• 责任者：Qi Youqiang (State Key Laboratory of Ore Deposit Geochemistry ; Institute of Geochemistry ; Chinese Academy of Sciences ; Guiyang 550002 ; China) ; Hu Ruizhong
• 刊名：Acta Geologica Sinica
• 出版年：2011
• 卷期：85(3)
• 关键词：基性岩 ; basic rocks ; 江西 ; Jiangxi Province ; 浙江 ; Zhejiang Province
• 页码：p.354-365
• 图表：7 illus., 2 tables, 71 refs.
• 分类号：0801
• issnNo：ISSN0001-5717
• isbnNo：CN11-1951/P

Mesozoic mafic dykes in the Jinqu basin, Gan-Hang tectonic belt are predominantly diabases. The K-Ar dating study shows that the mafic dykes with age ranging from 69.5 Ma to 131.7 Ma are the result of magma intrusion during the Cretaceous Period. The SiO₂ contents of 46.70% to 50.23% and K₂O+Na₂O of 4.01% to 7.82% suggest that they belong to alkaline and sub-alkaline rocks. The trace elements are characterized by enrichment in LREE and LILE (K, Rb, Ba), and depletion in HREE and HFSE(Ta, Nb, Ti). The mafic dykes mainly resulted from partial melting and fractional crystallization of olivine, clinopyroxenes, plagioclases and apatites. Mafic dykes at Anding, Jiangshan were the product of accumulation of plagioclase crystals accompanied by crystallization separation of pyroxene and apatite. The mafic dykes derived from the partial delamination of lower crust and underplating of basaltic magma in the Jinqu basin, Gan-Hang tectonic belt. Especially, reactivation of the deep fault played an important role in diagenesis of the mafic dykes.