陕西八卦庙金矿床构造特征及其对成矿的控制 |
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引用本文:.2001.Structures in the Baguamiao Gold Deposit of Shaanxi Province and Their Ore controlling Role[J].Mineral Deposits,20(3):229~233 |
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基金项目:973项目(Gl 999043200、95-预-39-VZ)、国家自然科学基金(40073010 ,49303041)和高等学校博士点基金 |
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中文摘要:文章对八卦庙金矿床的矿区构造特征、矿床地质和矿床成因作了系统的分析,认为在断陷盆地中形成的一套具有浊流沉积特征和热水沉积特征的含金高背景的赋矿岩石为金矿的矿源层。在褶皱造山过程中,金元素发生活化、再分配并在层间破碎带、构造片理化带及剪切带中预富集。在印支期燕山期的构造及伴随的岩浆热液作用下,金矿最终在构造有利部位富集成矿。该矿床构造控矿明显,因此,研究其构造特征对于搞清该矿床的成因,进行成矿预测,确定找矿标志有一定的指导意义。 |
中文关键词:金矿床 八卦庙 控矿构造 找矿标志 |
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Structures in the Baguamiao Gold Deposit of Shaanxi Province and Their Ore controlling Role |
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Abstract:It is considered that the Baguamiao gold deposit has intimate genetic connection with the process of the regional tectonic evolution in the Qingling orogenic belt. During Early Devonian, the southern edge of the North China plate was separated from the northern edge of the Yangtze plate along Fengzhen-Shanyang fault. The formation of a series of fault subsidence basins and netted syngenetic structures favored hydrothermal sedimentation. Continuous activation of the syngenetic fault and intermittent exhalation of ore-bearing hydrothermal water resulted in the formation of high-gold sedimentary rocks characterized by turbidite current deposition and hydrothermal sedimentation in the rifted oceanic basin, which served as ore sources. And Fengzhen-Shanyang syngenetic fault passed through the northern edge of the Bagua miao gold deposit. In Late Hercynian-Indosinian period, the strata were folded and changed in shape, forming overlap folds and a series of NWW- SEE trending interlayer fracture zones, schistosity zones and shear zones. Gold was reactivated, redistributed, and concentrated in the fracture belt by hydrothermal activity. During Yanshanian period, the irregular northern passive edge of the Yangtze plate , the divided ancient lands and the southern active edge of the North China plate collided continuously with each other and underthrusted, making the Devonian in the western and eastern Qinling area undergo uneven pressure. Strata in the east and in the west of the Fuping ancient land developed clockwise twist strain and anti-clockwise twist strain respectively. The structures experienced the changes from tension through compression to tension-twist. Magmatic hydrothermalism caused gold to reactivate, move and finally precipitate in favorable structures. These features are well developed. The orebodies are controlled by structures. There is a trend that the intensity of gold mineralization is getting stronger from south to north and from the shallow part to the depth. The ore-controlling features are clear. This conclusion can guide the study of ore genesis, the prospecting work and the determination of ore-hunting indicators . |
keywords:gold deposit, Bagua miao, ore-controlling structures, ore- hunting indicator |
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