY09);中国地质调查局项目(DD20190153)。

摘　　要：新沂地区花岗片麻岩位于苏鲁造山带的西缘。本文通过新沂地区花岗片麻岩岩相学、岩石地球化学、锆石U-Pb同位素年代学等方面的研究,探讨其成因与构造环境,以揭示Rodinia超大陆裂解事件在该地区的反响。研究认为:研究区花岗片麻岩属准铝质-弱过铝质A型花岗岩,具有高SiO_(2)、富碱、贫CaO、低Al_(2)O_(3)质量分数的特征,以及右倾海鸥型稀土元素配分模式,富集Rb、Zr、Hf等元素,严重亏损Sr、Eu、Nb、Ta等元素,形成年龄为746.0~742.5 Ma。新沂地区花岗片麻岩是来自下地壳物质为主、少量幔源物质的部分熔融,在岩浆演化过程中经历了以钾长石和斜长石为主的分离结晶,而后经过超高压变质作用最终形成。研究区花岗片麻岩形成于新元古代后碰撞伸展环境,是Rodinia超大陆裂解事件在苏鲁造山带新沂地区的最初响应。The granite gneiss in the Xinyi area is located on the western margin of the Sulu orogenic belt.This paper discusses its petrogenesis and tectonic environment by examining petrography,rock geochemistry,and zircon U-Pb isotopic chronology of the granite gneiss.It also reveals the repercussions of the breakup event of the Rodinia supercontinent in this area.The findings indicate that the granite gneiss in the study area belongs to the meta-aluminous-weak peraluminous A-type granite,characterized by high SiO_(2)content,rich alkali,low CaO and Al_(2)O_(3)contents,and a right-dipping seagull-type rare earth distribution pattern.It is enriched in Rb,Zr,Hf elements,while being severely depleted in Sr,Eu,Nb,Ta elements.The age of the granite gneiss is 746.0-742.5 Ma.The granite gneiss in the Xinyi area originated from the partial melting of lower crustal material and a small amount of mantle-derived material.In the process of magma evolution,it underwent the separation and crystallization of potassium feldspar and plagioclase,and eventually formed through ultra-high pressure metamorphism.The granite gneiss in the Xinyi area was formed in a post-collisional extensional environment in the Neoproterozoic,marking the initial response to the Rodinia supercontinent breakup event in study area of the Sulu orogenic belt.

关 键 词：苏鲁造山带 新沂地区 新元古代 花岗片麻岩 岩石成因 RODINIA超大陆裂解 

分 类 号：P581[天文地球—岩石学]