| 张志平,汪宏涛,董瀚,王晓东,贾怀波.西藏桑日县-桑耶寺一带火山-沉积岩地层锆石U-Pb年龄特征及地质意义[J].矿产勘查,2018,9(10):1869-1879 |
| 西藏桑日县-桑耶寺一带火山-沉积岩地层锆石U-Pb年龄特征及地质意义 |
| Characteristics of Zircon U-Pb Age and Geological Significance of Volcanic-Sedimentary Sequencesalong Sangri County-Samye Temple Belt, Tibet |
| 投稿时间：2018-06-29 |
| DOI： |
| 中文关键词: 桑日县 锆石U-Pb年龄 麻木下组 比马组 旦狮庭组 |
| 英文关键词: Sangri county, zircon U-Pb age, Mamuxia formation, Bima formation, Danshiting formation |
| 基金项目:中国地质调查局项目(编号:121201010000150014-46、DD20160015-08)资助。 |
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| 中文摘要: |
| 青藏高原中生代时期新特提斯洋演化及其相应的岩浆作用一直是高原基础研究的热点之一,其年代学系统研究对新特提斯洋及拉萨地块的地质演化具有重要的意义。桑日县-桑耶寺一带火山-沉积岩地层出露有叶巴组、麻木下组、比马组、旦狮庭组、门中组、温区组、典中组等,各地层时代在不同的文献中出入较大,文章在详细的野外调查及前人研究基础上,选择具有代表性的火山岩层位,系统采集火山岩样品,对其进行锆石 U-Pb测年,并对该区火山岩年龄进行系统研究。结果表明,桑日县以西至扎囊县桑耶寺一带,雅江结合带北侧出露的火山-沉积岩地层中的火山岩年代均为晚白垩世,在野外调查基础之上,结合岩石学和年代学,划分了麻木下组(90.24±0.41～99.9±0.7 Ma)、比马组(90.4±1.6～93.7±1.2 Ma)、旦狮庭组(87.26±0.76～88.9±1.3 Ma),并限定了其形成时代,进一步厘清了该区火山-沉积岩地层年代格架。 |
| 英文摘要: |
| The evolution of Neo-Tethys and associated magmatism during Mesozoic has become a topic of debate in the basic study of the Tibetan Plateau. The systematic Geochronology study on these volcano-sedimentary sequences is of great importance in understanding the evolution of the Neo-Tethys and the Lhasa Block. The outcrops of volcano-sedimentary sequences along Sangri County - Samye Temple Belt are the Yeba Formation, the Mamuxia Formation,the Bima Formation, the Danshiting Formation,the Menzhong Formation, the Wenqu Formation and Dianzhong Formation, and the age of these formations are discrepant in different papers. The authors of this paper carried out zircon LA-ICP-MS dating on the volcanic rocks and systematically analyzed their age on the basis of detailed field investigation and previous studies. In combination with the data available, they conclude that all of the volcanic rocks exposed along the Sangri County - Samye Temple Belt formed in Late Cretaceous . The authors divided the formations as the Mamuxia Formation (90.24±0.41～99.9±0.7 Ma),the Bima Formation (90.4±1.6～93.7±1.2 Ma), the Dianzhong Formation (87.26±0.76～88.9±1.3 Ma) specifically, and further clarified the chronology framework of volcanic-sedimentary sequences in this area. |
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