Studies On Gold Deposit Of Synthetic Information Mineralization Prediction In Longkou North Area Of Shandong Province

Shandong Province is one of the most important provinces producing gold in China, however Linglong and Jiaojia gold fields are two bright pearls among gold areas in Shandong. Due to the location, the gold mineralization prediction in the gold fields'northeast extension in Longkou is lag. The dissertation systematically collected the raw materials of mineral geology background, conditions of ore-controlling structures, geophysics-geochemistry and geological ore exploration in Linglong and Jiaojia gold fields of Jiaodong north uplift belt in Longkou area. Based on summarizing mineralization laws, regional tectonic framework, geophysical and geochemical information of quartz veins and altered rock-type gold deposits in Longkou area, the dissertation carried out large-scale synthetic information mineralization prediction, delineated mineralization of favourable predictable units and proposed exploration work of emphases targets area.1. The region structures are mainly tenacity- brittleness in Longkou, and structures are mostly towards NNE, NE and NW. The Linglong, Jiaojia, Fengyi structures tend towards NNE, Potouqing, Shuangmuding structures tend towards EW and Huangxian structure tend towards EW compose the essential structural framework. Gravity and aeromagnetic interpretation show that the region linearity structures of interpretation is basically anastomosis with regional tectonic in study area expect Jiaojia fracture structure, which extend is above the fact, and deepening of fracture structure is beyond 7km.The spatial distribution of gold deposit in the study area is mainly controlled by the North-East region fracture. And almost all the gold deposits (points) distributed in the direction of the Jiaojia fracture, Linglong fracture, Potouqing fracture and Fengyi fracture, which were playing a leading role on structure controlling. The fractures with different structural direction and time of stages not only controlled spatial distribution of different kinds of mines, but also controlled distribution of different time stratum, intrusive rocks and Huangxian basin. Strong regional faults structure activities, suffering the tectonics change, remelting, metasomatic alteration, remelting-metasomatic granite emplacement along the NE trending faults in deepping formation of Metamorphic rocks of late archean. A series of ductile-brittle faults in the rock and border have created good structure geological environment for gold deposit form in Longkou. The multi-stage evolution of construction also provided advantageous conditions for mineralization, and it showed extension characteristic that in the upper and lower part of major section distributed a certain scale of mylonites, powder rocks, chips rocks, angle rocks etc. These tectonic lithologic is mainly occurrence site in alteration-types gold deposits.2. The dissertation discussed the important role of stratum and intrusive rocks for gold mineralization in the Jiaodong northwest. By studying ore potentiality and analysis of ore source in the archaean stratum, the result indicated that aurum had negative correlation with other elements in Jiaodong group, however aurum in Linglong and Guojialing rock mass outcrop the study area had positive correlation with other elements. From metallogenic materials migration of microelement plane,it reflected the Jiaodong group had provided with material conditions of ore source rock and elements that carryover of Jiaodong group sedimentary formation provided ore source for gold deposit metallogenic.On the relationship of spatial distribution between two types of intrusive rocks and gold deposits that distributed in study area, almost all gold deposits(points) had related to those two types intrusive rocks and deposits directly distributed around the brim or contact zone among the gneissic granite and porphyritic granitite. The result showed that this type of distribution had a close relation with the thermal power of mineralization process the formation magmatic hydrothermal in Mesozoic. It confirmed main signs of gold deposit orientation that passed by the NE or NNE fault structure of the brim or contact zone between porphyritic granitite of Guojialing and gneissic granite of Linglong.3. The dissertation systematically discussed geochemical and geophysical field characteristics in the study area. The physical nature and magnetic characteristics of rocks and mines in Jiaodong region had great differences in contrast with the past measurement of rocks and petrophysical property from the output in the main metallogenic belts. The magnetic fields pattern of Linglong super-unit generally performed a steadily low magnetic field, Guojialing super-unit performed a regiment's massive magnetic fields patterns with Larger distribution and generally showed the characteristics of positive magnetic fields. Thought the gravity and magnetic fields partition in the study area, it's expounded the gravitational and magnetic field characteristics of distributed geological units in Longkou. Through contrasted interpretation of the linear, ring-type structure with regional distribution of the geological units and structures, it's reconfirmed scales, occurrences and trends of the linear structure nature etc, spatial distribution and contact relationship of ring-type magnetic body. Geochemical fields were divided by measured seven kinds of microelements content in Longkou and systematically discussed characteristics of the spatial distribution in low background, background, high background and unusual of microelements in Longkou. By geochemical parameters calculation, it showed the different microelements had different spatial variety characteristics, enrichment degree, concentration features in geologic body and confirmed the spatial scope of microelements composition abnormal finally.4. The dissertation summarized geological characteristics, mineralization laws, metallogenic background and functions and so on in the Linglongin quartz vein-type gold deposits, Jiaojia altered rocks gold deposits and typical deposits in Shandong Province. The studies showed that the gold deposits formation of altered rocks were strictly controlled by Goujialing granodiorite, Jiaojia faults structures and its sub-structures, Gold deposits were the same period and sources outcome with Goujialing granodiorite, and Linglong granites supplied for the material of ore sources during the deposits formation. The magnetic features of ore field showed that gold deposits mostly distributed in the brim and around of the magnetic bodies. The advantaged position of formative gold deposits was located in the turning sites, recesses, projecture or tongue protruding out site of magnetic bodies. It's also favorable location of formative gold deposits in what the abnormal axis overlaps, crosses, turning sites of First derivative of the effective. Linglong quartz veins-type gold deposits were mainly controlled by the secondary faults under Potouqing fractures footwall, gneissic biotite granite body of Shuangding sub-superunit and fine granite body containing garnets of Luoshan sub-superunit in Linglong superunits, which were mainly surrounding rocks of deposits. In the fracture of the dykes and fault gouge development area, it's easy to form gold deposits under the fractures footwall. It's the most advantaged spaces of mineralization gold deposits where the trend or tendency change took place, two or more group intersections of faults and the fissure of transition site from the presure to extension in faults zone. Meanwhile, the beresitization alteration belt within faults structures was alteration feature of gold enriched.5. On the basis of studying regional mineralization and typical deposit law systematically, the dissertation summarized Linglong-Jiaojia-type gold deposit prospecting model from geological, geochemical and geophysical of three aspects in Longkou. Geological prospecting model indicated that Jiaodong group was primary favorable stratum. The nature, occurrence and cross-cutting of fault were favorable location of metallogenic. The magmatic rocks signs related to gold mineralization were mainly Linglong biotite granite and Guojialing granitic diorite, and the acid and intermediate-basic vein rocks were close tightly with gold mineralization. The geophysical model showed that occurrence of gold bodies were mostly lie in contacts with the different lithology and intrusive rocks, different lithology and period intrusive rocks or within the fault zone of intrusive rocks, those reflected different geophysical models in Longkou. Geochemical model was mainly based on the features of water sediments and secondary halo, and summarized geochemical model of gold deposits area. According to the prospecting model statistical units was delineated in the study area. It's delineated 38 statistical units totally, which has predicted 26 units and known 12 units in what contain 2 units of Medium-sized known deposits, 2 units of small-sized known deposits and 8 units of known mineralized points.6. According to the theory of synthetic information mineralization prediction, the dissertation has made the large-scale gold mining prediction and evaluation in the study area. Prediction units had been evaluated through comprehensive appraisal for the study area through the data-processing of comprehensive information on the statistical units, study on favorable metallogenic, positioning prediction of mineral resources, quantitative prediction and estimates of resources. The prediction units evaluated gold resource amount to 106.97 tons. There were 4 units of most potential as medium-scale or beyond resources and evaluated about the gold resource amount to 22.01 tons, 4 units of most potential as small-scale or beyond resources and evaluated about the gold resource amount to 16.05 tons, 3 units of most potential as gold occurrence or beyond resources and evaluated about the gold resource amount to 4.5 tons.7. The dissertation pointed out that the investigation and assessment of mineral resources work should focus on searching for the middle and small gold deposits in Longkou. On the basis of studying momentous areas, deployment of exploration works should be from known to unknown, shallow to deep and mineral prospecting after a detailed investigation. The different regions of works diversity should be focused respectively, strengthen anomaly inspection and attach importance to apply the effective geophysical techniques. The authority put forward that the proposed work plans should focus on prediction units, using several technical methods, such as geological survey, geophysics, geochemistry, hydraulic environments Geological Survey, mineral prospecting projects and GIS methods and means...