摘要
中天山南缘艾尔宾山地区岩浆活动的产物可能记录着南天山洋盆与伊犁中天山板块的活动,对解决南天山洋盆的俯冲问题具有重要意义。本文对中天山南缘艾尔宾山志留纪花岗岩进行了系统的岩石学、地球化学及同位素年代学研究。对4件样品的LA-ICP-MS锆石U-Pb定年结果表明,该岩体的形成时代为志留纪;研究区岩石具有准铝质高钾钙碱性系列岩石特征,为I型花岗岩,岩浆来源可能为下地壳的部分熔融;在稀土元素球粒陨石标准化分布图上,表现为强烈的右倾近平行的曲线簇。大离子亲石元素Rb、Ba、K等明显富集;高场强元素Nb、Ta、Ti、P等强烈亏损,表现出岛弧岩浆岩的地球化学特征。综合分析认为志留纪侵入岩为火山弧花岗岩,是与洋壳俯冲作用有关的产物。
The product of magmatic activity in the Albin mountain area in the southern margin of the Middle Tianshan Terrane may record the interaction between the South Tianshan Ocean and the Middle Tianshan Terrane in Yili, which is of great significance for understanding the subduction of the South Tianshan Ocean. In this paper, petrology, geochemistry and isotope geochronology of Silurian granites in the Albin mountains in the southern margin of the Central Tianshan Terrane are studied. LA-ICP-MS zircon U-Pb dating of 4 samples suggests that these granites were emplaced in Silurian. The rocks are high potassium metaluminous I type granite, belonging to, calc alkaline series. Geochemistry of the rocks suggest that parental magmas may be derived by partial melting of the lower crust. All rocks have similar Chondrite-normalized patterns of rare earth elements(REE) and are enriched in LREE. They are characterized by the enrichment of LILE(Rb, Ba and K) and depletion of high field strength elements(HFSE, such as Nb, Ta, Ti, P), indicative of arc magmatism affinity. Thus, Silurian granitic plutons are arc granites and are related to the subduction of oceanic slab.
作者
刘世杰
弓小平
刘洋洋
王哲
李平
凤骏
刘祥
LIU Shi-jie;GONG Xiao-ping;LIU Yang-yang;WANG Zhe;LI Ping;FENG Jun;LIU Xiang(Xinjiang University Urumqi 830049, China;Geological Research Academy of Xinjiang, Urumqi 830011, China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2019年第2期317-329,共13页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金项目(41462004)
中国地质调查局地质调查项目(12120114058701)
关键词
中天山
侵入岩
部分熔融
志留纪
洋壳俯冲作用
middle Tianshan Terrane
granite
partial melting
Silurian
subduction of oceanic slab
