Abstract:The Yongan granitoid pluton, which is located in the southern Qinhang suture zone, is a part of the Darongshan-Shiwadashan composite pluton in southeastern Guangxi. The pluton is composed of porphyritic cordierite-biotite granodiorite. The results of zircon U-Pb dating indicate that the age of the Yongan pluton is 252.8±3.3 Ma, suggesting Late Permian granites. The geochemical characteristics of the granites of Yongan pluton show that the rocks are rich in Al, K. A/CNK ratios are higher than 1.1. The standard mineral corundum molecules are more than 1%. In addition, the rocks are enriched in LREE, and depleted in HREE, and exhibit obvious fractionation between LREE and HREE. The chondrite-normalized REE patterns show right declining, exhibiting enrichment of LREE and slightly negative Eu anomalies. The granites are enriched in large ion lithophile elements (Rb, Ba, K, Sr) and depleted in high-field strength elements (Nb, P, Ti,Ta) and Ba, Sr. Zircon Hf isotopic compositions of the porphyritic cordierite-biotite granodiorite are mainly characterized by εHf(t) values of -14~-8, and the two-stage model ages of 2.3 to 1.8 Ga. In combination with previous data and an analysis of mineralogy and geochemistry as well as the zircon Hf isotopes and trace elements, it could be concluded that the Yongan pluton is strongly peraluminous S-type granite derived from the crustal source. Though the mantle failed to provide the rock material, the heat for the formation of magma was probably provided by the mantle underplating. The granite was formed in an extensional environment of the post-collision stage.

Abstract:The tectonic setting and petrogenesis of the Paleozoic volcanic rocks, especially the Carboniferous and Permian volcanic rocks in the Beishan orogenic belt are problems of long controversy and have aroused much interest among geologists. The authors consider that the Carboniferous volcanic rocks belong to the andesitic basalt of tholeiite series and the Permian volcanic rocks belong to the andesitic basalt and subalkaline basalt of tholeiite and transition series. The samples collected from the Carboniferous and Permian volcanic rocks are characterized by slight enrichment of LREE and slight fractionation between LREE and HREE. The Carboniferous and Permian volcanic rocks which were contaminated by the crust are highly depleted in Nb, Ta and slightly depleted in Ti, whereas the Carboniferous and Permian volcanic rocks which were not contaminated by the crust are similar to ocean island basalts (OIB) and "hump-shaped" mantle-normalized multi-element patterns without negative Nb and Ta anomalies. The Carboniferous and Permian basaltic rocks were derived from the mantle plume, because some basalts which belong to the Carboniferous and Permian volcanic rocks were obviously contaminated by the crust, exhibiting geochemical characteristics of island-arc or active continental margin basalts. Combined with the research on tectonic evolution in the study area and the related tectonic setting discrimination diagram, the authors have reached the conclusion that the Carboniferous and Permian basalts were all formed in an intraplate setting.

Abstract:The Hebukesaier ophiolite was intruded by Early Silurian rhyolite porphyry in the Saier Mountain region of northern West Junggar. The rhyolite porphyries exhibit obviously high SiO₂ (70.88%~73.36%), Al₂O₃ (14.30%~15.31%) and extremely low MgO (0.36%~1.09%) values, and display relatively high Sr and low Y values with high Sr/Y (22.26~78.42) and (La/Yb)_N (20.27~24.24) ratios. Moreover, both rhyolite porphyries in the Saier Mountain and Early Silurian-Early Devonian adakitic rocks in the north of Xiemisitai Mountain show high positive εHf(t) values and young Hf model ages, and have low K₂O values, Mg^# values as well as compatible elements (Cr, Co, Ni). All these features prove that in Early Silurian-Early Devonian period these rocks in Saier Mountain and the north of Xiemisitai Mountain were formed by partial melting of lower juvenile crust rather than by subducted oceanic crust. From Early Ordovician to Early Devonian, the north of West Junggar underwent intra-oceanic subduction, arc-arc collision, the closure of the ocean and post-collisional extension processes. The ocean in the north of West Junggar might have been closed before Early Silurian, followed subsequently by post-collisional extension. In the post-collisional extension stage, the mantle-derived materials migrated upward and were mixed with juvenile crust-derived materials, forming a mixed magma chamber. Lots of 435~400 Ma A₂-type granites, I-type granites and a small amount of adakitic rocks were derived from this mixed magma chamber, and then the massive vertical crustal accretion was completed in this period.

Abstract:The (ultra-)high pressure eclogites from Sumdo area in eastern Lhasa terrane recorded the subduction and exhumation process of the Paleo-Tethys oceanic crust. Previous studies reported four main outcrops in Sumdo area, i.e., Sumdo, Xindaduo, Bailang and Jilang. Studying the peak metamorphic conditions and p-T path of Sumdo eclogite is of great significance for revealing the subduction and exhumation mechanism of Paleo-Tethys Ocean. In this paper, the authors chose Jilang eclogite for a case study, which has a mineral assemblage of garnet, omphacite, phengite, hornblende, rutile, epidote, quartz and symplectite (diopside+amphibole+plagioclase), and minor biotite. Garnet has a "dirty" core with abundant mineral inclusions and a "clear" rim with less mineral inclusions, showing typical growth zoning. From the core to the rim, Prp content in garnet increases while Grs content decreases, and the rim of garnets is wrapped by pargasite+plagioclase (An=28) corona, showing an amphibolite facies superimposition during retrogression. p-T pseudosection calculated with Domino contoured with isopleths of grossular and pyrope values in garnet and Si content in phengite constrained peak p-T conditions of Jilang eclogite as 563℃, 2.4 GPa. Combined with petrographical observation, the authors recognized four stages of metamorphism:① prograde metamorphism represented by the core of garnet and mineral inclusions therein; ② peak metamorphism represented by the rim of garnet, omphacite, phengite, glaucophane, lawsonite, rutile and quartz; ③ early stage retrograde metamorphism characterized by decomposition of lawsonite to epidote; ④ late stage retrograde metamorphism characterized by symplectites surrounding omphacite and cornona rimmed garnet. Jilang eclogite shows a clockwise p-T path, near isothermal decompression during exhumation, and is recorded as a high pressure, low temperature elcogite. Different from eclogites in other areas which are hosted by garnet-bearing mica schists or serpentinites, Jilang eclogites are enclosed in metamorphic quartzites, with relatively low p-T conditions. On the basis of mixture of rocks with various p-T conditions in this area, the authors infer that Jilang eclogite was derived from the shallow part of the subduction zone, and was exhumed by low density materials in the subduction channel.

Abstract:In this paper, the authors studied the major elements,trace elements, ⁸⁷Sr/⁸⁶Sr isotopes and water content of clinopyroxene megacrystals hosted by Maguan alkali basalt in southeastern Yunnan Province. All clinopyroxene megacrystals are aluminum augite, and their Mg^# are negatively correlated with Al, Fe, Ti, but positively correlated with Ca. MREE is relatively more enriched than HREE and LREE. The LILE (large ion lithophile elements) are obviously deficient. The HFSE (high field strength elements) Nb and Zr are depleted, but Hf is slightly enriched. Nb, Ta and Zr, Hf fractionation is obvious respectively, and Rb and Zr change dramatically. The ⁸⁷Sr/⁸⁶Sr ratios range from 0.703 92 to 0.705 06. All these data suggest that the clinopyroxene megacryst originated from the same parent magma as the hosted alkali basalt. The water content of clinopyroxene megacrystals is 318×10^-6~693×10^-6as measured by Micro-FTIR, which is richer than that of Nushan and Hanoba as well as the peridotite xenolith in Maguan. It indicates that the upper mantle is rich in water in the study area, suggesting oceanic subduction in Cenozoic. The western Pacific Ocean crust which reached the transitional zone retreated eastward in Neogene, whereas the Neo-Tethys ocean crust subducted northeastward. These factors were probably responsible for the abundant water in Maguan mantle. Subsequently, mgama was formed in the asthenosphere (or mantle transition zone) by the Neo-Tethys ocean crust subduction.

Abstract:Fluorite, barite and lead-zinc (mercury) minerals are widely distributed in northeastern Guizhou (Yanhe)-southeastern Chongqing (Youyang) area; nevertheless, there has been no direct isotope age evidence about the mineralization age. The Dazhuyuan fluorite deposit in the northeast of Guizhou is located at the southeast edge of the upper Yangtze block, the orebodies are hosted in the Lower Ordovician carbonate of Tongzi and Honghuayuan formations, controlled by NW-trending faults,and the deposit is the representative in the hydrothermal vein type fluorite deposits of this area. Therefore, the authors selected the deposit to carry out the dating of the mineralization by using the monomineral Sm-Nd isochron method and obtained the Sm-Nd isochron age of fluorite of 436±15 Ma (MSWD=0.85), and the age of associated calcite and fluorite assemblage of 430±13 Ma (MSWD=1.02); the two ages are consistent, indicating that the Dazhuyuan fluorite deposit was formed in Caledonian, and the ages are consistent with the ages (477~410 Ma) of the MVT lead and zinc deposits in west Hunan-east Guizhou area. The fluorite-barite deposits in this area are closely related to the main lead-zinc (mercury) deposits, and therefore the authors infer that they had the similar sources, and constituted a metallogenic series which had genetic relationship and were formed during the same tectonic movement period. All this indicates that Caledonian period was an impor-tant medium-low temperature hydrothermal metallogenic period for the formation of fluorite-barite and lead-zinc (mercury) deposits.

Abstract:The study of modes of occurrence of rare earth elements in the Kunyang phosphorite deposit shows that ∑REE values of the orebody vary between 50×10^-6 and 250×10^-6, characterized by relatively abundant HREE and less LREE. The content of Y is between 30×10^-6 and 155×10^-6. The content of ∑REE is positively correlated with the content of collophane. Heavy minerals prospecting results show that there is a lack of independent rare earth minerals in the Kunyang phosphorite deposit. Chemical phase analysis shows that rare earth elements mainly exist in the phosphate, and are extremely low in carbonate and silicate. LA-ICPMS results show that the values of rare earth elements in collophane are in the range of 280×10^-6~420×10^-6, and those in dolomite is less than 10×10^-6. Therefore, the rare earth elements should mainly exist in collophane as a result of isommorphic replacement of Ca.

Abstract:The compositions of chrysotile asbestos in four major mining areas of Xinkang in Sichuan, Shannan in Shaanxi, Akesaic in Gansu and Mangya in Qinghai were analyzed by FTIR, their cell viability was detected by MTT assay, and their cell apoptosis rate and cell cycle arrest were tested by flow cytometry. The authors compared and discussed the effects of chrysotile asbestos dust on cell proliferation, cell apoptosis and cell cycle arrest in four mining areas. The results show that the main phase of chrysotile asbestos in four mining areas was oblique fiber serpentine, the composition of Xinkang chrysotile asbestos was more complex than that of the other three kinds of chryso-tile asbestos, and the composition of Akesai is similar to that of the Mangya chrysotile asbestos. The chemical groups of chrysotile asbestos in the four major mining areas are basically the same, and the surface structure of Akesai and Mangya chrysotile fibers is better than that of Shannan and Xinkang. Four kinds of chrysotile asbestos can inhibit the proliferation of A549 cells in different degrees, inducing apoptosis and cell cycle arrest:the maximum apoptosis rate is (22.56±2.56)% in Mangya group, the lowest apoptosis rate is (19.57±3.07)% in the Shannan group; and the cell cycle arrest is mainly at G2/M stage. The proportions of G2/M stage (Xinkang, Shannan, Akesai, Mangya) are increased by 8.90%, 8.58%, 9.13% and 10.44% respectively. The capability of four kinds of chrysotile asbestos for inducing cell apoptosis and cell cycle arrest is in order of Mangya > Xinkang > Akesa > Shannan.

Abstract:In this study, the authors carried out sorption experiment with the purpose of understanding the effects of different relative molecular masses of dissolved organic matter (DOM) on PPCPs adsorption behavior. The authors chose carbamazepine (CBZ) as the target pollutants and quartz sand as the inorganic minerals, and used commercial humic acid (HA) to prepare DOM with ultrafiltration classification. Then the authors studied the impact of HA with different relative molecular masses on CBZ adsorption behavior based on fluorescence spectrum and infrared spectroscopy. It is found that, through ultrafiltration classification technology by 3 000 and 10 000 ultrafiltration membranes, the structures of HA are different. Large molecular weight fractions of HA which contain more hydroxyl and benzene ring are mainly hydrophobic substance with better stability and high degree of aromatic tectonics. However, the structure of HA with medium and small molecular weight is not very different. They contain more oxygen-bearing functional groups such as carbonyl and carboxyl groups which are mainly hydrophilic substances. DOM has a significant effect on the adsorption of CBZ onto quartz sand. Large molecular weight DOM promotes the adsorption of CBZ on quartz sand, while medium and small molecular weight DOM inhibits the adsorption of CBZ on quartz sand. The reason is that the large molecular weight DOM can bind on the mineral surface which increases the activity of adsorption sites on the dielectric surface and its aliphatic and aromatic substances have hydrophobic interaction with hydrophobic groups of CBZ. These effects make CBZ adsorb or accumulate on the surface of the medium, which promotes the adsorption of CBZ in quartz sand. The polar functional groups of small and medium molecular weight DOM can bind to the amide of CBZ through polar interaction and increase the solubility of the CBZ molecules, thus inhibiting the adsorption of CBZ on the quartz sand.

Abstract:In this study, A549 cells were exposed to PM_2.5 dustfall of different concentrations, respectively. MTT assay was used to evaluate cell viability. Cell morphology was observed through microscope after W-G staining. Fluorescence probe DCFH-DA and JC-1 were applied to label A549 cells after being treated by PM_2.5 to detect intracellular level of ROS and change of MMP, with the purpose of investigating the mitochondrial oxidative damage in A549 cells induced by PM_2.5 dust-fall. The results showed that, compared with the control group, A549 cell viability was (81.77±6.15)% after being exposed to PM_2.5 at 12.5 μg/mL for 3 h, and was declined in a dose-dependent manner and time-dependent effect. It was observed that cell morphology was changed, cell membrane was dissolved and cell micro-nucleus appeared after being treated with PM_2.5. In addition, the ROS levels were significantly higher than those of the control group; with the increase of PM_2.5 concentration, the fluorescence intensity showed an increasing tendency gradually. Simultaneously, the MMP levels were declined in a dose-dependent manner after being treated with PM_2.5. And there was a negative correlation between the ROS level and MMP (R²=0.878). It is inferred that PM_2.5 may stimulate the production of ROS and induce the declining of MMP, resulting in A549 cell mitochondrial oxidative damage.

Abstract:In order to explore the characteristics of acidification and heavy metal pollution in the sulfide-rich tailing pond, the authors chose the shallow (0~90 cm) section of Shuimuchong tailing reservoir in Tongling of Anhui Province as the research object. Its structural characteristics, mineral composition, heavy metals (Pb, Cd, Zn, Ni, Cr, Mn, Cu and As) content and morphology were studied in detail. The results show that the shallow layer of the tailings reservoir exhibits stratification, that is, the surface layer is strong hardened layer, followed by weakly hardened layer and loose layer, with an acidic environment. Tailing minerals are mainly pyroxene, feldspar, mica and gypsum, and are characterized by the fact that from shallow part to deep part, characteristic peaks of metal sulfides and carbonate minerals tend to be strengthened. Heavy metals show two types of enrichment:the top layer (0~30 cm, As, Pb) enrichment type and the middle (40~60 cm, Cd, Cu, Mn, Ni, Zn and Cr) enrichment type, in which Cu, Cd, As pollution is relatively serious. According to the correlation analysis, there exist some associated types between some metals, and pH is one of the important factors affecting the migration of heavy metals. The tailing heavy metals are mainly in the residual state, with Pb having the strongest potential migration potential, and As having the weakest potential, varying in order of Pb > Cd > Zn > Ni > Cr > Mn > Cu > As.

Abstract:Microscope, LA-ICP-MS, UV-Vis and other observational methods were used to perform the comparative analysis of conventional gemology, inclusions, chemical element content and spectral features of rubies from Burma and Mozambique. The results show that Burmese rubies exhibit strong red fluorescence under UV fluorescent light. They contain short needle-like rutiles, which are arranged at an angle of 60° with each other, and "syrup-like" structures. With the elemental features of low Fe, high V and high Ga, the UV-Vis absorption edge is smaller than 320 nm and the fluorescence at 694 nm is strong. Mozambique rubies have weak fluorescence under UV fluorescent light. Their characteristic inclusions are twin planes, disordered arrangement of rutile and amphibole crystals. With the elemental features of high Fe, low V and low Ga, UV absorption edge of Mozambique rubies is about 350 nm. The above properties can be used as original identification features of rubies from Burma and Mozambique.

Abstract:In this study, nephrite samples from Alamas and Karakash Rivers were collected. Also, serpentinite-related green nephrite samples were selected for comparison in colors. Methods such as electronic microprobe analysis and back-scattered electron images were employed to study the genesis and color-forming factors of nephrite. Based on whole-rock chemical analyses of nephrite obtained, the authors studied petrographic characteristics, mineral composition and color-forming factors. In this study, besides tremolite, associated minerals such as diopside, chlorite, actinolite, spinal, zircon, apatite, garnet, barite, pyrrhotine, graphite, calcite, and Fe(OH)₃ were found in nephrite. All samples have low concentrations of Cr, Ni (<100×10^-6) and spots of Mg/(Mg+Fe²⁺)-Si, suggesting all these samples are dolomite-related nephrite. According to the whole-rock analysis of nearly all data obtained, the data TFe₂O₃=0.33%~1.42%,TFe₂O₃=0.43%~0.96% and TFe₂O₃=0.77%~3.97% were found in white, white-green and green nephrite, respectively. Also, values of Cr and Ni in these samples have low concentrations below 60×10^-6 and 20×10^-6 respectively. These chemical compositions suggest that the increasing content of TFe₂O₃ in crystal structures in tremolite leads to change of the colors in nephrite from white to green. Large amounts of graphite and veinlets of Fe(OH)₃ lead to the black color of nephrite. Although both serpentinite-related and dolomite-related nephrite samples have predominated tremolite, serpentinite-related nephrite might have emerald color. In order to further study the coloring factors of Hetian nephrite, the authors collected samples of serpentinite-related nephrite in Canada for comparison. With serpentine-related nephrite in Candia as an example, in addition to the amount of Fe, a large amount of Cr (1 400×10^-6~5 100×10^-6) was found in them. The emerald color of serpentinite-related nephrite is related to 0.01~0.03 a.p.f.u. of Cr in C site in tremolite. By contrast, there exists nearly no Cr in C site in tremolite in dolomite-related nephrite. Based on the geological field observation and petrographic characteristics, the authors hold that the formation of Mg-skarn has experienced metamorphism, metasomatism and sulfur stages and tremolite formed through the replacement at the expense of the dolomite marble, diopside and other minerals. Multiple replacement of coarse-grained tremolite by fine-grained tremolite leads to the formation of nephrite.