地质与资源2018，Vol.27Issue(1)：41-47,59,8.
西秦岭天水地区晚三叠世柴家庄二长花岗岩及其暗色包体地球化学——岩石成因及岩浆混合作用
LATE TRIASSIC MONZOGRANITE AND ITS MAFIC ENCLAVES FROM THE CHAIJIAZHUANG PLUTON IN TIANSHUI AREA, WESTERN QINLING MOUNTAINS: Petrogenesis and Magmatic Mixing
摘要
Abstract
The Late Triassic granitoid is widely distributed in the western Qinling-Dabie orogenic belt.The paper chooses the Late Triassic monzogranite and mafic enclaves from Chaijiazhuang pluton of western Qinling Mountains for detailed petrological and geochemical study.Acicular apatite and plagioclase megacrysts are developed in the mafic enclaves,suggesting the magmatic mixing process.The mafic enclaves are characterized by low SiO2 (60.27％-60.38％),high Mg# (54-55) and Nb/Ta ratio (14.8-16.6),which indicates that they were derived from the partial melting of subeontinental lithospheric mantle.Geochemically,the host monzogranite shows adakitic affinity with enrichment of Sr and Ba,depletion of Y and HREEs,high Sr/Y ratio (88-98) and Y/Yb ratio (13-15),hinting at the residue of garnet in the source area.Combining with previous researches,it is suggested that the monzogranite in the study area is the product of partial melting of thickened lower crust under the post-collision extension background caused by the Late Triassic subducting slab break-off in Western Qinling orogenic belt.关键词
晚三叠世/岩石成因/埃达克岩/暗色包体/岩浆混合作用/秦岭造山带/板片断离作用Key words
Late Triassic/petrogenesis/adakite/maficenclave/magmaticmixing/Qinlingorogenicbelt/slabbreak-off分类
天文与地球科学引用本文复制引用
巨银娟,王邢颖,张泽中..西秦岭天水地区晚三叠世柴家庄二长花岗岩及其暗色包体地球化学——岩石成因及岩浆混合作用[J].地质与资源,2018,27(1):41-47,59,8.基金项目
国家自然科学基金项目“南北构造带中新生代构造演化”(编号41421002) （编号41421002）
陕西省青年科技新星项目“南秦岭五龙复式花岗岩体岩浆起源机制研究”(编号2014KJXX-60). （编号2014KJXX-60）
