Abstract:

The Tongka microcontinent block, situated in the eastern segment of the Bangong-Nujiang suture zone in the central Tibetan Plateau, preserves key evidence of the Early Jurassic tectonic evolution of the Tethyan Ocean through its metamorphic and magmatic records. Pelitic high-pressure granulites occur as interlayers within dominant felsic gneisses and are accompanied by leucosomes of varying scales. These granulites are primarily composed of garnet, kyanite, biotite, K-feldspar, quartz, with minor accounts of plagioclase, muscovite, sillimanite, and rutile. Integrated analyses—petrography, mineral chemistry, geochronology, and phase equilibrium modeling—reveal a clockwise metamorphic p-T-t path that can be divided into three distinct stages: ① Near-isobaric heating prograde metamorphic stage: this stage is characterized by prograde conditions of 0.70～0.88 GPa and 655～680℃, constrained by the compositions of garnet cores and associated biotite inclusions; ② Peak metamorphic stage: the peak mineral assemblage—garnet + kyanite + biotite + K-feldspar + quartz + rutile + melt ±plagioclase—formed under conditions of 0.98～1.06 GPa and 770～790℃, as indicated by phase stability fields and the compositions of garnet mantles and matrix biotite. Zircon U-Pb dating yields a metamorphic age of 175 Ma, representing the timing of high-pressure granulite-facies metamorphism; ③ Cooling and decompression retrograde stage: The retrograde assemblage of biotite + plagioclase + sillimanite + muscovite reflects post-peak conditions of 0.32～0.68 GPa and 600～725℃. This clockwise p-T-t path reflects crustal thickening associated with the collision between the Tongka microcontinent block and the Qiangtang terrane. The near-isobaric heating stage likely records prolonged thermal input from upwelling asthenosphere into the thickened lower crust of the microcontinent.

Abstract:

The oceanic subduction zones and collision orogenic belts are critical regions for the evolution and maturation of continental crust. However, the specific mechanisms driving crustal reworking and maturation remain subjects of considerable controversy. In this study, we employ an integrated approach that combines petrography, geochemistry,zircon U-Pb geochronology, and zircon Lu-Hf isotopic analyses to analyze the felsic gneisses and their internal leucosomes, basic gneisses, and diorites within the Guaijiaoliang-Shuangkoushan arc-related rock unit, in order to investigate the key mechanisms driving continental crust evolution in this region. Whole-rock geochemical analysis reveals that the felsic gneisses, basic gneisses, and diorites are enriched in large ion lithophile elements and light rare earth elements, while being depleted in high field strength elements, characteristic of typical arc magmatic geochemical signatures. The basic and felsic gneisses exhibit a continuous evolution in major element composition, suggesting that the protolith of felsic gneisses originated from the crystallization differentiation of basic magmas. The leucosomes within the felsic gneisses exhibit high SiO₂, Al₂O₃, and Na₂O contents but low K₂O, CaO, Rb/Sr, and Th/U ratios, characteristic of the geochemical features of trondhjemite, consistent with fluid-present melting. Zircon U-Pb geochronology reveals that the protolith of basic gneiss and diorites formed at 470.9±6.5 Ma and 441.6±3.0 Ma, respectively. Hf isotopic analysis reveals that the zircon εHf(t) values of the basic gneisses range from +6.74 to +11.26, whereas the εHf(t) values of the diorites vary from +5.13 to +8.06. The leucosomes in the felsic gneisses crystallized at 441.6±3.5 Ma, and their zircon εHf(t) values range from +7.24 to +12.27, which is consistent with those of the basic gneisses. Comprehensive analysis indicates that the Guaijiaoliang-Shuangkoushan arc magmatic-metamorphic unit records two phases of arc magmatic activity and one phase of metamorphic-anatexis. During the ~470 Ma oceanic crust subduction phase, subducted fluids facilitated partial melting of the mantle wedge, leading to the formation of the first phase of arc magmatism, i.e., the protoliths of the basic gneisses and felsic gneisses. During the transition from oceanic subduction to continental collision at ~440 Ma, the upwelling of the asthenosphere triggered partial melting of a hydrated mantle, resulting in the formation of diorites. The emplacement and crystallization of the diorites released heat and fluids, inducing hydrous partial melting of the felsic gneiss protolith. Both phases of arc magmatic activity and the subsequent anatexis events promoted the transformation of the continental crust from basic to acidic within the North Qaidam subduction-collision mélange belt. This suggests that arc magmatism and anatexis processes during the transition from oceanic subduction to continental collision were key factors driving the reworking and maturation of the continental crust.

Abstract:

The Jiao-Liao-Ji Belt is the most representative Paleoproterozoic orogenic belt in the North China Craton. It not only hosts massive Paleoproterozoic continental crustal sediments but also contains abundant Paleoproterozoic graphite deposits, making it an ideal natural laboratory for investigating the genesis of Early Precambrian graphite and early Earth's climatic conditions. We conducted detailed petrographic, geochemical, Raman spectroscopic, carbon isotopic, and zircon geochronological studies on the Nanshu graphite deposit in the Jiaobei area, southern Jiao-Liao-Ji Orogenic Belt. The results show that the ore-bearing rocks in the Nanshu deposit are primarily graphite-bearing diopside quartz gneiss, graphite-bearing garnet felsic gneiss, and graphite-bearing two-pyroxene granulite. Their carbon isotopic compositions (δ¹³C_VPDB) range from -13.42‰ to -10.17‰, -21.00‰ to -17.28‰, and -12.99‰ to -12.65‰, respectively. Graphite occurs as flaky or granular crystals uniformly distributed within these rocks. Geochemical characteristics indicate that the protoliths of the graphite-bearing rocks are mainly sandstone and shale that did not undergo long-distance transportation, and are products of an active continental margin. Raman carbon thermometry yields peak metamorphic temperatures of 693~796℃, corresponding to the high-amphibolite to granulite facies. We propose that the carbon source of the Nanshu graphite deposit was primarily organic matter mixed with minor inorganic carbon. Decarbonation (CH₄) during burial metamorphosis contributed significantly to the positive shift in graphite carbon isotopes. Additionally, in the protolith of diopside-quartz gneiss, inorganic carbon released through the metamorphic reaction CaMg(CO₃)₂+SiO₂=CaMgSi₂O₆+2 CO₂, also contributed to the enrichment of heavy carbon isotopes. Zircon U-Pb dating of graphite-bearing diopside quartz gneiss yielded detrital zircon ages ranging from 3.617 to 2.054 Ga, with a dominant peak at 2.46 Ga, and metamorphic zircon ages of 1.82 Ga. Integrating previous data from the Jingshan Group, we constrain the depositional age of the deposit to 2.1~1.9 Ga and the metamorphic-mineralization age to 1.82 Ga. We conclude that during 2.1 ~1.9 Ga, substantial organic matter was rapidly deposited together with terrigenous clastics in a back-arc basin along an active continental margin. This organic material was subsequently transformed into graphite and concentrated into economic deposits during graphitization associated with the arc-continent collision orogeny.

Abstract:

Cretaceous magmatic rocks are widely distributed in the northern the Lhasa Terrane, and the recorded magmatic-metamorphic events are of great significance for studying the petrogenesis and tectonic setting of Cretaceous magmatic rocks in the Lhasa Terrane. This paper reports the petrology, geochemical results and zircon U-Pb age of the Early Cretaceous granodiorite exposed in the Kongma area located in the northern Lhasa Terrane. The results show that the LA-ICP-MS zircon U-Pb age of granodiorite in the study area is 113.2±1.3 Ma, which belong to the late Early Cretaceous magmatism. These rocks are belong to the high potassium calc-alkaline series, with aluminum saturation index(A/CNK=1.05~1.12) and medium negative Eu anomaly, relatively enriched large ion lithophile elements Rb, Th, U, K, and deficient high field strength elements Ti, P, Ta, which is a peraluminous S-type granite. Geochemical characteristics of the rocks shows that they were originated from the partial melting of the ancient crust with the mixing of mantle materials. Combined with the regional data, it is believed that the granodiorite in the Kongma area was formed in the tectonic environment of the southward subduction collision of the Bangonghu-Nujiang oceanic crust in the late Early Cretaceous, which may be related to the asthenosphere material upsurge caused by the slab break-off under gravity drag.

Abstract:

This paper takes a certain cassiterite polymetallic sulfide ore deposit in Inner Mongolia as its research object, using methods such as the third-generation automatic quantitative analysis for mineral parameters (AMICS), a systematic process mineralogical study was conducted on the chemical composition, mineral composition, and grain size distribution of the ore, as well as the grain size, liberation characteristics, and occurrence characteristics of the main minerals, and the occurrence state of the primary target elements. The results indicate that the primary valuable elements in the ore are Cu, Ag, and Sn. Cu is primarily present as sulfide copper minerals such as chalcopyrite and tetrahedrite, Ag is mainly distributed in tetrahedrite in a solid solution form, and Sn is primarily present as cassiterite. Under coarse grinding conditions, although the liberation degree of individual sulfide minerals is less than 70%, the liberation degree of sulfide mineral aggregates reaches 80%. Considering the brittle and fragile nature of cassiterite and its tendency to occur in association with sulfide minerals, it is recommended that under coarse grinding conditions, mixed flotation be first used to recover the copper-silver sulfide mineral aggregates, followed by gravity separation to recover cassiterite. This provides a reference for the development and utilization of similar cassiterite polymetallic sulfide ores in Inner Mongolia.

Abstract:

Thallium (Tl), a strategically critical metal, holds significant application value in high-tech industries. The Nanhua As-Tl deposit in Yunnan Province represents one of the few independent thallium deposits worldwide, with ore bodies occurring as stratiform layers within thin-bedded dolomite of the Upper Jurassic Series. This study systematically investigates the deposit's mineral assemblages, textural characteristics, thallium occurrence modes, and enrichment mechanisms through comprehensive field surveys, petrographic observations, and analytical techni- ques including scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The results demonstrate that realgar and orpiment dominate the ore minerals, with hydrothermal mineralization divisible into two stages: Stage Ⅰ comprises realgar-orpiment-pyrrhotite-pyrite-(thallium minerals-chalcopyrite-galena) assemblages, while Stage Ⅱ is characterized by realgar-orpiment-thallium mineral assemblages. Stage Ⅰ realgar (Rlg1) appears as orange-yellow fine veins, contrasting with Stage Ⅱ realgar (Rlg2) exhibiting coarser orange-red veins. EPMA analyses reveal thallium primarily exists in two forms: discrete mineral phases and isomorphism. Beyond discrete thallium minerals, realgar, orpiment, pyrite, and pyrrhotite display anomalously high Tl concentrations, serving as principal carrier minerals. Pyrrhotite contains the highest Tl content (0.47%～1.89%, average 1.06%), showing strong positive correlation with As and negative correlation with Fe, suggesting coupled substitution of Fe by As³⁺+Tl⁺+Tl³⁺?2 Fe²⁺+Fe³⁺. Pyrite exhibits Tl concentrations of 0.04%～0.18% (average 0.10%) with similar elemental correlations, indicating direct Tl⁺ substitution for Fe²⁺ via 2 Tl⁺?□+Fe²⁺ (□ representing vacancy). Realgar contains slightly higher Tl (≤0.59%, average 0.13%) than orpiment (≤0.17%, average 0.07%), both likely incorporating Tl through isomorphism. Integrated studies suggest differential Tl enrichment correlates strongly with Tl-rich ore-forming fluids under low sulfur fugacity and reduced low-temperature conditions, identifying pyrrhotite as a key prospecting indicator for Tl-rich resources.

Abstract:

Mineral replacement reactions play an important role in the rare earth mineralization process of carbonatites, which reflect changes in the environmental conditions or fluid composition during the evolution of the system. Due to the close ionic size range of rare earth element ions and calcium ions, calcite can be transformed into rare earth carbonates under the action of hydrothermal solution containing rare earth element. Under the combined action of Ce³⁺ and H₂O, calcite can be gradually transformed into lanthanite [Ce₂(CO₃)₃·8 H₂O] (room temperature)→ calcioancylite [CaCe(CO₃)₂(OH)·H₂O] (70~110℃) →hydrobastnäsite (150~165℃) →cerianite (CeO₂) (200~250℃). The different binding forms of water in rare earth carbonate minerals can effectively reflect the ambient temperature. The co-participation of F^-, Ce³⁺ and H₂O can accelerate calcite to transform to rare earth minerals. Calcite can be converted into stable bastnäsite phase at room temperature, but fluorine is not easy to replace the hydroxy occupation in calcioancylite for further transformation into bastnäsite. F^-, OH^- and CO^2-₃ are important ligands responsible for the binding of rare earth elements, and play an important role in the migration, transformation and fixation of REEs in hydrothermal environment.

Abstract:

The Bohai Bay Basin is one of the important hydrocarbon-bearing basins in eastern China,and its complex reservoir-forming characteristics are closely related to modification by deep CO₂ injection and CO₂-rich hydrothermal activity. A comprehensive analysis of the correlations among CO₂ content, δ¹³C_CO2, and R/Ra indicates that the CO₂ in the basin is primarily derived from CO₂ released by deep mantle-derived magmatic activity. Statistical analysis of CO₂-bearing fluid inclusion data reveals a bimodal pattern in homogenization temperatures, suggesting that the study area reservoirs have undergone multiple episodes of hydrothermal modification. Additionally, this study summarizes various lines of evidence from petrology-mineralogy and geochemistry regarding the impact of hydrothermal activity on reservoirs. Petrological-mineralogical evidence includes typical hydrothermal minerals such as ankerite, pyrite, chlorite, and dawsonite. In regions like the Bozhong Depression, Jiyang Depression, calcite in reservoirs exhibits lower oxygen isotope values and positive Eu anomalies in rare earth elements,indicating a hydro- thermal origin. The modification of reservoirs by deep hydrothermal fluids shows significant spatial differences. Near areas of deep hydrothermal activity, CO₂-rich hydrothermal fluids significantly improve reservoir porosity and permeability through dissolution and thermal baking effects, with the peak of dissolution-induced improvement occurring at the leading edge of hydrothermal activity. In contrast, in areas far from deep hydrothermal activity, precipitation and cementation of authigenic minerals (e.g., dolomite, calcite, quartz) lead to reduced porosity and permeability.

Abstract:

In this study, to address the reservoir injury problem triggered by montmorillonite hydration and expansion in high-temperature sour reservoirs (60℃, pH=6.5) in Shengli Oilfield, high-temperature-resistant silicate mixing bacterium was isolated from in-situ formation water and named as SSB-Mnt, to investigate the coupling mechanism of the modification of the mineral structure of montmorillonite. Through multi-scale characterization by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy spectroscopy (SEM-EDS) and inductively coupled plasma-optical emission spectrometer (ICP-OES) combined with dynamic analysis of the elemental content of the system, it was found that SSB-Mnt synergized with electron transfer through the metabolic production of acid (pH value reduction from 6.6 to 5.5), the reduction of 43.8%～49.7% structural Fe³⁺ in montmorillonite was achieved within 30 days (average Fe²⁺ concentration 0.402 mmol/L). Mineralogical evidence suggests that microbial action resulted in montmorillonite interlayer collapse with a reduction in layer spacing from 1.49 to 1.22 nm, depolymerization of the silica-oxygen skeleton (reduction in the intensity of the Si—O—Si absorption peaks), and the formation of secondary minerals associated with elements Fe, Ca, Ti, and P. In this study, we explored the model of synergistic modification of high-temperature-resistant bacteria and minerals under reservoir conditions, and formulated the formulated medium, which provided a theoretical basis for the microbial anti-expansion technology in unconventional oil and gas reservoirs.

Abstract:

Anaerobic digestate from organic waste typically exhibits high concentrations of chemical oxygen demand (COD), phosphate and ammonia nitrogen, classifying it as recalcitrant high-strength organic wastewater. This study proposes supplementing digestate with sulfate as an electron acceptor for sulfate-reducing bacteria, aiming to rapidly degrade organic matter while inducing biomineralization to fix carbon, nitrogen, and phosphorus. To investigate the influence of magnesium and calcium ions on COD removal, biomineralization products, and carbon fixation in anaerobic digestate, batch biomineralization experiments were conducted using anaerobic systems with varying magnesium and calcium ion concentrations. The results show that under a total salinity of 10 g/L and a Mg²⁺/Ca²⁺ molar ratio ranging from 0.5 to 10, increasing the Mg²⁺ concentration from 0.12 g/L to 2.4 g/L boosted total organic carbon (TOC) degradation rates initially, but then caused them to decline. The optimal degradation rate was achieved at a Mg²⁺/Ca²⁺ molar ratio of 5, corresponding to 1.2 g/L of Mg²⁺. Furthermore, when the Mg²⁺/Ca²⁺ molar ratio was less than 1, calcite and struvite were the primary mineralization products, whereas monohydrocalcite and struvite prevailed for ratios above 1. These findings suggest that Ca²⁺ mainly facilitates carbon capture, while Mg²⁺ is crucial for immobilizing nitrogen and phosphorus. Consequently, the Mg²⁺/Ca²⁺ molar ratio serves as a key regulator of controlling both the types and proportions of carbonate and phosphate phases.

Abstract:

Electron Backscatter Diffraction (EBSD) technology has emerged as one of the pivotal analytical tech-niques in structural geology, particularly in the fields of microstructural analysis and rheological studies. Over the past two decades, this technology has made significant advancements, with sample scanning speeds multiplying, identification accuracy greatly improving, and data processing methods becoming increasingly diverse. Consequently, EBSD’s capability for microstructural analyses of geological samples has been increasingly enhanced, and its application in geological research has become more profound and widespread. Traditional EBSD technology can provide basic crystallographic information such as grain size, crystal orientation, and grain boundary distribution. With the rapid development of high-resolution EBSD technology, it has been widely applied to identify intragranular strain in crystals and to efficiently obtain additional key parameters on a large scale, such as Kikuchi band contrast and so on. The realization of three-dimensional expression of EBSD data, along with the integration of data together with other analyses methods, has significantly expanded the application prospects of this technology in geological studies. Since its establishment, the EBSD facility at the Key Laboratory of Continental Dynamics of Ministry of Natural Resources, has accumulated extensive testing experience, sample preparation techniques, and data processing methods over more than two decades. Based on this foundation, combined with previous research, this paper systematically reviews the latest advancements in the testing principles, technical developments, sample preparation techniques, data acquisition, and processing methods of EBSD. In addition, it highlights several typical cases of EBSD applications in geological research in recent years to more intuitively showcase the advancement of EBSD technology. It not only constructed a methodological system for multi-scale structural analysis, but also provided crucial experimental evidence for revealing the stratification of continental rheology, the mechanism of deep deformation and the process of tectonic evolution.

Abstract:

The paper is a systematic collection of 75 new minerals approved by the Commission on New Minerals,Nomenclature and Classification (CNMNC) of the International Mineralogical Association(IMA) in 2010, by listing mineral name, crystallochemical formula,crystal structure data,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 75 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 discover- ing, researching and naming new minerals in China and promote the standardization of Chinese names of mineral species.

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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:

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.

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.