Abstract:Middle-Late Jurassic persilicic volcanic rocks in Haimosaige area of Inner Mongolia constitute one of the most important part of Mesozoic volcanic rocks in the Da Hinggan Mountains. In this paper, the authors studied the ages and geochemical characteristics of the rocks so as to probe into their tectonic settings. The test and analysis were completed at Tianjin Institute of Geology and Mineral Resources. The zircon U-Pb dating by LA-MC-ICP-MS technique indicates that the crystallization ages of the volcanic rocks vary from 164.0±1.0 Ma to 155.5±0.9 Ma, suggesting middle-Late Jurassic. Geochemical researches indicate that the volcanic rocks from Haimosaige area are rich in silica (SiO₂=62.09%～77.57%), alkali (K₂O＋Na₂O=7.27%～10.13%), K(K₂O/Na₂O=1.10～2.82) and poor in calcium (CaO=0.16%～2.46%, 0.73% on average), magnesium (MgO=0.10%～1.08%, 0.29% on average, Mg^#<45) and have high FeO^T/MgO ratios (FeO^T/MgO=2.37～7.22, 4.49 on average), implying a typical high-K calc-alkaline to shoshonitic series with metaluminous and peraluminous features (A/CNK=0.98～2.29). The rocks are poor in rare earth elements with ∑REE being 137.6×10^-6～315.3×10^-6, enriched in LREE , LILEs (Rb, Ba, Th, K) and depleted in HFSE, especially Nb, Ta, Sr, P and Ti. The δEu values vary from 0.14 to 1.54 (0.51 on average), with most rocks having moderate negative Eu anomalies. Similar REE distribution patterns imply that the volcanic rocks came from the same magma source. Most of the volcanic rocks with the characteristics of post-collision granites have lower Sr (Sr=46.2×10^-6～799.3×10^-6, 208.0×10^-6 on average), high Yb (Yb=2.02×10^-6～4.23×10^-6) and obvious geochemical correlation. In combination with previous studies, the authors hold that the rhyolitic magma, which was in a post-orogenic extensional setting, was formed by varying degrees of the crust partial melting and the residua had a little plagioclase and hornblende. It was probably associated with the strike-slip and extension caused by the oblique subduction of the Palaeo-Pacific Ocena. These conclusions have most important significance for studying the volcanic activities and tectonic settings of Middle-Late Jurassic volcanic rocks. 164.0±1.0～155.5±0.9 Ma might indicate the transform from orogenic to post-orogenic extensional setting between Middle-Late Jurassic and Early Cretaceous. The results obtained by the authors impose new constraints on tectonic-magmatic evolution of the Da Hinggan Mountains in Middle-Late Jurassic and also provide basic information for further research.

Abstract:The Taili gneiss complex is exposed in the western Liaoning Province and mainly composed of gneissic granites, biotite plagioclase gneisses and hornblende plagioclase gneisses. Zircon U-Pb dating of these rocks indicates that the gneiss complex was formed in the late Neoarchaean (2 510～2 559 Ma), with ages similar to those of the "Suizhong granite". This suggests that the Taili gneiss complex is an important part of Archean basement of the North China Craton. Field occurrences and rock textures suggest that the gneiss complex is a suite of migmatites derived from syn-deformational anatexis, of which the hornblende plagioclase gneiss represents the "palaeosome", which was generated by a very low degree of partial melting with a few felsic veins inside. The felsic veins show the general characteristics of "leucosome". The biotite plagioclase gneiss represents the "residuum" after the low degree of partial melting, whereas the gneissic granite is the "neosome" characterized by the highest degree of melting. These rocks display a good gradational relationship in mineral content and geochemistry. In combination with previous zircon Hf isotopic data, the authors have reached the conclusion that the Taili gneiss complex originated from the anatexis of Mesoarchean ancient crust 2.8～3.0 Ga in age and recorded an important regional magmatic event of crustal reworking.

Abstract:The Shapinggou molybdenum deposit in Jinzhai County of Anhui Province is situated in the Qinling-Dabie orogenic belt, with mineralization substantially hosted in monzonitic granite porphyry, syenite porphyry and granite porphyry. Microscopic observation shows that the rocks mainly consist of plagioclase, potassium feldspar, biotite and quartz. With these minerals as the study objects, the authors used electron microprobe technology to analyze their mineralogical characteristics, and the results show that, in the rocks, the plagioclase is albite, K-feldspar is mainly perthite, and biotite is Mg-biotite rich in Mg, Al and K and depleted in Ca, with MF changing from 0.65 to 0.72. Chemical composition of biotite suggests that the intrusion is I-type granite, which is a sort of calc-alkali orogenic granite, materially sourced from both the crust and the mantle. Biotite geothermometer and geobarometer imply that the intrusion was consolidated at 500～580℃, with the oxygen fugacity ranging from 10^-14 to 10^-15.8 and the iron index being a good indicator for molybdenum mineralization.

Abstract:Ordos basin is the potential target zone of CO₂ underground storage in China. Well Zhongshenjian X is located near the Ejin Horo Banner, neighboring the underground CO₂ injection well "Zhongshenzhu One", and the two wells have the same formation system and rock composition. To predict the potential of carbon sequestration in the reservoir and the mudstone transformation conditions in the demonstration area and provide basic geological information and relevant data for numerical simulation of the CO₂ geological storage, the authors investigated petrologic and geochemical characteristics of Shiqianfeng Formation in well Zhongshenjian by means of polarizing microscope, SEM, X-ray diffraction and X ray fluorescence, and the results suggest that the sandstone of Shiqianfeng Formation is mainly feldspathic lithic sandstone and lithic feldspar sandstone, and the mudstone is mainly composed of quartz, clay minerals and feldspar, in which the clay minerals are mainly smectite and illite, followed by kaolinite and chlorite. It is inferred that sandstone in Shiqianfeng Formation could form the mineral trap relative to the CO₂ leaks by forming carbon sequestration minerals such as dawsonite, calcite, ankerite and siderite, and then the long-term and safe storage of CO₂ could be realized. In addition, metals were mobilized, resulting in the bleach of the red mudstone interlayer.

Abstract:The Deep Drilling Pprogram, namely SinoProbe-03-06, was implemented at Zhuanqiao, Lujiang City, Anhui Province, where thorium and uranium anomalies were found, which might indicate a high temperature mineralization style of uranium deposit in the depth of the basin. Abundant tourmaline-group minerals were found in the core, which could be classified into at least three types. The minerals exhibit some general features: ① sector and oscillatory chemical zoning of crystals; ② formation in high temperature; ③ Fe-Al, Fe-Mg coupled substitution; ④ high Mg content and evolution of varieties from Al-rich to Fe³⁺-rich through Fe-Al coupled substitution caused by the increase of f_O2. Tourmalines usually occur in high-temperature hydrothermal deposits and can be taken as efficient indicators for both prospecting and exploration of these important mineral deposits. The study indicates that the f_O2 of the fluids was rising and the fluids carried plenty of volatile materials such as F, B and H₂O with the evolution of the tourmaline, which provided a favorable environment for the formation of U⁶⁺ and the migration of some useful elements. These data also present some constraints on features of the fluids in the deep basin.

Abstract:Basic-ultrabasic rocks are developed in Taihang Mountain area. With olivine pyroxene hornblendite from the Yaogou hornblendite body in the Wang'anzhen batholith of north Taihang Mountains as the study object, the authors carried out a preliminary study of the mineralogical characteristics and formation conditions of the amphiboles so as to investigate their genetic significance. The results show that there are two kinds of amphiboles in the olivine pyroxene hornblendite, which belong to calcic amphibole with (Ca+Na)_B≥1.00 and Na_B<0.50. Their Si/(Si+Ti+A1) ratios are between 0.704 2 and 0.788 5, indicating that they are mantle amphiboles. Based on the relative content of Na, K, Ti, Al and Fe³⁺, the authors further divided the calcic amphibole into magnesium hastingsite in brown color and magnesium hastingsitic hornblende to edenitic hornblende in green color. The amphibole zonation indicates that the amphiboles were formed at different stages of the same magma crystallization characterized by different pressure and temperature conditions. The magnesium hastingsite was crystallized at high temperature and pressure and in great depth, belonging to the lower crustal environment. The edge of the amphibole was generated in a lower pressure crustal environment. The amphibole magma was derived from the upper mantle and began to concentrate before the Yanshanian movement in late Triassic. Later, intermediate-acid magma was emplaced to form a granitic batholith. These data indicate that partial melting in the lithosphere of the North China Craton took place in late Triassic and that the North China Craton started to be destroyed at that time.

Abstract:The north Gangdise Pb-Zn-Ag-Cu-Fe belt is one of the most important metallogenic belt in the Tibetan collisional orogenic belt. The Longmala deposit is located in the eastern part of the Gangdise metallogenic belt. Constraining the timing of mineralization of this deposit is crucial to the better understanding of the genesis of the deposit and the deep geodynamic processes which controlled the large-scale mineralization of this area. The electron microprobe analyses reveal that the altered mica is phlogopite. This paper presents the Ar-Ar dating results for magnetite mineralization conducted on phlogopites collected from the Longmala deposit. Phlogopite from the Longmala deposit yielded a well-defined ⁴⁰Ar/³⁹Ar plateau age of 56.32±0.48 Ma and an isochron age of 55.58±0.93 Ma. These ages suggest that the Longmala deposit was developed in the period of main collisional orogenic setting in Tibetan orogenic belt. Combined with the former research and the data of regional geology, the authors hold that the deep geodynamic process which controlled the formation of this deposit was the rollback of the Neo-Tethys slab.

Abstract:The Zhibula copper polymetallic deposit is a typical skarn type deposit in eastern Gangdise metallogenic belt of Tibet, and garnet is the main skarn mineral in the ore district, with most metal minerals occurring between garnet grains. In this paper, such means as detailed borehole logging, rock-mineral identification under microscope and electron microprobe analysis were used to divide the zoning into two different types. There obviously exists vertical garnet zoning as follows: Garnet is mainly andradite in tuff comprising the roof, the garnet center is dark-colored and the color gradually becomes lighter towards the margin, accompanied by the change of the chemical composition from pure andradite to grossular. Garnet is mostly grossular near the marble floor, the color becomes dark from the center to the edge and the main chemical composition changes from andradite to grossular while other chemical components change quite insignificantly. These characteristics suggest that two distinct wall rocks made different contributions to the garnet formation. In the upper part, tuff mainly provided Fe composition, whereas at the bottom, marble contributed Ca ingredient, and hydrothermal fluids contributed Si, Al and some Fe. The rim of the garnet zone is different from the core because the environment and material compositions changed gradually during the whole process. This well explains the vertical garnet skarn zoning characterized by the change of the grossular in the upper part to andradite in the lower part. At the same time, the characteristics and zoning of the garnet show that Zhibula is a metasomatic hydrothermal deposit. The results obtained by the authors not only provide the basic data for the study of deposit genesis but also indicate the criteria in search for similar deposits in this region.

Abstract:The Pa'nan deposit is a newly-discovered porphyry Mo deposit at the eastern edge of the Chongmuda-Nuri ore field in Shannan Prefecture of Tibet. According to field work, the vein-like monzonitic granite-porphyry related to mineralization intruded into the Paleocene granodiorite, resulting in strong molybdenite mineralization and hydrothermal alteration in the porphyry and the contact zone. The molybdenite mineralization was mainly related to the straight quartz vein where most molybdenite occurred with a minor impregnation in quartz veins near the surrounding rock. In this paper, direct Re-Os isotopic dating of molybdenites collected from the quartz-molybdenite veins in the Pa'nan porphyry Mo deposit was carried out, which yielded model ages ranging from 31.34 to 31.83 Ma, a weighted average age of 31.66±0.22 Ma and an isochron age of 32.4±1.5 Ma (MSWD=1.5). The model ages and isochron age are consistent within the error range. Therefore the data represent the ore-forming age of the Pa'nan deposit, which is basically consistent with the previous studies which suggest that the mineralization of the Chongmuda-Nuri ore field occurred in Oligocene (30～23 Ma). These data indicate that the Pa'nan deposit had a similar deep dynamic progress to the other deposits in the Chongmuda-Nuri ore belt. Nevertheless, the metallogenic epoch of the Pa'nan porphyry deposit is slightly earlier than that of the other deposits in the Chongmuda-Nuri ore belt, suggesting that mineralization was probably started at ca.32 Ma and related to the delamination of post-collision thickened mantle lithosphere.

Abstract:Located in Dong Ujimqin Banner of Inner Mongolia, the Highland 1017 Ag polymetallic deposit tectonically belongs to the easternmost part of Early Paleozoic Chaganobo-Aououte-Chaobuleng tectono-magmatic belt on the southeastern margin of the Siberian plate. The ore bodies mainly occur in sandstone of the Upper Devonian Angeeryinwula Formation and adamellite of middle Hercynian period, and the commercial types of ores include quartz-vein type and altered adamellite type. Fluid inclusions are well developed in quartz-type ores, and the majority of fluid inclusions consist of two phases of vapor and liquid. The homogenization temperature and salinity are in the range of 175～225℃ and 4.42%～11.46%, respectively. The ores have uniform sulfur isotopic composition with δ³⁴S varying from 3.4‰ to 8.0‰, suggesting that sulfur originated from the mixing and equilibrium processes of sedimentary and magmatic sulfur. The ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of sulfides from the ores vary in the range of 18.274 0～18.399 6, 15.539 9～15.561 6 and 38.036 3～38.177 2 respectively, implying that the lead was derived mainly from the interaction between uranium-depleted upper mantle and lower crust, and that ore-forming fluid was also contaminated by radioactive uranium-rich upper crust during its upward migration. δD_V-SMOW values vary from -103‰ to -125‰ and δ¹⁸O_V-SMOW range from 6.9‰ to 13.9‰, indicating that ore-forming fluid was the mixture of magmatic water and meteoric water. In combination with the regional metallogenic geological setting and geochemical characteristics of the Highland 1017 Ag polymetallic deposit, it is inferred that the ore-forming material was derived from the mixing process of deep magma and the upper crust, and the ore-forming fluid was the mixture of magmatic water and meteoric water. This deposit can be genetically regarded as the granitoid magmatic hydrothermal deposit with middle-low temperature and salinity.

Abstract:The Baogutu gold deposit consists of quartz-vein type and alteration type ore bodies. The hydrothermal process can be divided into four stages: coarse-grained quartz vein stage (Ⅰ), gold-bearing fine-grained sulfide-quartz vein stage (Ⅱ), gold-bearing coarse-grained native arsenic -stibnite-quartz vein stage (Ⅲ) and calcite vein stage (Ⅲ). Gold mineralization occurred at stage Ⅱ and stage Ⅲ, forming native gold and electrum enclosed by or coexisting with quartz, pyrite, native arsenic and stibnite. The total REE content of quartz veins formed at stage Ⅰ and Ⅱ is 0.83×10^-6～3.67×10^-6 and 11.01×10^-6～30.18×10^-6, respectively. The fractionation between LREE and HREE in stage Ⅰ quartz vein[(La/Yb)_N=8.53～21.89] is more obvious than that in stage Ⅱ quartz vein[(La/Yb)_N=6.90～10.40], although they all show LREE-enriched chon- drite-normalized REE patterns which are similar to patterns of porphyries in Baogutu area, with slightly positive Eu anomaly and negative Ce anomaly. The chondrite-normalized REE patterns of sulfide samples such as pyrite and pyrrhotite separated from altered host rock and quartz veins are also right-oblique and characterized by obvious Eu negative anomaly (δEu=0.50～0.64). According to the Eu and Ce anomalies of quartz veins and pyrite, it can be concluded that the oxygen fugacity of the ore-forming fluid decreases from stage Ⅰ to Ⅱ. The Co/Ni ratios (1.60～10.50) of pyrite indicate that the ore-forming fluid is mesothermal, which is consistent with the estimation based on As atomic percentage in arsenopyrite. The gold-bearing quartz veins in the Baogutu gold deposit are closely related to intermediate-acidic stocks and veins in space and time, and they also share similar chondrite-normalized REE patterns and oxidation state, which indicates that the gold mineralization in Baogutu gold deposit is genetically related to intermediate-acidic magmatism in Baogutu area.

Abstract:Located in the Middle Triassic Baifeng Formation of Western Guangxi, the Ronghua manganese deposit is the first economic Mn deposit discovered in Baifeng Formation. Based on geological exploration, laboratory analysis, testing and engineering work, the authors studied the ore deposit in such aspects as strata, structure, sedimentary evolution, ore-bearing horizon, ore body and ore characteristics, genesis and prospecting criteria and, on such a basis, reached the conclusion that the Ronghua manganese deposit is a typical sedimentary-manganese hat deposit, strictly controlled by strata and structure. The main types of manganese minerals include vernadite, psilomelane and pyrolusite. The formation of the ore deposit was mainly related to original sedimentation, weathering and leaching. There exists good prospecting potential between the turbidite of Baifeng Formation and the carbonate rock of Luolou Formation. The strata of the Baifeng Formation are widely exposed in western Guangxi. These typical prospecting criteria may contribute to finding new manganese deposits and have a universal meaning.

Abstract:Located in the middle part of the Changyi-Anqiu iron ore belt, the Lianhuashan iron ore deposit is considered to be a sedimentary metamorphic iron ore deposit occurring in the Xiaosong Formation of early Paleozoic Fenzishan Group. A comparative study of rock mineral composition, host rock and structure characteristics between this deposit and the skarn iron deposit shows that the Lianhuashan deposit is similar to the banded iron ore deposit. The REE values of the ore deposit are low. The shale-normalized REE patterns show relative depletion of LREE and enrichment of HREE, with obvious Eu, Y and La anomalies and no visible Ce anomaly. These characteristics indicate that REE of the Lianhuashan iron ore deposit originated from the mixture of volcanic hydrothermal and seawater. Y/Ho ratios show that the Lianhuashan iron ore deposit was metasomatised by seawater during its deposition. Trace elements, such as Ti, V, Co, Ni, Mn, Sr and Ba, are of low content. In the primary mantle-normalized trace element patterns, U, La and Hf have positive anomalies, Ba, Nb, Ta and Sr show negative anomalies, and ratios of SiO₂/Al₂O₃, Ni/Co, Sr/Ba and Ti/V indicate that the ore-forming materials were derived from the sedimentation of the volcanic matter. This study suggests that ferruginous material of Lianhuashan BIF was associated with volcanic hydrothermal solution and formed in a marine chemical sedimentary environment.

Abstract:Landfill leachate has encountered the severe treatment problem. Using cheap mineral materials as accelerants for the decomposition of organic pollutants in leachate is feasible. This study focused mainly on the efficiencies of anaerobic digestion of landfill leachate with the mediations of limonite and/or dolomite. Four groups of anaerobic bioreactors (control, limonite, dolomite, limonite with dolomite) were set. After anaerobic digesting for 19 days, the COD removal efficiencies for limonite and/or dolomite addition experiments were all over 80%, while the COD removal efficiency for control experiment was only 50%. The pH value in the control experiment changed insignificantly, while in mineral addition experiments there had obvious promotions (～0.5). The ammonia content changed little and did not show significant differences among experiments. This study demonstrates that the presence of limonite and/or dolomite minerals can promote the anaerobic digestion of organic matter in landfill leachate. The results obtained by the authors provide a feasible method for promoting the efficiency of landfill leachate treatment.

Abstract:As an adsorbent, natural pyrite was used to study adsorption characteristics of Rhodamine B (RhB), which was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). In this study, the factors which affect the adsorption of RhB by pyrite such as reaction time, pH, temperature and ionic strength were investigated. The maximum RhB uptake was 21.3 mg/g, which was observed at the equilibrium time 120 min and pH 4.0. The adsorption capacity of RhB increased gradually with adsorption temperature, while the ionic strength showed little effect on the adsorption process. The adsorption process was well described by the Langmuir isotherm model and the pseudo second-order kinetics model. Thermodynamics results confirmed that the adsorption was a spontaneous process. RhB loaded pyrite was regenerated through calcination in air. The results show that the regenerated pyrite could effectively remove 50% of RhB, demonstrating a strong reuse potential.

Abstract:Excess water phosphorus will cause phytoplankton blooms and result in eutrophication, so the decontamination of phosphorus becomes an urgent task in China. In this paper, adsorption of phosphorus was investigated by using industry expanded vermiculite collected in Henan Province. In this paper, phosphorus adsorption isotherm was examined, and the effects of pH value, adsorption time and dosage of vermiculite were investigated. During the agitated batch experiments, the leaching behavior of metals in vermiculite was studied and the reaction mechanism was revealed. The results show that precipitation reaction and ion exchange with iron and aluminum elements in vermiculite are the dominating mechanisms of phosphorus removal. With correlation coefficient of 0.985 1 and saturation adsorption capacity of 2.76 mg/g, Langmuir isotherm fitted the data of phosphorus adsorption on vermiculite very well. Finally, significant influence of pH value on phosphorus sorption was observed within the pH range of 3～9 in the tested sample system.

Abstract:Using in situ high temperature X-ray diffraction, the authors investigated the transformations from anatase to rutile at different temperatures (850, 863, 875, 888, 900℃). The experiment results of transition percentage versus time show that the conversion is first-order, and is characterized by an activation energy of 432.788±25.657 kJ/mol. The rate constants based on Arrhenius equation A is 4.847 454×10¹⁵ s^-1. ESEM was used to find out the influence of temperature and time on grain size growth. Two experiment groups, transformation completed samples sintering at different temperatures (888, 900, 930, 960, 1 000℃) for 10 hours and transformation completed samples sintering at 1 000℃ for different periods of time (0, 5, 10, 15, 20 h), were studied. ESEM images show that at 1 000℃, the influence of temperature on grain size growth is not observable and fine crystal form of rutile does not exist. At 1 000℃, grain size grows with increasing time. Fine crystal form of rutile exists after sintering for 10 hours. The relationship between ln D_t (D_t is the average grain size in time t) and time shows that grain size growth has experienced two different periods.

Abstract:Decomposition kinetics of magnesite was investigated by using thermogravimetric (TG) analysis. The activation energy (E) and pre-exponential factor (lgA) were calculated from Kissinger and Ozawa-Doyle equations, and the peak value of derivative thermogravimetry (DTG) data was used as the maximum temperature. The calculated E and lgA were 211.55 kJ/mol and 11.07 s^-1, respectively. The reaction mechanism was further discussed by using single-TG curve, multivariate no-linear regressions and Malek method, respectively. The obtained results indicate that the reaction was a three-dimensional phase boundary reaction (R3). The kinetic equation was as follows: dα/dT=(10^11.07/β)·e^{-211.55×103/(8.314×T)}·3(1-α)^2/3.

Abstract:The Houxianyu boron ore district in Yingkou of Liaoning Province is a new producing area of serpentine jades, in which Yingkou jades display the characteristics of rich Mg,high Fe and dark color. In this paper, the metallogenic process of the Yingkou jade is discussed based on an analysis of petrology, petrochemistry and geochemistry of the jades, in combination with the geotectonic background, data of dating and the experimental results of the MgO-SiO₂-H₂O system. The results show that the protolith was magnesium peridotite and carbonatite which was replaced by metamorphic hydrothermal fluid from granitization granite. It is held that the serpentine jade deposit was mainly formed during 1.95～1.85 Ga, with the pressure close to 500×10⁵～2 000×10⁵ Pa and temperature 400～250℃, suggesting that it is a mesothermal metamorphic hydrothermal metasomatic deposit.