首页|FORMATION OF GOLD-BEARING HYDROFRACTURING BRECCIA BODIES IN TECTONIC LENSES: A CASE STUDY ON SHUANGWANG GOLD DEPOSIT, SHAANXI, CHINA

FORMATION OF GOLD-BEARING HYDROFRACTURING BRECCIA BODIES IN TECTONIC LENSES: A CASE STUDY ON SHUANGWANG GOLD DEPOSIT, SHAANXI, CHINA

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Macro-microscopic tectonic analysis and lithologic features show that the gold-bearing breccia bodies in the Shuangwang gold deposit, for hydrofracturing of the deep-sourced and alkali-rich fluids in the Devonian sodic rock series, are identified as hydrofracturing breccia bodies. Since the Indosinian,intracontinental collisional orogenesis results in multiple fracturings and magmatic emplacements in the Qinling area. Deep-sourced fluids resulting from deep fractures and granitoid magmatic intrusion are of a supercritical nature. Joint action between the fluid-rock system and structures leads to hydroffacturing and ore formation of the gold deposit.Firstly, the progressive coaxial compression caused the competent sodic rock series and the incompetent pelitic rock series to be deformed and partitioned. Lens-like weak-strain domains are hence formed and distributed at the approximate equidistance zones and the linear strong-strain zones,respectively. Subsequently, the progressive non-coaxial shearing and right-lateral and high-angle oblique thrusting lead to the most developed fracture system in the core of the weak-strain domain to turn from compression to extension and to link up with the deep fracture systems. The periodical huge pressure decline in the pumping center causes the deep-sourced confined fluids to develop periodic tectonic pumping, hydrofracturing and precipitation-healing in the sodic rock series. The gold-bearing hydrofracturing breccia bodies are hence ultimately formed at near-equidistance tectonic lenses. On the basis of the above model, the predicted concealed gold-bearing hydrofracturing breccia bodies have been preliminarily validated by latest drillings.

hydrofracturingsodic brecciadeformation and partitioningShuangwang gold depositQinling

ZENG Qiaosong、WANG Jincao、CHEN Guanghao

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Key Laboratory of Mineralization Dynamics, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, China

School of Graduate Study, Chinese Academy of Sciences, Beijing 100083, China

Dept. of Resources and Environmental Engineering, Guilin Institute of Technology, Guilin, Guangxi 540014, China

国家"305"科技攻关项目Key Innovation Oriented Program

2003BA612A-06-01KZCX3-SW-13 7

2005

大地构造与成矿学(英文版)
中国科学院广州地球化学研究所

大地构造与成矿学(英文版)

ISSN:1006-513X
年,卷(期):2005.29(2)
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