LA-ICP-MS Zircon U-Pb Ages and Geochemistry of Neoproterozoic Low-Grade Metavolcanic Rocks in Wuyuan-Dexing Area of Northeastern Jianxi Province
详细信息
- 责任者：Liu Shuwen (Key Laboratory of Orogen and Crust Evolution ; Ministry of Education ; Peking University ; Beijing 100871 ; China) ; Yang Pengtao
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(2)
- 关键词：变火山岩 ; metavolcanic rocks ; 江西 ; Jiangxi Province
- 页码：p.581-593
- 图表：illus., 3 tables, 47 refs.
- 分类号：0802
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
Low-grade metamorphosed volcanic rocks consist mainly of metamorphic basalt, dacite and rhyolite in the Wuyuan to Dexing region of the northeastern Jiangxi Province. Whole-rock geochemical analyses reveal that the metabasalt has chemical features of the tholeiite, and the basaltic magma originated from low-degreed partial melting of a spinel lhezolite in disturbed deleted mantle. However, the dacitic magma was derived from a partial melting of a meta-greywacke, and the rhyolite was produced by the fractionation of the dacitic magma. LA-ICP-MS zircon U-Pb isotope dating indicates low-grade meta-dacite from the Wuyuan area was formed at 861±8Ma, and meta-rhyolite and tuffaceous slate from the Dexing area at 860±3Ma and 860±6Ma, respectively, which indicate that these metamorphic volcanic rocks erupted at Neoproterozoic Tonian era. Meanwhile, these samples also preserved some signatures of Neoarchean (2.8～2.5Ga), Middle-Late Paleoproterozoic (2.0～1.7Ga) and Mesoproterozoic (～1.0 Ga) inherited and/or captured zircon ages. Integrated the whole-rock geochemistry, petrogenesis and zircon ages, we suggest that these metamorphic volcanic rocks formed under an Early Neoproterozoic tectonic background of back-arc basin in Andes-type actively continental margin.
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