| 张志平,雒晓刚,罗云伟,贾怀波,刘东鹏.错果错-虾姑蛇绿混杂岩复理石沉积时代:来自改则县虾姑一带碎屑锆石的制约[J].矿产勘查,2019,(6):1255-1264 |
| 错果错-虾姑蛇绿混杂岩复理石沉积时代:来自改则县虾姑一带碎屑锆石的制约 |
| Age of flysch in Cuoguocuo-Xiagu ophiolitic melange:constraints of detrital zircon from Xiagu area, Gaize County, Tibet |
| 投稿时间：2019-01-10 |
| DOI： |
| 中文关键词: 狮泉河-永珠-嘉黎 错果错-虾姑 蛇绿混杂岩 虾姑砂岩 碎屑锆石 |
| 英文关键词: Shiquanhe-Yongzhu-Jiali, Cuoguocuo-Xiagu, ophiolitic melange, Xiagu's sandstone, detrital zircon |
| 基金项目:中国地质调查局项目(编号:1212011221089)资助。 |
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| 中文摘要: |
| 错果错-虾姑蛇绿混杂带位于狮泉河-永珠-嘉黎蛇绿混杂岩带中段,与其伴随的复理石是其洋盆沉积的记录,它的时代归属对约束狮泉河-永珠-纳木错弧后小洋盆的演化具有重要意义。本文以狮泉河-永珠-嘉黎蛇绿混杂岩带中段改则县错果错-虾姑蛇绿混杂带虾姑一带的碎屑岩为研究对象,对其进行岩石学和碎屑锆石年代学方面的研究。该区碎屑岩以薄层砂岩和页岩互层为主,具复理石沉积特征。砂岩碎屑锆石年代学分析结果显示,最小碎屑锆石年龄为119Ma,最小年龄峰值为120Ma,指示该地区碎屑岩的时代为早白垩世晚期。结合前人研究,在早白垩世晚期,北部的班公湖-怒江残余洋向南俯冲,南部的雅江洋向北俯冲,加快了中部狮泉河-永珠-纳木错小洋盆俯冲消减,冈底斯岛弧与喀喇昆仑-南羌塘-左贡陆块发生弧-陆碰撞,形成了规模有限的狮泉河-永珠-嘉黎蛇绿岩及早白垩世晚期残留海盆地,在虾姑一带沉积了虾姑碎屑岩,随后闭合,之后沉积了早白垩世末的多尼组和郞山组残海沉积。 |
| 英文摘要: |
| The Cuoguocuo-Xiagu ophiolitic melange zone is located in the middle part of Shiquanhe-Yongzhu-Jiali ophiolitic melange zone. Its age of the accompanying flysch is of great significance to constrain the evolution of the Shiquanhe-Yongzhu-Namucuo post-arc small oceanic basin, which recordding of oceanic basin sedimentation. The study of Cuoguocuo-Xiagu ophiolite and Flysch Deposits is blank in the area of Cuoguocuo-Xiagu in Gaize County. In this paper, we have carried out detailed petrological and clastic zircons chronology studies on the clastic rocks in the Xiagu area of the Cuoguocuo-Xiagu ophiolitic melange belt.The research shows the clastic rock in this area is mainly composed of thin sandstone and shale interbeds, which have characteristic of flysch. The chronological analysis of sandstone clastic zircons shows that the minimum clastic zircon is 119 Ma and the minimum age peak is 120 Ma, indicating that the age of clastic rock in this area is Early Cretaceous,detailed petrological and clastic zircons chronology studies are carried out. Combining with previous studies,the Bangong Lake-Nujiang residual ocean in the North subducted southward and the Yajiang Ocean in the South subducted northward, which accelerated the subduction of the Shiquanhe-Yongzhu-Namucuo small oceanic basin in the central part . The arc-land collision occurred between the Gangdese island arc and the Karakoram-Nanqiangtang-Zuogong block, resulting in the formation of a limited Shiquanhe-Yongzhu-Jiali ophiolite and the remnants in the late Early Cretaceous. In the sea basin, the clastic rocks were deposited in the area of Xiagu, then closed, and then the residual marine sediments of Duoni Formation and Langshan Formation were deposited at the end of Early Cretaceous. |
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