期刊
INTERNATIONAL GEOLOGY REVIEW
卷 65, 期 7, 页码 1000-1016出版社
TAYLOR & FRANCIS INC
DOI: 10.1080/00206814.2020.1857851
关键词
Mafic dykes; zircon and baddeleyite U-Pb geochronology; Sr-Nd isotopes; rifting; Rodinia; Altyn Tagh
类别
Through the research in the Altyn Tagh terranes in northwest China, it is found that the Yapuqiasayi mafic dykes in the North Altyn Tagh have similar age and petrogenetic characteristics to mafic igneous rocks in Australia, South China, Seychelles, Laurentia, and Tarim, indicating a possible relationship with the breakup of the Rodinia supercontinent.
Whether or not the Altyn Tagh terranes in northwest China were part of the Rodinia supercontinent is unclear due to the apparent absence of rift-related igneous rocks. We present U-Pb geochronology, mineral chemistry, whole-rock major and trace element and Sr-Nd isotope data for the Yapuqiasayi mafic dykes in the North Altyn Tagh. Zircon and baddeleyite from a mafic dyke sample yield indistinguishable U-Pb results and a weighted mean Pb-207/Pb-206 date of 740 +/- 11 Ma, interpreted as the igneous crystallization age. The dykes are tholeiitic in composition, with high TiO2, Zr/Sm and Zr/Y, resembling intraplate basalts. Whole-rock major and trace elements, together with Sr and Nd isotope data, indicate that the dyke magmas originated by 3-5% partial melting of a garnet-poor (<1%) asthenospheric mantle source and were variably modified by crustal contamination. These features, together with mineral chemistry and field observations, indicate that these mafic dykes formed in a continental rift setting, possibly induced above a mantle plume. We show that the Yapuqiasayi dykes are similar in age and petrogenetic characteristics to mafic igneous rocks in Australia, South China, Seychelles, Laurentia, and Tarim, and speculate that their emplacement in North Altyn Tagh was associated with rifting and break-up of the Rodinia supercontinent above a Neoproterozoic superplume.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据