BAI Bin1, YU Sheng1, LIU Jie1, BIAN Cheng-hui1, DAI Shuang2
(1. The Second Institute of Geology and Mineral Exploration of Bureau of Geology and Mineral Exploration and Development of Gansu Province, Lanzhou 730020, China;
2. College of Geology and Mineral Resources, Lanzhou University, Lanzhou 730000, China)
Abstract: In order to study the relationship between tectonic movements and gold mineralization in the Danghenanshan area, Gansu Province, the geochemical and chronological characteristics of the Meiligou pluton in the area have been studied in this paper. The Meiligou pluton, intruded along the NW-trending fractures, consists of quartz diorite porphyrite and diorite porphyrite, which occurred in the form of stock. The geochemical characteristics show that magmatic rocks in the Meiligou pluton belong to the sodium-rich potassium-poor meta-aluminum rock, with relatively enriched large ionic lithophile elements (LILE) including Rb, Ba, K and Sr, obviously right-declined REE patterns, and weak negative Eu anomalies. The LA-ICP-MS zircon U-Pb isotopic dating results indicate that this pluton is the product of magmatic activity in the middle Triassic (235±5 Ma). The frequent Triassic magmatic activities and strong tectonic movements in this area could have provided favorable physicochemical conditions for the gold re-enrichment.
Keywords: Geochemistry; Zircon U-Pb dating; Meiligou pluton; Danghenanshan; mineral exploration engineering
ACTA MINERALOGICA SINICA Vol. 41, No.2, 2021, page 181-189
