| The gold deposit in Shuijingtun, the representative of the middle size gold deposit in Zhangjiakou and Xuanhua in the northwest of Hebei, is located in the detachment zone outside the mantle branch of Zhangjiakou and Xuanhua. It is a quartz vein gold ore with the type of tectonic fracture zone controlled by multi-level fracture. In the process of geological evolution, a series of folds of different stages and fracture tectonic system are formed in this place, which controls the formation and evolution of the gold ore.Based on the previous studies, the present paper makes a research on the geological characteristics, ore-forming materials, ore-controlling structure, metallogenic regularity as well as ore genesis and analizes the mineralization with a new perspective of mantle branch. All of those show:1. The present paper holds that the gold ore of Shuijingtun is formed in ganzan age based on the researches on the mineralization age in Shuijingtun and other mines around. With the studies on the mineral inclusions by quartz and the isotopes of Sulphur, Lead, Carbon, hydrogen and oxygen, it is thought that the mineral in the gold ore is from the heart of the earth. From the heart to the surface of the earth, the temperature and pressure shift abruptly, and the shallowly seated fluids mixes with the ore-forming fluid and mutually replaces with the surrounding rocks, which leads to the formation fo the ore. During the evolution in the mantle, especially in the crust, it is unavoidable to be mixed with some crust-derived material, which is the reason why the data tested is between the area of the mantle and the crust.2. Despite the complex struture and the controlling of the mineralization to the output, each of the structural ore-control bear different significance. With the analysis on the tectonic evolution, it demonstrates that since indo-chinese epoch, there are three stages in the formation of the mine. They are indo-chinese epoch, yanshan epoch and himalayan epoch. The gold ore becomes more and more in the first epoch, and forms in the second one.3. On the complex alkaline monzonite. Through the study on its formation mechanism, active stages and Isotopic age, the writer thinks it is a phanerozoic complex rock controlled seriously by the active large fault zone of Shangyi-Chongli-Chicheng. 4. In Yanshan epoch, tectonic activity becomes more. The uplift of the metamorphic core complex makes the mantle in Zhangjiakou and Xuanhua. Furthermore, some detachment zone and vertically tensioning fracture are formed. The massive detachment of the main detachment zone with certain temperature and pressure cause the magma to move beyond the main zone. What's more, they also provide the channels and space to store the following ore liquid, as well as lead to the formation of ns-trending fracture system through which the newly hot ore liquid rises and alters with the rocks around. As a result, the gold formed before are activated and forms mines through the weak zone.5. Recently, more and more quartz vein containing gold are exploited. The writer also makes deep study and analysis on the source of the ore-forming elements, the ore-forming rules and models in Shuijingtun. From the present situation of protest and exploitation to the mine and the previous studies, the present paper holds that there is great potential to make a deep exploitation of the mine. |
