Abstract:Abstract：This paper primarily summarizes the basic characteristics of the major metallogenic belts in Central Asia and discusses the possible extensions of the major metallogenic belts from the adjacent regions of Xinjiang to Xinjiang. With the constantly changing knowledge of the division of metallogenic belts and types and characteristics of metallogenic formations in adjacent regions of Xinjiang, the authors emphasize that in comparing the geology and mineral resources in Xinjiang with those in its adjacent regions it is necessary to gain knowledge of their research histories and seek to make such comparison based on ascertaining basic ore-controlling elements. In addition, in Central Asia mineralization related to Early Paleozoic continental crustal accretion is quite important, while Late Paleozoic large-scale mineralization is more markedly manifested by inheritance and reworking of pre-existing ore-forming material and superimposition of new ore-forming material, thus forming compounding of multi-stage mineralizations. All these belong to the characteristics of the Central Asian metallogenic megaprovince and must be fully considered in the comparative study. Analysis and comparative study in the paper suggest the following six metallogenic environments as the major factors controlling the formation of large and superlarge deposits in the Central Asian metallogenic megaprovince： 1) numerous Precambrian blocks in Phanerozoic orogenic belts, in which important primary uranium deposits and rare metal deposits are formed; 2) Early Paleozoic continental-margin accretionary wedge and late Caledonian eastern Kokchetav and northern Junggar (beyond the territory of China), where there occur important gold and copper polymetallic deposits; 3) the circum-Balkhash Lake region surrounded by Caledonia and pre-Caledonian continental crust, where ore-forming processes show several peaks and superimposition on each other or certain regular migration; 4) an important Au-Cu-Mo-W metallogenic belt in the southern part of the Central Tianshan (beyond the territory of China), which shows distinct linear features and is related to a huge hydrothermal system that was active for ~70 Ma; 5) the post-collisional intracontinental environment in South Kazakhstan and areas south of it, where most U deposits in Meso-Cenozoic basins and Late Paleozoic superlarge sandstone-type copper deposits were formed and their ore-forming materials probably have deep sources; and 6) sites of intersection between the so-called large-scale “transverse structures” and metallogenic belts, where most important deposits in Central Asia occur.

Abstract:Abstract： Ore deposits are an important indicator for the tectonic evolution. The characteristics and space-time distribution pattern of ore deposits provide new constraints for reconstructing the tectonic evolution in the East Tianshan Mountains. Study indicates that the Paleozoic East Tianshan orogenic belt, sandwiched in between the Tuha block and Central Tianshan block, may be divided into three tectonic-strata (magmatic)-metallogenic belts in terms of spatial distribution, i.e.： the southern Tuha basin marginal copper metallogenic belt (north belt), Kanggur gold metallogenic belt (central belt) and Aqishan-Yamansu Fe (-Cu)-Ag- polymetallic metallogenic belt (south belt). The temporal evolution of the East Tianshan orogenic belt is distinctly characterized by three stages. (1) The southern margin of the Tuha Basin was an Ordovician-Devonian active continental margin, where there occurred a paleocontinental-margin metallogenic system including VMS Cu-Zn deposits and porphyry copper deposits. In the terminal Late Devonian-initial Early Carboniferous, the paleo-oceanic crust was subducted northward, closing the ocean, and the Central Tianshan block accreted and was amalgamated to the southern margin of the Tuha block (which belongs to the Kazakhstan-Junggar plate). (2) In the Early Carboniferous (Visean), the East Tianshan again underwent extension along the Kanggur suture, forming Carboniferous aulacogen volcanic-sedimentary rocks and a corresponding stratabound metallogenic system (including VMS type Cu-Zn deposits and volcanic-hosted Fe (-Cu) deposits and native copper deposits), and skarn type Ag polymetallic deposits formed during the closing stage of the aulacogen. (3) In the Early Permian, a Cu-Ni sulfide metallogenic system related to mantle-derived magma underplating and spanning tectonic units and gold deposits related to shearing formed in this area. Based on the above discussion, new suggestions about mineral prospecting in the East Tianshan area are put forward in this paper.

Abstract:Abstract：The newly discovered Karamay ophiolitic mélange distributed along the NW edge of the Junggar basin has a complete sequence of ophiolite and accretionary complex. From the basin edge toward the mountains, ultramafic rocks, mafic, pillow lavas and abyssal radiolarian cherts generally show a zonal distribution. The ultramafic rocks are unconformably overlain by volcanic molasse. The ages given by zircon SHRIMP dating of altered gabbro samples taken from the Baijiantan segment of the Karamay ophiolite mélange cluster at 414.4±8.6 and 332±14 Ma. This discovery provides important evidence for studying the ages of formation and elimination of the Central Asian ocean basin and also an important clue ｔｏ the determination of the nature of the basement of the Junggar basin.

Abstract:Abstract：The Buergen ophiolitic mélange belt found recently by the authors is exposed in the Ertix (Irtys) suture zone between the Siberiaｎ plate and Kazakhstan-Junggar plate in northern Xinjiang and extends in a NW direction. The rock is chiefly marked by mixing of blocks of various ophiolite components of varying size and nature in mylonized matrix. The matrix consists dominantly of mylonized volcanic rocks, tuff and strongly fragmented pyroclastic rocks. The ophiolite blocks are mainly carbonatized ultramafites (?), basalt, gabbro and cherts. Basalt has the OIB and IAB features. Tholeiite has a zircon SHRIMP U-Pb age of 352 Ma, suggesting that the formation of the ophiolites may have continued till the Late Devonian-Early Carboniferous. This discovery is of great significance for understanding the late Paleozoic ophiolitic mélange belt in the area north of the Junggar basin of China and its extension beyond China.

Abstract:Abstract:Based on previous research and zircon SHRIMP data, the authors suggest that the "Dahalajunshan Formation" should be disintegrated into several different formations. They establish a new formation named the "Laerdun Daban Formation" for the volcanic rocks exposed in the Laerdun Daban in the eastern segment of the West Tianshan, which are thought to be the product of La Te Carboniferous volcanism. The "Dahalajunshan Formation" will still be used for the Early Carboniferous rocks south of Xinyuan City. Volcanicsedimentary The volcanic rocks of the "Dahalajunshan Formation" exposed extensively in the western segment of the West Tianshan Mountains are relatively complex. Thus the name "Dahalajunshan Formation" will continue to be temporari Ly used for the Early Carboniferous rocks in the Dahalajunshan area Volcanicsedimentary south of Tekes where the original naming section of the "Dahalajunshan Formation" is distributed. The volcanic rocks distributed extensively in the northern part (Northern Gold Mine Area ZhaosuTekesiGongliuAxi) formed in the Late Devonian rather than in the Early Carboniferous as PR Evious believed. Therefore the authors suggest that a new name -- the Tekes Daban -- "Formation" be used for this suite of Late Devonian Volcanicsedimentary rocks.

Abstract:Abstract：Carboniferous volcanic rocks are widespread at peripheries of the Ili block of the West Tianshan. They are complex in lithology and mostly are associated or alternate with terrigenous clastic rocks. Geochemical study of volcanic rocks from the Axi, Nileke and Nalati sections in Yining suggests that these rocks belong to the calc-alkaline series composed of basalt, trachybasalt, basaltic andesite, basaltic trachyandesite andesite, rhyolite, dacite and trachyte. They have relatively high REE concentrations and are enriched in LREE relative to HREE, and in addition, they display a pronounced enrichment of LILE such as Th and Rb relative to HFSE such as Nb, Ta and Zr. Therefore the formation of these rocks is related to plate subduction. ｔｈｅ ｔrace element geochemical diagram further indicates that these rocks formed in a continental island-arc environment. The Early-Mid Carboniferous neritic-littoral sediments associated with them and the existence of the Late Devonian-Early Carboniferous Bayan Gol-Motuoshala ophiolite belt suggest that the Carboniferous calc-alkaline volcanic rocks on the northern margin of the Ili block are likely to have erupted in an active continental-margin environment and probably resulted from the subduction of the North Tianshan oceanic basin southward beneath the Ili block during the Late Devonian-Mid Carboniferous.

Abstract:Abstract：This paper reports the lead isotopic composition of volcanic rocks of the Qi’eshan Group and Yamansu Formation in the Qoltag ore belt and plagiogranite porphyry and copper ore of the Tuwu copper deposit and further discusses the tectonic evolution of this ore belt. The lead isotopic composition of volcanic rocks of the Qi＇eshan Group plots to the right of the geochron line, and has more radiogenic lead than the northern hemisphere reference line (NHRL), indicating the weak enrichment character. The lead composition of plagiogranite porphyry and copper ore of the Tuwu ore deposit lies in the field of the Qi＇eshan Group and has a similar character. The Yamansu Formation has more radiogenic lead than the Qi＇eshan Group and also shows the weak enrichment character. In the plumbotectonics diagram, the Qi＇eshan Group follows the mantle evolution curve, but the Yamansu Formation plots near the orogenic evolution line, indicating more continental crust involvement. The lead isotope composition of the Yamansu Formation samples shows the features of the linear array and falls between the Qi＇eshan Group and Central Tianshan granites, indicating the trend of mixing of the two end-members (Qi＇eshan Group and Central Tianshan granites). With enhancing fluid metasomatism, the Qi＇eshan Group and Yamansu Formation become more and more depleted in radiogenic lead, suggesting that the metasomatic agent was mainly derived from altered oceanic crust, without the involvement of pelitic sediments. The presence of more radiogenic lead in the Yamansu Formation than in the Qi＇eshan Group is mainly because its continental crustal basement was thicker so that it was subjected to stronger contamination with continental crust.

Abstract:Abstract：The Tengger Mountain-Ewirgol area is located in the boundary region of the East and West Tianshan Mountains. For a long time，no unified classification, age assignment, distribution range or nomenclature of stratigraphic units have brought many problems to the study of the Tianshan orogenic belt. Through 1∶50000 regional geological surveys of six sheets of the East and West Tianshan Mountains, two unconformities and a wealth of fossils have been found in the area of the original Qiergustao (Tengger) Formation in the North Tianshan Mountains. On that basis, combined with the differences in rock association, metamorphism and deformation, depositional setting, and isotope age data, the original Qiergustao (Tengger) Formation is further disintegrated into the Upper Devonian Tengger Formation (senso stricto), Upper Carboniferous Qiergustao Formation (senso stricto) and Houxia Formation and Lower Permian Aerbasayi Formation, and their ranges of distribution are mapped and the tectonic framework of the area is redefined. This study provides an important scientific basis for the correlation of stratigraphic units and tectonic division in the boundary region of the East and West Tianshan Mountains.

Abstract:Abstract：Ten lithofacies and their sublithofacies, including piedmont diluvial facies (fluvial facies), subaqueous delta facies, tidal flat facies, neritic facies, volcanic-sedimentary facies, volcanic outpouring facies, volcanic eruption facies, hydrothermal deposition facies, volcanic hydrothermal alteration facies and skarn facies, are recognized based on the lithofacies types and characteristics of Late Carboniferous sedimentary and volcanic rocks in the East Tianshan, Xinjiang. These characteristics indicate that the association of volcanic-sedimentary lithofacies formed on active continental margins in a continental compressional regime. The structure of vertical facies sequence indicates the strong volcanism occurred above and below the hydrothermal depositional facies, which provided heat needed for mineralization. In the Late Carboniferous Kumtag compressional basin, the vertical lithofacies sequence structure of the hydrothermal depositional facies is hydrothermal breccia subfacies→siderite rock/gypsum rock subfacies→ankerite rock subfacies→jasper rock subfacies→ankerite rock subfacies. This association is the lithofacies indicator for looking for large Kumtag type gypsum-siderite deposits in the East Tianshan. The general depositional sequence of the volcanic-sedimentary facies in the study area shows the trend of upward deepening facies sequence and then upward shallowing facies sequence. The provenance of clastic rocks was mainly the erosion area of the Variscan island arc zone in the north and the Central Tianshan basement uplift in the south. However, subaqueous volcanic eruption still took place in a neritic environment, showing the sedimentary characteristics of a hinterland basin in a continental compressional regime (Central Tianshan orogenic belt). The Late Carboniferous prototype sedimentary basin is likely to be a hinterland basin, which is favourable for preservation of large gypsum-siderite deposits.

Abstract:Abstract：In the Tarim plate there is a great deal of basic igneous rocks including basalt, diabase and basaltic andesite formed by the Early to Middle Permian intraplate magmatism, and their residuals cover an area of about 200 000 km2. The Permian was a very important transition stage in the evolution of the Tarim plate. In the late Early Permian the Tarim basin ended marine sedimentation and entered the stage of continental sedimentation. On the basis of an analysis of the characteristic of the Early to Middle Permian basaltic magmatism and Carboniferous to Permian sedimentary facies in the Tarim basin, this paper discusses the controls of this large-scale magmatism on the Carboniferous to Permian sedimentation and puts forward a model of the sedimentary response to the Early to Middle Permian basaltic magmatism in the Tarim plate.

Abstract:Abstract：The Sawu’er area in western Junggar is located in Jeminay County of the Altay region and Hefeng County of the Tacheng region, Xinjiang. Volcanism occurred in the area during the Middle Devonian to Early Permian, and it was particularly strong in the Permian. Permian volcanic rocks include the Ha＇erjiawu Formation and Kalagang Formation. The Ha＇erjiawu Formation consists of a suite of intermediate-basic and intermediate continental volcanic rocks and pyroclastic rocks, and the Kalagang Formation consists of a suite of intermediate-basic and intermediate-acid volcanic rocks and pyroclastic rocks. The volcanic rocks of the Ha＇erjiawu-Kalagang cycle include olivine basalt, basalt, trachybasalt, andesite, trachyandesite, rhyolite and pyroclastic rocks. According to the composite stratigraphic section of volcanic rocks and lithological and petrographic characteristics of volcanic rocks, the Permian volcanism in the Sawu’er area occurred in five phases；they are from early to late as follows：the intermediate volcanic eruption phase, intermittent basic volcanic eruption phase, acid volcanic eruption phase, small-scale intermittent intermediate volcanic exploration phase and basic volcanic outpouring phase. The Permian volcanic rocks are continental ones and have the characteristics of typical bimodal volcanic rocks. They formed in an extensional setting.

Abstract:Abstract：The Kalatag intrusion is the unique intrusion in the Paleozoic inlier on the southern margin of the Tuha basin. The major element characteristics show that the intrusion belongs to the sodian calc-alkaline series. The rocks are enriched in light rare earth elements (LREE) and large ion lithophile elements (LILE) such as Ba, K and La but depleted in high field strength elements (HFSE) such as Th, Nb, P and Ti and have weak negative Eu anomalies and low Sr isotopic ratios and high εNd(t) values (+7.74－+9.13). These characteristics indicate that：(1) the Kalatag intrusion has an affinity for mantle-derived rocks of a subduction zone and probably formed in an island-arc environment；(2)the intrusion was derived from a depleted mantle source and in the main has not suffered from contamination with older continental crustal material and its formation have a direct generic relation to the fractional melting of the north-dipping subducted Kanggur paleo-oceanic plate；and (3)the intrusion can provide the evidence that the south margin of the Tuha basin was an active continental margin during the late part of the Early Paleozoic and that the Kalatag porphyry-type gold-copper deposit is related to the subduction of the paleo-oceanic crust in this area.

Abstract:Abstract：Diabase dikes exposed on the northwestern margin of the Tarim basin contain 44.34%－49.3% SiO2 have higher values of Na2O+K2O (4.32%–6.04%) and Na2O/K2O (2.23－9.15), showing the features of intraplate basalt. The diabase is also characterized by a lower total REE content (∑REE=35.71－47.95 μg/g) and a higher ratio of (La/Yb)N (11.66－14.77) and no pronounced Eu anomaly. The geochemistry of the diabase suggests that it was derived from enriched mantle sources. 40Ar/39Ar dating of the diabase yields ages of 235.6 and 203.7 Ma. The above-mentioned geochemical characteristics combined with an integrated analysis of the Triassic-Jurassic sedimentary and tectonic settings of the western Tarim basin, especially the Tajikistan basin and Karakumy basin west of the Tarim basin suggest that：in the Triassic-Jurassic the western Tarim basin was in a prelude stage of Cretaceous-Paleogene intense subsidence and its main part was still in an uplift stage against the general extensional setting.

Abstract:Abstract：The Keyir Mountain area, located at the northern edge of the Kuqa-Baicheng depression of the Tarim Basin, is one of the favorable areas for the formation of sandstone-type uranium deposits in NW China. Field geological survey and interpretation of remote-sensing images have revealed that not only E-W-trending thrust faults and folds but also E-W-trending normal faults and a half-graben are developed in the study area. Stratigraphic correlation and development of unconformities indicate that these thrust faults and folds formed during the terminal Neogene to Early Quaternary, and E-W-trending normal faults and the half-graben formed later than the Middle Pleistocene. Therefore, the Late Cenozoic tectonic evolution process of the Keyir Mountain area is reconstructed. It is inferred that a regional N-S compressional environment occurred in the Neogene to early Pleistocene, while a local extensional environment from the late Pleistocene to present time. According to the above-mentioned study, combined with an analysis of the mineralization conditions for sandstone-type uranium deposits, the authors suggest that the uplifting segments of the a monoclinal zone in the northern part of the Keyir Mountain area are favorable areas for the formation of sandstone-type uranium deposits and should be firstly explored.

Abstract:Abstract:The Jurassic Shuixigou Group in the LowerMiddle western segment of the southern margin of the Ili basin is divided into four depositional systems based on field geological observations of outcrops and borehole cores and statistic analysis of plenty of borehole core records and logging interpretation data. The four depositional systems are the alluvial fan depositi Onal system of the Lower Jurassic Badaowan Formation, braided delta depositional system of the Lower Jurassic Sangonghe Formation and Middle Jurassic Lower Xishanyao Formation, shallow lacustrine and swampy depositional system of the Middle Jurassic Middle Xishanyao Formation and meandering river depositional system of the Middle Jurassic Upper Xishanyao Formation. The sed Imentary facies characteristics of each depositional system of the Shuixigou Group in western segment of the southern margin of the Ili basin are discussed in detail and the relationship between the formation of uranium deposits and the depositional Sandstonetype system and sedimentary facies of the Shuixigou Group is studied. The braided delta depositional system is the MOS T favorable one for the formation of uranium deposits whereas Sandstonetype; the distributary mouth bar and sheet sand subfacies of the delta front facies, the braided stream subfacies and the distributary channel subfacies of the delta plain facies and the and distal fan subfacies of Midfan the alluvial fan facies are the major sedimentary facies for sandsto Orecontrolling Netype uranium deposits.

Abstract:Abstract：The authors studied the mode of occurrence, main accompanying elements and precipitation mechanism of sandstone-type minerals in the Diantou area of the southeastern Ordos basin by using the electron microprobe and microprobe. The dominant uranium mineral in the study area is pitchblende, which occurs as microdisseminations filling in pores and cements of sandstone. The elements associated intimately with uranium are Fe, Se, Pb, Si, Ti, Cr and S and the mineral assemblage of uranium includes pyrite, galena, brannerite and its closely related selenium mineralization. The main uranium-bearing horizon contains rich organic matter and pyrite, intercalated with lenticular and banded coal seams. It contains abundant reducing material, which is favorable for uranium reduction and concentration. Therefore, the authors think that the reducing barrier and adsorption barrier are the main factors responsible for uranium deposition in the study area.

Abstract:Abstracts：The oxidized zone of the Hongshan high-S epithermal Cu-Au deposit in the Hami area, Xinjiang, NW China, occurs as a funnel in the upper part of the primary sulfide orebody, extending downward for 50-60 m. Many supergene minerals were found by X-ray diffraction (XRD), differential thermal analysis (DTA) and thermal gravimetric analysis (TGA), of which three sulfate minerals, krausite, rhomboclase and parabutlerite, were for the first time found in China. The chemical analysis of krausite gives the following results (%): H2O 6.35, SO3 49.72, Na2O 0.15, Fe2O3 26.00, K2O 12.47, FeO 0.25, SiO2 3.25, insoluble residue 0.85 and CaO 0.11 with a total of 99.15, and its XRD analysis presents the following characteristic spectra: 4.40 (100), 4.26 (70) and 6.58 (47). The results (%) of chemical analysis of rhomboclase are H2O 26.51, SO3 49.91, Na2O 0.03, Fe2O3 22.52, MgO 0.01 and CaO 0.03 with a total of 99.01；and the characteristic spectra of its XRD analysis are 9.16 (100), 3.29 (9) and 4.06 (8). The results (%) of chemical analysis of parabutlerite are H2O 24.82, SO3 38.53, Al2O3 0.18, Fe2O3 36.10, MgO 0.02 and CaO 0.04 with a total of 99.69, and its characteristic spectra of XRD analysis are 5.00 (100), 3.11 (41) and 5.85 (39). DTA further verified the reliability of these chemical data and explained the thermal reaction mechanism of these sulfates. These sulfate minerals have been used as a new type of acid resource for wet smelting of copper, showing great advantages in mineral beneficiation and environmental protection. So the paleoenvironment and paleoclimate may be deduced through an intensive study of the assemblages, sequence of occurrence and formation conditions of such sulfate minerals in the oxidation zone.

Abstract:Abstract：The Tulargen Cu-Ni-Co deposit, lying in the northeastern segment of the Kangurtag-Huangshan ductile sheer zone, is a semi-hidden deposit formed mainly by deep-level liquation of sulfide, combined with in-situ liquation and hydrothermal superimposition. Intrusion No.1 is characterized by whole-rock mineralization and can be divided into four rock facies：hornblende peridotite, pyroxene peridotite, hornblende pyroxenite and gabbro. The rocks show the features of repeated pulsatory magmatic upwelling and ore formation in a single phase. The m/f ratio of the intrusion varies from 3.1 to 4.8, falling into the range of ferrous-ultramafic rocks. The intrusion is featured by low Ti, low total alkalis and low Al2O3, similar to the petrochemical characteristics of the Huangshan-Jing＇erquan mafic-ultramafic complex. The REE distribution patterns and trace element and transition element spidergrams indicate that the No.1 and No.2 mafic-ultramafic intrusions in the Tulargen ore district are comagmatic and supplementary, implying that the deep part of the No.2 intrusion has a great ore potential though gabbro of the No.2 intrusion shows weak mineralization at the surface. According to the MT section across both the No.1 and No.2 intrusions, it is clear that they share only one magma conduit at depth and originated from the same magma source. Lower La/Sm (<2) and Th/Ta (4.6) ratios suggest a mantle origin of the ore magma and little contamination with crustal material during the emplacement of the intrusion.

Abstract:Abstract：The Kalaxianger porphyry copper deposit (belt) is located in a Late Paleozoic island arc on the southern margin of the Altay Mountains. The ore-bearing porphyries are mainly represented by mid-late Hercynian intermediate-acid porphyries and the country rocks are the Middle Devonian Beitashan Formation. Petrological and geochemical studies of the ore-bearing porphyries indicate that there are at least two types of porphyry in the study area, mainly including quartz monzonite and granodiorite. Some quartz monzonite has the distinct features of adakite：SiO2>56％，Al2O3>15％，MgO<3％，Sc<10％, positive Eu and Sr anomalies and initial 87Sr/86Sr<0.704. However, some porphyries, which have higher HREE contents (Y>18×10-6 and Yb>1.9×10-6), are deviated from the compositional range of adakite. The cause for higher HREE contents might be due to the existence of relict hornblende in the source region during subduction and melting of oceanic crust. Analysis of the chemical characteristics of rocks and geological conditions of the Kalaxianger copper belt shows that the study area probably has good porphyry copper metallogenic prospects.

Abstract:Abstract：In the Darbute-Baogutu area, western Junggar, there outcrop two types of intermediate-acid intrusive rocks：late Hercynian (<270 Ma) granite batholiths and late-mid Hercynian (330–320 Ma) intermediate-acid small porphyry bodies. The Baogutu porphyry copper deposit is hosted in the latter. The Major element and trace element analysis of the rocks indicate that the Baogutu copper-bearing small porphyry in the mine meets the conditions of adakitic rocks, i.e.：SiO2>56%, Al2O3>15%, MgO<3%, Y<18×10-6, Yb<1.9×10-6 and Sr>400×10-6 and pronounced HREE depletion. Its Nd and Sr isotopic compositions are close to that of MORB. However, the composition of some samples, which is characterized by relatively high MgO contents (>3%) and a relatively low LREE abundance), is deviated from the compositional range of adakitic rocks. According to the geochemical composition of porphyries, combined with the regional geological characteristics, the authors think that the Baogutu copper-bearing porphyry originated in an island-arc environment related to intraoceanic subduction but that the initial melt of the oceanic crustal slab was subjected to inhomogeneous contamination with mantle peridotite during its rise.

Abstract:Abstract：The Hongshan gold field is located at the north edge of the east section of the Qiugemingtashi-Huangshan ductile shear zone. The study of the genesis of the Hongshan gold deposit shows that its formation was strictly controlled by this ductile shear zone and that it belongs to a mylonite type or ultramylonite type deposit related to the ductile shear zone. Hornblende in granitic mylonite yields an Ar-Ar plateau age of 276.3 Ma, representing the upper limit of the ore-forming event of the Hongshan gold deposit. Sericite in gold ore samples give Ar-Ar plateau ages of 246.9 and 246.5 Ma, recording the age of the main mineralization stage of the gold deposit. The Ar-Ar plateau age of 246.5 Ma of the neogenic muscovite in mylonite is in agreement within error with that of the sericite in gold ore, which not only provides further evidence for the Hongshan gold deposit being of shear zone type origin but also puts a further constraint on the age of gold mineralization.

Abstract:Abstract：The Sangshuyuanzi ductile shear zone in the central segment of the South Tianshan is an east-west-trending shear zone, in which foliations, lineations and asymmetric structures are well developed. Based on a kinematic analysis,the authors think that the Sangshuyuanzi ductile shear zone is of sinistral strike-slip nature. 40Ar/39Ar dating of muscovites from mylonite in the shear zone yields a plateau age of 393±6 Ma and an isochron age at 389±3 Ma. 40Ar/39Ar dating of biotites from en-echelon fractures in the zone gives a plateau age of 366.5±2 Ma and an isochron age of 365.0±3 Ma. According to the above-mentioned study, combined with the regional tectonic background, this paper suggests that the Sangshuyuanzi ductile shear zone is a syncollisional strike-slip tectonic zone formed by oblique collision between the Tarim plate and the Kazakhstan-Ili plate, which resulted in strain partitioning parallelly to the boundary of the two plates.

Abstract:Abstract：Through continuous laser stepwise heating 40Ar/39Ar dating of two mica samples from auriferous phyllic mylonite of the Kekesayi and Alatasi gold deposits hosted in the Bu’ergen shear zone, the authors obtained plateau ages of 274.5±2.2 and 282.6±2.2 Ma and corresponding isochron ages of 275.8±5.2 and 283.1±5.2 Ma for the two deposits respectively. These ages suggest that the ductile-brittle shear of the Bu’ergen shear zone and formation of gold deposits occurred at the beginning of the Early Permian. These chronological data combined with regional geological data show that the formation and evolution of the Bu’ergen gold-bearing shear zone were mainly controlled by the tectonomagmatic event related to the regional sinistral ductile shear of the huge Irtysh (Ertix) strike-slip shear zone on the southern margin of the Siberian plate, and its tectonic setting is the post-collisional extensional environment of the Altay orogeny.

Abstract:Abstract:This paper summarizes recent research results and introduces ore deposit types and mineralization related to rocks. The dominant minerals under discussion Maficultramafic Vanadictitianomagnetite Coppernickel, are, chromite, magnetite, PGE, cobalt, gold, magnesium, apatite, diamond, asbestos, vermiculite, gemstone and jade. The genetic types of ore deposit Involved are mainly the magmatic type (including magmatic differentiation, magmatic injection, magmatic liquation and magmatic explosion), hydrothermal type, skarn type, metamorphic type, volcanic eruption type, supergene type (including weathering crust and placer deposits) and composite type. For convenience of mineral exploration and based on types of Orebearing MAF Icultramafic bodies, combined with the genetic types and tectonic setting of ore deposits, the ore deposits related to rocks may be classified into Maficultramafic three major ore deposit types, i.e. those associated with plutonic rocks, hypabyssal rocks and extrusive rocks, and several subtypes. The major types, geological characteristics, genetic features and case hist Ories of the ore deposits are introduced in details. Finally, on that basis, the mineralization related to the rocks are discussed at the Maficultramafic following four levels: (a) polymineralization of single deposits (b), different deposit types and mineral assemblages of one complex (c), association of different Maficultramafic rock suites, and (d) paragenetic relatio Nships with rock suites. Nonultramafic.

Abstract:Abstract：There are many fluid inclusions in quartz in the Hatu gold deposit. they are small in size，mostly ranging from 3 to 5μm，and poorly developed，suggesting that they underwent tectonic compression during their formation. The ore deposit formed at middle temperatures and a low salinity. The water in the fluid inclusions is mainly magmatic water with minor meteoric water. The ore-forming material of the deposit was mainly derived from deep sources. REE and carbon isotope analyses of quartz inclusions in wall rocks and orebodies indicate that the source of the REE and the mineralizer elemental carbon has little relation to the wall rocks，and that the mineralization of the Hatu gold deposit was less influenced by strata. The study of ore fluids in the Hatu gold deposit suggests that the gold orebody may still extend downward to a certain depth.

Abstract:Abstract：The element temporal-spatial distribution characteristics of systems are studied in the exploration-geochemical context by using element abundances, variation coefficients, and degrees of element disorder. On the basis of that study, the recognition and prediction of large ore deposit clusters are discussed and a prediction model is constructed. The authors suggest that attention should be paid to surficial geochemical processes when the element abundances, variation coefficients, and degrees of element disorder are used to evaluate a large ore deposit cluster and point out that this model is suitable to the important condition that there exists an internal relation between an element cluster and the geologic body in which the element cluster is hosted”. It is concluded that the Carboniferous pyroclastic rocks should be the target for gold search in Xinjiang.