矿床地球化学国家重点实验室知识库

Dabaoshan polymetallic deposit is located at the middle part of the Nanling granite belt, South China, which is a famous large deposit with a long history of mining. Much attention has been paid to the Mesozoic magmatism because recent research reveals that Mo(W)-ore related porphyries are the product of Yanshanian magmatism, while little effort has been done on the other stage magmatism. Based on the previous study, zircon LA-ICP-MS U-Pb dating has been conducted on different stage granites and mafic dykes in order to systematically clarify the magmatic activity of the studied area. The weighted average Pb-206/U-238 age of Xuwu rhyolitic porphyry is 426.9 +/- 2. 2Ma, and the weighted average Pb-206/U-238 ages are 162.2 +/- 0. 7Ma, 160.2 +/- 0. 9Ma and 161.2 +/- 0. 9Ma for Jiuquling granodiorite porphyry, Chuandu granodiorite and Dabaoshan granodiorite porphyry, respectively. Two mafic dykes recorded two magmatic events of 210. 4 +/- 1. 4Ma and 163. 9 +/- 1. 8Ma, respectively. Therefore, it is proved that the Dabaoshan area has gone through a multiple magmatic activity including Caledonian, Indosinian and Yanshanian. Middle-Late Jurassic mafic magma might have contributed to the Dabaoshan polymetallic mineralization.