Genesis and metallogenic characteristic of Dongnan Cu–Mo deposit associated granitoids:LA-ICP-MS zircon U–Pb dating and isotope constraint from Zijinshan ore field in southeastern China

The Dongnan Cu–Mo deposit,located in the southeast of the Zijinshan ore field(the largest porphyry–epithermal system in Southeast China),represents the complex magmatic and metallogenesis events in the region.The petrogenesis and metallogenesis of granitoids from the deposit are not determined,especially the interactions between ore-bearing(granodiorite porphyry)and barren samples(granodiorite and diorite).In the paper,the whole rock geochemical features shared a similar affinity to the middle-lower content and revealed that they derived from partial melting of the Cathaysian basement with the contribution of mantle materials,even represented that they generated in the plate subduction;LA-ICP-MS zircon U–Pb ages show that these granodiorites,granodioritic porphyry and diorite,were generated during 114–103 Ma.The ore-bearing samples mostly presented ε_(Hf)(t)of negative values(peak value is-4 to-3)with old two-stage Hf model ages(t_(DM)^(2))(peak value is 1.10–1.15 Ga),while the barren sample showed slightly negative ε_(Hf)(t)(peak value is-1 to 0)values with young t_(DM)^(2)(peak value is 1.00–1.05 Ga).The value of zircon Ce^(4+)/Ce^(3+)ratio mostly higher than 450 was first verified for the ore-bearing samples in the Dongnan Cu–Mo deposit,and the values of ore-bearing were found to be higher than those from the barren,which suggests that the ore-bearing formed in more oxidized parental magma with higher oxygen fugacity.Based on the geochemical characteristic of the element and isotope,we concluded that the Early Cretaceous multiphases magmatic activities,low melting temperature and low pressure of pluton,and high oxygen fugacity of zircon,were the favorable conditions for metallogenesis of Dongnan Cu–Mo deposit.

Mo SILTCIDE SYNTHISIS BY DUAL ION BEAM DEPOSITION

Mo silicides Mo_5Si_3 with high quality were prepared using ion beamdeposition equipment with two Filter Metal Vacuum Are Deposition (FMEVAD). When the number ofalternant deposition times was 198, total thickness of the coating is 40nm. The coatings withdroplet free can be readily obtained, so the surface is smooth. TEM observation shows that Mo and Sialternant deposition coating is compact structure. The fine Mo silicide grains densely distributedin the coating. The coating adherence on silicon is excellent.

Discriminating characters of ore-forming intrusions in the super-large Chalukou porphyry Mo deposit,NE China

The Chalukou porphyry Mo deposit, located in the Great Hinggan Range, is the largest Mo deposit in northeast China, although the age and genesis of the associated magmatic intrusions remain debated.Here we report zircon U-Pb ages and trace elements, whole rock geochemistry and Sre Nd isotope data with a view to understand the relationship between the magmatism and molybdenum mineralization.Zircon U-Pb analysis yield an age of 475 Ma for rhyolite in the older strata, 168 Ma for the premineralization monzogranite, and 154 Ma for the syn-mineralization granite porphyry. The granite porphyry and quartz porphyry are considered as the ore-forming intrusions. These rocks are peraluminous, alkali-calcic, and belong to high-K to shoshonitic series with a strong depletion of Eu. They also display characteristics of I-type granites. The rocks exhibit wide variations of(87 Sr/86 Sr)iin the range of 0.705426 -0.707363, and ε_(Nd)(t) of -3.7 to 0.93. Zircon REE distribution patterns show characteristics between crust and the mantle, implying magma genesis through crust-mantle interaction. The Fe_2O_3/FeO values(average 1) for the whole rock and EuN/Eu*Nvalues(average 0.45), Ce^(4+)/Ce^(3+) values(average 301)for zircon grains from the granite porphyry are higher than those from other lithologies. These features suggest that the ore-forming intrusions(syn-mineralization porphyry) had higher oxygen fugacity conditions than those of the pre-mineralization and post-mineralization rocks. The Chalukou Mo deposit formed in relation to the southward subduction of the Mongol-Okhotsk Ocean. Our study suggests that the subduction-related setting, crust-mantle interaction, and the large-scale magmatic intrusion were favorable factors to generate the super-large Mo deposits in this area.

Geochemistry and Sr-Nd-Pb Isotopes of the Granites from the Hashitu Mo Deposit of Inner Mongolia, China： Constraints on Their Origin and Tectonic Setting

The Hashitu molybdenum deposit is located in the southern part of the Great Hinggan Range, NE China. Molybdenum mineralization is hosted by and genetically associated with monzogranite and porphyritic syenogranite. Sr-Nd-Pb isotopes of the intrusions show that the porphyritic syenogranite has initial ^87Sr/^86Sr ratios of 0.70418-0.70952, ENd（t） values of 1.3 to 2.1 （t=143 Ma）, ^206Pb/^204Pb ratios of 19.191-19.573, ^207Tpb/^204pb ratios of 15.551-15.572, and ^208Pb/^204Pb ratios of 38.826-39.143. The monzogranite has initial 87Sr/86Sr ratios of 0.70293-0.71305, εNd（t） values of 1.1 to 2.0 （t=-147 Ma）, ^206Pb/^204pb ratios of 19.507-20.075, ^207Pb/^204Pb ratios of 15.564-15.596, and ^208Pb/^204Pb ratios of 39.012-39.599. The calculated Nd model ages （TDM） for monzogranite and porphyritic syenogranite range from 866 to 1121 Ma and 795 to 1020 Ma, respectively. The granitic rocks in the Hashitu area have the same isotope range as granites in the southern parts of the Great Hinggan Range. The isotope composition indicates that these granites are derived from the partial melting of a juvenile lower crust originating from a depleted mantle with minor contamination by ancient continental crust. The integrating our results with published data and the Late Mesozoic regional tectonic setting of the region suggest that the granites in the Hashitu area formed in an intra-continent extensional setting, and they are related to the thinning of the thickened lithosphere and upwelling of the asthenosphere.

Genesis of the Huoshenmiao Mo deposit in the Luanchuan ore district, China: Constraints from geochronology, ?uid inclusion, and H-O-Sisotopes

The Huoshenmiao δeposit is Mo skarn δeposit, located in the western part of the Luanchuan ore δistrict.Mineralization process can be δivided into a skarn and a quartz-sulfide episodes with six stages: prograde(I), retrograde(II), quartz-K-feldspar(III), quartz-molybdenite(IV), quartz-pyrite(V), and quartzcalcite(VI). A combined study of geochronology, fluid inclusion(FI), and stable isotopes was conducted to constrain the mineralization age, source of ore materials, as well as the origin and evolution of the ore-forming fluids. Molybdenite Ree Os δating indicates that the δeposit was formed in the Late Jurassic(~145 Ma). The δ^(34)S values of sulfides range from 3.0‰ to 7.1‰, implying that the ore materials in the δeposit are magmatic in origin. Three types and six subtypes of FIs are δistinguished, namely, aqueous two-phase(W_1-and W_2-type), δaughter mineral-bearing multiphase(S_1-and S_2-type), and CO_2-bearing three-phase(C_1-and C_2-type). In stages I and II, the W_1-type FIs δisplay homogenization temperatures(Th) from 496°C to >600°C, with salinities of 14.9-18.3 wt.% NaCl eqv. The FIs in stages III, IV and early stage V composed of coeval S-, C-and W-types, respectively homogenize at similar Th, suggesting the occurrence of boiling. The W1-type FIs in late stage V and stage VI, yield Th of 102-406°C and salinities of 0-4.7 wt.% NaCl eqv. The δD_(H_2O)and δ^(18) O(H_2O)values of the ore-forming fluids in quartz-sulfide episode vary from-112‰ to-76‰, and 11.0‰ to 1.0‰, respectively. All these above observations reveal that the early ore-forming fluids are magmatic in origin, and characterized by high temperature and moderate to high salinity, and gradually evolve to low temperature, low salinity meteoric water. The Huoshenmiao Mo δeposit is associated with the magmatism event induced by the protracted subduction of the Izanagi plate beneath the eastern China continent. The δecrease in temperature, salinity and f(O_2), as well as change of p H δue to boiling and fluid-rock interaction, are the main factors controlling Mo δeposition.

The Late Early Cretaceous Mo Mineralization in the South China Mo Province: Constraints from U–Pb and Re–Os Geochronology of the Lufeng Porphyry Mo Deposit

Compared to other Mo provinces,few studies focused on the South China Mo Province(SCMP),especially for Early Cretaceous Mo mineralization.The Lufeng porphyry Mo deposit in the SCMP is characterized by disseminated and veinlet-type mineralization in granite porphyry,gneiss,and rhyolite.In this study,six molybdenite samples yield a Re–Os isochron age of 108.0±1.8 Ma,which is consistent with the zircon U–Pb age of the granite porphyry(108.4±0.8 Ma).The coincidence of magmatic and hydrothermal activities indicates that Mo mineralization was associated with the intrusion of granite porphyry during the late Early Cretaceous.A compilation of U–Pb and Re–Os chronological data suggests that an extensive and intensive Mo mineralization event occurred in the SCMP during the late Early Cretaceous.The marked difference in molybdenite Re contents between Cu-bearing(85–536 ppm)and Cu-barren(1.3–59 ppm)Mo deposits of the late Early Cretaceous indicates that the ore-forming materials were derived from strong crust–mantle interactions.Together with regional petrological and geochemical data,this study suggests that late Early Cretaceous Mo mineralization in the SCMP occurred in an extensional setting associated with the roll-back of the Paleo-Pacific slab.

Re-Os geochronology of Cu and W-Mo deposits in the Balkhash metallogenic belt,Kazakhstan and its geological significance

The Central Asian metallogenic domain （CAMD） is a multi-core metallogenic system controlled by boundary strike-slip fault systems. The Balkhash metallogenic belt in Kazakhstan, in which occur many large and super-large porphyritic Cu--Mo deposits and some quartz vein- and greisen-type W-Mo deposits, is a well-known porphyritic Cu--Mo metallogenic belt in the CAMD. In this paper 11 molybdenite samples from the western segment of the Balkhash metallogenic belt are selected for Re--Os compositional analyses and Re--Os isotopic dating. Molybdenites from the Borly porphyry Cu deposit and the three quartz vein-greisen W--Mo deposits--East Kounrad, Akshatau and Zhanet--all have relatively high Re contents （2712--2772 μg/g for Borly and 2.267--31.50 μg/g for the other three W-Mo deposits）, and lower common Os contents （0.670-2.696 ng/g for Borly and 0.0051--0.056 ng/g for the other three）. The molybdenites from the Borly porphyry Cu--Mo deposit and the East Kounrad, Zhanet, and Akshatau quartz vein- and greisen-type W-Mo deposits give average model Re--Os ages of 315.9 Ma, 298.0 Ma, 295.0 Ma, and 289.3 Ma respectively. Meanwhile, molybde- nites from the East Kounrad, Zhanet, and Akshatan W-Mo deposits give a Re--Os isochron age of 297.9 Ma, with an MSWD value of 0.97. Re--Os dating of the molybdenites indicates that Cu-W-Mo metallogenesis in the western Balkhash metallogeuic belt occurred during Late Carboniferous to Early Permian （315.9--289.3 Ma）, while the porphyry Cu--Mo deposits formed at ~316 Ma, and the quartz vein-greisen W--Mo deposits formed at ~298 Ma. The Re--Os model and isochron ages thus suggest that Late Carboniferous porphyry granitoid and pegmatite magmatism took place during the late Hercy- nian movement. Compared to the Junggar-East Tianshan porphyry Cu metallogenic belt in northwestern China, the formation of the Cu-Mo metallogenesis in the Balkhash rnetallogenic belt occurred between that of the Tuwu-Yandong in East Tianshan and the Baogutu porphyry Cu deposits in West Junggar. Collectively, the large-scale Late Carboniferous porphyry Cu-Mo metallogenesis in the Central Asian metallogenic domain is related to Hercynian tectono-magmatic activities.

Geochemical Characteristics and Genesis of the Metallogenic Rocks in the Chagande'ersi Molybdenum Deposit in Wulatehouqi,Inner Mongolia

Geochemical characteristics of the Chagande＇ersi molybdenum deposit in Inner Mongolia and its genesis were analyzed in this study using rock mineralography and rock geochemical testing. The mineralized country rocks of the Chagande＇ersi molybdenum deposit consist mainly of medium- to fine-grained monzogranite, medium-to fine-grained rich-K granite, with minor fine-grained K- feldspar granite veins and quartz veins. The rocks are characterized by high silica, rich alkali, high potassium, which are favorable factors for molybdenum mineralization. The rocks have the Rittmann index ranging from 1.329 to 1.961, an average Na20＋K20 value of 7.41, and AI2Oa/（CaO＋Na20＋K^O） 〉1, suggesting that the rocks belong to the high-K calc-alkaline peraluminous granite. The typical rock samples are enriched in Rb, Th, K and light rare earth elements, depleted in Sr, Ba, Nb, P and Ti, and these features are similar to that of the melt granite resulting from collision of plate margins. The JEu of the rocks falls the zone between the crust granite and crust-mantle granite, and are close to that of the crust granite; （La/LU）N indicates the formation environment of granite is a continental margin setting. The Nb/Ta ratios are close to that of the average crust （10）; the Zr/Hf ratios of monzogranite are partly below the mean mantle （34-60）, while the Zr/Hf ratio of K-feldspar granite are close to the mean value in the crust. Comprehensive analyses show that the granite in this area formed during the transition period between tectonic collision and post-collision. During the plate collision and orogeny, the crust and mantle material were mixed physically, remelting into lava and then crystal fractionation, finally gave rise to the formation of the rock body in this area. This has close spatial and temporal relation with the molybdenum mineralization.

Geology,Geochemistry and Zircon U-Pb Geochronology of Porphyries in the Dabate Mo-Cu Deposit,Western Tianshan,China:Petrogenesis and Tectonic Implications

The Dabate Mo-Cu deposit is a medium-sized porphyry-type deposit in the Sailimu Lake region, western Tianshan, China. We present the geology, geochemistry and zircon U-Pb geochronology of granite porphyries from the Dabate district with the intent to constrain their tectonic setting and petrogenesis. Porphyries in the Dabate district include granite porphyry I（gray white color with large phenocrysts）, granite porphyry II（pink color with small phenocrysts） and quartz porphyry. Granite porphyry II is the Cu and Mo ore-bearing granitoid in the Dabate deposit. LA-ICPMS zircon U-Pb analyses indicate that granite porphyry II was emplaced at 284.2±1.8 Ma. Granite porphyry I and II have similar geochemical features and are both highly fractionated granites：（1） They have high SiO2 content（70.93–80.18 wt% and 72.14–72.64 wt%, respectively）, total alkali（7.58–8.95 wt% and 9.35–9.68 wt%, respectively）, mafic index（0.95–0.98 and 0.93–0.94, respectively） and felsic index（0.79–0.94 and 0.89–0.91, respectively）;（2） They are characterized by pronounced negative Eu anomaly, ＂seagullstyle＂ chondrite-normalized REE patterns and ＂tetrad effect＂ of REE;（3） They are rich in Rb, K, Th, Ta, Zr, Hf, Y and REE, but depleted in Sr, P, Ti and Nb. The magma of granite porphyries in Dabate can be interpreted to have been generated by partial melting of the upper crust due to mantle-derived magma underplating in a post-collisional extensional setting.

Skarn mineralogy and its geological significance for the Tayuan (Cu-Mo)-Pb-Zn deposit, northern Daxinganling metallogenic belt

The Tayuan(Cu-Mo)-Pb-Zn deposit is located in the northern part of Daxinganling,NE China.Lenticular ore body occurs in the skarn zone.The skarn minerals mainly include garnet,pyroxene,epidote and wollastonite.Electron microprobe analysis shows that the end member of garnet is mainly andradite(Ad_(62-97)Gr_(11-45),the pyroxene is mainly diopside,and epidote is mainly clinozoisite.These characteristics indicate that the Tayuan polymetallic skarn deposit is mainly calcareous skarn.Sometimes the content zonation can be observed in garnets.With one garnet crystal,content is shifty from the core to the rim.In general,the iron content in the core is higher than in the edge.The content in the garnet shows that the garnet in the Tayuan deposit formed from weak oxidation in alkaline environment with the oxygen fugacity increasing,suggesting that the hydrothermal fluid evolved from an acidic to a slight alkaline state.In the Tayuan polymetallic deposit,the ratio of Mn/Fe in pyroxene is about 1.3,and of Mg/Fe,it is about 2.The components of garnet in the Tayuan deposit plot in the field of the typical skarn Zn,Cu,Mo deposits in the world.

Origin of the Newly Discovered Zhunuo Porphyry Cu-Mo-Au Deposit in the Western Part of the Gangdese Porphyry Copper Belt in the Southern Tibetan Plateau,SW China

The newly discovered Zhunuo porphyry Cu-Mo-Au deposit is located in the western part of the Gangdese porphyry copper belt in southern Tibet, SW China. The granitoid plutons in the Zhunuo region are composed of quartz diorite porphyry, diorite porphyry, granodiorite porphyry, biotite monzogranite and quartz porphyry. The quartz diorite porphyry yielded zircon U-Pb ages of 51.9±0.7 Ma（Eocene） using LA-ICP-MS, whereas the diorite porphyry, granodiorite porphyry, biotite monzogranite and quartz porphyry yielded ages ranging from 16.2±0.2 to 14.0±0.2 Ma（Miocene）. CuMo-Au mineralization is mainly hosted in the Miocene granodiorite porphyry. Samples from all granitoid plutons have geochemical compositions consistent with high-K calc-alkaline series magmatism. The samples display highly fractionated light rare-earth element（REE） distributions and heavy REE distributions with weakly negative Eu anomalies on chondrite-normalized REE patterns. The trace element distributions exhibit positive anomalies for large-ion lithophile elements（Rb, K, U, Th and Pb） and negative anomalies for high-field-strength elements（Nb and Ti） relative to primitive mantlenormalized values. The Eocene quartz diorite porphyry yielded εNd（t） values ranging from-3.6 to-5.2,（-（87）Sr/-（86）Sr）i values in the range 0.7046–0.7063 and initial radiogenic Pb isotopic compositions with ranges of 18.599–18.657 -（206）Pb/-（204）Pb, 15.642–15.673 -（207）Pb/-（204）Pb and 38.956–39.199 -（208）Pb/-（204）Pb. In contrast, the Miocene granitoid plutons yielded ε（Nd）（t） values ranging from-6.1 to-7.3 and（87Sr/86Sr）i values in the range 0.7071–0.7078 with similar Pb isotopic compositions to the Eocene quart diorite. The Sr-Nd-Pb isotopic compositions of the rocks are consistent with formation from magma containing a component of remelted ancient crust. Zircon grains from the Eocene quartz diorite have ε（Hf）（t） values ranging from-5.2 to ＋0.9 and two-stage Hf model ages ranging from 1.07 to 1.46 Ga, while zircon grains from the Miocene granitoid plutons have ε（Hf）（t） values from-9.9 to ＋4.2 and two-stage Hf model ages ranging from 1.05–1.73 Ga, indicating that the ancient crustal component likely derives from Paleo- to Mesoproterozoic basement. This source is distinct from that of most porphyry Cu-Mo-Au deposits in the eastern part of the Gangdese porphyry copper belt, which likely originated from juvenile crust. We therefore consider melting of ancient crustal basement to have contributed significantly to the formation Miocene porphyry Cu-Mo-Au deposits in the western part of the Gangdese porphyry copper belt.

Hot Corrosion Behavior of Sol-Gel Nano Structured Zirconia Coated 9Cr1Mo Ferritic Steel in Alkali Metal Chlorides and Sulphates Deposit Systems at High Temperatures

Fused salt accelerated hot corrosion is quite common in gas turbines, fossil fuelled devices, waste inclinators, pyrochemical systems, etc. Presence of fused salt on metal surface dissolves their existing oxide layer. This results in an increase in oxidation rate of the metal. Since, zirconia coating is well recognized for corrosion protection under high temperature oxidative environment, we have developed zirconia coating on 9Cr1Mo ferritic steel and their oxidation performance was evaluated in LiCl-NaCl and Na2SO4-K2SO4 salts deposit system in air atmosphere at 650?C and 850?C, respectively. Before coating development, zirconium based sol was synthesized using zirconium (IV) propoxide as a precursor. Oxidation test results indicated that the zirconia coated specimens shows more than two times higher corrosion resistance in LiCl-NaCl and three time higher corrosion resistance in Na2SO4-K2SO4 salt deposit, respectively.

Rare Earth Element Behaviour in theWunugetushan Copper - Molybdenum Deposit,Inner Mongolia, and Its Implications

Considering porphyry and wall rocks as a whole system, the behaviour of rare earth elements (REE) in hydrothermal alteration and mineralization of the exceedingly large Wunugetushan porphyry Cu-Mo deposit of Inner Mongolia has been studied. It has been found for the first time that there exists complementary REE variation in hydrothermal alteration between porphyry and wall rocks, and Eu depletion has certain significance in indicating mineralization. Based on an analysis of the variation in REE contents of relevant minerals during the hydrothermal alteration, the ore-forming fluids are inferred to be depleted in ∑REE, comparatively enriched in ∑Y and strongly depleted in Eu. In the intermediate-strong alteration zones, porphyry and wall rock took part in hydrothermal metasomatism and alteration almost in equal ratio mass. Furthermore, studies of REE and hydrogen and oxygen isotopes and fluid inclusions confirm the existence of hydrothermal convection and the possibility of supplying part of ore materials by the wall rock and indicate that the application of REE geochemistry in mineral prospecting is promising.

Fluorite REE characteristics of the Diyanqinamu Mo deposit,Inner Mongolia, China

The Diyanqinamu Mo deposit, a newly discovered porphyry deposit in the northern-central part of the Great Xing'an Range, Inner Mongolia, China, is characterized by widely distributed fluorite. It is important to note that almost all the fluorite that is paragenetic with molybdenite is purple. The Tb/Ca–Tb/La ratios of these purple fluorite samples show that they have a hydrothermal origin.The unidirectional solidification texture at the apex of the aplitic granite and the low F contents in the andesite suggest that most of F in fluorite was derived from granitic melts. These observations suggest that the fluorite was related to the magmatic-hydrothermal fluids. All the fluorite separates have consistent total REE contents with LREE-depleted, HREE-enriched, negative Eu anomaly,unapparent Ce anomaly and positive Y anomaly. These characteristics are significantly different than those of country granite, andesite and tuff whole-rock. The positive Y anomaly of the fluorite separates implies that the hydrothermal fluids migrated a long distance, as suggested by the fact that the fluorite-molybdenite veins were mostly hosted in andesite and tuff, far from the Mo ore-forming granites. The features of LREE-depleted and HREE-enriched fluorite are due to the REE-complex in the F-enriched fluids during migration. The stronger negative Eu anomaly of fluorite than those of country rocks suggests that the Eu anomaly of the original hydrothermal fluid was enhanced by the high temperature(generally above 200 or250 °C). The widespread magnetite in the studied deposit indicates that the magmatic-hydrothermal fluid was oxidized at early stage. On the other hand, the pyrite was also paragenetic, with the molybdenite and unapparent Ce anomaly implying that the hydrothermal fluid probably experienced oxygen fugacity decreasing during migration,which is important for Mo mineralization.

Effect of Al in Ti－microalloyed Mn－Ni－Mo welding wire on microstructure and toughness of deposited metal

The effect of Al in Ti-microalloyed welding wire on microstructure and toughness of deposited metals is studied.The results show that the deposited metal toughness worsens with increasing Al in wire' The mechanism of Al is as follows:(1) Al makes oxygen content in deposited metal increase.(2)Al restrains the formation of Ti-rich oxide inclusion, which causes granular bainite microstructure in deposited metal.(3)The content of solute Ti in deposited metal increases with Al content in welding wire,as a result,a part of carbonrich constitution in deposited metal is in the form of twin martensite.

Geochemical Characteristics and Significance of Major Elements, Trace Elements and REE in Mineralized Altered Rocks of Large-Scale Tsagaan Suvarga Cu-Mo Porphyry Deposit in Mongolia

The alteration types of the large-scale Tsagaan Suvarga Cu-Mo porphyry deposit mostly comprise stockwork silicification, argillization, quartz-sericite alteration, K-silicate alteration, and propylitization. The mineralized and altered zones from hydrothermal metallogenic center to the outside successively are Cu-bearing stockwork silicification zone, Cu-beating argillized zone, Cu-Mo-bearing quartz-sericite alteration zone, Cu-Mo-bearing K-silicate alteration zone, and pro- pylitization zone. The K-silicate alteration occurred in the early phase, quartz-sericite alteration in the medium phase, and argillization and carbonatization （calcite） in the later phase. Ore-bearing-altered rocks are significantly controlled by the structure and fissure zones of different scales, and NE- and NW-trending fissure zones could probably be the migration pathways of the porphyry hydrothermal system. Results in this study indicated that the less the concentrations of REE, LREE, and HREE and the more the extensive fractionation between LREE and HREE, the closer it is to the center circulatory hydrothermal ore-forming and the more extensive silicification. The exponential relationship between the fractionation of LREE and HREE and the intensity of silicification and K-silicate alteration was found in the Cu-Mo deposit studied. The negative Eu anomaly, normal Eu, positive Eu anomaly and obviously positive Eu anomaly are coincident with the enhancement of Na2O and K2O concentrations gradually, which indicated that Eu anomaly would be significantly controlled by the alkaline metasomatism of the circulatory hydrothermal ore-forming system. Therefore, such characteristics as the positive Eu anomaly, the obvious fractionation between LREE and HREE and their related special alteration lithofacies are suggested to be metallogenic prognostic and exploration indications for Tsagaan Suvarga-style porphyry Cu-Mo deposits in Mongolia and China.

Electroless Deposition of Fe-Mo-W-B Amorphous Alloys

The preparation, formation mechanism, surface appearance and structure of electroless plating Fe-Mo-W-B amorphous alloys were systematically studied. The deposition rates of the deposits in different bath composition as plated were measured. The formation mechanism of the deposits was discussed. The parameter for amorphous structures formation was suggested for the deposits.

Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni-Mo. The Ni-Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni-Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni-Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2-30 A/dm2.We find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni-Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction（XRD） analyses of Ni-Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy（SEM） tests indicate that Ni-Mo coatings present cracks and pores.

Geology,Geochemistry,and Genesis of the Tongcun Reduced Porphyry Mo(Cu) Deposit,NW Zhejiang Province,China

The Tongcun Mo（Cu） deposit in Kaihua city of Zhejiang Province,eastern China,occurs in and adjacent to the Songjiazhuang granodiorite porphyry and is a medium-sized and important porphyry type ore deposit.Two irregular Mo（Cu） orebodies consist of various types of hydrothermal veinlets.Intensive hydrothermal alteration contains skarnization,chloritization,carbonatization,silicification and sericitization.Based on mineral assemblages and crosscutting relationships,the oreforming processes are divided into five stages,i.e.,the early stage of garnet ＋ epidote ± chlorite associated with skarnization and K-feldspar ＋ quartz ± molybdenite veins associated with potassicsilicic alteration,the quartz-sulfides stage of quartz ＋ molybdenite ± chalcopyrite ± pyrite veins,the carbonatization stage of calcite veinlets or stockworks,the sericite ＋ chalcopyrite ± pyrite stage,and the late calcite ＋ quartz stage.Only the quartz-bearing samples in the early stage and in the quartzsulfides stage are suitable for fluid inclusions（FIs） study.Four types of FIs were observed,including1） CO2-CH4 single phase FIs,2） CO2-bearing two- or three-phase FIs,3） Aqueous two-phase FIs,and4） Aqueous single phase FIs.FIs of the early stages are predominantly CO2- and CH4-rich FIs of the CO2-CH4-H2O-NaCl system,whereas minerals in the quartz-sulfides stage contain CO2-rich FIs of the CO2-H2O-NaCl system and liquid-rich FIs of the H2O-NaCl system.For the CO2-CH4 single phase FIs of the early mineralization stage,the homogenization temperatures of the CO2 phase range from 15.4 ℃ to 25.3 ℃（to liquid）,and the fluid density varies from 0.7 g/cm^3 to 0.8 g/cm^3;for two- or three-phase FIs of the CO2-CH4-H2O-NaCl system,the homogenization temperatures,salinities and densities range from 312℃ to 412℃,7.7 wt%NaCl eqv.to 10.9 wt%NaCl eqv.,and 0.9 g/cm^3 to 1.0 g/cm^3,respectively.For CO2-H2O-NaCI two- or threephase FIs of the quartz-sulfides stage,the homogenization temperatures and salinities range from255℃ to 418℃,4.8 wt%NaCl eqv.to 12.4 wt%NaCl eqv.,respectively;for H2O-NaCl two-phase FIs,the homogenization temperatures range from 230 ℃ to 368 ℃,salinities from 11.7 wt%NaCl eqv.to16.9 wt%NaCl eqv.,and densities from 0.7 g/cm^3 to 1.0 g/cm^3.Microthermometric measurements and Laser Raman spectroscopy analyses indicate that CO2 and CH4 contents and reducibility（indicated by the presence of CH4） of the fluid inclusions trapped in quartz-sulfides stage minerals are lower than those in the early stage.Twelve molybdenite separates yield a Re-Os isochron age of 163 ± 2.4 Ma,which is consistent with the emplacement age of the Tongcun,Songjiazhuang,Dayutang and Huangbaikeng granodiorite porphyries.The 〈S18OSMow values of fluids calculated from quartz of the quartz-sulfides stage range from 5.6‰ to 8.6‰,and the 〈JDSMOw values of fluid inclusions in quartz of this stage range from-71.8‰ to-88.9‰,indicating a primary magmatic fluid source.〈534SV-cdt values of sulfides range from＋1.6‰ to ＋3.8‰,which indicate that the sulfur in the ores was sourced from magmatic origins.Phase separation is inferred to have occurred from the early stage to the quartz-sulfides stage and resulted in ore mineral precipitation.The characteristics of alteration and mineralization,fluid inclusion,sulfur and hydrogen-oxygen isotope data,and molybdenite Re-Os ages all suggest that the Tongcun Mo（Cu） deposit is likely to be a reduced porphyry Mo（Cu） deposit associated with the granodiorite porphyry in the Tongcun area.

Surface structure and catalytic activity of electrodeposited Ni-Fe-Co-Mo alloy electrode by partially leaching Mo and Fe

Ni-Fe-Mo-Co alloy electrode was prepared in a citrate solution by electrodeposition, and then Mo and Fe were partially leached out from the electrode in 30% KOH solution. The unique surface micromorphology of a hive-like structure was obtained with an average pore size of about 50 nm. The electrode has a very large real surface area and a stable structure. The effects of sodium molybdate concentration on the composition, surface morphology, and structure of electrodes were analyzed by EDS, SEM and XRD. The polarization curves of the different electrodes show that the catalytic activity of electrodes is strongly correlated with the mole fraction of alloy elements (Ni, Fe, Mo, Co), and the addition of cobalt element to Ni-Fe-Mo alloy improves the catalytic activity. The Ni35.63Fe24.67Mo23.52Co16.18 electrode has the best activity for hydrogen evolution reaction(HER), with an over-potential of 66.2 mV, in 30% KOH at 80 ℃ and 200 mA/cm2. The alloy maintains its good catalytic activity for HER during continuous or intermittent electrolysis. Its electrochemical activity and catalytic stability are much higher than the other iron-group with Mo alloy electrodes.