Abstract:Geochemical characteristics of the volcanic rocks in middle Wusunshan of West Tianshan Mountains were studied in this paper, and the results show that all the basalts and andesites are tholeiitic volcanic rocks, with enrichment of LREE [(La/Yb)_N=3.44～11.36] and weak depletion of Eu (δEu= 0.79～1.13); andesite and rhyolite are significantly enriched in highly incompatible elements (Cs, Rb, Ba, Th, U) and LREE; basalt and acid rock samples show slight difference, but all the samples obviously have negative anomalies of Nb, Ta and Ti. Nevertheless, the characteristics of basalts are similar to those of intraplate basalt: the (Th/Nb)_N range from 2.02 to 8.12, (Nb/La)_N range from 0.40 to 0.45, by far less than 1; La/Ba ratios are low (0.01 to 0.07) and Ba/Nb ratios are high (90 to 410); average Zr/Nb ratio is 16.48, close to the ratio of primitive mantle (15.71 ); Ta/Nb, Hf/Ta, Th/Yb ratios are averagely 0.10, 3.77, 0.64 respectively, close to their upper crust ratios (0.10, 3.50, 0.48); Zr content is larger than 90×10^-6, Zr/Y ratios are about 4; Except for some active elements (Cs, Rb, Ba), values of trace elements are close to their values in the lower crust. Combined with the geological characteristics of this area, the authors consider that this region might have been in the post-collision extension phase in the Carboniferous, with local rifting characteristics. The distinct depletion of Nb,Ta and Ti might have been caused by the hybridization of the lithosphere, and the environment of the Middle Wusunshan volcanic rocks should have belonged to the post-collision extension phase.

Abstract:The features of zircons are obviously controlled by their formation environment and can be used to verify their origin and the evolution process of the host rock magma. The authors studied the trace elements and genesis of the zircons from the granite porphyry in the Dalingshang tungsten deposit of Jiangxi Province and investigated the magma evolution process by means of cathodoluminescence and LA-ICPMS. The Dalingshang tungsten deposit is an important deposit inthe Dahutang ore concentration area. It is a superlarge W-Cu-Mo polymetallic deposit found in 2010. The mineralization of the Dalingshang tungsten ore deposit was closely related to the granite porphyry, but the zircons in the granite porphyry have not been studied in detail yet. Yanshanian magmatic zircons, inherited magmatic zircons and captured zircons were found in the granite porphyry in the Dalingshang tungsten deposit. The Yanshanian magmatic zircons seem to be the typical hydrothermal zircons with the features of non-cathodoluminescence, low Th/U ratios (<0.1), relative enrichment of LREE and weak positive anomaly of Ce. Nevertheless, they also display the characteristics of both hydrothermal zircons and magmatic zircons, with some samples falling in the hydrothermal zircon area whereas others in the magmatic zircon area in the diagrams of (Sm/La)_N-La,δCe-(Sm/La)_N, and δCe-δEu and(Sm/La)_N-(Lu/Gd)_N. Yanshanian magmatic zircons should be a part of magmatic zircons, as shown by the fact that their average zircon Ti thermometer geological temperature is 872 ℃ and their host rocks are relatively fresh hypabyssal intrusive rock. It is thought that the zircons in pegmatite have features of hydrothermal zircons but no features of magmatic zircons. Compared with the features of zircons in pegmatite, the Yanshanian magmatic zircons should be considered to have been formed before the pegmatite stage. According to all features mentioned above, the authors have arrived at the conclusion that the Yanshanian magmatic zircons in the study area should be classified as the magmatic zircons formed in the magma with rich hydrothermal fluids before the pegmatite stage. The magma rich in hydrothermal fluids could contain a lot of metals that formed the metal deposit late, and hence researchers should pay more attention to the magma so as to find more information about the ore deposit. The captured zircons show uneven lighting gray and white CL images with some non-cathodoluminescence edges in the cracks of the zircons. The captured zircon has high Th/U ratios (>0.4), relatively low LREE/HREE and positive anomaly of Ce. In the diagrams of (Sm/La)_N-La,δCe-(Sm/La)_N, and δCe-δEu and (Sm/La)_N-(Lu/Gd)_N, the captured zircons all fall in the magmatic area. The zircon Ti thermometer geological temperature is 766 ℃. All features point to the conclusion that the captured zircon should be the magmatic zircon and its formation was controlled by Jinningian magmatism. The study of the regional geological condition has revealed that the captured zircon must have only come from the granite diorite of Jinning Period because the granite diorite of Jinning Period was the unique magma product in Jinningian period in the study area. The cores of inherited zircons show gray and white cathodoluminescence and their edges have no cathodoluminescence. Their ratios of Th/U and LREE/HREE are between those of the Yanshanian magmatic zircons and the captured zircons. In the diagrams of (Sm/La)_N-La, δCe-(Sm/La)_N, and δCe-δEu and (Sm/La)_N-(Lu/Gd)_N, all inherited zircons are in the area between magmatic zircons and hydrothermal zircons. Their average zircon Ti thermometer geological temperature is 744℃. The inherited zircon cores have the same properties as the captured zircons and their new zircon edges have the same properties as the Yanshanian magmatic zircons. So it is reasonably considered that the granite diorite of Jinning Period was one of the original rocks of the granite porphyry rock.

Abstract:The Dongshengmiao deposit is a superlarge lead zinc polymetallic deposit occurring in the Langshan-Zhaertaishan metallogenic belt of Inner Mongolia, and the main ore-bearing rock is the second Formation of Langshan Group. In this paper, the authors combined the study of multiple suites of core samples which cover the main ore-bearing rock series with the recent study of hydrothermal deposits abroad, and arrived at some new understanding of the major orebody of the Dongshengmiao deposit. The rock and ore in different lithologic members have different fabric characteristics: in the middle of the fourth lithologic member, siderite ores show fine mosaic texture and massive structure, with obvious characteristics of chemical sedimentation; at the bottom of the fourth lithologic member, sphalerite ores of the No. 2 orebody exhibit hypautomorphic-allotriomorphic crystalline granular texture or dissolution texture, and mostly show massive, banding or brecciated structure, with obvious filling-metasomatic phenomenon; stockwork mineralization is generally existent in the third lithologic member which is sericite-grapholite based, with very common later hydrothermal filling phenomenon. In addition, geochemical study of the rock and ore indicates that siderite ore shares similar trace element enrichment and REE distribution pattern to sphalerite ore, so they may have had the same provenance. However, sericite-grapholite in the third lithologic member has different trace element enrichment features and REE distribution curves,probably resulting from multi-stage hydrothermal activity. It is worth mentioning that we can find dolomite-marble fragment breccia which belongs to upside wall rock and they are different from sericite-grapholite fragment breccia. The dolomite-marble fragment breccias resulted probably from replacement. Comprehensive analysis shows that stockwork mineralization in the third lithologic member was caused by later hydrothermal filling, while the No.2 orebody at the bottom of the fourth lithologic member might have resulted from ore-bearing hydrothermal selective replacement of carbonate strata, and siderite orebody's mineralization might be attributed to the migration of the iron-rich hydrothermal solution to the bottom of ocean and the subsequent precipitation. Ore-bearing hydrothermal replacement played a key role in the ore-forming progress of the major orebody in the Dongshengmiao deposit. The result achieved by the authors has deepened the understanding of the SEDEX deposit.

Abstract:The Nixintage magnetic iron deposit is situated in the east Awulale metallogenic belt, western Tianshan Mountains, Xinjiang. Several large-sized and medium-sized iron deposits have been found in this belt, and their genetic types as well as the contact relationship between them have become problems of heated debate in this area. A series of systematic researches have been conducted to discuss the ore genesis. Stratigraphic study and drilling projects reveal that the orebodies are hosted in basaltic trachyandesite, trachyandesite and pyroclastic rocks of Lower Carboniferous Dahalajunshan Formation, which contain 3 main iron orebodies. They are all concealed orebodies and occur in bedded and stratoid forms. Ore structures mainly include disseminated type, brecciated type, massive type and striped type. The main ore mineral in the iron ore is magnetite, followed by hematite, with minor pyrite and limonite and occasional geikielite. The main altered minerals in the wall rocks include chlorite, epidote and carbonate. On the basis of the study of ore fabric and paragenetic association of minerals, the metallogenic stages of the Nixintage iron deposit can be divided into two periods: magmatic metallogenic period and hydrothermal period. The orebodies and their wall rocks have similar chondrite-normalized REE patterns and rich LREE. The orebodies and their wall rocks also have similar trace elements characteristics, relatively rich in Th as well as U and poor in Nb, Ta and Sr. REE and trace elements charactersitics show that they are homologous. The study of petrography demonstrates that orebodies and their wall rocks are products of a developed basaltic magma rather then the products of andesitic magma. The general negative anomalies of Nb, Ta in the orebodies as well as their wall rocks and the negative anomalies of Ti in the wall rocks show that the ore-forming parental magma was probably the basaltic magma formed in an island-arc environment. In conclusion, the Nixintage magnetic iron deposit resulted from differential evolution of basaltic magma formed in an island-arc environment during the Carboniferous period. This magnetic iron ore deposit belongs genetically to volcanic magmatic-hydrothermal compound type.

Abstract:The Nantai Mo polymetallic deposit is hosted in the Kuanping Group in the North Qinling belt, and its stratoid and lenticular orebodies occur in the porphyry and the contact zone between the marble of the Kuanping Group and the porphyry. Mineralization occurs as disseminations, lumps and veinlet-disseminations. Wall rock alteration is well developed and mainly comprises potassium-silicate alteration, skarnization and carbonatization. The ore-forming process can be divided into two metallogenic periods: skarn and quartz-sulfide, and the quartz-sulfide period represents the main molybdenum mineralization episode. Fluid inclusions in quartz phenocrysts and quartz-molybdenite veins can be divided into four types, i.e., L-type aqueous fluid inclusions, V-type aqueous fluid inclusions, C-type three-phase CO₂-bearing inclusions and S-type multi-phase inclusions containing daughter minerals. Homogenization temperatures of fluid inclusions at the early stage of quartz phenocrysts can be divided into three intervals, i.e., 340～400℃, 220～280℃ and 140～200℃, with salinity being 57.90%～>73.96%, 30.06%～38.01%, 3.39%～18.55%, respectively. The temperatures of the main mineralization stage in quartz-molybdenite veins were 280～380℃, 200～240℃ and 120～180℃, with salinities ranging from 0.43% to 12.85% ω(NaCl_eq). The late stage in non-mineralization quartz veins has only homogenization temperatures of 120～240℃, with salinities ranging from 1.91% to 10.73% ω(NaCl_eq). Coexistence of two or more types of fluid inclusions in the three homogenization temperature intervals of the principal mineralization stage with corresponding salinities homogenized to divergent phases at similar temperatures suggests that boiling had already occurred several times during the ore-forming evolution and was probably the dominated factor for metal precipitation. This phenomenon is comparable to things of the Qiushuwan Mo (Cu) deposit in North Qinling. δ³⁴S values of sulfides associated with mineralization range from -0.3‰ to 7.2‰, 3.1‰ on average, indicating that sulfur was derived from deep-seated magma. δD_V-SMOW values of sulfide-bearing quartz vary between -103‰ and -76‰, with corresponding δ¹⁸O_H2O values between 4.01‰ and 5.55‰, impling that the ore-forming fluids of the main mineralization stage in the Nantai Mo polymetallic deposit were mainly derived from magmatic fluids, with some addition of the meteoric water.

Abstract:Garnet is one of the main indicator minerals of kimberlite type diamond deposits in Mengyin, Shandong Province. In order to determine the types of complex color garnets in diamond deposits of Mengyin and the relations between characteristics of garnet and ore potential, the research group systematically sampled the garnets in kimberlite of different mineralization degrees in ore deposits. The MgO, SiO₂, FeO, TiO₂, Al₂O₃, Cr₂O₃, CaO, MnO values of 50 single crystal garnets in the kimberlite were measured by electron microprobe spectrometer. 128 garnet single crystal lattice parameters were measured by X-ray single crystal diffraction. Some data were obtained: In the garnet, MgO values vary in the range of 14.44%～23.44%, SiO₂ 40.34%～43.64%, FeO 5.87%～16.97%, TiO₂ 0.00%～1.45%, Al₂O₃ 14.25%～22.30%, Cr₂O₃ 0.00%～11.88%, CaO 2.88%～6.68%, CaO/MgO ratios are in the range of 0.12 ～ 0.44, FeO/MgO 0.25～1.15, Cr₂O₃/Al₂O₃ 0.00 ～ 0.61, and TiO₂/Al₂O₃ 0.00～0.07. According to the above data, the garnets in kimberlite of Mengyin are probably of the magnesium, iron and calcium- aluminum chromium garnet series. In order to divide types of the garnets in kimberlite, the authors calculated the formula of the 50 garnets according to the chemical composition, and the results show that the chemical formula of garnet group minerals in kimberlite is A₃B_{2 3}. Group A cations are composed of Mg²⁺, Ca²⁺ and Fe²⁺. Divalent cation is mainly Mg²⁺. Mg²⁺ occupies about 53%～82% of the dodecahedron cavity center. Ca²⁺ occupies less than 7%～17% of the dodecahedral cavity center. Fe²⁺ occupies around 5%～31% of the dodecahedron cavity center. Group B cations are composed of Al³⁺, Cr³⁺ and Fe³⁺. Trivalent cation is mainly Al³⁺, with [AlO₆] octahedra occupying up to some 62%～92%, and [FeO₆] and [CrO₆] octahedra occupying less than 38%. According to different cations that occupy dodecahedral cavities and octahedral cavities, garnets in Mengyin can be divided into 10 subspecies. According to Dawson-Stephens garnet classification methods, garnets in kimberlite of Mengyin are mainly of G9 and G10. The content of Cr₂O₃ in G9 garnets is low, the content of CaO is high, and iron chromium garnet end-member is characterized by a high percentage of molecules, with the color being mainly of purple series. G10 garnets are mainly in the coarse-grained kimberlite diamond, with a large number of diamond inclusion garnets belonging to this class, which reflects the genetic relation of coarse-grained garnet with diamond. G10 garnet may indicate the existence of diamond-bearing kimberlite body. According to the composition of garnets in kimberlite of Mengyin, the garnet of kimberlite in diamond of this area had formation pressure of 6.0～9.0 GPa. It is inferred that garnet in kimberlite of Mengyin should belong to asthenosphere. Lattice parameter statistics of 128 garnets show that lattice parameters of garnets from Mengyin are distributed in the range of 1.151～1.161 nm, with the frequency distribution in the range of 1.154～1.160 nm. Purple garnet lattice parameters indicating no ore, lean ore, medium ore-bearing rock and rich ore rock are 1.162 nm, 1.159～1.160 nm, 1.156～1.160 nm and 1.155～1.157 nm respectively. From barren rock through lean ore rock, medium ore-bearing rock, to rich ore rock, purple garnet lattice parameter values tend to decrease. Purple garnet cell parameters thus have obvious prospecting implications for kimberlite in Mengyin of Shandong Province.

Abstract:The Xinliaodong Cu polymetallic deposit is a newly-discovered copper ore deposit in eastern Guangdong Province. Chlorite is one of the main hydrothermal alteration minerals genetically related to copper mineralization in this ore district. According to the mineral intergrowth association, the chlorites of Xinliaodong Cu polymetallic ore district can be classified into two types: the chlorite which coexists with sulfide and the chlorite which occurs individually. Both chlorites exhibit foliate, fibrous or vermicular aggregation forms. By means of microscopic and electron microprobe analysis, the authors investigated chemical composition and texture of the chlorite and concluded that chlorites in the Xinliaodong Cu polymetallic deposit have the following characteristics: ① with the increasing altitude, the Si and Mg components of the chlorite related to mineralization increase gradually, the Al, Fe and Mn components gradually decrease, but the regularity is not apparent for the chlorite which had nothing to do with mineralization; ② the two types of chlorite are mainly Fe-rich chlorites composed of prochlorite and brunsvigite; ③ they were formed by hydrothermal alteration of pelitic or mafic rocks, and the phenomenon that Fe-Mg substitution dominates the octahedral substitution suggests that their formation had to do with the iron-rich and relatively acid environment; ④ according to the chlorite geothermometer, the two types of chlorites were formed at temperatures of 166.32～245.62℃(averagely 219.15℃)and the chlorite coexistent with sulfide had a relatively higher formation temperatures, but both of them were in the range of low-moderate temperature; ⑤ the main formation mechanisms of the two types of chlorites were dissolution-crystallization and dissolution-migration-crystallization.

Abstract:The Cretaceous rocks which contain glauconite at different stages of glauconitization lie under the glauconitic sandstone beds in the Xiala section in southwestern Tibet. To better understand the glauconitization process as well as the mechanism and factors that controlled the formation of glauconite, the authors studied the glauconite at different stages of glauconitization in the Cretaceous rocks of the Xiala section by means of petrographical microscope, Scanning Electron Microscope (SEM), and the Electron Probe Micro-Analyzer (EPMA). The results show that the glauconite generally occurs as granular aggregates composed of lamellae on the micron scale and has evident characteristics of replacement. The replacement of K in alkali feldspar dominated the interface migration reaction, which was controlled by a coupled dissolution-precipitation process, and a later stage of recrystallization. A long-term low-energy environment was necessary for the newly formed glauconite to retain the shapes of original mineral grains. Three factors were crucial at the initial stages of glauconitization: supply rates of sediment, dissolution rates of the substrate, and the redox condition near the reaction surface. The widespread occurrence of berthierine indicates that reducing condition was prevailed, and that glauconite only developed under local suboxic condition. The relatively high K₂O content and low TFeO content of glauconite at different stages of glauconitization indicate that the process of glauconitization in the Xiala section could not be explained by the neoformation theory or the two-stage model postulated by previous researchers, because unlike the glauconitization of K-deficient minerals, the process in the Xiala section did not require a second stage of K enrichment.

Abstract:Five different types of amygdaloid complexes were found in vesicular basalt of Puge County, south Sichuan, mainly calcite amygdaloid complex and asphalt (bitumen) amygdaloid complex. The babingtonite amygdaloid complexes are spheroidal with 5～8 mm in diameter. A commonly recognized mineral sequence of the amygdaloid complex from the wall inward is quartz→brunsvigite→babingtonite. The babingtonite crystals are black and lamellar, and are composed of five pinacoids. X-ray micro-diffraction measurements indicate that babingtonite is triclinic, with space group P. Chemical composition analyses show that babingtonite has the following data: SiO₂ 53.55%, CaO 18.84%, Fe₂O₃ 13.65%, FeO 9.68%, MgO 1.44%, H₂O⁺ 1.74%, and FeO/Fe₂O₃=0.709, whereas brunsvigite has the data SiO₂ 33.17%, Al₂O₃ 13.03%, Fe₂O₃ 8.45%, FeO 13.06%, MgO 18.82%, H₂O⁺ 12.12%, CaO 0.87%,and FeO/ Fe₂O₃=1.55. The evolution of mineral associations in babingtonite amygdaloid complexes suggests that the ore-forming fluids at the late stage converted from Mg- and Fe-rich fluids to Si- and Ca-rich fluids. Babingtonite crystallized in a transitional environment from meta-acid and weak reduction to meta-alkaline and weak oxidation.

Abstract:The Hutouya Pb-Zn ore deposit in Qinghai Province, a typical skarn polymetallic deposit in the Qimantag metallogenic belt, is characterized by intense magmatism and a combination of Fe, Cu, Mo, Pb, Zn and some other metallogenic elements. In this paper the authors studied in detail the typomorphic characteristics of chemical composition of sphalerite in this deposit by electron microprobe analysis so as to investigate the distribution and enrichment patterns of Fe and Cd in sphalerite from this deposit. Microscopic observations show that sphalerite can be divided into three generations varying in color from black to light yellow gradually. Accordingly, distinct mineral assemblages of ores are characterized by the variation from sphalerite-(galena-chalcopyrite)-pyrite-pyrrhotite through sphalerite-galena-chalcopyrite-pyrite-(pyrrhotite) to spalerite-galena-calcite (or quartz). Electron microprobe analyses suggest that the early-stage sphalerite exhibits enrichment of Fe and depletion of Zn, Cd. In contrast, the late-stage sphalerite shows relative depletion of Fe and enrichment of Zn, Cd. A range of ore-forming temperatures from 148 to 262℃ is estimated according to the content of FeS in the sphalerite. The deceasing content of FeS in the spahlerite in the three generations is consistent with the corresponding decrease of ore-forming temperatures, namely from 262～258℃ through 260～200℃ to 248～148℃. In combination with the sphalerite Zn/Cd ratios, it is suggested that the Hutouya Pb-Zn deposit is a mesothermal deposit. Spatially, the flowing direction of the hydrothermal flux in this deposit was consistent with the strike of the orebody from NWW to SEE. Zn increased, Fe decreased, and the range of Zn/Cd ratios increased in the flow direction. The Zn, Fe, Mn elements of sphalerite in the Hutouya Pb-Zn deposit show characteristics of the typical skarn (magmatic hydrothermal) deposit, obviously different from things of SEDEX deposits, stratabound deposits, hydrothermal and hot brine mixed zinc deposits. Coupled with the geological characteristics and ore-forming processes, the authors hold that the Hutouya Zn-Pb deposit is a mesothermal skarn-type one.

Abstract:The Shilongtou gold deposit in Kaihua of western Zhejiang lies in the Anhui-Zhejiang-Jiangxi fault-fold belt, with its orebodies obviously controlled by regional faults. In order to understand the mineralogy of pyrite and the indicator of gold mineralization, the authors studied the pyrite by using X-ray diffraction (XRD) analysis, electron microprobe analysis and sulfur isotopic composition analysis. The results show that major metal minerals are pyrite and arsenopyrite, with minor limonite and pyrrhotite, whereas gangue minerals are dominated by quartz, sericite, illite and dolomite. Electron microprobe analyses of auriferous pyrite show that the (Fe)/(S+As) ratios are between 0.777 and 0.886, indicating that it formed at the middle to shallow depth. Co content is relatively low (64×10^-6～111×10^-6), and Au/Ag ratios vary from 3.6 to 17.8, suggesting that it formed in a low temperature environment. Co/Ni ratios are between 1.95 and 4.47, with an average of 3.59, indicating its hydrothermal genesis. The high As content and the As-Co-Ni ternary diagram show that the hydrothermal fluid was related to primary magmatic activity, with a nature of underground thermal brine. Sulfur isotope values vary from 6.14‰ to 8.27‰, similar to those of ultramafic rocks from deep crust, with the values affected by crustal sulfur at the later stage.

Abstract:Interbedded sand-mud stones are developed widely in the F reservoir of the Songliao Basin, and kaolinite and illite are main clay minerals in the F reservoir, which are very important for the physical property and the effective development of the reservoir. The study of the 90 pieces of natural cores shows that both permeability and porosity of the F reservoir increase with the increase of kaolinite relative content and decrease with the increase of illite relative content. Sand-stone layer has good permeability and high kaolinite relative content, and in this layer secondary illite seldom deposits in-situ, resulting in the existence of large amounts of erosion pores. In contrast, the mud-shone layer has poor permeability and high relative content of illite. Moreover, the fiber-style existence of illite and book-stack-style existence of kaolinite make the sand-stone permeability much better and the mud-stone permeability much worse. The effect of kaolinite and illite on the reservoir physical properties can be detected by in-house core flow experiments. The results show that the F reservoir has a medium but slightly weak velocity sensitivity and a medium but slightly strong alkaline sensitivity, and that the velocity sensitivity of the reservoir will increase with the increase of kaolinite and illite absolute content, and the alkali sensitivity will increase with the increase of kaolinite absolute content but has no relationship with the illite content. More attention should be paid to the kaolinite-oriented velocity and alkaline sensitivity, for the relative content of kaolinite approximates half of all clay content in this reservoir.

Abstract:The ore-forming metallogenic specialization of felsic rocks is closely related to oxygen fugacity. In this paper, however, oxygen fugacity is considered to be one of the necessary but not sufficient conditions for ore formation, and the analytical thinking concerned is partly based on the authors' geological field work. The metallogenic significance of oxygen fugacity is divided into metallogenic specialization and ore-bearing potential. Two aspects of understanding have been otained: ① Porphyry Cu-Au deposits derived from the reduced I-type granitoid should have a high oxygen-fugacity origin; different sub-regions within the covariogram of oxygen fugacity versus other geochemical parameters, such as degree of magmatic evolution, temperature, pressure, pH, sulfur fugacity and rock-type, correspond to different metals' geochemical behavior or mineralization, respectively, and oxygen fugacity versus rock-type seems to be of significant specialization; ② The evolution from metallogenic specialization to real metallogenesis is the evolution from magma to hydrothermal solution and then from hydrothermal solution to ore; during such a process, oxygen fugacity is also an essential controlling factor for elemental geochemical behaviors, whose influence on mineral precipitation, however, should not be overemphasized, because some kinds of precipitation might have had nothing to do with oxygen fugacity.

Abstract:Ge exhibits siderophile, lithophile, chalcophile and organophile behavior in different geological environments, and it has been widely used in the study of mineral deposits, environment sciences and so on. Previous testing technology has restricted the development and application of germanium isotopes in Earth science, but limited research on germanium isotopes has indicated great application potential in cosmography, oceanography and so on. In this paper, the authors summarize the chemical preparation and mass spectrometry, and review the isotopic compositions and fractionation mechanism in nature and experiments.

Abstract:With its unique green color and pellet-like shape, glauconite contrasts remarkably with the surrounding rocks. Currently there are three generally adopted concepts: glauconite is a kind of typical marine sedimentary mineral, special in-situ glauconite is one of the diagnostic minerals indicative of slow depositional rate, weak reduction and deep-water environment, glauconites are often deposited during the transgressive period, and therefore the glauconite-bearing formations in shallow sediments are often regarded as condensed section in the transgressive period. Glauconites are ideal measurement objects of K-Ar and ⁴⁰Ar/³⁹Ar ages. Their genesis, evolution, and sedimentary as well as stratigraphic significance have been widely used. It should be noted that glauconites can be formed in a variety of sedimentary environments, only in-situ glauconites can be used to identify the condensed section, but its age may be younger or older than the real age.

Abstract:Based on the study of hydrothermal experiment on the interaction between the albite and CO₂ fluids at different temperatures (75, 100, 125, 150 and 175℃) by the FYX-1 microautoclave, the authors investigated the possibility of geological storage of CO₂ which can considerably help slow global warming. The results suggest that the corrosion intensity of albite is gradually enhanced as the temperature increases. Magnesite, siderite and other carbonates begin to generate at about 150 ℃, and the content is apparently increased at 175℃. The result indicates that the CO₂ can be captured in the mineral in the form of carbonate, and the temperature for the capturing is around 150℃.