Petrogenesis of Late Mesozoic Diabase Dikes in Zhejiang-Fujian Provinces: Constraints from Ar-Ar Dating and Geochemistry
详细信息
- 责任者：Qin Shecai (Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Fan Weiming
- 刊名：Acta Petrologica Sinica
- 出版年：2010
- 卷期：26(11)
- 关键词：辉长岩 ; gabbros ; 岩石地球化学 ; lithogeochemistry ; 浙江 ; Zhejiang Province ; 福建 ; Fujian Province
- 页码：p.3295-3306
- 图表：3 illus., 4 tables, 36 refs.
- 分类号：0801
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The diabases from Wencheng in Zhejiang Province and Yongtai in Fujian Province that intrude into the Late Mesozoic intermediate-felsic volcanic rocks in SE China were formed at 90~94 Ma under an extensional setting. All features were quite different from those mafic magmas derived from asthenosphere. However, neither crustal contamination and/or assimilation via fractional crystallization nor magma mixing processes could well explain the observed elemental and isotopic variations in these rocks. By contrast, the combined geochemical data suggest that these diabases were formed through different proportional mixing between an enriched lithosphere component and the underlying asthenosphere under an extensional regime throughout the SE China continent. The Wencheng diabases with more evolved Sr-Nd isotopic compositions were derived from such a mixed source containing a higher proportion of enriched component, whereas the asthenosphere component was greater in the melting source for the Yongtai diabases to account for their less evolved Sr-Nd isotope signatures.