On The Research Of Mesozoic Nappe Tectonic And Iron Polymetallic Metallogenic Regularity In The Wuyi Mountain Eastern Foothill

Nappe tectonics in the Wuyi mountain eastern foothill to deepen the basic geological research, guide the eastern region "three under" prospecting work deployment has important realistic significance. The whole process of thesis research combined with geological prospecting practice,the mainly cognition is as follows:The nappe in the Wuyi Mountain eastern foothill was the expression of the lithosphere spheres of layer performance, formed in the mid crust low velocity layer. The nappe structure was mainly distributed in the uplift zone of northwestern Fujian,the transition zone between the uplift in northwestern Fujian and the depression in southwestern Fujian,internal depression basin in southwestern Fujian and the east edge of the depression basin in southwestern Fujian of four main parts, different parts of the nappe structure differences. The Mesozoic nappe is from North West to South East nappe feature, there are two types of thick crusted and thin crusted nappe structure zone. Thin crusted nappe tectonic nappe distance is less than25km, thick crusted thrust nappe structure distance is greater than120km.The formation and evolution of wuyi mountain eastern foothill nappe experienced Indosinian folds and nappe structure formed in early Yanshan stage, thrust nappe tectonic development stage, late Yanshan tectonic transformation stage as well as the Himalayan reverse thrust stage. Through syntectonic granite porphyry dating at Guangping town in Datian county, determine the formation age of142.22±0.74Ma.3. The Mesozoic nappe in the Wuyi Mountain eastern foothill along six different lithologic interface development, the interface is early had detachment, later by the nappe structure transformation, become an important place for hydrothermal vents and mineral deposits. The Late Carboniferous and Early Permian carbonate rock strata in top and bottom interface is the most important position of ore-bearing bed of the iron polymetallic ore for this area.4. Since the late Triassic-cretaceous, the granitic magma in the Wuyi Mountain eastern foothill had obvious evolution trend from west to east, the trend and nappe tectonic evolution trend had the similarity. Combination of Wuyi Mountain eastern foothill are widespread in the earth’s crust low-velocity layer as well as the characteristics of the thin lithosphere, think nappe tectonic compression leads to the middle crust low-velocity layer of horizontal movement, is mainly controlled by the regional granitic magma evolution factor.By four typical deposits, such as Longyan Makeng iron polymetallic deposit and Pantian iron polymetallic deposit and so on,this paper expounds the nappe and iron polymetallic relations, and regional nappe tectonic ore-controlling model is established. Dating By the method of zircon uranium-lead to the granite rock mass related to mineralization in Pantian iron polymetallic deposit and yangshan iron polymetallic deposit,the measured age were131.68±0.48Ma and130±1Ma, and the iron polymetallic metallogenic epoch related to nappe.was Determined.Combined with the regional geological, geophysical rospecting, geochemical and remote sensing geologica materialized comprehensive information and mineral resources potential evaluation related achievements, analyses the Wuyi Mountain eastern foothill iron and copper polymetallic deposit main ore-controlling factors and prospecting marks, and divided into six iron polymetallic metallogenic prospect areas.