海南抱伦矿区构造变形、成矿时代与金矿化关系研究

Structural Deformation, Age of Ore-formation and Origin of Baolun Gold Deposit in Hainan Island, South China

抱伦金矿床位于海南岛西南部乐东县境内,是一个以石英脉型为主的大型金矿床。野外地质调查表明,矿区大致经历了三期构造变形:早期(D1)NE向褶皱,中期(D2)NNW向褶皱和剪切变形,晚期(D3)脆性断层和节理。其中,中期的NNW向右行剪切变形为金矿体的赋存提供了主要空间,金矿化主要发生于三个不同的阶段,以第一阶段(自然金-Q2石英阶段)最为重要,形成了大量自然金,为主要矿化阶段。对切割矿体的细晶岩脉中锆石的定年研究表明,抱伦金矿化主要与印支期尖峰岭花岗岩浆活动有关,而与燕山晚期岩浆活动关系不大。

The Baolun gold deposit, located in the Ledong county, southwestern of Hainan Island, is a large-size quartz vein type gold deposit. The ores are strongly controlled by a series of NNW-trending brittle-ductile shear zones. Detailed field mapping showed that there are at least three phases of deformation in the mine and the adjacent areas, which include the early NE-trending synclinorium formation（stage D1）, the middle NNW-trending structural deformation（stage D2）, and the late brittle faults and joints（stage D3）. The NNW-trending dextral shear zones, formed in deformation stage D2, are the ore-controlling structures which offer essential channel ways and space for activation and enrichment of metallogenic materials. There are three stages of gold mineralization and the first stage is the most important one. Moreover, according to the zircon U-Pb dating results of the aplite granite which cuts the ore vein, we propose that the gold mineralization was associated with the post-magmatic hydrothermal activity of the Jianfengling intrusions, and irrelevant to Late Yanshanian Qianjia intrusions.