Characteristics of soure region and tectonic implications of Early Indosinian Weiya gabbroic rock,ea

• 作 者: 张遵忠 顾连兴 邵毅 许建荣 翟建平 吴昌志 郑远川 唐俊华 汪传胜 三金柱
• 机 构: East China Mineral Exploration and Development Bureau for Non-ferrous Metals,East China Mineral Expl
• 出 处: Journal of Central South University of Technology
• 发表日期: 2008年02期
• 关键词: rock tectonic Tianshan carbonate magma texture parental subduction Permian Trias

Based on the detailed petrographic study,the characteristics of source region of the Weiya gabbro and tectonic implications were studied.The results show that the gabbroic rock consists mainly of gabbro,with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradually transitional contact with gabbro,indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite.The former is mainly composed of olivine(65%-70%),spinel(10%-15%),hornblende(5%-10%) and phlogopite(5%-10%);the latter consists mainly of clinopyroxene(70%-80%),spinel(15%-20%) and phlogopite(0-10%),with minor amounts of carbonate(0-2%).No olivine or orthopyroxene is found.The gabbro is composed mainly of clinopyroxene(35%-40%),plagioclase(An 55-65,40%-45%),hornblende(5%-15%),with variable amounts of carbonate(0-5%).Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic.

Based on the detailed petrographic study, the characteristics of source region of the Weiya gabbro and tectonic implications were washed. The results show that the gabbroic rock consists mainly of gabbro, with less amount of ultra-mafic rocks.The ultra-mafic rocks show cumulate texture and are gradual transitional contact with gabbro, indicating that they are cumulate products of parental magma.The ultra-mafic rocks consist mainly of spinel periodite and spinel clinopyroxenite. the former is mainly composed of olivine (65% -70%), spinel ( Hornblende (5% -10%) and phlogopite (5% -10%); the latter consisting mainly of clinopyroxene (70% -80%), spinel 0-10%), with minor amounts of carbonate (0-2%). No olivine or orthopyroxene is found. The gabbro is composed mainly of clinopyroxene (35% -40%), plagioclase (An 55-65, 40% 45%), hornblende (5% -15%), with variable amounts of carbonate (0-5%). Petrographic observations show that the source region of the Weiya gabbroic rock is water-rich due to intensive intra-continental A-type subduction occurring in this region during late Permian to early Triassic