刘宝星,裴先治,李瑞保,陈有炘,王盟,赵少伟.南秦岭勉略构造带横现河地区变质沉积岩形成时代及物源——来自LA-ICP-MS碎屑锆石U-Pb年龄的证据[J].西北地质,2020,53(2):77-101 LIU Baoxing,PEI Xianzhi,LI Ruibao,CHEN Youxin,WANG Meng,ZHAO Shaowei.Age and Provenance of the Metasedimentary Rocks of Hengxianhe Area in Mianlue Tectonic Belt of Southern Qinling: Evidence from Detrital Zircons LA-ICP-MS U-Pb Dating[J].Northwestern Geology,2020,53(2):77-101
南秦岭勉略构造带横现河地区变质沉积岩形成时代及物源——来自LA-ICP-MS碎屑锆石U-Pb年龄的证据
Age and Provenance of the Metasedimentary Rocks of Hengxianhe Area in Mianlue Tectonic Belt of Southern Qinling: Evidence from Detrital Zircons LA-ICP-MS U-Pb Dating
投稿时间:2019-10-12  修订日期:2019-12-02
DOI:10.19751/j.cnki.61-1149/p.2020.02.005
中文关键词:  南秦岭;勉略构造带;朱家山岩组;乔子沟岩片;碎屑锆石U-Pb定年
英文关键词:South of Qinling;Mianlue Tectonic Zone;Zhujiashan Formation;Qiaozigou Slice;detrial zircon LA-ICP-MS U-Pb dating
基金项目:国家自然科学基金项目“扬子地块西北缘碧口群构造属性及与Rodinia超大陆聚合-裂解关系”(41872233)和“秦岭-祁连结合部位早古生代晚期岩浆事件及其对构造演化的启示”(41872235),陕西省基金项目“勉略宁地区中新元古代中酸性侵入岩构造属性研究”(2019JM-312),中央高校基本科研业务费资助项目(300102279108)
作者单位
刘宝星 长安大学地球科学与资源学院, 陕西 西安 710054 
裴先治 长安大学地球科学与资源学院, 陕西 西安 710054
西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054 
李瑞保 长安大学地球科学与资源学院, 陕西 西安 710054
西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054 
陈有炘 长安大学地球科学与资源学院, 陕西 西安 710054
西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054 
王盟 长安大学地球科学与资源学院, 陕西 西安 710054
西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054 
赵少伟 长安大学地球科学与资源学院, 陕西 西安 710054
西部矿产资源与地质工程教育部重点实验室, 陕西 西安 710054 
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中文摘要:
      朱家山岩组、乔子沟岩片位于南秦岭勉略构造带横现河以北,是勉略构造带中强烈韧性变形的沉积岩系,是勉略构造混杂岩带的基质岩系,研究其形成时代、沉积物源,对于深入了解勉略构造带的形成时代与构造演化具有重要意义。笔者以横现河以北地区朱家山岩组、乔子沟岩片中的变质沉积岩(绢英千枚岩)为研究对象,进行碎屑锆石LA-ICP-MS锆石U-Pb年代学研究,探讨其形成时代及沉积物源。所获得的碎屑锆石年龄可以分为3组:古生代年龄组(375~542 Ma),可以划分为晚古生代早期-早古生代晚期年龄组(375~424 Ma),主要峰值为390 Ma、394 Ma,早古生代早期年龄组(530~542 Ma);新元古代年龄组(552~977 Ma),可以划分为新元古代晚期年龄组(552~797 Ma),主要峰值为758 Ma、787 Ma,新元古代早中期年龄组(800~977 Ma),主要峰值为855 Ma、951 Ma;中元古代晚期年龄组(1 008~1 124 Ma)。朱家山岩组、乔子沟岩片碎屑锆石最小年龄组分别为375~385 Ma(平均年龄为380.3 Ma)、377~389 Ma(平均年龄为383 Ma),说明朱家山岩组、乔子沟岩片浅变质沉积岩系的沉积时代不早于中-晚泥盆世。综合研究认为2件样品物源主要都来自勉略构造带、碧口微地块和扬子板块北缘地区的岩浆岩,沉积环境为裂陷盆地且由伸展裂陷过渡为稳定的台盆-台地沉积。
英文摘要:
      The Zhujiashan Formation and Qiaozigou Slice are located in the north of Hengxianhe of Mianxian-Lueyang Tectonic Belt in the south of Qinling,which are the sedimentary rocks with intense ductile deformation in the Mianlue Tectonic belt. As the basement rock series of the Mianlue Tectonic belt,it is of great significance to research the yielded ages and sediment provenances for understanding the yielded ages and tectonic evolution of the Mianlue Tectonic belt. In this paper,the metamorphic sedimentary rocks (sericite phyllite) are studied by LA-ICP-MS detrial zircon U-Pb chronology in Zhujiashan Formation and Qiaozigou Slice in the north of Hengxianhe area to explore their yielded ages and sediment provenances. The obtained detrital zircon age can be divided into three groups:the Paleozoic age group, the Neoproterozoic age group and the Late Mesoproterozoic age group. the Paleozoic age group(375 to 542 Ma) can be divided into the early Late Paleozoic-late Early Paleozoic age group (from 375 to 424 Ma) and the Early Paleozoic Age group (from 530 to 542 Ma), with the prominent peaks age being 390 Ma and 394 Ma. the Neoproterozoic age group (from 552 to 977 Ma), with the prominent peaks age being 758 Ma and 787 Ma, can be divided into late Neoproterozoic age groups(from 552 to 797 Ma)and the Early-Middle Neoproterozoic age group (from 800 to 977 Ma) with the prominent peaks age being 855 Ma and 951 Ma. The Late Mesoproterozoic age is from 1008 to 1124 Ma. the minimum age group of detrital zircons of Zhujiashan Formation and Qiaozigou Slice is from 375 to 385 Ma (average age 380.3 Ma) and from 377 to 389 Ma (average age 383 Ma),indicating that the sedimentary age is not earlier than the Middle-Late Devonian. Comprehensive study shows that the provenances of the two samples are mainly derived from magmatic rock in Bikou block of Mianlue Tectonic Zone and the northern margin of Yangtze plate. The sedimentary environment is rift basin, and from extensional rifting to stable platform-platform deposition.
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