论文摘要
Many granodiorite porphyries with coppermolybdenum mineralization, as an important part of Yidun island arc complex orogenic belt, have been explored in the southern part of the Garzê-Litang suture zone in recent years. In this paper, the emplacement age of Boniangou quartz-monzonite porphyry is extracted by using LA-ICP-MS zircon U-Pb chronology method, which is used to compare with other granodiorite porphyry in the region. Most zircon grains are euhedral, and transparent to light brown, with clear igneous oscillatory or planar growth zonation in their CL images. The Th contents of zircon are 135–1055 ppm while U contents are 216–1377 ppm, and the Th/U ratio are 0.37–0.94, all of which prove that the zircons belong to magmatic zircons. Analyses of 20 zircon grains from sample yielded 206Pb/238U age of 211 to 225 Ma, and is projected on the U-Pb harmonic map in the vicinity of the harmonic line with weighted mean 206Pb/238U age of 217±1.8 Ma（1σ, MSWD=1.17, Fig. 1）. Combined with the previous research results, it can be known that quartz-monzonite porphyry from Boniangou was formed in the process of the western subduction of Garzê-Litang ocean. Regionally, a large number of diagenetic age of previous studies on the porphyry bodies of the ore deposits in the area, e.g. the porphyry age range of the Xuejiping deposit is 213–215Ma, and the porphyry age range of the Pulang mining area is 215 –219 Ma, while Boniangou and Degongniuchang are of 217 and 216 Ma respectively. The above age data indicates that the porphyry bodies in the Xuejiping and Pulang mining areas are the same as the porphyry bodies in the Boniangou mining area, which are the products of the magmatic action during the westward subduction of the Garzê-Litang oceanic crust. On the other hand, the age of porphyry diagenesis has a tendency to gradually decrease from east to west, which is consistent with the direction and angle of the Garzê-Litang ocean subduction. At the same time, the metallogenic porphyry in the southern part of the Yitun island arc shows a trend of eastward extension. The discovery of the Boniangou and Degongniuchang ore-bearing porphyry provide a new vision for finding porphyry polymetallic deposits in the Garzê-Litang suture zone.
论文目录
文章来源
类型: 国际会议
作者: WANG Fudong,MA Pengcheng,LI Hujie
来源: 第九届世界华人地质科学研讨会 2019-06-01
年度: 2019
分类: 基础科学
专业: 地质学,地质学,地质学
单位: School of Environment and Resource, Southwest University of Science and Technology
分类号: P588.1;P597.3
DOI: 10.26914/c.cnkihy.2019.028407
页码: 227-228
总页数: 2
文件大小: 171k
下载量: 1