地质学报2011，Vol.85Issue(3)：354-365,12.
赣杭构造带金衢盆地燕山期基性脉岩地球化学特征及成因探讨
Geochemical Characteristics of the Yanshanian Mafic Dykes in the Jinqu Basin, Gan-Hang Tectonic Belt and Its Petrogenesis
摘要
Abstract
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 69.5Ma to 131.7Ma 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). Magma came from relative depleted mantle to enrich mantle; with (87 Sr/86 Sr)i ＝ 0.70642 ～ 0.70869, (143Nd/144Nd)i＝0.512244～0.512352,εNd(t)=-2.3～-5.9. Source magma tends to change from relatively depleted mantle near the center of the tectonic belt to enriched mantle on both flanks of the belt. 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.关键词
赣杭构造带/金衢盆地/基性脉岩/元素地球化学/岩石成因Key words
Gan-Hang tectonic belt/ Jinqu basin/ mafic dykes/ elemental geochemistry/ petrogenesis引用本文复制引用
齐有强,胡瑞忠,刘燊,冯彩霞,田建吉,冯光英,王涛..赣杭构造带金衢盆地燕山期基性脉岩地球化学特征及成因探讨[J].地质学报,2011,85(3):354-365,12.基金项目
本文为国家自然科学基金项目(编号40903018,40634020和40773020),国家重点基础研究发展计划项目(编号2007CB411408),贵州省科技基金(黔科合J字[2009]2248号)及中国科学院地球化学研究所矿床地球化学国家重点实验室自主课题联合资助的成果. （编号40903018,40634020和40773020）
