Ar-Ar and U-Pb geochronology of Late Paleozoic basalts in western Guangxi and its constraints on the eruption age of Emeishan basalt magmatism |
| |
Authors: | Email author" target="_blank">Fan?WeimingEmail author Wang?Yuejun Peng?Touping Miao?Laicheng Guo?Feng |
| |
Institution: | (1) Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 510640 Guangzhou, China;(2) Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029 Beijing, China |
| |
Abstract: | The Late Paleozoic layered or stratoid-layered basalts in western Guangxi have similar elemental and isotopic compositions
to Emeishan high-Ti basalts. Whole-rock 40Ar/39Ar and SHRIMP zircon U-Pb dating were carried out for the representative basalt samples in three typical profiles in the area.
Three basalts from the upper segment of Yangxu profile and lower segment of Yufeng and Min’an profiles yield the 40Ar/39Ar plateau ages of 253.6/+-0.4 Ma (20BS-71), 255.4±0.4 Ma (20BS-99) and 256.2±0.8 Ma (20BS-119), respectively. Twenty-three
analyses on 23 zircons of the basalt from the upper segment of Yangxu profile give a weighted mean 206Pb/238U age of 253.7 ±6.1 Ma with an MSWD = 2.8. These new and published geochronological data for Emeishan large igneous province
(LIP) indicate that the Emeishan LIP was initiated at ∼260 Ma, voluminously erupted between 253 and 256 Ma, and possibly ended
at ∼251–253 Ma: The age (251–260 Ma) is generally consistent with that of the associated environmental deterioration and mass
extinction events at the end-Guadalupian and Permo-Triassic boundary. These precise geochronological data provide important
constraints on the dominantly eruptive time of the Emeisban LIP and understanding of the distribution of Emeishan high-Ti
basalts and its mantle plume dynamics. |
| |
Keywords: | radiometric dating zircon basalt mantle plume |
本文献已被 CNKI 万方数据 SpringerLink 等数据库收录! |
| 点击此处可从《中国科学通报(英文版)》浏览原始摘要信息 |
| 点击此处可从《中国科学通报(英文版)》下载免费的PDF全文 |