| Haxiyatu Iron-polymetallic deposit is one of the typical skarndeposits with the contribution of mantle-derived component in East Kunlun region, which is founded in Jinshuikou rock group distribution area recent years, iron, gold, zinc is believed to get to a medium-sized scale, and has a great prospection potential. By using petrology, mineralogy, geochronology, geochemical and other research methods, combined with previous studies, we put forward a new understanding on thegeological characteristics of the dynamics in the deep earth of Triassic, then analyzes the Haxiyatu deposit on this basis, and establish metallization mode combined with tectonic background, meanwhile, by the contrast of stratigraphic formatiom and the character of the magnetic rocks, and discussed the similarities and differences between Haxiyatu deposit and other skarn deposits, and broaden the way of regional prospecting.Achievements by study:1.By a comparective study on 784 isotopic age distributions and geological evolution collected,the results indicate that subduction and collision extensive influence in the East Kunlun area because of closure for the Paleo-Tethys remnant, which reflected in strong magmatism in Indosinian and more skarn deposits formation.These suggest that: Subduction collision can provide good conditions for skarn mineralization in geological background during Indosinian. Simultaneously,granitic rocks with dark enclaves is a product of crust-derived mixed with mantle-derivedit,which has experiencing multiple MASH process(Melting Assimilation Storage Homo-genization).In mixed magma, the maficrichendmember was made of dioritic magma which evolved from gabbroic magma, and endmember is in the enrichment of iron, gold and other elements because of the deep source, providing adequate material for the metal mineralization.2.The orebodies, as stratiform and stratoid, was layered pattern formation along the ground, and owning diverse texture and structure types, mainly includinghypidiomorphic granular structure, irregularly-shaped structure, metasomatic texture, including structure, and the textures containing massive texture, dense disseminated texture, disseminated texture, star bulk-star-shaped texture, banded construction;wall rock alteration types are: skarn, silicification, chlorite, epidote petrochemical, carbonate and so on. The line 3rd is the center according to the distribution of skarn, and garnet skarn belt, diopside skarn belt, epidote skarn belt, actinolite silicon skarn belt, tremolite skarn belt are distribution on the west and east.3.The petrogenic time of the quartz dioriteis 246.8±1.8 Ma, mining area periphery granodiorite age is 240.1±0.8Ma, by LA-ICP-MS isotope measurement technology dating of zircons indicating the Haxiyatu depositis formed before Early Triassic. Magnetite δ18O value is between 2.7‰~4.1‰, implying atmospheric precipitation was mixed into the ore-forming fluid besides the magma water. Pyrite and sphalerite δ34S varied from 4.63‰ to 6.30‰,and δ34S=3.77‰ totally, means that S is root in the crust-mantle magma mixing, and rere mixed with crustal material. Pyrite variation range of lead isotopic ratios is small(208Pb/204 Pb, 207Pb/204 Pb, 206Pb/204 Pb ratios of sulfide ores are 38.471~38.629, 15.627~15.671 and 18.435~18.473, respectively), showing a crust-mantle mixing characteristics, besides, formation also provides a rich iron for mineralization.4.According to the geological characteristics of the deposit that metallogenic elementsinclude:(1) The brittle contact zone of gneiss and marble in the mining area, and marble is benefit for skarn migmatization of the prerequisites.(2) Mine NE trending faults has a close relationship with East Kunlun regional faults, probably caused the small secondary faults, but has a deep depth of cut.(3) Quartz flash long rockwith crust mantle mixing genesis is faraway from theore body, providing enough space and time for iron intake after rockshallow emplacement. According to geotectonic background in the same period,considers the mineralization process may be as follows:after subduction slab, crustal-mantle magma mixed in the deep earth,atmospheric rainfall and formation syngenetic water sinking along the secondary fault zone caused by Queensland fracture during magma emplacement gap. Meanwhile, metals leached out from the formation mixed with quartz diorite again forming the ore-forming fluid. Influenced by pressure difference, the ore-forming fluid rise along the crack surface, then causing ore-bearing hydrothermal bedding replacement of carbonate rocks, forming skarn deposit when comeing across these different mechanical properties to the nature of the fragile after formation interface, forming early magnet ore body, metal sulfide, native gold, etc after the skarn stage of acid leaching the same time. Although deposit is a typical characteristics on skarn deposit zonation and metasomatic reaction, more in line with the defined stratabound skarn deposits. This paper argues that the West Kazakhstan Tutieduo metallic ore deposits Genesis belongs to stratabound skarn card rock types on the genesis of ore deposits. |
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