Abstract:An Early-Middle Silurian granodiorite rock was found for the first time in Kuerliang Group during the process of the 1∶50 000 geological survey in Kuerliang area, northern West Kunlun Mountains. Through the LA-ICP-MS zircon U-Pb geochronological study, a weighted mean ²⁰⁶Pb/²³⁸U age of 429.6±1.4 Ma(MSWD=0.69) for the zircons in granodiorite was obtained. Geochemical characteristics show that the granodiorite is typical adakite with high SiO₂(68.85%~72.49%), Al₂O₃(14.08%~15.36%), Sr(480×10^-6~ 812×10^-6), Sr/Y(53.2~111.0), and low Y(7.31×10^-6~10.30×10^-6), Yb(0.34×10^-6~0.48×10^-6). In addition, it exhibits significant fractionation between LREE and HRE and is depleted in HREE with slight Eu anomaly(0.86 < δEu < 1.03, 0.98 on average). The rock has a relatively high proportion of K₂O(2.92%~3.48%) and low proportions of MgO(0.69%~0.84%), Mg^#(26.4~32.6), Cr(15.1~28.2), and Ni(3.54~5.39), with Na₂O/K₂O ratios being 1.03~1.46(1.21 on average). These characteristics suggest that the granodiorite was a product of partial melting of a thickened lower crust, and a crustal thickening occurred in the West Kunlun Mountains in Early-Middle Silurian when the crustal thickness was greater than 50 km. Together with regional geological data, the authors hold that the Proto-Tethys Ocean basin, taking Kuda-Qimanyute ophiolite mélange as a symbol, had been closed before Early-Middle Silurian, and then entered the collisional orogenic period. This research provides a reliable petrological evidence and precise chronological data for the collisional orogenic event after the closing of Proto-Tethys Ocean.

Abstract:Ulan Obo mafic-ultramafic rocks, located along the Inner Mongolia-Da Hinggan Mountains orogenic belt, consist of harzburgite, gabbros and diabase. Geochemical data indicate that serpentinized peridotites are mantle-derived peridotite. Gabbro and diabase are tholeiitic rocks and similar to N-MORB in LILE components. They together consist of ophiolitic complex. Mineralogical analyses reveal that the olivine in peridotite is forsterite(Fo=91.10~91.81), and chromite has high Cr^# and Mg^#(61.04~64.44, 50.40~56.37) and belongs to pecotites. Clinopyroxene occurs in both mafic and ultramafic rocks, it is endiopside in peridotite and augite in diabase and is different in scale from sahlite to augite in gabbros. Orthopyroxene only occurs in harzburgite and belongs to cilinoenstatite. Zircon U-Pb weighted average age of gabbro is 344.5±1.5 Ma, suggesting that the ophiolite formed in early Carboniferous period. Geochemical and mineralogical researches suggest that Ulan Obo ophiolitic complex formed at the fore-arc setting of the Paleo-Asian Ocean in late Paleozoic period. Petrogenesis of Ulan Obo ophiolitic complex shows favorable conditions for chromite deposit formation,and therefore emphasis must be paid to the chromites in further exploration and prospecting.

Abstract:Located in the eastern part of the Chagan Obo-Aoyoute-Chaobuleng magmatic belt at the southeastern edge of the Siberian plate, the Arehada area has wide distribution of Late Paleozoic granite, comprising mainly porphyritic and medium-fine grained granite. Zircon LA-ICP-MS U-Pb isotopic dating indicates that the petrogenetic ages are 319.0±5.0 Ma(MSWD=4.9), 324.0±2.0 Ma(MSWD=1.3) and 332.0±8.5 Ma(MSWD=5.7). The results show that all the granites are of early Carboniferous, belonging to middle Hercynian period. In situ rare earth elements analyses of zircons show the depletion of LREE and enrichment of HREE as well as the obvious existence of positive Ce anomaly and negative Eu anomaly, suggesting that zircons are of typical magmatic origin. Analyses of zircon Lu-Hf isotopes show that these granites have εHf(t) values of -0.71~+10.21 with Hf modal ages of 709~1 436 Ma, indicating that the granite in Arehada area was derived from mantle during Meso-Neoproterozoic period. Based on the isotopic ages and zircon rare earth elements data in combination with geological survey and regional tectonic evolution, the authors hold that a tectonic-magmatic activity occurred during 310 to 330 Ma in the Arehada area.

Abstract:In this paper, the authors investigated rare earth minerals in the weathering granite crust of the Gangxia REE deposit in Anyuan, southern Jiangxi, with the purpose of revealing the morphology and distribution of secondary weathering-related rare earth minerals. Samples collected from different layers of the studied weathering crust were purified by separation. The main clay minerals closely related to rare earth minerals are kaolinite and halloysite. FE-SEM and TEM results indicate that, in this profile, nano-sized REE-bearing minerals occur in two modes: some micro-grains are attached on the surface of some minerals, whereas others exist as aggregates of rare earth minerals(possibly cerianite). The results help to understand the process of secondary enrichment of rare earth elements during weathering of granites in South China.

Abstract:The Songligou gold deposit(26 t Au) which is confined in NWW-trending fracture of Meso-Neoarchean to Paleoproterozoic Taihua Group gneiss is located in the Xiong'er Mountain area, forming a part of the southern margin of the North China Craton. The ore-forming hydrothermal processes can be divided into four stages: pyrite-quartz stage, quartz-pyrite stage, gold-tellurides stage, and quartz-carbonate stage. Microscopic observation reveals that large amounts of tellurides display affinity with gold. In order to clarify mineralogy, intergrowth relationships and ore-forming conditions, the authors conducted electron microprobe and energy spectrum analyses. The results show that there are many subtypes of tellurides such as rucklidgeite, altaite, tellurobismuthite, calaverite, petzite, buckhornite and tetradymite. Additionally, abundant native gold and a littlle bismuthinite were also detected. The Songligou gold deposit is a Te-Au gold deposit related to magmatism. Gold mainly exists in the forms of native gold and Au-Ag-telluride. Au and Ag were transported by the bisulfide complexing. Condensation of Te₂(g) and H₂Te(g) into chloride solution containing noble metals seems to have been the main mechanism for telluride precipitation. Furthermore, phase diagrams and chemical reaction equations suggest that gold and tellurides formation was mainly controlled by the t, f_Te2, f_S2, f_O2 and pH value. Pyrite-quartz stage and quartz-pyrite stage formed under the conditions log f_Te2 < -14.4, and log f_S2=-11.1~-6.5. Gold-tellurides stage formed under the conditions t=110~313℃, log f_Te2=-15.2~-9.4, and log f_S2=-16.5~-14.6, with increasing f_O2 and reducing pH value. Overall, the discovery of telluride in the Songligou gold deposit provides an ideal basis for deciphering the genesis of this deposit, and also offers useful information for exploration of the similar gold deposits in this area.

Abstract:The mineral composition and microstructure of the parting of Guanbanwusu mining area in Jungar Coalfield were analyzed with X-ray diffraction, Fourier transform infrared spectrum and Scanning electron microscope. The results indicate that partings are widely distributed in the bottom layer of No.6 coal seam of the Guanbanwusu coal mine, showing lamellar output. The main mineral in the partings is kaolinite followed by a very small amount of boehmite and other minerals. The molar ratio of SiO₂/Al₂O₃ is approximately 2.00~2.10, which is close to the theoretical ratio of the kaolinite group minerals. The sample has a low content of Fe and Ti. The single-crystal form of kaolinite is mainly hexagonal plate, flaky stacked polycrystalline, as shown by scanning electron microscope. The size of the single-crystal is less than 5 μm. The kaolinite in the gangue of the Guanbanwusu mining area has high crystallinity, which can be used to produce ceramics.

Abstract:The Jilongshan skarn Au-Cu deposit is a representative skarn deposit in southeastern Hubei Province. Its orebodies are mainly hosted in the contact zone between the carbonate of the Lower Triassic Daye Group and the granite diorite porphyry. The ore-forming process can be divided into four stages, namely prograde skarn stage, retrograde skarn stage, quartz-sulfides stage and carbonate stage, and the precipitation of Au and Cu occurred at the quartz-sulfides stage. Microscopic observation and electron microprobe analysis suggest that Au and Ag occur mainly as visible Au minerals(native gold, electrum) and visible Ag minerals(hessite, matildite), respectively, and Au minerals occur mainly as inclusions in chalcopyrite and tetrahedrite or micro-fracture fillings in pyrite. Abundant Te-Bi minerals, such as tetradymite and aikinite, were observed in the Jilongshan Au-Cu deposit. In high temperature hydrothermal fluids, Au and Ag elements were probaboy transported as chloride complexes. With the decreasing temperature of the fluid and the variation of compositions, Au and Ag elements might have been transported as sulfide complexes and bismuth-telluride melts or complexes. At the quartz-sulfides stage, fluid boiling and sulfurization resulted in the decrease of f_S2 and the increase of f_Te2. When fluids lay in the oxygen fugacity range of pyrite-pyrrhotite buffer, pH values assumed neutral-to-alkaline nature, -10.7 < logf_Te2 < -8.4 and -11.4 < logf_S2 < -10.6, there existed the transfer and enrichment of Au by Te, Bi and As elements, which resulted in the formation of the Jilongshan skarn Au-Cu deposit.

Abstract:Located in the northwestern part of the Gangdise polymetallic belt of Tibet, the Galale Cu-Au deposit discovered in recent years is a typical magnesian skarn-type deposit. Based on large-scale geological mapping together with previous studies, the authors systematically analyzed geological features and ore-controlling factors of the Galale Cu-Au deposit. The main strata outcropped in this area consist of dolomite and dolomitic limestone of the Lower Cretaceous Jiega Formation underlain by interbedded sandstone, siltstone and rhyolitic-dacitic volcanic rocks of the Lower Cretaceous Langjiu Formation. There are at least three phases of deformation: the first period formed NW-trending folds and NE-striking tensional cross faults, the second one formed NE-trending folds, NE-striking longitudinal compression faults and small-sized tensional cross faults in NW direction, and the third period formed nearly NS-trending normal faults. According to the temporal succession, the intrusive rocks in the mining area include porphyritic quartz diorite of late Yanshanian period, diorite-porphyrite, quartz diorite, granodiorite and granitic porphyry. The typical magnesian skarn was formed near the contact zones between quartz diorite, granodiorite and dolomite, dolomitic limestones of the Jiega Formation, and the skarn was formed in two periods: the skarn of early period is composed of olivine, humite, a small amount of spinel, garnet and diopside, whereas the wet skarn of late period is composed of serpentine, phlogopite and a small amount of epidote, superimposed upon the stem skarn or existent at the outside, forming many lithologic zones, such as olivine+spinel+humite±garnet±phlogopite zone, phlogopite+serpentine±olivine±garnet ±diopside zone, serpentine+phlogopite+epidote±diopside zone, and serpentine±phlogopite of marble zone. The orebody is mainly hosted in the serpentine+phlogopite zone, which is mostly in the form of stratiform, stratoid, massive and other irregular structures. Moreover, the main metallic minerals are magnetite, pyrite, chalcopyrite, bornite, chalcocite, natural gold and so on, accompanied by silicification, chloritization and carbonation. The mineralization in this area is closely related to the emplacement of granodiorite and quartz diorite, controlled by NE, NW-trending folds and related faults. The skarns are controlled by potential lithologic characters such as lamellar dolomite and sandy dolomite of middle Jiega Group, with the orebody located in the skarn zones of high permeability.

Abstract:A series of sediments-hosted vein-tpye copper deposits have been discovered in the western part of the basin. The Kedengjian vein-type copper deposit is one of these deposits in Lanping basin. The Cu mineralization mainly occurs as sulfide-bearing quartz-carbonate veins in faults and fractures, hosted by volcanic rocks of Triassic Cuiyibi Formation(T₃c). Ore-forming process of the Kedengjian copper deposit can be divided into two stages: the major stage(massive polymetallic sulfide quartz vein stage), and the late stage(carbonate-quartz stage). A detailed study of fluid inclusions led to the recognition of two types of fluid inclusions, i.e., aqueous water, and CO₂H₂O inclusions, with the aqueous water inclusions being dominant. Total homogenization temperatures range from 180℃ to 240℃, with corresponding salinities from 8% to 14% NaCl equivalent. These characteristics of fluid inclusions in the Kedengjian copper deposit are comparable with those of basinal mineralization systems, which formed most Pb-Zn deposits in the Lanping basin. The H, O isotope studies of inclusions in quartz suggest that the ore-bearing fluid was derived from atmospheric water. The δ³⁴S of sulfide minerals are widely variable between -20.8‰ and -9.4‰, indicating that the sulfur was derived from the sedimentary rocks of the basin. Comprehensive studies indicate that the ore-forming materials originated mainly from sedimentary rocks, and the ore-forming fluids were mainly composed of basinal brines, derived from formation water in strata and meteoric water.

Abstract:As one of the common manganese oxides easily generated and widely distributed in the supergene environment, manganite participates in the formation of Fe(Ⅲ) oxides, affecting the migration, transformation and fate of Fe²⁺ in aqueous systems. In this study, the redox mechanism was studied by determining the intermediates, and the influence of initial pH and air(oxygen) on the processes was studied in simulated aqueous systems with pH value in the range of 3-0~7.0. The influence of Fe²⁺ concentration, pH value, and air(oxygen) on ferric(hydr) oxide crystal strucutres, chemical compositions and the redox rate was studied in closed and open aqueous systems. The results indicate that goethite and lepidocrocite are formed as the major products of Fe²⁺ oxidation by manganite. Goethite and lepidocrocite tend to be formed when pH values are controlled at 3.0~5.0 and 7.0, respectively. High concentration of Fe²⁺ facilitates the formation of lepidocrocite. The introduction of air(oxygen) is convenient for the generation of goethite of high crystallinity. The redox rate of manganite and Fe²⁺ increases with the increase of pH value and oxygen partial pressure in reaction systems. The present study facilitates the understanding of the natural genesis of ferric oxides on the surface of manganese oxides.

Abstract:Nianzishan District of Qiqihaer City was awarded the title of "Hometown of Chinese Maifan Stone" by the Committee of Chinese Hometown of Specialty in 2001. In this paper, the specific surface and pore properties, cationic exchange capacity(CEC) and pH buffering capacity of the Nianzishan Maifan Stone were tested and analyzed to reveal the basic structural and functional performances of Maifan stone; in this way, the adsorption performances of Nianzishan Maifan Stone for Pb²⁺, Cd²⁺ and Cr³⁺ can be explored respectively. It is indicated that Nianzishan Maifan Stone shows a cationic exchange capacity(CEC) of 13~20 mmol/100 g, with the sponge macro-porous structure. The pH values of acid and alkali solutions can be adjusted to a neutral point efficiently when the Nianzishan Maifan stone is added, especially for the acid solutions. The heavy metal adsorption performances of Nianzishan Maifan Stone are Pb²⁺ > Cr³⁺ > Cd²⁺.

Abstract:Mineral material plays a very important role in wastewater treatment and sludge modification. Microbial metabolites are important components of the biological treatment system, and also play a very important role in improving the pollutants removal efficiency and methane production. In this study, the authors analyzed and characterized the soluble microbial products(SMP) and extracellular polymeric substances(EPS) produced from the graphite dosed anaerobic system. The results show that graphite exerts significant effects on the composition and content of the EPS and SMP, mainly due to the adsorption effect of graphite and its environmental toxicity. Fourier transform infrared spectrum(FTIR) analysis results show that adding graphite does not influence the types of the active group in SMP and EPS, but the relative content is changed. Three-dimensional fluorescence spectrum analysis results show that the main fluorescent materials in the SMP are humus(coenzyme NADH) and tryptophan analogs, whereas the main fluorescent materials in EPS are humic acid and tryptophan analogs. Fluorescence spectrum analysis results also indicate that graphite could significantly reduce the tryptophan and humic acid analogs. Graphite decreases the relative hydrophobicity of the sludge and improves the surface free energy, which is beneficial to the formation of microbial aggregates.

Abstract:The chemical compositions and component distributions of Pinctada martensii pearls from Japan were investigated by synchrotron X-ray fluorescence spectrum. The results clearly show that these pearls contain Ca, Sr, Ba alkaline-earth metal elements, Mn, Fe, Cu, and Zn 3d transition metal elements and rare earth elements. In pearls, these elements present some distributions in space: the nucleus surface has the highest concentrations of rare earth elements and the concentrations of rare earth elements in the nacre and nucleus are roughly equal; in the nucleus there exists decreasing tendency of elements Mn and Fe from the superficial part to the surface; both Mn and Fe exhibit sharp fall in the same circle of the nacre, showing a certain correlation, and the place of sharp fall seems to be the dividing line of nacreous layer and prismatic layer; element Mn mainly exists in prismatic layer; the distributions of elements Sr and Ba show negative relationship with element Ca.