Study On Geological Conditions Of Ore Forming And Directions Of Ore Prospecting Of Tungsten Ore Deposits In The Western Qilian Mountains

Last century 70s, Ta'ergou and Ye'mahe tungsten deposits had been found. In recent years the continuously discovered and explored a large tungsten ore deposit in Xiaoliugou and a series of tungsten mineralization points in Da'heishan, Ga'zihei, Xiao'erbotou and Longmen in the western Qilian Mts. demonstrated this area has good geological conditions to form tungsten ore deposits. The timely study on geological conditions of ore forming and research on rule of concentration and mineralization of tungsten in the western Qilian Mts. is especially important guiding to find tungsten in this area. Based on systemic collection and reorganization dates of geological minerals, geophysical prospecting, geo-chemical prospecting, remote sensing, field observation, sample collecting and analysis, absorbing recently important studies on fluid in this area, this paper discussed the geological conditions of ore forming and research on rule of concentration and mineralization of tungsten in the western Qilian Mts., setting up models to find tungsten ore deposits and pointing out prospecting directions in this area. The main results in this thesis are following: 1) Tungsten ore deposits strictly lie in the marginal zone of the "ancient separate terrain". Large-scale tungsten ore deposits are mainly hosted in metamorphic neutral-basic volcanic rock ~ clastic rock stratum of Proteroza ear; 2) Tungsten ore deposits related to intermediate-acid granitic bodies. Based on petrology, mineralogy and geochemistry of tungsten-bearing granitic rocks, temporal and spatial distribution of intermediate-acid granitic bodies. This granitic rock belts in the area have been recognized: Northern Qilian marginal rock belt; Northern Qilian rock belt; Central Qilian rock belt; Southern Qilian rock belt. This paper proposed that acid granite bodies were closely related with the formation of tungsten deposits; 3)The distribution of tungsten ore deposits had been limited by NW and NEE two groups of deep-big faulted structure. The hosted state of tungsten ore bodies should been controlled by NW, NE and NNW two or more than two groups of secondary breaks systems. The ore bodies are often faulted by late SN faults; 4) Tungsten minerogenitic has the nature of series in this area, from the mineralization of greisenization W(Mo) or resemble porphyry Cu,Mo in granite ore bodies to skarnic W (Cu) mineralization in exocontact to quartz vein W(Ag) mineralization in exocontact to hydrothermal vein Ag(Pb. Zn) mineralization far from contact zone. These constituted a complete zonal succession of mineralization. 5) In the western Qlian Mts., the main clues for prospecting are: pre-Cambrian ancient stratum, intermediate-acid granite, the anomalous area of W-Mo-Cu elemental combination in geo-chemical exploration and abnormal area of havy concentrate where scheelite, euxenite and cassiterite exceptionally appear; 6) The main wall-rock alteration that closely adjacent to tungsten ore deposits and tungsten mineralization points are: skarnization,...