Abstract:

The source characteristics and origin of high-Ti (HT) and low-Ti (LT) magma types are the first-order geodynamic question for the Large Igneous Provinces (LIPs) and mantle plume, especially the Emeishan LIP (ELIP). In this study, we report LA-ICP-MS zircon U-Pb ages, as well as mineralogical, geochemical, and Sr-Nd isotopic data on the Late Permian basalts in the Xiaogaoshan, Yanyuan, Sichuan. The Xiaogaoshan basalts can be classified as LT/HT transitional type and sodic tholeiitic rock series. Clinopyroxene crystallization temperature and pressure are 1 061 to 1 180℃ and 190 to 352 MPa. The X_Mt of Fe-Ti oxides (0.24 to 0.38) indicates a relatively low oxygen fugacity environment and the Fenner trend of fractional crystallization (evolving to iron-enriched). The zircon U-Pb data yield age is 260.2±5.0 Ma, i.e., the peak magmatism of the ELIP. The chondrite-normal- ized rare earth elements (REE) patterns and the primitive mantle-normalized spidergrams show oceanic island basalt (OIB) affinity, with a trend to E-MORB (enriched Mid-Ocean Ridge Basalts). The rocks have low age-corrected (⁸⁷Sr/⁸⁶Sr)_i ratios (0.704 650 to 0.705 035) and positive εNd(t) values (+2.91 to +3.02). The geochemical and isotopic features suggest that the lavas have not undergone any significant crustal contamination, and the source is dominated by "plume" components. The Late Permian Xiaogaoshan basalts have a co-genetic relationship with the picritic porphyries in the Pingchuan iron oxide deposit via fractional crystallization. REEBOX PRO modeling of the adiabatic decompression melting for the Emeishan basalts indicate that the mantle sources of the Emeishan basalts are characterized by the primitive mantle (PM). Only HT basalts can be generated at elevated mantle potential temperatures (t_p=1 550℃ to 1 690℃) beneath a lithosphere that is 140 km thick. In contrast, expanded melting temperatures (t_p=1 400℃ to 1 690℃) and regime spread over LT and HT basalts beneath a considerably thinned lithosphere (50 km). Therefore, the origin of the Emeishan basalts, both LT and HT, is through a continuous melting process of the same source. The modelling suggests that the Xiaogaoshan basalts most likely formed under a thinner lithosphere (50 km), with melting temperature and pressure conditions of 1 403℃/2.38×10³ MPa to 1 557℃/3.55×10³ MPa.

Abstract:

Many red chert blocks and some irregular stripped manganese-oxide aggregates and crusts are developed in the laterite on the top of the Santaishan peridotites, western Yunnan. Those cherts and manganese nodulars are unlike the marine facies ones in shape, chemical compositions and mineral assemblage. Those dark manganese-oxide aggregates and crusts can be classified as ferri-manganese and cobalt-manganese oxides. The energy spectrum analytical results show the ferri-manganese oxides are complicated and nonuniform in their chemical compositions, with main Mn and Fe and minor Al, Co, Ni, K and Ba elements. The separation degree between Mn and Fe elements is low with Mn/Fe ratios of 0.1~12.6. The cobalt-manganese oxides consist of main Mn, Co, Al, Ni and minor K, Ca and Si, showing high separation degree between Mn and Fe. X-ray powder diffraction analyses show that the ferri-manganese oxides occur as hollandite in crystal structure, and coexist with cryptocrystalline hematite, goethite and clay minerals, having capability of enrichment in Al, K, Ba, Co and Ni elements. The cobalt-manganese oxides is with lithiophorite crystal structure, and is associated with cryptocrystalline hematites and cherts, having capability of enrichment strongly in Co, Al and middle in Ni elements. Based on the methods of energy spectrum, microprobe, X-ray powder diffraction, and whole rock chemical analyses, we conclude that those manganese-oxide aggregates and crusts are generated in the supergene conditions of long-lasting leaching by atmospheric precipitation, acidification and redox on the peridotites, where Ca and Mg in the silicate minerals are lost and Si, Fe and Al are residual. Silicic acid was retained and altered to cherts due to poor drainage condition. Iron- and manganese-oxide gels were precipitated as aggregates and crusts under the alternation of wetting and drying climates. The supergenesis has transformed the peridotites to Fe, Al, Ni, Co, Cr, Mn, Sc and Y enriched laterite with potential economic values.

Abstract:

The Shitouzui Cu-Fe deposit is one of the typical skarn deposits in the southeastern Hubei Province. Currently, its mineralization age and the evolution process of ore-forming fluids are not clear yet. Based on the field research and petrographic observation, three generations of garnets were identified in this deposit, and in situ EMPA, LA-ICP-MS trace element and U-Pb dating of garnets were conducted for a systematic study. The results indicate that Grt1 (Adr_61~68Grs_28~36) has small compositional variation, and formed by diffusion metasomatism; Grt2 (Adr_63~89Grs_7~33) with oscillatory zoning exhibits significant compositional variation and formed by infiltration metasomatism; the composition of Grt3 (Adr_82~89Grs_5~11) is uniform and it resulted from crystallization of residual fluid. Y/Ho values (19.24~32.13, averaging at 26.46) suggest that the garnets in the Shitouzui deposit have the same magmatic fluid source. Relatively LREE-enriched and HREE-depleted patterns reflect that all these garnets precipitated in weakly acidic fluid condition. The characteristics of δEu, Sn and REE concentration indicate that the ore-forming fluid changed from relative reduced to oxidized condition, the intensity of water/rock reaction showed an increase to decrease feature, respectively, during the formation from Grt1, Grt2 to Grt3. The LA-ICP-MS U-Pb dating result of Grt2, 138 ±1 Ma, accurately constrains the Cu-Fe mineralization age of the Shitouzui deposit and further confirms the close genetic relationship between the mineralization and the Tonglüshan quartz diorite. The mineralization of the Shitouzui Cu-Fe deposit is a response to the early Yanshanian magmatic activity in southeastern Hubei Province.

Abstract:

The Lanxiagou molybdenum deposit, situated in northern Hebei Province within the western Yan-Liao Metallogenic Belt, primarily hosts molybdenite within granitic gneisses, with only sporadic mineralization in granitic intrusions. The influence of magmatic activity on molybdenum mineralization remains a key research focus. Zircon U-Pb dating reveals the granitic intrusion formed at 134.9±0.94 Ma (Early Cretaceous), coeval with regional magmatic events. Geochemically, the Lanxiagou granite exhibits high SiO₂ (75.41%~76.21%), alkalis (Na₂O+K₂O=8.04%~8.73%), and Al₂O₃ (12.19%~12.64%) with low CaO (0.44%~0.85%), classifying as high-K calc-alkaline, weakly peraluminous granite. It displays enrichment in LILEs (Rb, Th, U) and LREEs, depletion in HREEs and HFSEs (Nb, P, Ti), and moderate Eu anomalies (δEu=0.31~0.40). EPMA analyses indicate crust-derived ferromagnesian biotite (high Mg, Fe, K; low Ca, Na) and albite (high Al, Na; low K, Ca). Mineralogical and geochemical signatures suggest a differentiated I-type granite with crystallization differentiation of biotite, plagioclase, and apatite. Zircon εHf(t) values (-18.16 to -14.76) and t_DM2(Hf) ages (2 570~2 117 Ma) indicate derivation from Paleoproterozoic lower crustal melting. The biotite in the intrusion exhibits relatively high oxygen fugacity (above the NNO buffer), with crystallization temperatures of 599~776℃, consolidation pressures of 164~260 MPa, and emplacement depths of 6.23~9.90 km, indicating formation under temperature and oxygen fugacity conditions favorable for molybdenum mineralization and significant exploration potential.

Abstract:

The red siliceous rocks of the Late Devonian Hongshanliang Formation in the Baogutu tectonic belt, Western Junggar, are extensively developed, comprising approximately 80% of the total stratigraphic thickness. Studying its geochemical characteristics can reveal the genesis of the rock and indicate the tectonic environment, and provide new sedimentary information for the study of the Late Devonian tectonic paleogeographic evolution in the area. The upper siliceous rocks are predominantly red to reddish-brown, with poorly developed bedding, and mainly occur in massive or banded forms. They are often associated with volcanic lava or within volcanic rock interlayers, but no sponge spicules have been observed. The middle siliceous rocks are red, display thin-bedded structures with well-developed stratification, and frequently exhibit sedimentary lamination with abundant sponge spicules. These rocks are interbedded with tuffaceous siltstone and tuffaceous argillaceous siltstone. The lower siliceous rocks, which are red or gray, show transitional lithological and petrographic features between the two aforementioned types. The upper and lower siliceous rocks are relatively low in SiO₂ (71.90%, 87.48%), CaO (1.45%, 1.28%), P₂O₅ (0.09%, 0.06%) and δEu, and high in TiO₂ (0.57%, 0.2%), Al₂O₃ (13.47%, 5.54%), MgO (1.80%, 0.94%), Na₂O (3.93%, 0.64%), K₂O (2.05%, 1.14%), Na₂O/K₂O (1.35, 0.40), Al₂O₃/(Al₂O₃ + ^TFe₂O₃) (0.74, 0.71) and Sc, V, Cr, Cu, Zn, Sr, Y, Zr, La, Ce, Nd, Yb, Lu, ΣREE, Th/Sc, Th/U. The content and corresponding ratio of the major elements in the siliceous rocks in the middle are just the opposite, with high SiO₂ (91%), CaO (2.14%), P₂O₅ (0.48%), low TiO₂ (0.07%), Al₂O₃ (1.05%), MgO (0.32%), Na₂O (0.14%), K₂O (0.14%), Al₂O₃/(Al₂O₃+^TFe₂O₃) (0.37), and significantly depleted in Sc, V, Cr and other elements that are relatively enriched in magmatism. The correlation ratios and graphic analysis show that the volcanism in Hongshanliang Formation had experienced a strong→weak→strong changing process from bottom to top. The upper and lower siliceous rocks are mainly volcanogenic silicon, which are formed in the back-arc basin margin area near the arc volcano, while the middle siliceous rocks are mainly biogenic, which are formed in the back-arc basin environment during the volcanic dormancy period.

Abstract:

Titanite U-Pb dating is a significant way to investigate the geological processes such as metamorphism and partial melting. Here, we evaluate in situ titanite U-Pb dating method based on three well-known titanite standards (BLR-1, Ontario, Pakistan), using ThermoFisher Scientific iCapRQ quadrupole-inductively coupled plasma-mass spectrometer (Q-ICP-MS) coupled with 193 nm ArF excimer GeoLas HD laser-ablation system. After evaluating the influence of beam diameters, laser energy, and repetition rates on the U-Pb isotopic fractionation, the optimal instrumental conditions were confirmed at 5～8 J/cm²,5～8 Hz,44 μm. Besides, the titanite standards were accurately determined with ages of 1 047±6 Ma for BLR-1, 1 055±6 Ma for Ontario, 21.0±0.6 Ma for Pakistan. Further, we chose the granulitized eclogite and its partial melts from the central Himalaya for titanite U-Pb dating. Two types of titanite were recognized from the Himalayan granulitized eclogite and its partial melts, metamorphic type in eclogite and peritectic type in the leucosome. The metamorphic titanites in granulitized eclogites are characterized with lower Nb, Ta, Y but higher Nb/Ta. The U-Pb ages for three sets of metamorphic titanites are 14.1±1.6, 14.2±0.4 and 15.3±2.5 Ma. However, titanite commonly appears as the retrograded product and records the cooling age in eclogite, hence this study insists that granulitized eclogite from the central Himalaya has retrograded into granulite facies to high amphibolite facies at 15～14 Ma, combined with the Zr thermometer (700～850℃) of the titanite. The peritectic titanites with melt inclusions occurred are characterized with higher Th, Nb, Ta, REE and Th/U ratio but lower Nb/Ta ratio than the metamorphic type. Forty laser analyses for the peritectic titanite yield intercept ages of 12.1±1.7 Ma, consistent with the zircon rims (13.5±0.9 Ma) from the leucosome, but much younger than the zircon mantle (17.3±3.2 Ma), these results indicate eclogite from the central Himalaya has undergone decompression melting during the middle Miocene. Two different types of titanite U-Pb dating limit the retrograde metamorphism time of granulite facies to high amphibolite facies at 15～14 Ma and the partial melting age at about 12 Ma during the exhumation process.

Abstract:

Supercritical geothermal resource is a kind of renewable and clean energy with great potential. Its formation and development process is accompanied by strong water-rock chemical reaction. By conducting dissolution experiments of potassium feldspar in pure water at 300~500℃ and 25~50 MPa, this study clarified the influence of temperature and pressure changes on the solubility of potassium feldspar under sub-critical to supercritical geothermal conditions, and revealed the evolution mechanism of its dissolution behavior. The results show that: ① Both temperature and pressure are important factors affecting the solubility of potassium feldspar under subcritical and supercritical geothermal conditions. ② At 400℃, the solubility of potassium feldspar is positively correlated with the pressure. When the pressure is 35 MPa, the solubility of potassium feldspar increases first, then decreases and then increases with the increase of temperature, showing a fluctuation phenomenon. ③ The variation characteristics of the solubility of potassium feldspar are related to the sharp changes in the properties of water (density, hydrogen bond, dielectric constant) under sub-critical and supercritical geothermal conditions. The results contribute to a better understanding of hydrogeochemical processes in supercritical geothermal systems.

Abstract:

Traditional water-rock reaction experiments under high temperature high pressure (HTHP) conditions often result in precipitation or adsorption of the products during the subsequent cooling processes. This issue can be overcome by synthetic fluid inclusion, which enables in-situ entrapment of fluid samples under HTHP conditions, and analyses of fluid composition using a LA-ICP-MS. This study simulates the HTHP (200℃ and 10 MPa) water-rock reaction process between basin brine (NaCl/NaCl+CaCl₂) and basement rocks (Triassic diabase, lithic limestone, and Middle Triassic tuff) in Lanping Basin, Southwest China, and uses synthesis fluid inclusion in calcite to trap the fluid during reaction. By comparing the fluid composition before and after water rock interactions, we are able to explore the origin of ore-forming metals in the fluids, and their contributions to the formation of the Mississippi Valley-type (MVT) Zn-Pb deposits in the basin. Based on microthermometric analyses, the freezing temperature point of synthetic fluid inclusions trapping a 3 m NaCl + 0.15 m CaCl₂ fluid ranged between -13.6 and -11.4℃, while that trapping a 3 m NaCl fluid ranged between -11.8 and -10.7℃, indicating that the fluid composition trapped within these inclusions is consistent with the initial fluids loaded in our experiment. Furthermore, both microthermometric and LA-ICP-MS analyses demonstrated that this synthetic fluid inclusions method using calcite as the host mineral has a nice potential in simulating the relatively low-temperature fluid-rock interactions in nature.

Abstract:

The paper is a systematic collection of 121 new minerals approved by the Commission on New Minerals,Nomenclature and Classification (CNMNC) of the International Mineralogical Association(IMA) in 2019, by listingmineral name, crystallochemical formula,crystal structuredata,physical and optical properties, locality of origin and occurrence, relationship with other minerals, source of mineral names, chemical reaction and spectroscopic characteristics.It's very meaningful that Chinese names of 121 new minerals have been examined and revised under the authority of Chinese Commission of New Minerals and Mineral Names.As a part of the comprehensive introduction to discovery and research of new minerals in the world,this paper will provide reference for the work of discovering, researching and naming new minerals in China and promote the standardization of Chinese names of mineral species.

Abstract:

Deep-sea rare earth element and yttrium (REY) resources are crucial to the development of modern industry. However, the overexploitation of terrestrial REY resources has led to a series of environmental and sustainability issues. The discovery of deep-sea REY resources offers new opportunities for global REY supply, but key scientific questions such as the sources of REY, the minerals hosting these elements, and the mechanisms of ore formation still require in-depth investigation. On the technical front, challenges include the high difficulty and cost of deep-sea mining, immature purification and smelting technologies, and insufficient environmental impact assessments. This paper systematically summarizes the "source-transformation" processes, the state of existence, the ore-forming mechanisms, and the current technical challenges and environmental issues faced by deep-sea rare earth resources. Moreover, this article emphasizes the needs to strengthen fundamental research, technological innovation, and international cooperation to promote the efficient and environmentally friendly development of deep-sea REY resources. Additionally, it calls for the establishment of comprehensive environmental impact assessment systems, the optimization of market forecasting models, and the rational utilization of these resources within the framework of international law to ensure national resource security and promote global sustainable development.

Abstract:

Basalt is the most widely distributed extrusive rock in nature, with large reserves. Basalt ore, which meets industrial standards and has economic mining value, is widely used in various industrial fields because of its unique natural properties and excellent performance. Although China is rich in basalt mineral resources and widely distributed, there is less research on this deposit in the academic community. It is of great significance to summarize the distribution characteristics of basalt ore resources and the current situation of industrial development and utilization in China. This paper summarizes the domestic and foreign research, combs the distribution characteristics of basalt deposits in China, and summarizes the basalt ore, deposit types, industrial development and utilization status. The research shows that the total basalt volume in China is estimated to be about 2 trillion cubic meters, and the basalt ore mining volume has reached 91.5 million tons by the end of 2023, and is still increasing year by year. Basalt deposits can be divided into tholeiitic, calc alkaline and alkaline basalt deposits according to the difference of geochemical composition. From the perspective of ore types, there are mainly five types of basalt deposits for construction, cast stone, rock wool, veneer and cement mixture, among which basalt ore for construction and alkali basalt deposits are the most common. In terms of industrial development and utilization, basalt is mainly used in the field of construction and building materials. In addition, basalt can also be used as a solidification material for nuclear waste, carbon fixation material and agricultural fertilizer. With the development of the country, the mining and consumption of basalt ore in industry are increasing year by year with an average annual growth rate of 7%, and the compound annual growth rate of market scale is more than 10%. The market prospect is good. In the process of development and utilization, domestic basalt ore accounts for 98.5% of the consumption in the field of construction and building materials, while it only accounts for 1.5% in other fields. It is expected that in the future, basalt ore and its deep-processing products will expand their application in a broader field, which has become an inevitable trend.

Abstract:

Hornblende is one of the widely distributed rock-forming minerals, and the contents of Mg²⁺ and Fe²⁺ are the basis for naming tremolite-ferroactinolite series, which is of great significance to the research of mineralogy, petrology and gemmology. In this paper, tremolite-ferroactinolite series samples from eight places of different origin were collected, and systematic Raman spectroscopy and electron probe quantitative analysis were carried out. It was found that the Raman spectrum peaks of hornblende series minerals varied regularly in the range of 3 600～3 700 cm^-1, and the peak area had a good linear correlation with the contents of magnesium and iron obtained by electron probe. The method of calculating Mg²⁺ and Fe²⁺ contents in tremolite-ferroactinolite by Raman peak area is concluded, which can be applied to rapid and non-destructive analysis for tremolite-ferroactinolite series minerals.

Abstract:

Indium (In), a crucial metal, serves as a significant raw material in the domains of emerging industrial technologies as well as national defense and security. China is one of the most important countries of indium resources in the world, and southeast Yunnan plays the same role in our country. In this paper, the distribution and occurrence of indium in typical deposits such as Zhengcaidong and Laoyingwo in the Puxiong Pb-Zn metallogenic belt at the northern margin of Gejiu granite in Yunnan Province have been studied. LA-ICP-MS in situ trace element test of sphalerite shows that the indium content of sphalerite in Zhenngcaidong deposit ranges from 37.71×10^-6 to 403.88×10^-6, with an average of 157.44×10^-6. The indium content of sphalerite in Laoyingwo Pb-Zn deposit ranges from 378.58×10^-6 to 1 060.08×10^-6, with an average of 631.46×10^-6. The indium content in sphalerite is an order of magnitude higher than that in indium-rich deposits abroad. In addition, many Pb-Zn deposits (occurrences) occur in the Puxiong Pb-Zn metallogenic belt, and sphalerite is the dominate indium-bearing mineral in this region. Therefore, we suggest that the Puxiong Pb-Zn metallogenic belt is also an important indium metallogenic belt, which has important research and utilization values.

Abstract:

This paper discusses the petrogenesis of the two-mica granite and its genetic relationship with pegmatite in Jiajika area, west Sichuan Province, by detailed field investigation and laboratory analysis. The whole rock analytical results show that SiO₂ content of two-mica granite is 73.93%~75.06%, and total alkali is 7.90%~8.36% with high concentration of K, suggesting high-K calc-alkaline series; the content of Al₂O₃ is 14.24%~14.77%, and A/CNK=1.14~1.24, implying strong peraluminous S type granite; ΣREE=31.18×10^-6~41.67×10^-6,LREE/HREE=4.15~6.41,δEu=0.46~0.70, and CaO/Na₂O=0.07~0.12(<0.3),indicating that its source might have been pelite with rare content of psammite, and high ratio of Al₂O₃/TiO₂ (133.1~279.8) implies that it is high-pressure-low-temperature post-collision granite. The SiO₂ content of the granite pegmatite is 72.59%~80.91%, the total alkali is 5.26%~10.60%, Al₂O₃ is 11.79%~17.64%, σ=0.74~3.80; A/CNK=0.98~2.38; ΣREE=4.03×10^-6~8.29×10^-6, LREE/HREE=2.61~10.40, and δEu=0.18~0.68. There are considerable differences between two-mica granite and granite pegmatite in the aspect of the content of major and trace elements. And there is close genetic relationship between granite and pegmatite in the area. Magma immiscibility might be the key factor for the formation of (ore-bearing) granite pegmatite. The pegmatite melt riched in volatile components might be separated during the upwelling of granite magma and metasomatized minerals in wall rock to further concentrate rare metal elements during its migration. The difference between two-mica granite and pegmatite might cause the apparent differences in REEs and elements such as Th, Sr, Ti, Y, Rb and Nb. The different characteristics of pathways and environments that the pegmatite melt passed and emplaced might have resulted in element concentration variance in different sites. In comparison with two-mica granite, there existed a certain degree of jumping characteristic during the formation and evolution of the pegmatite in Jiajika area.

Abstract:

Guilin Chicken Blood Red Jasper (CBRJ) is a kind of quartz jasper. It is characterized by bright red to black colors and high hardness. However, few researches have been focused on the field occurrence, geological background, rock structure and genesis of its color. Field surveys indicate that the Guilin CBRJ is hosted in low-grade metamorphic sandstones which experienced vapor-water hydrothermal metamorphism and iron oxide dissemination. It occurs in the Sanmenjie Formation of Neoproterozoic Danzhou Group in Longsheng area in the north of Guangxi. Tectonically, the ore deposit of Guilin CBRJ is located at the juncture of Yangtze and Cathaysian plates, which has undergone a complex geological process. Its formation was related to multi-phase tectono-magmatic activities from Neoproterozoic to Triassic. Detailed analyses of mineralogy, micro-texture and geochemical composition of Guilin CBRJ were carried out by polarizing microscope, X-ray diffraction, and electronic microprobe. The results indicate that the CBRJ is mainly composed of quartz and hematite, with dolomites in some samples. Quartz grains exhibit two types of allotriomorphic equigranular texture and idiomorphic porphyroblastic texture. The latter one, in which distinct enlargement texture can be observed, reveals a metasomatic metamorphism phase. Hematite occurs in three types: ① single crystal existent between or inside the quartz particles, ② dusty crystals wrapped in the quartz particles, and ③ disseminated crystals filled between the quartz particles. The Fe³⁺ in the hematite should be responsible for the color of the CBRJ. Electron microprobe analysis shows that the hematites of single crystal and disseminated crystals have 78.9%～85.6% iron oxides, but the dusty crystal is too small to be analyzed. In combination with the different generations of quartz and hematite, the authors have reached the conclusion that the formation of different types of these minerals in the Guilin CBRJ was consistent with the regionally geological evolution in this area.

Abstract:

The Hongyuntan iron deposit is hosted in pyroclastic rocks of the Lower Carboniferous Yamansu Formation. The ore bodies occur as layers, stratoid bodies or lenses. The principal ore mineral is magnetite, together with minor maghemite, specularite, pyrite and trace chalcopyrite. The gangue minerals include garnet, diopside, actinolite, chlorite, tremolite, epidote, biotite, albite and quartz. The ore structures are mainly of massive and disseminated forms, with occasional banded or veined forms. The ore textures are of subhedral-anhedral granular and metasomatic types. The wall rock alteration shows symmetrical zoning, and the alteration colors change from dark to light from ore bodies outwards. On the basis of observed mineral assemblages and ore fabrics, two periods of ore deposition were recognized, i.e., skarn period and hydrothermal ore-forming period, which could be further subdivided into four metallogenic stages, namely skarn stage, retrograde alteration stage (main ore-forming stage), early hydrothermal stage and quartz-sulfide stage. Electron microprobe analyses show that the end member of garnet is mainly andradite-grossularite. The composition of pyroxene is mainly diopside-asteroite. The amphiboles is composed mainly of actinolite and tremolite with minor magnesiohornblende. The composition of these skarn minerals suggests that skarn in the Hongyuntan iron deposit is calcic skarn, belonging to metasomatic skarn. The characteristics of main and trace elements suggest that the formation of magnetite was closely related to the skarn. In combination with geological characteristics, the authors suggest that the skarn might have resulted from interaction between Ca-rich pyroclastic and Fe-rich magmatic hydrothermal fluid which was transported along the fault system. The formation of magnetite was hence related to the regressive metamorphism of the skarn.

Abstract:

This paper has mainly recommended a mineral abbreviation list (see Table 2 and Table 3). Table 2, which contains 243 minerals, was compiled by IUGS Subcommittee on the Systematic of Metamorphic Rocks (SCMR) in 2007. The author selected other 29 minerals and, on such a basis, formulated Table 3. Thus, the total mineral abbreviations come to 272. It is hoped that they can be popularized in future and become more and more perfect through utilization, so as to provide a basis for ultimate standardization and unification.

Abstract:

This paper presents partition coefficients of 69 chemical elements (Li, Rb,Cs, K, Na, Ca, Ba, Sr, Mn, Fe, Mg, Cu, Pb, Zn, Co, Ni, Be, La, Ce, Nd,Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, Sc, Cr, In, Ga, Al, B,Cd, Sb, Bi, U, Th, Zr, Hf, Si, Ti, Ge, Sn, Mo, Nb, Ta, W, V, P, F, Cl,S, N, O, C, As, Pu, Re, Os, He, Ne, Ar, Kr and Xe) and the univalent radical (OH) in 28 minerals (olivine, clinopyroxene, orthopyroxene, amphibole,biotite, Phlogopite, plagiocla-se, K--feldspar, quartz, magnetite, ilmenite, garnet,zircon, apatite, allanite, topaz, sphene, cordierite, hauyne, leucite, nepheline,whit-lockite, brookite, petovskite, melilite, armalcolite, spinel and rutile) from 8 types of rocks, namely metaluminous (ultra) basic rock, peralkaline (ultra) basic rock, metaluminous intermediate rock, peralkaline intermediate rock,metaluminous acid rock, peralkaline acid rock, peraluminous acid rock and ultra-acid rock. It is found through an integrated ahalysis and comparison that the composition and structure of minnerals and melts seem to be the most important factors controlling mineral-melt element partitioning. Importanceshould be attached to minral structure and Al-supersaturation of melt which have, not been discussed by research workers. Finally, the present state and theproblems to be solved in the study of mineral--melt element partition coefficients are analysed, and the future trends of this research field are predibted.

Abstract:

本文以表格的形式列举了经国际矿物学协会(IMA)新矿物与矿物命名委员会(CNMMN)批准、并于2003年度正式发表的新矿物共55种,其中硅酸盐31种,磷酸盐5种,砷酸盐2种,硫酸盐4种,硫化物3种,碳酸盐2种,钒酸盐2种,硼酸盐1种,硒化物1种,硫盐1种,氧化物1种,氢氧化物1种,复杂卤化物1种.文中表格依次列出了矿物的中外文名称及化学式、晶系及晶胞参数、主要粉晶数据、物理性质、光学性质、产状及共生(伴生)组合等.

Abstract:

The combination of multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) and laser ablation provides a useful tool for tracing the geological process by analyzing minerals under microscales. As one of the non-traditional stable isotopes, boron isotope has attracted more and more attention. In this study, the authors developed an in-situ method for high-precision analysis of B isotope in tourmaline with high-content boron and muscovite with low-content boron. Tourmaline and glass reference materials were applied to correcting the mass fractionation respectively, and in-situ B isotopes of two natural samples from southwestern Tianshan were also tested. In addition, the boron isotope of the in-house standard T-PKU was calibrated as -13.07‰±0.42‰ (2SD, n=66). The above testing results reveal that the condition of LA-MC-ICPMS is stable for a long term and suitable to producing high quality data about tourmaline with minimum spot size of 10 μm and muscovite with > 20×10^-6 B concentration. The B isotopes of tourmaline and paragonite in Tianshan samples are helpful for tracing fluids sources.

Abstract:

Highgrade black jadeite is a kind of upscale and fashionable jade material that has become one of the jadeites characterized by fastest growing values in the past 20 years. Based on a comparison of mineralogical and geochemical characteristics between black jadeites (inky black jades）from different producing areas of the world, the authors hold that the black jadeites currently on the market can be mainly classified into jadeite jade, omphacitic jadeite jade and hornblende jade whose main components are jadeite, omphacite and dark green hornblende respectively. They include blackchicken jade, ink jadeite and blackkosmochlor from Myanmar and jade negro and galactic gold from Guatemala, with blackchicken jades similar to those from Myanmar also seen in Japan and Kazakhstan. The research results suggest that the main mineral composition, jade structure and inclusion characteristic combinations of black jadeite jades from different producing areas have their respective typomorphic natures, which can be used as the distinctive characteristics for their sources.

Abstract:

Early Paleozoic volcanic rocks in Tianshui and Baoji areas along the eastern segment of North Qilian orogenic belt consists of Hongtubu basaltic lavas and Chenjiahe intermediate-acid volcanic rocks. Geochemical analyses show that Hongtubu basaltic lavas are similar to the intercalated basalts in Chenjiahe intermediate-acid volcanic rocks in characteristics, both fallen in the tholeiite series with high TiO2 (1.50%～2.73%). Their∑REE are 65.97×10-6～133.46×10-6 and 78.04×10-6～175.55×10-6 respectively， both are slightly enriched in LREE ［(La/YbN being 2.00～4.40 and 2.71～4.40 respectively］，and both have no obvious Eu anomaly or weak Eu negative anomaly（δEu being 0.85～1.10 and 0.85～0.99 respectively）. Basalts from two groups are typically characterized by selected enrichment of LILEs, low abundances of HFSEs relative to NMORB, and prominent troughs of Nb and Ta, with low Nb/La ratio（0.28～0.43）, which indicates the affinity of these volcanic rocks to island arc tholeiite（IAT）. In addition, εNd（t）（+2.22～+4.08）values of basalts suggest that their mantle sources are similar to the depleted mantle source. Zr/Nb=17.21～36.33 and Ce/Nb=5.73～8.17, implying geochemical characteristics of N-MORB. Sr, Nd and Pb isotopes from Hongtubu basalts are similar to those in Chenjiahe basalts in composition. In the diagrams of εNd(t)-(87Sr/86Sr)t, (207Pb/204Pb)t-(206Pb/204Pb)t,(87Sr/86Sr)t-(206Pb/204Pb)t and εNd(t)-(206Pb/204Pb)t for basalts, the data are fallen in the DM, EMⅠand EMⅡ areas, probably with a little crustalontamination, indicating that the magma of basalts might have had a mixed gin.Thentermediate-acid volcanic rocks from Chenjiahe belong to the calc-alkaline series,they have relatively high abundances of REE∑REE=127.51×10-6～276.01×10-6）, and are significantly enriched in LREE[（La/YbN= 4.79～13.51]. Most intermediate-acid volcanic rocks show weak Eu negative anomaly (δEu=0.53～1.20). The trace element patterns of Chenjiahe acid volcanic rocks are similar to those of the ocean ridge granite (ORG), with marked troughs of Nb, Ta, Zr and Hf. A synthetic study shows that the Chenjiahe intermediate-acid volcanic rocks in the eastern segment of North Qilian orogenic belt were formed in an island-arc setting, whereas the Hongtubu basalts were formed in an intra-arc rift setting (or an initial back-arc basin setting), probably being products of the early spreading evolution of the island_arc system towards the back-arc basin in the eastern segment of North Qilian during late Early Paleozoic. The results obtained provide evidence for the existence of the trench-arc-basin system at the juncture of Qilian and North Qinling orogenic belts.

Abstract:

The geochemical characteristics and abnormal sources of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn in the soil of Southern Xuancheng were analyzed and studied by using the 1:250 000 land quality geochemical survey data. It is found that the geological background is the main controlling factor for the content of soil elements, and that the spatial distribution characteristics of heavy metal elements in the surface and deep soil in the area are significantly consistent with the geological background and sedimentary environment. The high content of heavy metal in the soil parent rock geological background (Hetang Formation, Piyuancun Formation and Lantian Formation, etc) is the main influencing factor for the high anomaly of soil heavy metal elements. In addition, mining and atmospheric dry and wet deposition are also one of the factors affecting high anomaly of heavy metals in soil. It is found that Pb, Hg, Cd and Cr in soil have input sources of atmospheric dry and wet deposition. The main impact index of heavy metal in soil pollution risk in the survey areas was Cd. The proportion of samples that soil Cd exceeded the control value of soil pollution risk of agricultural land was 2.56%. The morphological analysis results show that soil Cd is mainly in ion-exchange state. Combined with crops investigation, it is found that there is a certain ecological risk in the area with high abnormal soil Cd.

Abstract:

The Cuonadong leucogranite is one of the most important parts of North Himalayan leucogranite belt. Geochemical data show that Cuonadong leucogranite is the calcium alkaline and strong peraluminous granite with high silica (SiO₂ is 74.20%~74.52%), poor iron (Fe₂O₃ is 0.04%~0.20%, FeO 0.04%~0.58%), poor magnesium (MgO is 0.06%~0.14%), and calcium alkaline (σ is 2.15~2.32) as well as strong peraluminous nature (A/CNK is 1.11~1.15). Its total rare earth is relatively low (∑REE is 47.24×10^-6~57.59×10^-6), with enrichment of LREE (LREE is 39.85×10^-6~49.23×10^-6), depletion of HREE (HREE is 6.91×10^-6~8.68×10^-6) and obvious negative Eu anomaly (0.49~0.80). It is characterized by an enrichment of some large ion lithophile elements (Rb, Th, U, K) and loss of high field strength elements (Nb, Ta, Zr Ti). Zircon U-Pb dating results show that the Cuonadong leucogranite's formation time is Miocene (21 Ma), which belongs to the peak of the late stage of north Himalayan leucogranite (24~12 Ma). Zircon εHf(t) values are negative with a wide variation (-3.92~-17.64), which shows that its magma source was the crust, mostly from the metapelite, with the probable mixing of many kinds of materials in its source. The petrogenesis of Cuonadong leucogranite is that the high Himalayan crystalline rock series experienced decompression melting during the rapid pull-back of the plate in the post-collision tectonic setting, with the initial magma crystallization temperature being 675~702℃.

Abstract:

Quantitatively determining the timescale during mantle-derived magma ascent from the source to eruption or emplacement is essential for the understanding of magmatism, however, the timescales of eruption/emplacement are still poorly constrained. Shanxi Datong Cenozoic volcanic field, north of the North China Craton, is an ideal area for the investigation. In this study, we focused on the mantle olivine xenocrysts entrained in ca. 0.2 Ma Shenquansi alkali basalt, and its timescale of residence in the host magma prior to eruption. According to mineral chemistry, cores of these mantle olivine xenocrysts have Fo values up to 97.7, which can be defined as extremely magnesian olivine. They are also characterized by the extremely low contents in Ca, Mn and Ni, suggesting they were captured from metasomatized mantle peridotite. Moreover, both of the mantle olivine xenocrysts display complex CaO profiles, attributed to complex magmatic processes in the magma plumbing system. The reaction rim widths of one olivine xenocryst vary significantly, implying it has experienced multiple crack processes when captured or dur- ing transport. The Fo values of the mantle olivine xenocrysts rims are about 70, indicating they are in diffusion equilibrium with the host magma (alkali basalt) at rims. Timescales obtained by Fe-Mg diffusion chronometry of olivine mantle xenocrysts show that they have only resided in the magma for months. For a lithospheric mantle thickness of 40~70 km, the fastest average ascent rate may exceed 500 m/d.

Abstract:

In this paper,LA-ICP-MS zircon U-Pb dating was carried out for four samples of volcanic rocks from Qingshan Group in Jiaodong area and, as a result, their concordant ages were obtained, which are 119.4±0.9 Ma, 118.2±1.0 Ma,120.2±0.9 Ma and 120.0±0.8 Ma, respectively. The results show that all the volcanic rocks in Jiaodong area were formed from about 120 Ma to 118 Ma in the Early Cretaceous period. The ages of Qingshan Group volcanic rocks from Shandong Province controlled by Tan-Lu fault are similar to those from the Su-Wan segment of the Tan-Lu fault zone,but younger than those around the Tan-Lu fault zone,which indicates that the duration of volcanic eruption along Tan-Lu fault is probably longer than the duration in other areas under the background of lithospheric thinning in eastern China. Geochemically, all the intermediate and acidic volcanic rocks have high K₂O, ALK, LREE values and low MgO, TiO₂, Ni, Cr, HREE values. According to the geochemical features, the volcanic rocks can be subdivided into trachyte-trachydacite and rhyolite. The trachyte-trachydacite is characterized by LILE enrichment(Rb,Ba,K)and HFSE depletion(Nb,Ta,Ti,P), but the rhyolite exhibits stronger depletion of Ba,Sr and HFSE (Ti,P). Compared with the rhyolite,the trachyte-trachydacite possesses higher Sr and Ba values as well as La/Nb and Ba/Nb ratios,but lower Rb/Ba ratios and δEu values. All these data indicate that they might have been derived from different magma sources. It is inferred that the trachyte-trachydacite rocks were derived from the mixture of the partial melting of the lower crust(Yangtze Craton or North China Craton)and enriched lithospheric mantle. In addition, the rhyolites were related to the partial melting of the lower crust in the regional extension environment and high geothermal anomaly background with crystallization differentiation during the magma evolution.

Abstract:

Cordierite is a mineral material characterized by low thermal expansion coefficient and good thermal shock resistance. Cordierite mineral material is relatively rare in nature, so cordierite is synthesized usually by the method of artificial synthesis. Based on the newest investigation results of synthetic cordierite, this paper deals with the progress of researches on such synthesis methods of cordierite as high purity oxide solid reaction at high temperature, natural mineral solid reaction at high temperature, the utilization of industrial wasted materials, the employment of agricultural wasted materials, the sol-gel and the low-temperature combustion synthesis. At present, the method of natural mineral solid reaction at high temperature is used for the preparation of cordierite in industry. In spite of a lot of advantages, this method also has many disadvantages. Therefore, the development trend of cordierite synthesis seems to solve the problem as to how to apply other synthesis methods to industrial preparation.

Abstract:

At present, the infrared transmission spectroscopy is the best technique for determining whether jadeite is polymer-impregnated or not, and the infrared reflectance spectroscopy is a nondestructive and rapid determination method that provides mainly the fundamental frequency vibration spectra data of minerals and shows new application potentials in gemological research, especially in the identification of gem species. The gemological application of IR reflectance spectroscopy and the identification system of IR spectra of gems, including a database of 318 spectra and a searching and identifying program, are described in this paper.

Abstract:

Petrology, geochemical and Nd isotopic data are reported for the Neoproterozoic Danba metabasalt in the Kangdian Rift on the western margin of the Yangtze block. Samples were collected from alkaline basalts, which are enriched in MgO, TiO₂, with Mg^# being 0.51～0.59. They have high total rare earth elements and show high fractionation between LREE and HREE. The trace elements are characterized obviously by enrichment of Th, Nb, Ta, Zr, Hf and LREE but depletion of Y and HREE. Their geochemical and Nd isotopic characteristics suggest that they are similar to OIB. The basaltic magma was generated in an intraplate setting, and was generated by partial melting of OIB mantle source region, with variable degrees of contamination of SCLM during magma ascending; in addition, some samples might have experienced contamination of the lower crust. These samples reveal some plume magmatism characteristics in petrochemistry, and imply that magmatism was probably related to the Neoproterozoic plume event, which resulted in the breakup of Rodinia supercontinent.

Abstract:

As more and more treated turquoises appear on Chinese gem market, the authors collected lots of turquoises from different deposits on Chinese gem market in order to sum up the characteristics of the natural turquoises on Chinese gem market. At the same time, different types of treated turquoises were studied to find general difference between them and natural turquoises. The results show that natural turquoise and treated turquoise have different shades of color, inclusions and appearances. IR spectra of both natural and treated turquoises were studied, indicating that there are absorption peaks at 1 735, 1 600 and 1?500 cm^-1 in treated turquoises, which are caused by the man-made polymer. If the turquoise is treated by polymer, there are absorption peaks at 1 735, 1 600 and1 500 cm^-1 in a turquoise, and this can serve as convincing evidence in this aspect.

Abstract:

The newly-exposed lower strata of the Xiamaling Formation near Tielingzi Village in Jixian County contain rich siderites. This paper reports the basic geological characteristics of these siderite-rich strata in terms of the field outcrop, petrology and major elements. Studies show that the profile is characterized by black shale interbedded with silty iron-rich layers/siderite concrete layers, and also has minor siltstone. Some iron-rich strata have turned into limonite layers in the outcrop because of intense weathering. Siderite is the main iron mineral phase in the strata. Siderites can form iron concretes, showing micritic or microcrystalline granulitic textures under the microscope, or form silty ferruginous layers with almost a comparable amount of silty quartz; it can also distributed sporadically in siltstone and black shale with relatively coarse particles. There also exists very little siderite residue in weathered limonite layers. The overall features of major elements show that the strata are rich in SiO₂, TFe and TOC, but poor in MnO, CaO, MgO, P₂O₅ and S. Except for ferriciron in weathered layers, there is mainly ferrous iron in the strata. The TOC content decreases in order of siderite concrete, silty iron-rich layer, black shale and siltstone. The correlation diagram between TFe and Al₂O₃ content shows a negative correlation in iron-rich layers, while a positive correlation between them exists in normal black shale and siltstone, which suggests that iron in the former form originated from the ocean itself, while iron in the latter form originated mainly from terrigenous detritus. In addition, FeO content has a positive correlation with TOC content in fresh samples, which implies that the genesis of siderites may have some relationship with organic matter.

Abstract:

From the discovery of the first new mineral hsianghualite in 1958 to the end of 1995,74 new minerals found in China had been approved by IMA CNMMN. Among them, 2/3 were discovered after 1981. The discovery of new minerals in China has the following features:(1) With the development of analytical methods, the number of new minerals discovered per year increases gradually: from the end of 1950s to 1960s, only one new mineral was discovered every year on the average, whereas from 1980s till now, three new minerals were discovered averagely every year. (2) The structures of many new minerals have been determined. (3) Most of the new minerals are in the lower category, mainly in the monoclinic system, and perfect crystals are rare; hsianghualite has the most abundant crystal faces, whose ideal faces can reach 146. (4) Among those new minerals, silicates take the first place in number, followed by native elements, alloys, and then oxides. (5) The modes of occurrence of new minerals are varied, most of them occurring in oxidized zones of various deposits and deposits related to ma fic or ultramafic rock masses. There are a few new minerals occurring in skarn and placer deposits or even in cosmic dusts and meteorite.(6) The new minerals are characterized by wide but uneven distribution. Till now, new minerals have been discovered in 20 provinces or autonomous regions, especially in Hebei, Qinghai, Inner Mongolia and Henan. The number of new minerals found in North China is larger than that found in South Chine. (7) The number of discoverers of new minerals is in tens. The first discoverer of new mineral is Prof. Huang Yunhui, whereas Prof. Yu Zuxiang is the one who discovered the most numerous new minerals in China, totally disclosing 11 new minerals by himself or together with other experts. Most of the discoverers are members of the Chinese Academy of Geological Sciences, China University of Geosciences, and Institute of Geochemistry, Academia Sinica as well as other educational and scientific research institutions. The discovery of new minerals has promoted the development of mineralogy in China. Tens of discoverers were awardees of the National Natural Sciences Prize or the Science and Technology Progress Prize of the Ministry of Geology and Mineral Resources for the discovery and research results of new minerals in 1980s. More than 60 new mineals discovered in China were collected by the Geological Museum of China, with some of them exhibited in the Minerals and Rocks Exhibiting Room.

Abstract:

Indosinian S-type granites are widely distributed in central Inner Mongolia on the northern margin of North China landmass. Spread in nearly EW direction, the granites have formed a gigantic compound granite belt, with porphyritic biotite-admellite and moyite being the two main types. SiO2is abundant, Al2O3is 12.38%~15.34%. A/NKC (molecule ratio)>1.1, K2O/Na2O=1.1~3.1,δ=1.9~2.6,ΣREE is 45.778 ×10-6~486.501×10-6, andδEu=0.1~0.8. A series of zircon U-Pb surface ages (207~227 Ma) for the granites have been recently obtained from 1/50 000 regional geological survey. As the lithofacies and geochemical characteristics of the granites are similar to those of S-type granites, the authors conclude that the Indosinian granite in this area was formed in a post-collision setting instead of in the setting of syn-collision between North China plate and Siberia plate.