| 摘要: |
| 老挝琅勃拉邦构造带位于印支板块西部，是东南亚特提斯域内的重要构造带之一。该地区多期次的岩浆活动记录了多阶段的构造岩浆演化，但与古特提斯洋闭合过程相关的岩浆活动报道相对较少，导致与该过程相关的构造-岩浆-成矿作用关系理解不清。本文在野外地质观察和岩相学研究的基础上，对老挝琅勃拉邦地区石英闪长岩开展了锆石U-Pb LA-ICP-MS定年，分析结果表明，石英闪长岩结晶年龄为260.5±1.8 Ma，表明琅勃拉邦构造带存在中晚二叠世岩浆活动。结合前人研究结果，本文认为该中酸性侵入体很可能是古特提斯洋板片东向俯冲，难河-沙缴弧后盆地关闭过程中岩浆活动的产物，且为琅勃拉邦构造带向南连接至难河-程逸结合带提供了新资料。 |
| 关键词: 锆石U-Pb定年 琅勃拉邦构造带 石英闪长岩 古特提斯洋 |
| DOI：10.19826/j.cnki.1009-3850(2020)01-0068-08 |
| 附件 |
| 投稿时间：2019-10-21修订日期：2020-01-02 |
| 基金项目:本研究得到中国地质调查局地质调查项目“东南亚大型锡铜金矿资源基地评价冶（DD2019444）、“老挝、柬埔寨及邻区矿产资源潜力评价冶（DD20160107）的资助。 |
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| Zircon U-Pb dating of quartz-diorite from Luang Prabang tectonic belt in Laos: Implication for eastward subduction of the Paleo-Tethys Ocean |
| GUO Linnan, HOU Lin, NIE Fei, LIU Shusheng, Xu Siwei, ZHANG Qiming |
| (Chengdu Center, China Geological Survey, Chengdu 610081, China) |
| Abstract: |
| The Luang Prabang tectonic belt in Laos is located in the western of Indo-China Plate, and it is one of the important tectonic belts in Southeast Asia-Tethys domain. Multi-stage magmatic activities in this area recorded multi-stage tectonic-magmatic evolutions. However, there are few reports on magmatic activity related to the closure process of Paleo-Tethys Ocean, thus the relationship of tectonic evolution-magmatism-metallogenesis in the process remain controversial. Based on field geological observations and petrographic studies, this article carried out zircon U-Pb LA-ICP-MS dating of quartz diorite in Luang Prabang, Laos. The results show that the crystalline age of the quartz diorite is 260.5±1.8 Ma, indicating a Middle-Late Permian magmatic activity in the Luang Prabang tectonic belt. Combine with previous studies, we believe the medium-acid intrusive rock is likely to be the product of magmatic activity during the eastward subduction of the Paleo-Tethys Ocean-plate and closure of the Nan-Sra Kaeo backarc basin. It also provides new data indicating that the Luang Prabang tectonic zone may link to the Nan-Uttaradit to the south. |
| Key words: Zircon U-Pb dating Luang Prabang tectonic zone Quartz diorite Paleo-Tethys Ocean |
