The Characteristics Of Regional Aeromagnetic & Satellite Gravity Data And Regional Metallogenic Environments, Western Tianshan,China

In the western Tianshan area of Xinjiang, the level of the geological work there have been low, but recent years, the mineral exploration have developed rapidly, there is urgent need of studies about tectonic structure environment and regional regularity of ore formation. Taking the theory of minerogenetie series as guideline and combing the analysis of some typical metal deposits, this paper concluded and defined the distribution characteristics and boundary position of different tectonic structure units of the western Tianshan area by systematically analyzing regional aeromagnetic and satellite gravity data of the western Tianshan area. This paper also concluded the dominant metallogenic minerals' ore-controlling factors and distribution rules of different tectonic units, which point out different prospecting directions further, and discussed and deduced the tectonic characteristics and distribution characteristics of Carboniferous-Permian rift rally in Yili.According to analysis of the regional Bouguer gravity data and aeromagnetic data:the south boundary of the Central Tianshan tectonic unit in the western Tianshan area is the South Nalati Fault, which is separated with the southern Tianshan tectonic unit by the Nalati miscellaneous rock belt and separated with the northern Tianshan in the north by the Nileke deep fault. The west is the Yili archicontinent constructed by the scattered proterozoic metamorphic crystalline block and the embed phanerozoic orogenic belt. The Nalati miscellaneous rock belt belongs to the collision orogenic formation with different nature, which formed a multi-order brittle-ductile deformation zone and granitic intrusions related to different phases of collision in the curst, forming the most important orogenic gold metallogenic belt in the western Tianshan which has great prospecting potential.The Yili Carboniferous Rift belongs to continental rifts, and most eruptive (irruptive) rocks are medium-acidic, which is mingled with some medium-basic magmatite. The rifting scale of the rift valley is gradually reduced from west to north with broken block state, and the depth of the break is gradually shallow from west to east with setback type. The iron-polymetallic mineral cultivated in the rift valley has favorable metallogenic condition, having great prospecting potential, especially in the eastern section, where the rift valley is relatively shallow and the temperature is high. Ore bearing hydrthermal solution is easy to form magma type, skarn type and hydrothermal type iron polymetallic minerals in the relatively shallow parts. With the rift valley is gradually deepened towards west, the longer the time, the lower the temperature, where always form relatively low-temperature hydrothermal enrichment-type iorn ore. The Permian continental phase medium basic volcanic rock distributed near Nileke is local continental rifts developed on the basis of the Yili Carboniferous rift, which have short tectonic evolution time and limited influence range, and is the favorable location for searching porphyry type and hydrothermal type copper which has a closer relationship with continental (sub) volcanic rocks.According to analysis of the regional Bouguer gravity data:the high-gravity abnormal area responded to the Yili archicontinent is very clearly, and the western section of Yili Carboniferous Rift and the central and western section of Permian rift in southern Nileke County are all superimposed on the Yili archicontinent. The Tulazu volcanic basin, which is rich in Ash and Illmande and other medium-sized gold deposits as well as copper and lead-zinc deposits (points), is located on the Yili archicontinent. The Nileke deep fault stretched to the northwest is passed the southern part of the basin, and the south of Nileke County with many copper deposits (points) is located on the Yili archicontinent (central and western), but the number and scale of copper deposits in the east part is small.