| 张存威.垮石岩断裂构造应力场模拟与东北寨金矿体定位分析[J].地质找矿论丛,1991,(4):90-97 |
| 垮石岩断裂构造应力场模拟与东北寨金矿体定位分析 |
| THE SIMULATION OF TECTONIC STRESS FIELD OF KUASHIYAN FAULT ZONE AND THE EMPLACEMENT OF GOLD OREBODY,DONGBEIZHAI |
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| DOI：10.6053/j.issn.1001-1412.1991.4. 009 |
| 中文关键词: 构造带 模拟实验 应力场 应力梯度 金矿体 |
| 英文关键词: |
| 基金项目: |
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| 摘要点击次数: 1096 |
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| 中文摘要: |
| 东北寨金矿床严格受岷江南北带之垮石岩断裂控制。矿体与断面空间形态之弧形弯曲密切相关。模拟实验证明,矿体定位于下盘应力等差线梯度大的部位,并严格受低差应力(σ1-σ3)域、最小主压应力(σ3)集中域和应变大的部位控制。 |
| 英文摘要: |
| The Dongbeizhai Au deposit is strictly controlled by Kuashiyan fault which is a member of Mingjiang tectonic zone. The fault separates upper-Palaeozoic carbonate rock and Mid-Triassic clastic rock. The emplacement of Au orebody bears ralation to the atc-shaped thrust plane which is the best space for mineralization, especially when the fault plane is curved towards the hanging wall. Otherwise ore bodies pinch out. The formation and distribution of the shape of fault surface and the faul trock zones are ralated not only to the difference of mechanical properties of the rocks but also to the distribution and development of the tectonic stress field. The simulation of stress field by photoelasticity indicates when two kind of materials with different mechanical property and with a curved contact boundary are pressed, the stress field of their contect boundary changes evidently. The stress field differs not only from the two plates but also at the same plate. The polycarbomate plate is used to simulate the stratum containing ordbody. It controls directly the orebodies because of its weak mechanical property, intense deformation and evident stress gradient. The compute of stress field with finite element method reveals the same result and indicates that the fault surface is evidently a varying boundary of the stress field and the stress gradient. The fault plane has the minimum horizontal stress difference(σ1-σ3)and the sudden drop of stress gradient, it controls the flow field of ore fluid acumulation. The place has the highest value of σ3 and the sudden rise of σ3 gradient. when the compressive stress releases after the strata is fractured, elastic rebound occurs and the fault zone becomes the favourable place for ore fluid permeation and orebody emplacement. Moreover, the low energy and low pressure environment due to the intense strain and large voume loss of the strata also makes the fault zone a favourable place for orebody emplacement. |
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