| 冈底斯中部松多岩组形成时代及物源:来自碎屑锆石U-Pb年代学证据 |
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| 引用本文： | 解超明,宋宇航,王明,范建军,张红雨,郝宇杰.冈底斯中部松多岩组形成时代及物源:来自碎屑锆石U-Pb年代学证据[J].地球科学,2019,44(7):2224-2233. |
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| 作者姓名： | 解超明 宋宇航 王明 范建军 张红雨 郝宇杰 |
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| 作者单位： | 1.吉林大学地球科学学院, 吉林长春 130061 |
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| 基金项目： | 中国地质调查局项目DD20160015自然资源部东北亚矿产资源评价重点实验室自主课题基金资助DBY-ZZ-18-06国家自然科学基金项目41872231中国地质调查局项目DD20160026国家自然科学基金项目41602230 |
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| 摘 要： | 冈底斯中部广泛发育的松多岩组因缺少化石依据，其沉积时代一直存在争议，严重制约了对冈底斯古生代构造演化的认识.在详细野外地质调查基础上，利用LA-ICP-MS锆石U-Pb同位素定年对松多岩组中变质砂岩进行了锆石U-Pb同位素测定，获得变质砂岩中最小碎屑锆石年龄值为316 Ma，时代为晚石炭世，代表了松多岩组形成时代的下限.通过碎屑锆石年龄示踪和区域对比研究，松多岩组物源很可能来自拉萨地块内部(南拉萨地块和北拉萨地块)，可能是松多古特提斯洋初始洋盆的沉积记录.研究区松多岩组沉积时代下限的厘定，进一步完善了该区晚古生代地层系统，对冈瓦纳大陆北缘晚石炭世－早二叠世岩相古地理研究具有重要意义.
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| 关 键 词： | 青藏高原 冈底斯 晚石炭世-早二叠世 松多岩组 碎屑锆石 物源 年代学 |
| 收稿时间： | 2018-11-18 |
Age and Provenance of Sumdo Formation in Central Gangdise,Tibetan Plateau: Detrital Zircon U-Pb Geochronological Evidence |
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| Abstract: | The Sumdo Formation, which is widely developed in the central Gangdise, has been controversial in its stratigraphic age due to lack of fossil evidence, seriously restricting our understanding of structural evolution in the Sumdo area. In this paper, on the basis of detailed field geological investigation, LA-ICP-MS U-Pb dating was carried out on detrital zircons from metamorphic sandstones of Sumdo Formation. The minimum zircon age of detrital zircon in metamorphic sandstones is 316 Ma, the Late Carboniferous, representing the lower limit of the main depositional age of the Sumdo Formation. Provenance analysis indicates that the sedimentary detritus was sourced from the Lhasa terrane itself (South and North Lhasa terranes), and may be the sedimentary record of the initial ocean basin of Sumdo Paleo-Tethys Ocean. The determination of the age of the Sumdo Formation has further improved the Late Paleozoic stratigraphic system in this area and is of great significance to the study of lithofacies and paleogeography of the Late Carboniferous-Early Permian in the northern margin of the Gondwana. |
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