• 责任者：Yu Yushuai (Wuhan Institute of Geology and Mineral Resources ; Wuhan 430205 ; China) ; Yang Zhusen
• 刊名：Geology and Prospecting
• 出版年：2013
• 卷期：49(5)
• 关键词：花岗闪长岩 ; granodiorites ; 西藏 ; Tibet
• 页码：p.897-906
• 图表：7 illus., 2 tables, 37 refs.
• 分类号：0801
• issnNo：ISSN0495-5331
• isbnNo：CN11-2043/P

     The Nixiong ore-field is an important part of Coqin-Shenzha iron and copper metallogenic belt. The Gunjiu iron deposit is a typical repre- sentative of the Nixiong ore-field. The granodiorite and monzogranite in this deposit are associated with iron mineralization. In order to discuss the source, characteristics of the magma and to reveal the physical, chemical conditions in the process of magma emplacement and crystallization, this work has made detailed mineralogical identification and electron microprobe analyses of minerals fi＇om granodiorite. The results show that the granodiorite is mainly com- posed of plagioelase, potassium feldspar, quartz, amphibole, biotite and few accessory minerals. Electron microprobe analyses indicate that the amphibole which is poor in titanium but rich in magnesium is attributed to magnesiohornblende. The biotite belonging to magnesian biotite is of magmatic genesis. The analysis shows that the granodiorite belongs to calc-alkaline I-type granite, and granodiorite was formed from a mixed magma between the partial inch- ing materials of the crust and asthenospheric mantle in late Early Cretaceous. According to the chemical composition amphibole and biotite, the granodior- ite crystallization occurred under the conditions of high oxygen fugacity about logfo2 = - 14 ~ - 16, high temperature of 630 ~ 680~C and press of 1.5 x 10s -3.0 x 10Spa.