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    吴美仁, 陈祺, 王先广, 陈国华, 万浩章, 严加永, 欧阳永棚. 赣东北枣林碧玄岩地球化学特征及成因[J]. 中国地质, 2019, 46(4): 850-860. DOI: 10.12029/gc20190415
    引用本文: 吴美仁, 陈祺, 王先广, 陈国华, 万浩章, 严加永, 欧阳永棚. 赣东北枣林碧玄岩地球化学特征及成因[J]. 中国地质, 2019, 46(4): 850-860. DOI: 10.12029/gc20190415
    WU Meiren, CHEN Qi, WANG Xianguang, CHEN Guohua, WAN Haozhang, YAN Jiayong, OUYANG Yongpeng. Geochemistry and petrogenesis of the Zaolin basanite in the northeastern Jiangxi Province[J]. GEOLOGY IN CHINA, 2019, 46(4): 850-860. DOI: 10.12029/gc20190415
    Citation: WU Meiren, CHEN Qi, WANG Xianguang, CHEN Guohua, WAN Haozhang, YAN Jiayong, OUYANG Yongpeng. Geochemistry and petrogenesis of the Zaolin basanite in the northeastern Jiangxi Province[J]. GEOLOGY IN CHINA, 2019, 46(4): 850-860. DOI: 10.12029/gc20190415

    赣东北枣林碧玄岩地球化学特征及成因

    Geochemistry and petrogenesis of the Zaolin basanite in the northeastern Jiangxi Province

    • 摘要: 在中国东部赣东北朱溪矿集区枣林地段发现两条新生代碧玄岩岩脉。地球化学研究表明该碧玄岩具有低SiO2(41.08%~42.94%), 高Mg#(0.61~0.65), 高TiO2(2.19%~2.43%), 高Na2O+K2O(4.95%~6.30%)的特点。∑REE为299.16×10-6~375.00×10-6, LREE/HREE比值为5.45~6.71, 表明轻稀土富集, δEu为0.88~0.94, 具微弱Eu负异常。微量元素特征表现出较高Ni、Cr、Sc含量, 蛛网图显示明显富集Nb、Ta、Th、Zr等元素, 亏损Ba、Ti、K、P等。主量元素相关图解和不相容元素比值显示岩石在演化过程中未遭受地壳混染。综合分析岩石微量元素数据及相关图解, 文章认为由于太平洋板块俯冲, 导致软流圈地幔携带碳酸盐熔体上涌与岩石圈地幔相互作用, 使得0.2%~0.5%石榴石相二辉橄榄岩与0.5%~1%尖晶石相二辉橄榄岩发生部分熔融, 生成碧玄岩原始岩浆。

       

      Abstract: Two Cenozoic basanite dykes were newly discovered in the Zhuxi ore-concentration area, northeastern Jiangxi Province, eastern China. They have high SiO2 (41.08%-42.94%), Na2O+K2O (4.95%-6.30%), TiO2 (2.19%-2.43%) contents, and high Mg# (0.61 -0.65). Geochemistry characteristics of these basanite dykes show they are enriched in Nb, Ta, Th, Zr, Ni, Cr, Sc, while depleted in Ba, Ti, K, and P. Their ∑REE values are from 299.16×10-6 to 375.00×10-6% with LREE/HREE ratios of 5.45-6.71 and δEu values of 0.88 to 0.94. According to the geochemical discrimination diagrams and the ratios of incompatible elements, we suggest that the basanite dykes were derived from partial melting of garnet forsterite (0.2%-0.5%) and herzolite (0.5%-1%), which may be caused by upwelling of carbonate melt in the asthenosphere mantle in response of the subduction of the Paleo-Pacific Ocean.

       

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