Study On Regional Geological Characteristics And Metallogenic Geological Background Of Xunhua Area,Qinghai Province

Qinghai Xunhua area located in the conjunction of Qilian and West Qinling orogens, where is middle of Central Orogenic Belt, it had undergone the Complex and some multiple sedimentation-magmatic-tectonism in the Early Paleozoic and early late PaleozoicMesozoic era, and had provided a favorable geological background conditions and metallogenic environment for metal mineralization. Mineralization has the characteristics of period, minerals and multi-type. This area has many different kinds of ore, ore deposit types of complex, ore-forming age span is great, the metallogenic geological conditions are unique, and has found more than ten mines, which is one of important nonmetallic mineral origin in eastern region of Qinghai province. Paper is based on the instruction of plate tectonics and regional metallogenic theory, through on-the-spot field and Combined with the past data of geology and mineral resources, carried out the research of regional geological characteristics and metallogenic geological background in the region of Xunhua. Systematically summarizes the ore-forming geological conditions, ore-controlling factors under different geological periods, different background, probe into the ore-forming geological background and ore-forming regularity, and points out that the important prospecting marks of this area. The study has important geological significance on regional metallogenic prediction. Made the following knowledge and main progress:1、Redistribute the main ore-bearing bed in the research area. The Hualong group are divided into two lithologic members and set up a set of volcanic rock series which temporarily belongs to Cambrian gap of Liudaogou groups. Deposited assemblage Formation of Triassic Longwuhe group is divided into five paragraph, Limestone, fine clastic rock and breccia paragraphs, combination of rhythm, paragraphs, silty slate. The magmatic rock which closely relatedto the mineralization in the Caledonian and Indo Chinese epoch is divided into some intrusive body.2、The study area across two metallogenic belt of Qilian and Qinling mountains, the main metallogenic period is Caledonian epochin the north of the South Qilian Hualong micro plot of in the north of the area. The main development of deposit are magmatic liquation type Cu-Ni deposit, pegmatite type rare metals, non-metallic mineral deposits, which mineralization related closely to the subduction geological background. In the North rim of the western in the West Qinling of in the south of the area,the main metallogenic period is Indo-Chinese epoch and the main development of deposit are Porphyry, skarn type, tectonic altered rock type poly metallic deposit, and they formed in the structural transformation which form active continental margin to continental land collision orogenic in late Triassic.3、In the South Qilian Hualong micro plot, the Ore deposits are mainly distributed in the magnesium iron-super magnesium iron rock belt and pegmatite in the dike,which intrusive in metamorphic strata(Hualong group). Taking magnesium iron- super magnesium iron rock and dike rocks direct ore-prospecting criteria. In the north rim of the western in the West Qinling,the Ore deposits are mainly distributed in the periphery of intermediate acidity rock, and the site of contact with surrounding rock mass,The prospecting direction focus on the contact zone of intermediate irruptive rock and carbonate rock,and the intersection part or dike which located in the fracture of north west and north east. Both are controlled synthetically by strata, structure, magmatic rocks. So the comprehensive research suggests that the South Qilian Hualong micro plot is the metallogenic prospect areas of magmatic mold Cu-Ni ore,and the Gangcha area which locate the North rim of the western in the West Qinling is the metallogenic prospect areas of copper, gold, iron ore whose type are Porphyry and skarn.