Abstract:Abstract：The geotectonic nature of the South China has been debated for a long time between the Old Land or craton and the Folded Geosyncline or orogenic belt. The authors insist on that it is an orogenic rather than a cratonic area, because South China is rare of Early Precambrian terrains, widespread of huge volume of geosyncline-facies sediments with age of <1.0 Ga, significantly affected by multi-cyclic tectonic movements after 1.0 Ga, and developed with multistage Phanerozoic granitoids. Considering that famous platforms or Old Lands in the world do not contain tungsten deposit, and that South China is the most important tungsten metallogenic province in the world, in this paper the authors introduce the geochemical principles in W mineralizing processes, the geochemical characteristics and genetic tectonic setting of W-bearing granitoids in South China; and thereby, through study of regional mineralization, confirm that the South China is tectonically an orogenic belt.

Abstract:Abstract：The massive sulphide ore from the Hongtoushan deposit are composed mainly of pyrite, pyrrhotite, chalcopyrite, sphalerite, quartz, hornblende and biotite. As starting material, the ore was dried and mounted in a tri-axial stress machine. The experiment started with stepwise raise of axial pressure, confining pressure and temperature, and stopped when these parameters reached 1276 MPa, 414 MPa and 350°C, respectively. Then, the sample was cooled in air to room temperature. The run product was characterized by cataclasis of pyrite and quartz, and plastic deformation of pyrrhotite, chalcopyrite, sphalerite and mica. As veins and networks, remobilized chalcopyrite, pyrrhotite and minor sphalerite cut pyrite porphyroclasts. This experiment shows that fluids released by fluid inclusions in response to tectonic stress are sufficient to cause mobilization and remobilization of ore materials even though no external water is added.

Abstract:Abstract：In this paper we introduce several breakthroughs in geodynamic or tectonic issues resulted from studies on ore-systems, and propose that ore-systems can serve as an ideal geodynamic probe. Usually formed in multiple geological processes, ore-systems record complete geological information. Compared to other kinds geologic bodies, ore-systems are more precisely studied through prospecting and/or mining. As a consequence, ore-systems can provide accurate indicators to geodynamic settings and evolution. We set up a preliminary linkage between major ore-systems and geodynamic settings; and propose several important scientific approaches for solving long-standing geodynamic controversies by the study of ore-systems.

Abstract:Abstract：In general, the copper-gold (-silver-niobium-platinum group element-rare earth element-uranium) deposits that contain iron oxides (magnetite and/or hematite) more than 20% are called iron oxide copper-gold (IOCG) deposits. The geological features, metallogenic mechanism and prospecting models have been extensively and intensively studied both at home and abroad. The geology of the major IOCG deposits worldwide has been summarized in this paper. Meanwhile, the ore-forming processes and prospecting criteria on these typical IOCG deposits have also been discussed. Our preliminary studies show that both iron-only deposit and IOCG deposit belong to the oxide iron ore-forming system, but they are the end-member of the system, respectively. Therefore, the iron-only deposits should not be listed in the IOCG family at present. Based on our knowledge obtained from the geological field investigation on the Australian typical IOCG deposits, the tectonic setting and geological features of the iron-copper deposits occurring in Xinjiang, Yunnan, Sichuan，Anhui and Hainan provinces (or autonomous regions) have been analyzed. Among these studied deposits, the Yamansu, Tianhu, Laoshankou, Qiaoxiahala, Dahongshan, Etouchang, Daxiaoling, Lala and Shilu deposits show a lot of similarities to these typical IOCG deposits. To demonstrate the genetic type and ore-forming mechanism of these iron-copper deposits, the comprehensive studies will be needed.

Abstract:Abstract：Calcium isotope, one of non-traditional stable isotopes, has been a research hotspot in isotope geochemistry field since the last decade. Calcium isotope ratios are widely measured by TIMS or MC-ICP-MS, and are expressed as δ44/40Ca or δ44/42Ca respectively. Variations of δ44/40Ca in nature are mainly from -2.0‰ to 2.0‰, spanning only a limited range of 4.0‰. The hypotheses of kinetic and equilibrium fractionation can interpret some of calcium isotope fractionation observations, but more work is needed to better understand the fractionation mechanism. Up to now the geological application of calcium isotope includes：(1)Paleoceanography temperature reconstruction based on δ44/40Ca of planktonic foraminifera G. sacculifer；(2) Geochemical cycling of calcium in ocean；(3)Estimation of pCO2 in terms of seawater calcium concentration.

Abstract:Abstrct：Recently, series of major breakthroughs for porphyry copper exploration have been made in the Gangdese Metallogenic belt in Tibet. Alteration and mineralization ages of the Gangdese porphyry-skarn Cu(Mo) deposits concentrate in the range of 30～12 Ma, formed in the extension environment of late stage of collision between India and the Asian continents or the transitional environment from the post-collisional compression setting to strike-slip extension. However, the independent porphyry molybdenum deposit associated with the collisional setting has not been reported so far. This paper studies the ore-bearing porphyries, the types and horizational and vertical zonation of hydrothermal alteration, the characteristics of hydrothermal vein system and mineralization, according to the systmatic fieldwork and the mapping work of the drilling holes. The granitic porphyry is the ore-forming intrusion with intensive alteration of 9 km2 in area. It concludes that, Sharang porphyry molybdenum is single porphyry molybdenum without any other important accompanying metal resources and it has been formed in the main collisional setting around 55 Ma. This study compares the scale of alteration and the intensity of mineralization with the same type of molybdenum deposits. Based on the comparisons and the results of TEM and induced electrical survey, the Sharang porphyry molybdenum deposit has rather large vertical extension to 800 m in the depth and showes excellent metallogenic conditions and great potential for further exploration. The establishment of the Sharang single porphyry molybdenum deposit will enrich the metallogenic pedigree of the giant Gangdese porphyry metallogenic belt. This discovery has a great significance for regional research and prospecting.

Abstract:Abstrate：Located in the western part of the Min-Li metallogenetic belt, wetern Qinling Mountains, the Zhaishang gold deposit is a recently discovered large Carlin-type disseminated gold deposit. Examination of ores by optical microscope, EPMA and ICP-MS from the the deposit, has revealed a scheelite enrichment. On the basis of chemical-analytical data, several independent scheelite orebodies are located. It belong to Au-Sb-W deposit association of gold-scheelite-stibnite. In some ways, it can be compared with the Manaoke gold deposit in Sichuan with respect to geological setting, host lithology, mineralization style, mineral assemblages, geochemical association and metallogenic processes involved. Since in the Devonian and Triassic strata in the triangular border region of Sichuan， Gansu and Shaanxi provinces， as so-called golder trangle， coith many gold deposits or occurrences similar to the Zhaishang deposit，it is obviously of great importance to evaluate the value of tungsten and other elements in these gold deposits.

Abstract:Abstract：Zircon LA-ICP-MS U-Pb age of the Cenozoic silver-bearing trachytic tuff from the Sanshui basin ranges from 90 to 3175 Ma. The zircon age of the Cenozoic volcanic rocks indicates that the zircon grains were captured during the formation and ascending of the volcanic melts. The occurrence of zircon grains with ages (2489 Ma±30 Ma,3175 Ma±38 Ma shows that the basement of the Shanshui basin contains the Archean relict zircon. The occurrence of zircon grains in Proterozoic age indicates that the Proterozoic basement of the Cathaysian block underwent structural-magmaic activities (955~1148 Ma) at the same period as the Grenville orogeny and the Neoproterozoic structural-magmatic activities (798 Ma±12 Ma, 883 Ma±10 Ma). The region of the Sanshui basin underwent Caledonian (438.0 Ma±6.8 Ma), early Yanshanian (~160 Ma), late Yanshanian(±98.2±1.1Ma), and Himalayan structural-magmatic events. The multi-structural magmatic events correlate well with the formation of deposits occurred in the southwestern rim of the Sanshui basin. It is concluded that the multi-structural-magmatic events are the key factors controlling the formation of the deposits in the southwestern rim of the Sanshui basin. The South China Fold belt underwent Himalayan ore-forming event and the rim regions of the faulted basins in the South China Fold Belt that underwent multi-structural-magmatic activities are favorable target area for mineral prospecting.

Abstract:Abstract：Mineralization of the Bayan Obo REE-Nb-Fe ore deposit presents very special geochemical characteristics, suggesting the multi-stage mineralization incredible. The forming age of dolomite as the major ore-bearing stratum must be no later than the mineralization of the Bayan Obo ore deposit. Geological age of Bayan Obo Group has been in dispute in long-term period, and changed many times, but abundant paleontological evidences prove that the age of the Bayan Obo Group is between Sinian and Ordovician. The dolomite is a hydrothermal sedimentary formation and the carbonate veins are formed from hydrothermal replacement of the metamorphic rock or sandstone, and consequently, the zircons from the carbonate veins must be originated from the zircons of metamorphic rock or sandstone. Even though these zircons are reformed by the hydrothermal fluid, it is reasonable that the calculated U-Pb ages of these zircons are older than the ore-forming age. Huge amounts of Sm-Nd isochron ages of the Bayan Obo deposit have been reported. Though they mainly concentrate in the range of 1.2-1.6 Ga, some of them are ~400 Ma, ~800 Ma, and ~1000 Ma, and most of them have large inaccuracy. Considering that the Bayan Obo deposit is formed in a single mineralization period, all the 98 Sm-Nd data from published papers about Bayan Obo are calculated by Isoplot program. 98 data can be synthesized in a straight line(only 2 data are far from the isochron line)with correlation coefficient R= 0.96325, and gield t=1125.8±32.5 Ma（λ=6.54×10-12a-1）, εNd=-3.02, which shows that the Sm-Nd isotope clock after the onset of 1125.8±32.5 Ma has never been disturbed by subsequent geological events. Therefore the ore-forming age of the Bayan Obo deposit should be no earlier than 1125.8±32.5 Ma. The molybdenite Re-Os model age and the pyrite Re-Os isochron age of 439 ± 8 Ma and 439 ± 86 Ma respectively, which is consistent with the age of paleomicroplant fossils. Assuming that Sm-Nd isotopic clock is very perseverant and difficult to be reset by general geological events, the ore-forming age of 439 Ma is admissible.

Abstract:Abstract：This paper report the LA-ICP-MS zircon U-Pb age data of the alkaline rocks and lamprophyres in the Gejiu tin district, Yunnan Province. Combined with the character of local geology and geophysical of this area, authors try to discuss the geodynamic setting of western Cathaysia block during Late Yanshan epoch. The dating data shows the alkaline rocks formed at 79.9 Ma and the age of lamprophyre is 82.0 Ma, both of which emplaced during late Yanshanian epoch. Based on the previous geophysical profile, tectonic evolution, and the data achieved this time as well as the rock formation we propose that the Gejiu giant tin deposit formed in an extensional setting in Late Yanshanian epoch.

Abstract:Abstract：Adakites are intermediate to felsic igneous rocks, andesitic to rhyolitic in composition (basaltic members are lacking). They have trondhjemitic affinities (high-Na2O contents and K2O/Na2O 0.5) and their Mg no. (0.51), high contents of Ni (20×10-6-40×10-6) and Cr (30×10-6-50×10-6) contents are higher than in typical calc-alkaline magmas. Sr contents are high (>300 ×10-6, until 2000 ×10-6) and REE show strongly fractionated patterns with very low heavy REE (HREE) contents (Yb≤1.8×10-6, Y≤18 ×10-6). These rocks are depleted in Nb and Ta compared with other igneous rock. The tectonic formation of adakites are still disputed at present, the points of views are: 1) the melting of young oceanic crust during the subduction；2) delamination or foundering of dense mafic lower crust rocks (e.g., eclogite and garnet pyroxenite) in mafic lower crust to the mantle during continental orogenesis. Consequently, the Fe-Cu-Mo mineralization is closed related to the formation of adakites. On detailed review of geochemical data and geological environment in Shaxi porphyry Cu-Au deposit (central Anhui), we fund the close link between adakite and the regional Cu-Au mineralization. The mineralized model for Shaxi porphyry Cu deposit can be explained by the subduction of the western Pacific plate in the early Cretaceous, whose process released large ion lithophile element (LILE)-rich fluids rise up into the mantle wedge, inducing both its metasomatism and partial melting, trigger a large mount of Cu-Au and fluids materials to the crust environment and melting the subduction plate formed the adakitic assemblage and Shaxi porphyry Cu-Au deposit.

Abstract:Abstract：There were two intensive igneous activities in North China. The early stages of magmatism is charecteristized by Jurassic high-Sr quartz diorites and the latter stage is charateristic of Cretaceous shosholites. These rock series represent two different geological setting of crust thichenning and lithospheric thinning, respectively. The transition of two igneous activities occurred at about 130 Ma. The development of Cretaceous alkaline rocks in North China shows that in the lithosphere extension occurred in Cretaceous. This conclusion can also been verified by seism profile, the ages of extensional and compressional structures, the ages of metamorphose core complexes, strike-slip ages of Tanlu fault zone. The lithosphere extension took place in the Early Cretaceous, and the boundary of Late Jurassic-Early Cretaceous is the tectonic turnning point in North China.

Abstract:Abstract：The single grain zircon CL images and the SHRIMP U-Pb zircon dating for the Biotite-actinolite schist of the Wudaogou Group in the east of Yanbian, yield seven sets of concordant ages and one set of discord ages for 21 zircon spots. The concordant ages are 1347.8 Ma, 844.8 Ma, 340.2～313.7 Ma（Mean=323±23Ma，MSWD = 0.23, reliability = 0.88）, 292.9～288.3 Ma（Mean=291 ±25 Ma，MSWD = 0.031, reliability=0.86),279.2～266.2 Ma（Mean=279 ±28 Ma，MSWD = 0.031,reliability=0.86）,127.4～124.2 Ma（Mean=126.5±3.7 Ma，N=5，MSWD=0.12；reliability＝0.97）and 116.1～106.3 Ma（Mean= 115 ±39 Ma，N＝2，MSWD =1.2, reliability= 0.27）,respectively;and the discord ages show that the lower and upper intercept ages are 451±120 Ma and 1811±400 Ma（MSWD = 7.2）,respectively. The results indicate that the provenance of the biotite-actinolite schist is clastic materials from Mesoproterozoic, Neoproterozoic and early Paleozoic；the sedimentary diagenesis and metamorphism of Wudaogou Group accurred in Carboniferous and lower-Permian. The wudaogou Group has been reworked two times by magmatism and alteration during the periods of 279.2～266.2 Ma and 126.5～106.3 Ma.

Abstract:Abstract：The Xitieshan lead-zinc deposit is located close to the northern margin of the Qaidam basin, Qinghai Province, Western China. Both stratiform and vein-type orebodies occur in each of the three units of the Ordovician Tanjianshan group. These units are the O3tnb schist, the transition zone between O3tnb and the marble layer, and the O3tna-2 schist. In addition, there are irregular orebodies in the marble layer. Based on investigation of orebody distribution, and ore structures and textures, genetic types of the orebodies are summarized. Stratiform orebodies in all the three strata can be ascribed to the SEDEX-type. Among them, those hosted in the O3tnb schist and in the transition zone between the O3tnb schist and the marble are proximal, while vein-type mineralisations stratigraphically bellow these orebodies are thought to represent feeding zones. By contrast, stratiform orebodies in the O3tna-2 schist were formed by distal exhalative sedimentation. Irregular orebodies in the marble layers are likely to have been formed by post-orogenic hydrothermal mobilization/remobilization of metals from surrounding rocks or the stratiform orebodies. Vein-type orebodies in the O3tna-2 schist were also produced by post-orogenic hydrothermal overprinting, and possibly served as feeding zones for the irregular orebodies in the marbles.

Abstract:Abstract：The Sabei tin ore deposits in the eastern Junggar are mainly developed in the quartz veins of the biotite granites and alkali amphibole-bearing quartz veins of the alkali-enriched granites. Zircons were selected from the cassiterite-bearing quartz veins of the biotite granites for SHRIMP U-Pb zircon dating, and yielded an age of 324.2±3.4Ma, implying the tin mineralization age. This age approximates to the formation time of the Laoyaquan-Hongtujing and Sujiquan biotite granitic batholith with 358.6 Ma～304±2 Ma, and obviously is earlier than those of the Sabei alkali-enriched granites (306±3 Ma～314±5 Ma) and alkali amphibole-bearing quartz veins (263.6±3 Ma～307±11 Ma) . We propose the existence of at least two periods of tin-mineralization, which is consistent with the post-collisional plutonic rocks (330 Ma ~310 Ma and 305 Ma～280 Ma) in the eastern Junggar and correspond to the first two phases of the three post-collisional mineralization (340 Ma～330 Ma，300 Ma～285 Ma，270 Ma～260 Ma) in the northern Xinjiang Province. Accordingly, we conclude that, the formation of the Sabei tin ore deposits has a multi-phase feature and is related not only to the alkali granites, but also to the biotite granites; the above two types of tin deposits and related alkali-enriched granites were resulted from the late paleozoic post-collisional magmatic and metallogenic events in the northern Xinjiang Province, a tin metallogenic system associated with late paleozoic post-collsional alkalic granites may be well developed in the Kalamaili ore deposits zone.

Abstract:Abstract：The Duanhe gold deposit is a quartz-vein type gold deposit, located in Luoning County, Henan Province. The gold deposit mainly includes Shizhaigou and Lingdong mining areas that comprise of three to four gold-bearing quartz veins, respectively. The ore-forming process includes three stages, i.e. the early, middle and late stages, characterized by mineral assemblages of quartz-pyrite, quartz-polymetallic sulfides and quartz-carbonate, respectively. The most intensive gold mineralization is developed in the middle stage, secondarily in the early stage. Fluid inclusions in quartz of three stages are mainly H2O-rich. Some inclusions contain a little of CO2 in gas and liquid phases. Pure H2O inclusions can be also observed. Homogeneous temperatures of the early-, middle- and late-stage fluid inclusions are 240.9~315.9 °C, 188.7~304.5 °C, and 137.3~259.3°C respectively in the Shizhaigou; while in the Lingdong mining area are 303.7~343.1°C, 251.8~325.4°C, and 305.7~355.0℃, respectively. In the Shizhaigou the salinities are (6.74~12.85)wt% NaCl.eq, (2.41~8.68) wt% NaCl.eq and (2.24~7.86) wt% NaCl.eq, respectively; and in the Lingdong mining area are (5.11~11.70) wt% NaCl.eq, (2.74~10.11) wt% NaCl.eq and (0.53~6.74) wt% NaCl.eq, respectively. The ore-fluids of these two mining areas were characterized by moderate-temperature and low-salinity at the main metallogenic stage. The early-stage ore-fluids were mixed hydrothermal solutions of reworking and metamorphic fluids, containing a small amount of CO2. From early to late stage, the CO2 content and salinities of fluids gradually decreased. From early to late, homogeneous temperatures of fluid inclusions in Shizhaigou mining area decrease gradually, whereas increase after a firstly decrease in Lingdong mining area. This, together with that the temperatures of each stage of the Lingdong area are generally higher those of the Shizhaigou area, suggests that the ore-forming fluid-system were driven by magmatic heat, and that the Lingdong area is more close to and was reheated by the blinded pulsing magmatic intrusion which was possibly seated beneath the south of the Duanhe deposit.

Abstract:Abstract：The Poshan superlarge silver deposit is located in the western end of the Weishancheng Au-Ag-dominated poly-metallic ore belt in Tongbai Mountains. The orebodies hosted in the horizons of carbonaceous sericite schist of the upper part of Neoproterozoic Waitoushan Formation (Pt3w3). Strictly controlled by the hosting strata and the Heqianzhuang anticline, the occurrences of orebodies are mainly shaped as stratiform, lode or lens. The dominated ore-type is altered tectonite. The ore-fluid belongs to the mesothermal, low salinity, low density, CO-2rich and K+-SO2-4 type fluid system. The ore-forming fluids were metamorphic in origin and generally evolved into meteoric water-sourced fluid in late metallogenic stage. The ore-forming elements including S and Pb must be mainly sourced from the Waitoushan Formation. The K-Ar isotopic ages of hydrothermal sericite and minette dyke are 103.6 Ma and 134 Ma, respectively, indicating the metallogenesis of the Poshan silver deposit formed in Early Cretaceous, when a tectonic setting changed from collisional compression to extension in Qinling-Tongbai orogen belt.

Abstract:Abstract：The Qiyugou gold deposit, Songxian County, Henan Province, is associated with subvolcanic breccia pipes in the Xiong'er terrane, southern margin of the North China craton. In hydrothermal quartz three types of fluid inclusions can be observed. They are H2O-rich, daughter mineral-bearing, and CO2-rich. The initial ore-forming fluids are magmatic in origin and characterized by high temperature (>350°C), high salinity (>30wt%NaCl.eqv), high oxygen-fugacity and CO2-rich. Then the fluids boiled and resulted in CO2-release, oxygen-fugacity decrease and rapid precipitation of ore-forming materials. The late stage fluids, characteristic of low temperature, low salinity and lack of daughter mineral, could be sourced from meteoric water. The ore-forming fluid system and geological characteristics of the Qiyugou gold deposit suggest that it is a typical explosive breccia-type gold deposit, instead of an epithermal-type deposit.

Abstract:Abstract：The Tangjiaping Mo deposit in Henan Province is located in the Dabie orogenic belt. In quartz three types of fluid inclusions can be observed, namely CO2-rich (bearing) fluid inclusions, aqueous solution fluid inclusions and daughter-crystal-bearing fluid inclusions, based on the petrography, microthermometric measurement and Laser Raman microprobe analysis. The homogenization temperatures vary from 126.7°C to 472.1°C, the calculated fluid salinities cluster in two ranges, i.e., (0.18-14.21) wt% NaCl.eqv and (33.10-54.37) wt% NaCl.eqv, with densities changing from 0.38 to 1.21 g/cm3. Daughter minerals, mainly halite and metallic sulfide, can be recognized in fluid inclusions. The homogenization temperature and salinity of fluid inclusions reduce gradually outward from the center of ore-forming porphyry system. From early to late the fluid system evolved from and high temperature and high salinity to low temperature, and low salinity; and the trapped pressure reduced, indicating the mineralization depth became shallower gently. The Re-Os isotopic model ages of molybdenite are between 113 Ma and 118 Ma, about 10 Ma later than the crystalline age of the Tangjiaping granite porphyry. The ore-system was formed in waning stage extension setting of the inter-continental collision between Yangtze Block and North China Block.

Abstract:Abstract：The Zhaiwa Mo deposit, in Luoning county, Henan province, is located in the Xiong'er Terrane in southern margin of North China Craton. Its ore bodies, occurring as lode, are hosted in biotite-amphibole-plagiogneiss of the Taihua Group and controlled by subsidiary faults of the Machaying fault which is the south boundary fault of the Xiong'er terrane. Three stages of hydrothermal ore-forming process are recognized, Quartz-molybdenite(Ⅰ), which is the main metallogenic stage, Quartz-polymetallic sulfide(Ⅱ) and Quartz-carbonate(Ⅲ). Two types of fluid inclusions, i.e. H2O-NaCl, daughter mineral-bearing, are observed. Laser-Raman spectrum showing that the most important component of fluid inclusion is water. From early to late stages, homogeneous temperatures of fluid inclusions change from 100~260 °C (Ⅰ), through 110~160°C (Ⅱ), to 120~180°C (Ⅲ), this showing that the Zhaiwa Mo deposit belongs to low-temperature hydrothermal deposit; salinities change from 2~25 wt%NaCl.eqv(Ⅰ), through 6~30 wt%NaCl.eqv (Ⅱ), and to 7~25 wt%NaCl.eqv(Ⅲ). The broad range of homogeneous temperatures of stageⅠ, the evolution of salinities from bimodal to unimodal, and negative correlation between homogeneous temperatures and salinities indicate that fluid mixing is the most important metallogenic mechanism in Zhaiwa Mo deposit. The characteristic of fluid inclusion in Zhaiwa Mo deposit are high density, high salinities and low temperature, which is the result of CaCl2-bearing fluid involved in ore forming process, the mixing of hot magmatic fluid and cold CaCl2-bearing brine result to precipitation of molybdenite. In summary, The geological and fluid inclusions features of the Zhaiwa Mo deposit are similar to intrusion-related deposit, we affirm that the Zhaiwa Mo deposit is a intrusion-related Mo deposit.

Abstract:Abstract：Wulaga gold deposit is controlled by both fracture zone and intermediate-acidic porphyry. In the mining district, Heilongjiang Group metamorphic rocks are considered as the main source bed. The Yanshanian plagioclase-granitic porphyry is the wall rock and provided the heat source for the gold mineralization process. The locations of the ore bodies are the places of fault intersection or the fault extensional sections due to attitude change. And the ore bodies are distributed in raking and stepwise pattern. The ore minerals are mainly composed of native gold, pyrite, marcasite, stibnite and native silver while the gangue minerals are mainly chalcedony quartz, colloid opal, carbonate, adularia, sericite and kaolinite. Gold ores are of colloidal, fine grain and cataclastic textures and veinlike, stockwork and brecciated structures. Thus, the gold ores show typical low temperature characteristics in texture, structure and mineral assemblages. Based on microscopic study, it is found that aqueous two-phase and small amount of pure aqueous-phase fluid inclusions dominate in quartz. It is suggested that the ore-forming fluid belongs to H2O-NaCl system and the fluid is characterized by low salinity (from 1.22% to 5.4% NaCl.eqv) and low density (from 0.88 to 0.96 g/ cm3). The forming temperature ranges from 140℃ to 220℃. The average value of pressure is 23.24 MPa and the mineralizing depth is about 2.32 km. With respects to stable isotopic features of the fluid inclusions, the values of δDSMOW are between -78.25‰ and -132.64‰ while those of δ18OH2O are from -3.7‰ to 6.23‰. It is concluded that the ore forming fluids are mainly meteoric water. Finally, it is suggested that the deposit belongs to a low sulfadation epithermal gold deposit that was formed from neutral, reduced and low temperature hydrothermal system.

Abstract:Abstract：Mineral association, ore structures and textures of the Bairendaba Ag polymetallic ore deposit in Keshiketeng banner were confirmed. Wall rock alterations are silicification, potassic alteration, sericitization, phyllic alteration, chloritization, fluoritization, carbonation and argillation. The mineralization process can be divided into four stages: porodic pyrite-quartz stage, arsenopyrite-iron rich sphalerite-pyrrhotite-quartz stage, polymetallic sulphide-quartz stage and fluorite-carbonate-quartz. Polymetallic sulphide-quartz stage is the main stage of silver mineralization. Previous publications on the study of fluid inclusion indicated that the characteristics of fluid inclusion are gas-liquid phases, moderate or low temperature, low salinity, and CO2 bearing. Based on tectonic setting, geological characters and fluid inclusion characters of the deposit, the Bairendaba deposit might be an epithermal silver deposit or a silver orogenic deposit, or superposition of both.

Abstract:Abstract：Using electronic microprobe, the mineralogical study of samples from level 29 of V3 vein of the Woxi deposit in western Hunan province shows that the ore minerals include major native gold, stibnite, sphalerite and Sb-Pb mineral phase. The mineralogical assemblage of the deep ore is more complicated than those of the shallow levels. The native gold from level 29 contains 0.52% Ag, 1.42% Sb, 4.48% Pb and 5.65% Bi in average, respectively, much higher than those from shallow places (above 24 flat). The gold fineness is <995 at deep, but >999 at shallow. All the facts above show that the position beneath the present mining levels is potential for Au-Pb-Zn- Bi±Cu poly-metalic orebodies; and that future deep prospecting should pay attention to poly-metallic mineralization.

Abstract:Abstract：The Zhashui-Shanyang basin is developed with hydrothermal sedimentary rocks and flysch formation, which were reworked by strong magmatism and faulting. The basin has good ore-forming conditions and is now an important ore-cluster area. To date, remarkable Ag-Pb-Cu-Zn deposits have been found in Devonian carbonate strata, with numerous no-evaluated geochemical anomalies, indicating that the basin is potential for ore exploration. In this paper it is suggested that the reworked hydrothermal sedimentary type poly-metal deposit, albite breccia type gold deposit, metamorphosed sedimentary type magnetite deposit, and porphyry-skarn type copper (molybdenum) deposit can be found in the Yindongzi-Tongmugou siderite-Ag-Pb-Zn-Cu-Au belt, Dongchuan-Xiaochuan Pb-Zn-Cu-Au belt, and the Cu-Au-Ni(Co)-Mo metallogenic belt along the Fengzhen-Shanyang fault. Particularly, the Gangou-Waizhanggou-Shuangyuangou-Tudigou area in north side of the Fengzhen-Shangyang fault, the Lijiabian-Nengshuigou-Zhangshigou area in the south side of the Fengzhen-Shangyang fault, and Mujiazhuang-Xiaotai area can be targeted for copper exploration. The areas surrounding or beneath the campus of the Mujiazhuang Cu deposit and Yindongzi Ag-Pb-dominated poly-metal deposit are favorable for new deposits or orebodies.

Abstract:Abstract：The Wengquangou vonsenite deposit, Fengcheng county, Liaoning Province, is located in the Liao-Ji Palaeoproterozoic rift and hosted in the boron-bearing series within the Lieryu Formation, lower Liaohe Group. The main ore-minerals are ludwigite, magnetite and szaibelyite, coexisting with gangue minerals including serpentine, dolomite and phlogopite. The magnetite can be distinguished in terms of occurrence from coarse-grained metamorphic (I), fine-grained hydrothermal (II) and stockworks (III). Type I is optically homogeneous and Types II and III appear to be heterogeneous. As detected using electronic microprobe and energy spectroscopy, the homogeneous magnetite has higher contents of Mg and Al and lower Si content than the heterogeneous, resulting in that Type I is harder than types II and III. It is possible that the discrepancy in element contents caused the transformation from homogeneous to heterogeneous magnetite. Study on magnetite shows that the formation process of the Wengquangou deposit includes sedimentary-metamorphism and hydrothermal overprint.

Abstract:Abstract：Oil sands, also known as asphaltic sands, containing a natural sandstone of asphalt or other rock. This article mainly discusses the occurrence of oil sands, petrology, porosity and oil content of the reservoir. To understand the fromation of the Fengcheng oilsands, this article analysis the structure, diagenesis and biodegradation, ie. three conditions for the formation of oil sands. The regional faults serve as trapping structures; the unconformities play a role of migration pathways；and the diagenesis and biological degradation of oil sands ultimately result in the formation of the oil-bearing sands. Study of the features and origin of oil-sand reservoir can help exploration and mining of the oil-sand resources in the northwest margin of the Junggar Basin.

Abstract:Abstract：Passive ultra-low electromagnetic (ULEM) detection technique is one of the effective means for detection of subsurface and deep geological bodies and resources. However, the curves of ULEM detection obtained using the existing processing methods is sensitive to the noises, which could hamper the correct interpretation of resulting detection signal curves. In this paper, the signal energy was introduced to the processing of the detection signal. Firstly, according to the calculating principle of the signal energy, the energy value of the ultra-low electromagnetic signal for each sampling depth was calculated, and the energy curve was then generated. The obtained energy curve was analyzed and compared with the existing detection curves, such as the maximum and minimum of the magnitude, for some specific applications. The experimental results showed that compared with existing methods, the proposed signal energy method can more accurately reflect the characteristics of the rocks. The proposed method could facilitate the geological interpretation of the resulting curves.