梁志勇,李鹏举,焦世文,鲁有朋.西秦岭北缘甘加—麻当地区玄武岩地球化学特征及成因探讨[J].甘肃地质,2023,(4):13-22 |
西秦岭北缘甘加—麻当地区玄武岩地球化学特征及成因探讨 |
Geochemical Characteristics and Genesis of Basalts in Ganjia-Madang Area, Northern Margin of West Qinling |
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DOI: |
中文关键词: 西秦岭 甘加地区 麻当地区 玄武岩 地球化学 岩石成因 |
英文关键词:basalt geochemical characteristics petrogenesis west Qinling |
基金项目:本研究得到甘肃省科技计划(22YF7GA050)、中央引导地方科技发展资金项目(YDZX20216200001297)、甘肃省基础地质调查项目(4500689978)联合资助 |
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中文摘要: |
西秦岭北缘夏河县甘加—麻当地区零星分布有火山岩,通过对该地区玄武岩开展野外地质调查与室内元素地球化学测试,并进行分析研究表明甘加—麻当玄武岩属于一套钠质—钾质过渡的碱性玄武岩。玄武岩强烈富集大离子亲石元素Rb、W、Sr和高场强元素U、Nb、Ta、Hf,亏损Cs、Ba、Th等元素,显示出典型的OIB型特征,其形成环境为大陆板内环境,推测岩浆起源于亏损的软流圈地幔,其复杂的地球化学特征表明,岩浆经历了较为强烈的岩石圈—软流圈相互作用,与印支期造山运动后岩石圈拉伸有关。 |
英文摘要: |
Volcanic rocks are scattered in the Gangjia and Madang areas of Xiahe County. Preliminary research shows that the Gangjia-Madang basalt belongs to a set of alkaline basalt with transition from sodium to potassium. The basalt is strongly enriched in large ion lithophile elements Rb, W, Sr and high field strength elements U, Nb, Ta, Hf, while deficient in Cs, Ba, Th elements, showing typical OIB characteristics. Its formation environment is continental plate environment, and it is speculated that the magma originated from the deficient asthenosphere mantle. The magma experienced a relatively strong lithosphere-asthenosphere interaction, which is related to the lithosphere stretching after the Indosinian orogeny. |
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