| Structural geochemistry of gold mineralization in the Linglong-Jiaojia district, Shandong Province, China |
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| 作者姓名： | Huan-zhang LU Guy Archambault LI Yuansheng WEI Jiaxue |
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| 作者单位： | [1]Centre d＇ètudes sur les ressources minèrales, Universitè du Quèbec a Chicoutimi, Chicoutimi, Quebèc, G7H 2BI, Canada [2]Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China [3]Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing 100027, China [4]Guangzhou Institute of Geochemisto＇, Chinese Academy of Sciences, Guangzhou 510640, China |
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| 基金项目： | This paper is a part of results from the project "Shear Zone Control Gold Deposits in China" supported by the National Natural Science Foundation of China and an international exchange project supported by the same institution (to Lu). |
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| 摘 要： | The Linglong-Jiaojia district is one of the most important regions containing gold deposits in China. These gold deposits can be divided into: a) the pyrite-gold-quartz vein type (Linglong type), which is controlled by brittle-ductile to ductile deformation structures, and b) the alteration-zone type (Jiaojia type), characterized by small veinlets, or the disseminated type recognized in brittle shear zones. Lode gold deposits in the Jiaojia area occur in NE brittle fracture zones, formed in a dominantly simple shear deformation regime, mainly in thrust attitude with a minor sinistral strike slip component. In the Linglong area, the lode gold deposits are located at the intersection of three types of structures: NNE and NE brittle-ductile fault zones and the ENE ductile reverse shear zone in the south of the area. The structural characteristics of these brittle shear zones are consistent with a tectonic NNW-SSE principal stress field orientation. Similar stresses explain the ENE Qixia fold axes, the Potouqing and several other ENE reverse ductile shear zones elsewhere in the region, the Tancheng-Lujiang fault zone and its subsidiaries in the vicinity of the Linglong-Jiaojia district, as well as the southern ENE suture zone north of Qingdao. Therefore these structural systems occurred as part of different major tectonic events under NNW-SSE compression principal stress fields in the area. Gold deposits are hosted in smaller-scale structures within the brittle fault zones and brittle-ductile shear zones. Although ore bodies and, on a smaller scale, quartz ore veins often seem to be randomly oriented, it is possible to explain their distribution and orientation in terms of the simple shear deformation process under which they were developed. The progressive simple shear failure is characterized by various fracture modes (tension and shear) that intervene in sequence. The tension and shear fractures are influenced by the stress level (depth of burial beneath the paleosurface) in their structural behavior, show variable dilatancy (void openings) and extend on all scales. By making use of these characteristics, a progressive failure analysis can be applied to predicting the shape and extent of ore bodies as well as the styles of mineralization at any given location.
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| 关 键 词： | 剪切区域 地球化学 改造类型 中国 |
| 收稿时间： | 25 September 2006 |
| 修稿时间： | 2006-09-25 |
Structural geochemistry of gold mineralization in the Linglong-Jiaojia district,Shandong Province,China |
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| Huan-zhang LU Guy Archambault LI Yuansheng WEI Jiaxue.Structural geochemistry of gold mineralization in the Linglong-Jiaojia district, Shandong Province, China[J].Chinese Journal of Geochemistry,2007,26(3):215-234. |
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| Authors: | Huan-zhang Lu Guy Archambault Li Yuansheng Wei Jiaxue |
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| Institution: | (1) Centre d’études sur les ressources minérales, Université du Québec à Chicoutimi, Chicoutimi, Québec, G7H 2B1, Canada;(2) Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, China;(3) Institute of Mineral Deposits, Chinese Academy of Geological Sciences, Beijing, 100027, China;(4) Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China |
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| Abstract: | The Linglong-Jiaojia district is one of the most important regions containing gold deposits in China. These gold deposits can be divided into: a) the pyrite-gold-quartz vein type (Linglong type), which is controlled by brittle-ductile to ductile deformation structures, and b) the alteration-zone type (Jiaojia type), characterized by small veinlets, or the disseminated type recognized in brittle shear zones. Lode gold deposits in the Jiaojia area occur in NE brittle fracture zones, formed in a dominantly simple shear deformation regime, mainly in thrust attitude with a minor sinistral strike slip component. In the Linglong area, the lode gold deposits are located at the intersection of three types of structures: NNE and NE brittle-ductile fault zones and the ENE ductile reverse shear zone in the south of the area. The structural characteristics of these brittle shear zones are consistent with a tectonic NNW-SSE principal stress field orientation. Similar stresses explain the ENE Qixia fold axes, the Potouqing and several other ENE reverse ductile shear zones elsewhere in the region, the Tancheng-Lujiang fault zone and its subsidiaries in the vicinity of the Linglong-Jiaojia district, as well as the southern ENE suture zone north of Qingdao. Therefore these structural systems occurred as part of different major tectonic events under NNW-SSE compression principal stress fields in the area. Gold deposits are hosted in smaller-scale structures within the brittle fault zones and brittle-ductile shear zones. Although ore bodies and, on a smaller scale, quartz ore veins often seem to be randomly oriented, it is possible to explain their distribution and orientation in terms of the simple shear deformation process under which they were developed. The progressive simple shear failure is characterized by various fracture modes (tension and shear) that intervene in sequence. The tension and shear fractures are influenced by the stress level (depth of burial beneath the paleosurface) in their structural behavior, show variable dilatancy (void openings) and extend on all scales. By making use of these characteristics, a progressive failure analysis can be applied to predicting the shape and extent of ore bodies as well as the styles of mineralization at any given location. |
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| Keywords: | shear zone gold-bearing quartz vein alteration type Linglong-Jiaojia area China |
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