西峡北部秦岭群变质沉积岩锆石SHRIMP定年:物源区复杂演化历史和沉积、变质时代确定

万渝生; 刘敦一; 董春艳; 殷小艳

西峡北部秦岭群变质沉积岩锆石SHRIMP定年:物源区复杂演化历史和沉积、变质时代确定

- 1.
  中国地质科学院地质研究所,北京离子探针中心,北京 100037
- 2.
  中国地质科学院,北京 100037
基金项目:
本文受中国地质构造区划与区域地质调查综合集成项目(1212010811033)和中国地质调查局重点项目(1212010711815)联合资助.

收稿日期: 2010-12-06

修回日期: 2011-01-06

刊出日期: 2011-04-30

SHRIMP zircon dating of meta-sedimentary rock from the Qinling Group in the north of Xixia, North Qinling Orogenic Belt: Constraints on complex histories of source region and timing of deposition and metamorphism.

- 1.
  Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
- 2.
  Chinese Academy of Geological Sciences, Beijing 100037, China

Received Date: 06 December 2010

Revised Date: 06 January 2011

Publish Date: 30 April 2011

摘要

摘要: 本文对秦岭群典型分布区西峡北部一个遭受高级变质作用的碎屑沉积岩样品(黑云斜长片麻岩)进行了锆石年代学研究。阴极发光图像显示锆石普遍具有核-边结构。在U-Pb年龄谐和图上数据点分散分布,年龄变化范围为>3.0Ga到~400Ma。结合以往研究,获得如下结论和认识:(1)秦岭群变质沉积岩的变质原岩形成于古元古代之后,其中一些可能形成于中元古代晚期甚至更晚,原秦岭群是由不同时代地质体组成,需进一步解体; (2)锆石特征表明,岩石遭受加里东期强烈变质,变质作用经历了高角闪岩相-麻粒岩相向角闪岩相的转变过程;(3)秦岭造山带及邻区存在长期复杂的早期演化历史。
- 碎屑锆石 /
- SHRIMP定年 /
- 变质时代 /
- 秦岭群 /
- 秦岭造山带
Abstract: This paper carried out a geochronological research on zircons from a meta-sedimentary rock (biotite plagioclase gneiss) sample in the north of Xixia, a typical distribution area of the Qinling Group in the Qinling Orogen Belt. The zircons show complex core-rim structures in CL images. A total of 56 analyses on forty-seven zircons have ages ranging from >3.0Ga to ~400Ma. Combined with early data, some conclusions can be drawn as follows. (1) The protolith of the meta-sedimentary rock of the Qinling Group was formed after Paleoproterozoic with some probably being Late Mesoproterozoic or even later, the original Qinling Group may be made up of rocks of different ages; (2) the zircon features show that the studied rock underwent metamorphism from upper amphibolite-granulite facies in early stage to amphibolite facies in late stage during the Early Paleozoic; (3) the source region providing detritus for the Qinling sediments shows a long and complex evolution history, there might be Archean basement in Qinling and adjacent areas.
- Detrital zircon /
- SHRIMP dating /
- Metamorphic age /
- Qinling Group /
- Qingling Orogen Belt

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西峡北部秦岭群变质沉积岩锆石SHRIMP定年:物源区复杂演化历史和沉积、变质时代确定

SHRIMP zircon dating of meta-sedimentary rock from the Qinling Group in the north of Xixia, North Qinling Orogenic Belt: Constraints on complex histories of source region and timing of deposition and metamorphism.

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