地质学报2013，Vol.87Issue(2)：167-177,11.
广东凡口MVT铅锌矿床成矿年代——来自辉绿岩锆石SHRIMP定年证据
Metallogenica Age of Mississippi Valley Type Pb-Zn Deposit in Fankou,Guangdong: Evidence from SHRIMP U-Pb Zircon Dating of Diabase
摘要
Abstract
The Fankou MVT-type lead-zinc deposit located in northern Guangdong province is one of the largest Zn-Pb deposits in China, with a proven reserves of up to 10 million tons. It occurs in dolomitized limestone in the upper part of the Devonian transgressive sequence as irregular lead-zince orebodies, which are controlled by the NNE-trending faults and cut by NWW or NNW-trending diabase veins. Diabases close to ore bodies are carbonatized and clayizized. Diabases cut through both Zn-Pb ore bodies and dissemiated Zn-Pb veinlets, indicating the diabase formed later than mineralization. The fact that the ore-forming continued a long term and the diabase intruded at the late period of the ore-forming support that the diabase and the lead-zinc ore formed at almost the same period. The SHRIMP U-Pb zircon ages of the diabase are 2213～ 957 Ma, 341～216 Ma, 138～ 127 Ma and 122 ～90 Ma. The first two groups of the ages represent the captured zircons. Comparing the geological characteristic and evolution, ages of uranium deposit and diabases, we can infer that the deposit formed at 122～90Ma (Cretaceous Period) in the extensional tectonic environment corresponding to the formation of large scale red bed basin. Thus, the ore-forming model of the Fankou deposit is established as fallows: since early Cretaceous, red bed basins started to develop within the South China area due to uplift of Wuyi mountains which held back the moisture air from Pacific ocean, with the lead-zinc deposits distributed mainly around the margin of the red bed basins, and mixing of brines from the red bed basins and the sulfur-rich reductive brines from the hydrocarbon layer resulted in the formation of the Zn-Pb deposits.关键词
密西西比河谷型/铅锌矿床/红层盆地/成矿年代/辉绿岩Key words
Mississippi-valley type/ lead-zinc deposit/ red bed basin/ ore-forming age/ diabase引用本文复制引用
祝新友,王京彬,刘慎波,王艳丽,韩英,甄世民,郭宁宁..广东凡口MVT铅锌矿床成矿年代——来自辉绿岩锆石SHRIMP定年证据[J].地质学报,2013,87(2):167-177,11.基金项目
本文为全国危机矿山接替资源找矿项目"湘南-粤北地区锡钨多金属矿床成矿规律总结研究"(编号20089927)、科技部支撑课题"MVT型铅锌矿深部勘查技术与找矿示范研究"(编号2009BAB43B05)、广西"地质工程中心重点实验室建设"项目(编号11-031-20-K2)共同资助的成果. （编号20089927）
