Dachang Tin-polymetallic Ore Field, West Ore Zone Metallogenic Model And Prospecting For Prediction

The Master's thesis is completed based on two projects. One is the cooperative project in enterprises and university of research on the mineralization enrichment regularity and application of tong ken tin veinlets in Dachang. The other is the national technology research project on exploration technology and model for next latent resources in large-scale tin-mine (project code: 2004BA615A-03). Through collecting systematically and analyzing scientific data and results made by other geological workers, the thesis focus on discussing the geological characteristics, mineralization material source, mineralization era and genesis of the typical ore deposits, such as Changpo-Tongken ore deposit (ore body: 91~#, 92~# and veinlets) and Longtuoshan ore deposit (ore body:100~#)in the west belt of the Dachang tin poly-metallic field, with the methods of structural geology, petrology and mineral deposit studying, geochemistry and so on. And the metallogenic model is established in the end. After summing up the prospecting mark and establishing the prospecting direction, we extract prospecting information to prospect in the mining area and up side of F1 fault, which from the results of the geology, geochemistry, geophysics and remote sensing.Though above research, we have made the main following achievement:1. The research of the regional mineralization shows: the mineralization in the west belt of Dachang tin-polymetallic ore field is controlled by multiple factors, such as stratum, tectonic and magmatic rock .The most favorable ore bed location is reef limestone in Mid-Devonian period stratum, silicon rock in later Devonian period stratum and the banded limestone in later Devonian period stratum. The main structure controlling mineralization is the northwest-oriented Dachang F1 fault and the Dachang reverse anticline. The high quality ore bed easy to locate in intersection of the northwest-oriented structure and its sub- northeast-oriented structure. And the Yanshan period concealed magma activity also one of the main mineralization controlling factors.2. The location of main ore deposits in the west belt is dual controlled by Dachang fault and Dachang reverse anticline. There are two types of ore bodies, one is layer-formed ore body, and another is vein-formed ore body. From the top to bottom, the vertical distribution shows as following: issue-vein type, vein type layer-fracture type and to profiling-layer type. The concealed magmatic rock is center of mineralization element distribution horizontally. Research indicates that the vein-mineralization formed later than profiling layered-mineralization.3. The mineral substance of ore deposits in Changpo-Tongken mining area not only from stratum, but also from magma. But in the Longtoushan mining area, the mineral substance of its ore deposits is mainly from stratum. In Devonian period, mineral substance has initial enriched through the hot water with mineral substance sedimentation activity. The multi-phase activity of the magma invasive in Yanshan period bring some mineral substance from the magma rock to stratum, also cause the mineral substance activate, relocate and re-enrich in stratum.4. Applying remote sensing and geophysics prospecting, it is reduced that a concealed magma rock is located in a deeper area. Geophysics prospecting result indicates: there are several geophysical anomalies in east of Tong-ken mining area; some geophysical and geochemical anomalies lie in northeast of F1 fault.5. Extracting prospecting information, combined with mineralization marks, metallogenic prognosis is put on in two favorable areas. It is found many orebodies of economic value including No. 5 tin orebody , and some new types of mineralization through some verification projects, which will creates huge economic benefits to the enterprises.