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  

The geochemistry and petrogenesis of Cenozoic basalt in Sofular-Acigl Maar,Central Turkey

作　　者：雷杭山 马倩[1] 刘泽[1] 赵志丹[1] 朱弟成[1] 莫宣学[1] LEI HangShan MA Qian LIU Ze ZHAO ZhiDan ZHU DiCheng MO XuanXue(State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Science and Mineral Resources, China University of Geosciences , Beijing 100083, China)

机构地区：[1]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,北京100083

出　　处：《岩石学报》2017年第8期2619-2632,共14页Acta Petrologica Sinica

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

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。Sofular-Acigl Maar basalt is one of Quaternary volcanic rocks located in the eastern part of Cappadocia volcanic province（CVP）. Compared with other igneous rocks in CVP,Sofular-Acigl Maar basalt has experienced low degree evolution and is close to primitive magmas in composition. There are two episodes of magmatism recorded in the basalt. Fo in olivine xenocrysts is up to 89,and spinel inclusions have low Cr-# and high Al content. These properties show the source of the early magma would be lithospheric mantle,which was metasomatized by slab-derived fluids. ΣCe/ΣY and Th/Nb ratios are respectively 1. 39- 2. 11 and 0. 15 - 0. 16,143Nd/144Nd ratio is between 0. 51287 - 0. 51288 in the host basalts,except for sample TCA02. Therefore,the late basaltic magma has similar characteristic of continental rift basalt,and is originated from asthenospheric mantle. In contrast to the early-middle Pleistocene calcalkaline magma in CVP,the late alkaline basalt has lower HFSE negative anomaly and enrichment of LILE（ e. g. K,Ba）. Thus,it indicates an injection of metasomatized lithospheric mantle into the basaltic melt during magma evolution.

关 键 词：新生代玄武岩 捕掳晶 软流圈地幔 土耳其中部阿哲格尔火山湖 

分 类 号：P588.145[天文地球—岩石学]