Leucogranites discovered in the Ailaoshan-Red River shear zone（ASRR） were related to the anatexis event and mark the beginning of left-lateral strike-slip movement of the ASRR. U–Pb dating of zircon from the leucogranites yields an age of about 27 Ma, suggesting the late Oligocene anatexis event. Geochemical characteristics suggest that they are geochemically similar to Himalayan leucogranites（enriched in the large-ion lithophile elements, and depleted in high-field-strength elements） and experienced highly fractional crystallization of K-feldspar and zircon. Low 87Sr/86Sr（t）（0.7072–0.7111）, high εNd（t）（–1.53 to –3.61） and εHf（–5 to +1.8） with old two-stage Hf model ages of 1.24–1.02 Ga in zircon imply that they are probably derived from partial melting of the amphibolite（old crustal materials） at the lower crust. Compared with previous studies of metamorphism of the ASRR, these leucogranites are considered to be generated in a highly dynamic setting from extrusion to extension and mark the beginning of left-lateral slip-strike movement of the ASRR at 27 Ma.
类型: 国际会议
作者: HE Xiaohu,TAN Shucheng,LIU Zheng,ZHOU Jiaxi,YANG Siqi
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: Yunnan UniversityKunming University of Science and Technology
分类号: P542;P588.245
DOI: 10.26914/c.cnkihy.2019.028292
页码: 34-35
总页数: 2
文件大小: 241k
下载量: 1
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