土耳其中部阿哲格尔火山湖新生代玄武岩的地球化学与岩石成因

发布时间：2018-07-02 14:13

本文选题：新生代玄武岩 + 捕掳晶　；参考：《岩石学报》2017年08期

【摘要】：阿哲格尔火山湖玄武岩是位于卡帕多利亚火成岩省(CVP)东部的第四纪火山岩之一。与CVP中其他火山岩相比,玄武岩具有演化程度较低,成分上更接近原始岩浆的特征。玄武岩记录了两期深部岩浆活动:橄榄石捕掳晶Fo值高达89,尖晶石包裹体具有低Cr~#、高Al的特征,表明了早期岩浆源区可能为受俯冲板片流体交代的岩石圈地幔;除样品TCA02外,玄武岩ΣCe/ΣY比值为1.39~2.11,~(143)Nd/~(144)Nd比值为0.51287~0.51288,Th/Nb比值为0.15~0.16,具有大陆裂谷玄武岩的特征,反应了晚期的碱性岩浆起源于软流圈地幔。与CVP早-中更新世钙碱性岩浆相对比,晚期碱性岩浆的高场强元素(如Nb、Ta)具有弱的负异常,K、Ba等大离子亲石元素富集程度较低,揭示了岩浆在上升演化过程中存在富集交代的岩石圈地幔物质的加入。
[Abstract]:Ajagher volcanic lake basalt is one of the Quaternary volcanic rocks located in the eastern part of CVP. Compared with other volcanic rocks in CVP, basalts have a lower evolutionary degree and are more similar to the characteristics of primitive magma. Two periods of deep magmatic activity have been recorded in basalts: the Fo value of olivine is as high as 89, spinel inclusions are characterized by low Cr-#and high Al, indicating that the early magmatic source area may be lithospheric mantle metasomorphic by subduction plate fluid, except for sample TCA02. The 危 Ce- / 危 Y ratio of basalt is 1.39 ~ 2.11 ~ (143) ND / 144ND ratio of 0.51287 ~ 0.5128 ~ 8 / T / NB = 0.15 ~ 0.16, which is characterized by continental rift basalt, which reflects that the late alkaline magma originated from the mantle of the asthenosphere. Compared with the CVP calc-alkaline magma in the early and middle Pleistocene, the high field strength elements of the late alkaline magma (such as NbTa-Ta) have a low enrichment degree of large ion lithophile elements, such as the weak negative anomaly, such as Knaiba, and so on. It is revealed that there are enriched metasomatic lithospheric mantle materials in the process of magma uplift and evolution.
【作者单位】：地质过程与矿产资源国家重点实验室中国地质大学地球科学与资源学院;
【基金】：国家重点研发计划(2016YFC0600304) 国家“973”项目(2015CB452604) 国家自然科学基金项目(41273044、41225006) 中国地质调查局工作项目(1212011121260、1212011121066) 长江学者和创新团队发展计划(IRT1083)联合资助
【分类号】：P588.145

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