The Western Yunnan is one of the important parts of the East Tethys tectonic belt, and its geotectonic framework is of great significance to the evolution of the global Tethys. The Tethys tectonic belt in western Yunnan consists of several blocks and tectonic zones, such as Simao Block, Baoshan Block, Tengchong Block, the Changning-Menglian junction zone belonging to the Paleo-Tethys belt and the Gaoligong collision zone belonging to the Neo-Tethys belt. This paper reports zircon U-Pb dating and Hf isotopic compositions of granitiods in the Tengchong Block and the Baoshan Block. It reveals three stages of the Mesozoic-Cenozoic magmation in the Tengchong block: 115 ～ 118 Ma, 67 ～ 74 Ma and 51 ～ 55 Ma. All samples dated at different ages have a wide range zircon eHf（t） values（-13.1 ～ 8.8） and varying Hf-isotope model ages（0.4 ～ 1.8 Ga） and were derived from anatexis of crustal materials with varying contributions from mantle-derived components. In the Baoshan Block, the Early Paleozoic granitoids were dated at 480 ～ 486 Ma and 447 ～ 472 Ma and the Mesozoic-Cenozoic granitoids were dated at 83 ～ 85 Ma and 60 ～ 66 Ma. All analyses from ten samples have a wide range zircon eHf（t） values（-2.1 ～-12.4） and varying Hf-isotope crustal model ages（1.6 ～ 2.2 Ga）. Thegeochemical signatures indicate that the Baoshan Block granitoids are S-type granite in character and were derived mainly from anatexis of ancient crustal materials with varying contributions from mantle-derived components. The comparability of geochronology, geochemistry and tectonics in the Tengchong Block, the Baoshan Block and the Lhasa Terrane, together with the data of atratigraphy and paleobiogeography, suggest that the Tengchong Block and the Baoshan Block may represent part of an Early Paleozoic magmatic arc in the Gondwana continental margin facing the proto-Tethyan Ocean, all of which experienced similar tectonomagmatic histories since the Early Paleozoic.
类型: 国际会议
作者: DONG Meiling,DONG Guochen,XIE Jincheng,GAO Mengyao
来源: 第九届世界华人地质科学研讨会 2019-06-01
年度: 2019
分类: 基础科学
专业: 地质学,地质学
单位: Cores and Samples Center of Land & Resources,China Geological SurveyState Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources,China University of GeosciencesChinese Academy of GeologicalSciences
分类号: P588.121;P597
DOI: 10.26914/c.cnkihy.2019.028382
页码: 185
总页数: 1
文件大小: 74k
下载量: 1
本文来源: https://www.lunwen90.cn/article/7508c4374bc2fd607a24bc6a.html