Abstract:Petrological and petrochemical characteristics of samples from four Neo-Archean banded iron ore deposits of Baiyuli, Baizhiyan and Ekou in Wutai Mountain area and Qian'an in eastern Hebei Province are reported in this paper. Some comparisons are also made with Anshan iron deposit in Liaoning, Hanwang iron deposit in Shandong and some other iron deposits of the same kind abroad. The authors have found that these iron deposits have highly consistent characteristicss in the following four aspects: all of the samples are depleted in Th, U, La, Ce, P and Sm and enriched in K, Nb, Sr, Hf, Er and Ti; as one of the characteristics of Archean marine sediments, they all have very low REE content, with the average values of the iron deposits in the four areas being 27.65×10-6, 14.56×10-6, 19.03×10-6 and 16.46×10-6 respectively; all of the iron deposits in the four areas are depleted in light rare earth elements and enriched in heavy rare earth elements, with Pr/Yb ratios in the range of 0.81～1.84, 0.35～1.21, 0.76～1.33 and 0.95～1.92 respectively; they have obvious positive anomalies of Y and Eu, with ratios of Eu/Eu* being 2.55～3～36, 2.07～2.25, 1.44～2.56 and 1.43～3.77 respectively, suggesting characteristics of sea water and high temperature seafloor hydrothermal solution. Therefore, the Fe-Si formations were probably formed in a hot sea water environment. In addition, as the values of δ34S of pyrite associated with BIF are close to zero, the authors hold that the sulfur might have come from the mantle. It is thus concluded that the studied BIF are chemical sedimentaryore deposits formed in a high temperature sea water environment after the derivation of silicon and iron from mantlederived volcanic eruption or exhalation.

Abstract:Metamorphic rocks of the Mesoproterozoic Aksu Group are developed in Aksu area, southwestern Tianshan Mountains. Based on detailed field and petrographic observation as well as geochemical investigation, the authors hold that the protoliths of the gneiss and the hornblende schist are felsic volcanic rocks and mafic rocks respectively, whereas the protoliths of mica schist are graywacke. Chemical components of the gneiss indicate that SiO2 and Al2O3 content of the samples varies from 72.36% to 74.6% and from 12.28% to 13.55%, respectively. TiO2, Fe2O3, FeO, MnO, MgO and CaO content is obviously low: Fe2O3=0.44%～1.2%, FeO=0.68%～1.74%，MgO=0.23%～1.17%，and CaO=0.41%～1.31%. Chemical components of the hornblende schist suggest that TiO2, TFe2O3, MgO and CaO content is obviously high: TiO2=2.27%，TFe2O3=15.79%，MgO=5.77%，and CaO=7.75%, but SiO2 and Al2O3 content of the sample is only 49.88% and 12.9% respectively. Compared with PASS, mafic rocks are rich in SiO2 and Na2O (varying from 61.51%～75.53% and 1.33%～4.38%, 69.16% and 2.91% on average respectively), but poor in Al2O3, TFe2O3, MgO and CaO. The petrological and chemical characteristics of the gneiss and hornblende schist suggest that the rocks are of calc-alkaline series, with σ from 1.8 to 2.3, and the chrondrite-normalized REE patterns are all characterized gnificant enrichment of light rare elements, with no significant fractionation of heavy rare earth elements. In the by si MORB normalized multi-element variation diagram, multi-element variations show relative concentration of K, Rb, Th, evident depletion of Ti, Nd, Ta, and clear negative P anomalies. The chrondrite-normalized and PASS-normalized REE patterns of the mica schist are similar to patterns of active continental margin and continental arc greywacke. All the gneiss samples are plotted in the field defined by volcanic arc granites in geochemical-tectonic discrimination diagrams，which suggest that they were formed in a continental volcanic arc closely related to the subduction zone. This conclusion is also supported by the geochemical-tectonic discrimination diagrams of the simultaneously-deposited metamorphic sedimentary rocks. In both La-Th-Sc and Th-Sc-Zr/10 discrimination diagrams, almost all of the samples are plotted in the continental arc. Chemical characteristics of the mica schist suggest that it was formed in a sedimentary environment related to continental island arcs, such as back arc basin. Combined with regional background, all these characteristics suggest that metamorphic rocks in the Aksu Group were formed in a continental volcanic arc-back arc basin and might have been related to a global supercontinent Columbia event.

Abstract:The Songpan-Garze fold belt （SGFB） on the eastern margin of the Qinghai-Tibetan Plateau covers a huge triangular area bounded by Yangtze （South China）， North China and Qinghai-Tibetan Plateau blocks It has gone through two orogenic phases, i.e., Paleotethys and Neotethys，with the major deformation stagesoccurring in Late Triassic. Mesozoic intermediate-acid intrusives, composed of both normal calc-alkaline and high Sr low Y granitoids, are widely distributed in the Songpan-Garze fold belt. The investigation of their petrogenesis, characteristics of the sources and geodynamic significances is very important in understanding the evolution of SGFB characterized by poorly-exposed basement. The authors studied petrology， geochemical composition and zircon U-Pb chronological characteristics of Lanniba and Yangfanggou granitoids in the southern part of the Songpan-Garze fold belt as well as their petrogenesis and geological significance. The study of Lanniba and Yangfanggou granitoids formed during the post-collision period can shed light on such problems as regional tectono-magmatic events， basement nature and tectonic evolution. Cathodoluminescence（CL）images show that the zircons are big and idiomorphic and have clear magmatic oscillatory zoning， suggesting magmatic origin. U-Pb zircon LA-ICPMS dating shows that the Lanniba and Yangfanggou granitoids have magmatic crystallization ages of around 211 Ma. These granitoids are high-K calc-alkaline（even shoshonite），with intermediate to high SiO2（58.31%～68.02%） and metaluminous characteristics（A/CNK=0.68～0.99）Rocks in the southern part of the Lanniba granitoids contain high Al2O3（15.85%～16.27%）and K2O（3.29%～3.40%），intermediate MgO（1.16%～1.47%），high Sr（869×10-6～1032×10-6），low Y（9.53 ×10-6～9.85×10-6）with fractionated REE［（La/Yb）N＞31］and also have some dark inclusions. These rocks are very similar to the K-adakite derived from partial melting of thickened lower crust. Yangfanggou and the northern part of the Lanniba granitoids are very similar to each other in major and trace elements. In contrast with the southern part of Lanniba granitoids，they have higher K2O（4.08%～5.96%） and Y（19.71×10-6～27.76-6）, lower Sr（664×10-6～868×10-6），and obviously lower Sr/Y ratio（29.39～42.05），showing characteristics of high-K calc-alkaline I-type granitoids; thus they might have been derived from partial melting of thickened lower crust. Field geological and geochemical characteristics indicate that the granitoids contaned mantle components，thus providing heat and part of source materials for the Mesozoic granites in Songpan-Garze fold belt. The involvement of mantle-derived magma and the existence of ultrahigh-K calc-alkaline I-type granitoids（211±2 Ma）indicate that the Songpan-Garze orogen was under an extensional scheme at least in Late Triassic period.

Abstract:Albitite, a special kind of sedimentary rock in South Qinling, is mainly distributed in Devonian and Silurian strata of Fengxian-Taibai, Shanyang-Zhashui and Zhen'an-Xunyang basins. It is closely related to many large-middle lead-zinc and gold deposits in the South Qinling orogenic belt. Occurring in clastic rocks or carbonate rocks in the stratified or stratoid form, albitite shows a conformable contact and gradual relationship with the strata and has thick-bedded, massive and brecciated structures. XRF dating of albitite shows that it is enriched in primary elements such as Na2O, A12O3 and SiO2 and trace elements such as Pb, Zn, Au, Ag and Cu. The enrichment of element Ba and the Fe-Mn-(Co+Cu+Ni)×10 projection indicate a hydrothermal sedimentary origin. However, the diagram of TiO2-Al2O3 suggests it also has some characteristics of terrigenous deposit. Ti and Al probably came from the clay matter of clastic sediments. The REE data by ICP-MS show that albitite and strata have similar total REE, HREE and LREE. The chondrite-normalized REE patterns of albitite and regional strata are quite similar, caused probably by the mixture of hydrogenous sediments. Albitite was formed at the sedimentary or early diagenetic stage, simultaneity with the formation of normal sedimentary rocks. Therefore it is a special kind of hydrothermal sedimentary rock, having characteristics of both marine sedimentary rock and typical hydrothermal sedimentary rock. The albitite is of sedimentary lithogenesis of mixed hydrothermal solution with enriched Na and metallic elements by extracting ore-forming elements from the strata and mixing with non-consolidated sedimentary concretions at the seabed.

Abstract:Different types of marine carbonate rocks have different capabilities of resisting diagenetic alteration and preserving coeval seawater information. Aragonite and high-magnesium calcite minerals, for example, are liable to suffering from relatively strong diagenetic alteration, and their preservation of the coeval seawater information is therefore relatively poor; by contrast, low-magnesium calcite mineral has much better capability for preservation of the coeval seawater information. It is thus thought that the evaluation of marine samples of different rock types for their diagenetic alteration and preservation of the coeval seawater information is a necessary basic work in sedimentary geochemistry and chemostratigraphy. The analyses of rock fabrics, cathodoluminescence and trace elements of Triassic marine samples of different rock types from the Huaying Mountains of eastern Sichuan were conducted in this paper to evaluate their capabilities for resisting diagenetic alteration and preserving coeval seawater information. The results indicate that the calcareous mudstone samples show strong luminescence, their average Mn concentration is higher than 800×10-6, average Sr concentration is only 280×10-6, average Mn/Sr ratio is higher than 3.3, which is the highest average Mn/Sr ratio in all the samples of different rock types. The micrite samples mostly show extremely weak or weak luminescence, with only a few samples showing moderate or strong luminescence, their average Mn concentration is 213×10-6, average Sr concentration is 704×10-6, and average Mn/Sr ratio is 0.44. The very fine-crystalline dolomite shows relatively weak luminescence, their average Mn concentration is 119×10-6, average Sr concentration is 86×10-6, which is the lowest average Sr concentration in all the samples, and average Mn/Sr ratio is 1.46. The grainstone samples show no luminescence, their average Mn concentrations is only 4×10-6, which is the lowest average Mn concentration in all the samples, average Sr concentrations is 1015×10-6, which is the highest average Sr concentration in all the samples, and average Mn/Sr ratio is very low (lower than 0.004). In summary, the Triassic marine samples of different rock types from the Huaying Mountain of eastern Sichuan have different capabilities for resisting diagenetic alteration and preserving coeval seawater information. All the calcareous mudstone samples which have the highest average Mn concentration, relatively low average Sr concentration, relatively high Mn/Sr ratio and strong luminescence could not represent the coeval seawater, so they must be excluded. Most micrite samples which have relatively low average Mn concentration, relatively high average Sr concentration, relatively low Mn/Sr ratio and weak luminescence or moderate luminescence could represent the coeval seawater, but a few of them must be excluded. A few of very fine-crystalline dolomite samples which have relatively low average Sr concentration and relatively high Mn/Sr ratio could not represent the coeval seawater, even though they have relatively low average Mn concentration, weak luminescence or moderate luminescence, but other samples still represent the coeval seawater. The grainstone samples which used to be regarded as rocks liable to suffering from stronger diagenetic alteration have low Mn concentration, high Sr concentration, and no luminescence, so that their diagenetic alteration might have been related to early seawater cementation or deep-buried trapped marine fluids, rather than to meteoric water.

Abstract:Based on detailed field survey of oil sand outcrops at the top of the middle Triassic Upper Karamay Formation and on the bottom of lower Jurassic Badaowan Formation in Tuziakeneigou on the northwest edge of Junggar basin, the authors measured 11 single sand beds in the oil sand outcrop of Upper Karamay Formation whose lithology is mainly grayish-brown pebbly coarse sandstone and medium-coarse sandstone, and identified 12 single sand beds which are products of multistage migration and superposition of channels in the oil sand outcrop located on the bottom of Badaowan Formation, where every single sand is composed of fining-upward positive rhythm composed of pebbly sandstone, medium coarse sandstone, fine sandstone and siltstone. Thin section analysis reveals that oil sand beds are mainly lithic sandstone and the content of feldspar and quartz is very low, which indicates that rock compositional maturity is low, stability of sandstone is in a low degree and these beds are fairly close to the source area. Textural maturity of sandstone is in a medium degree. In Upper Karamay Formation, lake and delta sedimentary facies, 2 subfacies composed of shore and shallow lake and braided delta front and 3 microfacies composed of lacustrine swamp, subaqueous distributary channel and interdistributary bay were recognized, and it is found that oil sand beds are mainly developed in the subaqueous distributary channel sand bodies, with a high oil content of 9.62%， the average porosity of oil sands of 28.6%, and the average permeability of 65.3×10-3μm 2. In Badaowan Formation, 3 sedimentary subfacies were recognized, i.e., riverbed, bank and alluvial flat deposit of braided river, with 5 microfacies, namely, channel lag, mid-channel bar, natural levee, alluvial flat and back swamps. The oil sand beds are mainly developed in the mid-channel bar sand bodies of braided river, with an oil content of 5.8%, the average porosity of oil sands of 31%, and the average permeability of 2602×10-3μm2. It is thus concluded that oil sand beds in Tuziakeneigou have good reservoir quality and oil-bearing property. Group composition of oil sand beds is mainly non-hydrocarbon and asphaltite, with only a small amount of saturated hydrocarbon and aromatic hydrocarbon, reflecting the serious degradation of oil sands.

Abstract:Viewed from sedimentary records, the uplift and deformation in the southeastern margin of Sichuan basin occurred later than late Jurassic. Prior to this event, there existed a favorable petroleum geological conditions resulting in large scale hydrocarbon accumulation in this area. However, hydrocarbon accumulation was destroyed and adjusted by uplift and deformation of the sedimentary sequence. It is of great significance to determine the time limit of uplift and analyze its effect on hydrocarbon accumulation. Based on apatite fission track analysis of eight samples from different strata in the southeastern margin of Sichuan basin, the authors confirmed the Mesozoic-Cenozoic uplifting time limit and discussed its tectonic and petroleum geological significance. The apatite track lengths are distributed mostly in the single peak form, with a few in the double-peak form. The mean track length is between 10 μm and 13 μm, and standard error is between 1.5 μm and 2.5 μm. The distribution characteristics of fission tracks suggest that the samples have experienced a slow cooling process. The thermal history simulation results show that all the samples have not experienced obvious subsidence since they entered the partial annealing zone. Almost all the samples have experienced three uplift periods, i.e., fast uplift in the early period, gentle uplift in the middle period and fast uplift in the late period, with the uplift time being different in different areas. The first uplift period in the southeastern margin of Sichuan basin occurred at about 90～60 Ma, and the arrival at the margin of the basin occurred at 40～35 Ma after northward transmission. Almost all of the samples experienced fast uplift events in late Cenozoic, and the time limit of them are within 10 Ma, with most of them being younger than 5 Ma and a few of them younger than 2 Ma. From the angle of plate tectonics, the uplift of this area in Himalayan period was related to the uplift of Tibet. From the angel of petroleum geology, the intense uplifting in the southeastern margin of Sichuan basin might have on the one hand destroyed the existent gas accumulations but on the other hand created favorable conditions for the formation of fractured gas accumulations and water-soluble gas accumulations.

Abstract:The mineralogical characteristics of garnets from Xinditaga Group, Kuruk Tag, Xinjiang, have been rarely discussed by former researchers. In this paper, the mineralogical features of the red garnets produced in this area were investigated by using hydrostatic methods, refractometer, spectroscope, electron microprobe analysis and X-ray powder diffraction analysis. The crystal forms of garnets are mainly rhombic dodecahedron, icositetrahedron and their combination form. The garnets are bright red to dark red in color, and have abundant fractures and internal crystal inclusions, causing the tremendous decrease of the hosts' transparency. The relatively light elements Ca2+, Mg2+ and Mn2+ substitute for Fe2+ so that the density of the garnets is lower than the average value of almandine. The strong bands in optical spectra of almandine indicate that Mg2+ rarely replaces Fe2+. With regard to garnets formed in different metamorphic stages, the results of EPMA show that from the garnet's core to rim, the amount of almandine end-member tends to increase, namely the mole fractions of the almandine end-members of samples Garnet 1, Garnet 2, Garnet 3 and Garnet 4 are 63.906%～72.408%, 65.663%～71.880%, 64.689%～71.711% and 50.011%～71.780% respectively. Moreover, the content of spessartine end-member shows a trend of decrease from the garnet's core to rim, that is, the mole fractions of spessartine end-members of samples Garnet1 to Garnet4 are 23.417%～12.900%, 20.211%～12.258%, 21.124%～13.297% and 41.943%～18.523% respectively. In addition, the pyrope end-member increases in content from core to rim in which the mole fractions from sample Garnet1 to sample Garnet4 are 8.963%～11.880%, 10.200%～12.681%, 11.170%～12.500% and 5.411%～7.302%. However, the calcium series of garnets are relatively low in amount and relatively stable. The calcium series consists of grossularite, andradite and uvarovite, in which the mole fractions from sample Garnet1 to sample Garnet4 are 2.662%～4.320%, 3.066%～3.695%, 2.484%～3.406% and 2.395%～4.222%. The chemical composition of garnets acts as an indicator of the metamorphic grade, namely the contentof Fe2+, Mg2+ increases and that of Mn2+, Ca2+ decreases as metamorphism progressed. The content of spessartine end-member in garnet is higher in lower metamorphic grade, and with the increase of metamorphic grade, the stability of Mn2+ becomes lower, due to which the amount of Mn2+ decreases under the increasing pressure, Fe2+ substitutes for Mn2+ by entering the crystal structure of the garnet, due to which the amount of almandine increases subsequently. The content of pyrope end-member in garnets contained in metamorphic rocks indicates a higher metamorphic temperature. The content of calcium series garnet end-member reflects the forming pressure of a garnet. This suggests that the formation temperature generally increases from core to rim, implying that the metamorphic grade is getting higher; however, the pressure remains basically stable. X-ray powder diffraction analyses show that almandine and a small amount of quartz are contained in the garnet specimens. The refined cell parameter is 1.1535 nm and the standard deviation is 0.00048, which is within the numbers 0.0001 and 0.0099. The cell parameter is higher than that of the theoretical value 1.1526 nm, because there are more larger ions like Ca2+, Mn2+ than smaller ions like Mg2+ in replacing Fe2+.

Abstract:The Mandaleke ophiolite belongs to the late Paleozoic ophiolite belt i n South Tianshan Mountains and is composed of serpentinized peridotites, basalts and radiolarian cherts. The chromite or Cr-spinel occurs in the serpentinized p eridotites as a ubiquitous accessory mineral, some of which has the podiform tex ture. Petrographic observation and electron microprobe analysis indicate that th e Cr-spinel grains display obvious composition zoning, suggesting the path of su ch thermal events as crystallization, upwelling and alteration. The core of the Cr-spinel crystal represents the provenance where the mineral crystallized. The authors thus chose cores of the Cr-spinel to trace the nature of the mantle and the whole crystals to deduce the thermal events that the host rocks have experie nced. On the basis of olivine_spinel geothermometry, the crystallized temperatur e of the anhedral core is estimated to be from 1359℃ to 1394℃, 1379℃ on average. Similarly, according to the Cr-spinel geobarometer, the mantle pressur e i s estimated to be from 2.76 GPa to 3.00 GPa, 2.87 GPa on average, while the oxygen fugacity relative to FMQ buffer is FMQ-1.50～ FMQ-2.92 log units, FMQ-2.14 log units on average. Furthermore, the degree of partial melting of the man tle is estimated to be from 16.7% to 18.0%, 17.3% on average, in the light of its relationship with Cr#. These parameters provide some clues of the physi cochemical conditions: these peridotites were derived from garnet lherzolites lo cated in the asthenosphere of the upper mantle, and the incompatible element-dep leted mantle might have resulted from previous partial melting. The tectono-disc rimination diagrams imply that the Mandaleke ophiolite was formed in a fore-arc setting. The compo sitional zoning suggests that the peridotites have undergone a thermal path of d ecreasing temperature and increasing oxygen fugacity. It can be inferred that the mantle peridotites experienced the process from a high temperature and high pr essure mantle (lower oxygen fugacity) stage to a thrusting slice stage to reach the crustal surface, where they were subjected to regional metamorphism (higher oxygen fugacity).

Abstract:Glauconite is closely linked to some particular sedimentary environments and conditions. Authigenic glauconite grains were discovered in micritic limestones of 3rd Member of the Late Carboniferous-Early Permian Amushan Formation in Xi Ujimqin Banner, Inner Mongolia. Through analyzing the sedimentary environment of Amushan Formation, the authors have found that the glauconite grains commonly occur as colloids around calcite cement and assume granular structure, which are indicative of typical authigenic feature, suggesting that the glauconite grains were less influenced by later diagenesis. There are framboidal pyrites around glauconite grains, implying that the sedimentary environment of glauconite grains in Amushan Formation was probably weakly reductive. The spectral curve of glauconite in limestone of Amushan Formation demonstrates typical glauconite composition characteristics. The EPMA data indicate that they are highly mature in nature. Through a comparative study of EPMA data of glauconite samples collected from different areas and different environments (such as Cambrian glauconitic limestone in Texas of the USA, glauconitic sandstone of the Late Proterozoic Qingbaikou System in Western Hills of Beijing, authigenic glauconite grains form Cretaceous sandstone in Jixi basin of Heilongjiang, and authigenic glauconite grains from micritic limestones in Late Carboniferous-Early Permian Amushan Formation of west Ujimqin, Inner Mongolia), an ideal glauconite sedimentary environment model has been established in this paper, which shows that the authigenic glauconite grains in Amushan Formation might have benefited from the semi-closed reductive microenvironment produced by the biological clastic rock at the top of the open clastic platform and the glauconitization probably occurred in the normal shallow water of slight reduction with low-oxygen levels in the air. The sedimentary environment of the low clastic rock and upper limestone of Amushan Formation in this area was characterized by two transgressions and two regressions. The formation of glauconite in Amushan Formation may represent the beginning of the transgression. The discovery and study of glauconite in this area have an important significance in such research fields as regional correlation, tectonic evolutionary framework and regional tectonic environmental analysis.

Abstract:The medium-sized Wutubulake iron deposit in the eastern extension of the Altay ore belt within Xinjiang is hosted in the metamorphosed volcaniclastic-sedimentary sequence of the Upper Silurian-Lower Devonian Kangbutiebao Formation. The ore bodies in the ore deposit occur as stratoids or lenses, surrounded by skars minerals. Skarn minerals include garnet, chinopyoxene, scapolite, albite, actinolite, epidote, chlorite, apatite etc. whereas ore minerals are mainly magnetite, with minor pyrite, chalcopyrite, pyrrhotite, molybdentite etc. Field evidence and petrographic observation indicate four stages of metallogenesis, i.e., prograde stage, retrograde stage, sulfide stage and supergene stage. Electron microprobe analyses show that the end member of garnet is mainly andradite, with the calculated end number dominated by andradite (And: 72.89%～84.09%, 78.44% on average), followed by almandite (Alm: 8.23%～12.86%) and grossularite (Gro: 3.47%～14.97%), both of which are less than 20%. The composition of pyroxene is mainly diopside, with a small amount of augite. The end member of diopside is dominated by wollastonite (Wo: 43.48%～45.84%), followed by enstatite (En: 27.02%～34.14%) and ferrosilite (Fs: 18.72%～25.56%). The amphiboles show insignificant compositional variation, mostly being ferrotschermakite. The composition of these skarn minerals suggest that skarn in the Wutubulake iron deposit is calcic skarn, belonging to metasomatic skarn. The epidote is rich in Al and Ca but poor in Fe and Ti, indicating that Fe and Ti were separated out at the same time of the formation of epidote. Electron microprobe analyses show that the composition of magnetite is mainly FeOT (91.17%～93.63%), and most magnetite has similar chondrite_normalized rare earth element distribution patterns and is enriched in light rare earth elements, with an obvious Eu positive anomaly, which is similar to the rare earth element distribution patterns of skarns in this area. The Ni/Co values of magnetite range from 0.15 to 4.29, but most of them are lower than 1.0. All of these characteristics suggest that the formation of magnetite was closely related to the skarns. The above mineralogical characteristics are similar to things of minerals in typical metasomatic skarn iron deposits, implying that the Wutubulake iron deposit is a metasomatic skarn iron deposit. In combination with the geological characteristics, the authors hold that the skarns might have resulted form hydrothermal interaction with metamorphic volcanic and carbonate beds and lenses, and the formation of magnetite was related to the retrogressive metamorphism of the skarns.

Abstract:There are abundant rare metals such as Li, Nb, Ta, Rb, Cs and Be in granitic pegmatites of Lushi County, Henan Province. The paragenetic minerals include spodumene, lepidolite, elbaite, quartz, feldspar, muscovite etc. The proved reserves of spodumene are highest in these minerals. The authors made a systematic study of mineralogical characteristics of spodumene from Guanpo pegmatites in Henan Province by such means as hand specimen and microscopic observation, X-ray powder diffraction（XRD）, Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence analysis and ICP-MS. According to hand specimen and microscopic observation, the main mineral compositions of spodumene-bearing granitic pegmatites are spodumene, quartz, feldspar and muscovite. The average content of spodumene is about 40% in the pegmatite ore. Spodumene commonly occurs as coarse pillar and flaky crystals. There are relatively fine-grained garnet, tantalite and pyrite in pegmatitese. X-ray powder diffraction and infrared spectroscopic analyses show that spodumene is in a good crystallization condition with less impurities. Infrared spectroscopic data of samples show some deviations in comparison from standard data of spodumene. These deviations mainly suggest that Li—O vibration shifts to high wave（466 cm-1, 472 cm-1）, and AlⅥ—O bending vibration （588 cm-1, 585 cm-1）and AlⅥ—O elastic vibration（637 cm-1, 639 cm-1）shift to low wave. The reason of producing deviation lies in isomorphous substitution in crystal lattice of spodumene with substituting Na+, K+, Ca2+ for Li+ or substituting Mg2+, Fe2+, Mn2+ for Al3+. Lithium content is high in the spodumene, as shown by the analysis of trace elements. The content of Li2O in spodumene is 6.56%～6.82%. X-ray fluorescence analyses show that there are isomorphous substitution in crystal lattice of spodumene, with substituting Na+, K+, Ca2+ for Li+. There are negative abnormal phenomena of europium (Eu) in the spodumene, as shown by analyzing chondrite-normalized REE patterns of spodumene from Guanpo. Regional geological geomorphology of this area shows that spodumene was crystallized later than plagioclase in the course of magmatic differentiation. The production of Eu anomaly is related to plagioclase crystallization in magmatites. Different minerals have different REE distribution coefficients. Plagioclase has much stronger distribution coefficient to Eu than to other REE. Eu anomaly was formed in the course of magmatic differentiation with plagioclase crystallization. Spodumene crystallization occurred later than plagioclase crystallization. The research results show the content of Li2O in spodumene has reached industrial grade. Spodumene is an important ore material for lithium exploration in this area.

Abstract:The electrostatic self-assembly method (ESAM method) was used to prepare natural clinoptilolite supported-nano titanium dioxide photocatalysts with the purpose of immobilizing nano titanium dioxide and improving the photocatalytic efficiency of the photocatalysts. (OCH3)3Si(CH2)3SH silane was modified on natural clinoptilolite by dry process. Sulfhydryl group (—SH) of the silane was then oxidized to electronegative sulfonic acid group (—SO3H) by 30% H2O2/HOAc oxidant. On the effect of electrostatic interaction, the electronegative clinoptilolite was self-assembled together with titanium polycation to form clinoptilolite-titanium dioxide compound. The natural clinoptilolite supported-nano titanium dioxide photocatalysts were obtained after the calcinations of the above samples at a certain temperature. The materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Methyl orange (MO) was used to estimate the adsorption and photocatalysis of the materials. The results show that the anatase begin to transform to rutile when the calcination temperature is above 600℃. Nano titanium dioxide is evenly distributed on the surface and in the pores of natural clinoptilolite. The materials exhibit a synergistic effect of adsorption and photocatalysis on methyl orange. The decoloration rate of MO solution catalyzed by samples calcined at 200℃ reaches 79.36% after illumination for 1 h. The material prepared by the ESAM method exhibits higher photocatalytic activity than that prepared by the traditional method.

Abstract:Clay minerals have such main types as illite, chlorite, smectite and kaolinite. They could record rich information of climatic and environmental changes during their formation and hence are good proxies in climatic and environmental study. Many factors such as tectonic movement, climate, basin size, surface parent rocks, soils, vegetative cover, landscape, water media properties, wind and diagenesis, affect the clay mineral formation. The types and quantity of clay minerals in strata depend on these factors in varying degrees. Tectonic movement and climate are two primary factors which dominate the types and quantity and control other secondary factors which influence clay mineral formation. It is very difficult and unsuitable to analyze climatic and environmental changes during the tectonic movement phase only by clay minerals. For a long geological time which has tectonic movement, sedimentary facies and palaeogeography must be used to decipher paleogeography and plaeo-environment information. However, under stable tectonic movement, which spans usually a short geological time, other information factors keep stable and clay minerals are formed mainly through climatic factors. They record the real information of climate and environment changes and hence can be used as climatic proxies. Basin change of climate and environment could be inverted. So, climate is the key factor for forming clay minerals and determining their amounts. Strata-tectonic analysis must be done when clay minerals are used to decipher climatic and environmental information. In a word, when tectonic movement is stable, climate becomes the dominate factor affecting clay mineral formation. The other secondary factors keep invariant and clay minerals carry the major climatic information，and they can be used to decipher climatic and environmental history. The mixture of clay minerals caused by ground hydrographic systems affects the signal clearness of clay minerals carrying major climatic information and environments. Sedimentary-buried diagenesis of clay minerals in strata shouldn't be ignored in analysis.

Abstract:China has very rich resources of anhydrite, and anhydrite resources only in Hanshan of Anhui Province has reached 60 million tons. The development of natural anhydrite as a binding material has important research value in developing low carbon economy and energy conservation. The composition, structure and hydration hardening performance of natural anhydrite were analyzed in this paper. The activity and improvement of the activity of natural anhydrite by adding different activators were studied. Hydrous mechanisms of natural anhydrite were also analyzed. Taking natural anhydrite (Ⅱ type anhydrous gypsum) produced by Hanshan County of Anhui Province as the major raw material, the influences of five kinds of chemical activators（K2SO4, FeSO4·7 H2O, CaO, Na2C2O4 and calcined alum） on the hydration property of natural anhydrite were investigated. The hydration rates of anhydrite with different contents were detected using the gravimetric method. The composition and microstructure of hydrated products of natural anhydrite were characterized by XRD and SEM. The activated mechanism of hydration activity of natural anhydrite was further discussed. The experimental results indicate that the chemical activator the authors used could obviously promote the hydration rate of natural anhydrite, and the crystal microstructure of the hydration and hardened body was also notably improved after doping activator. The natural anhydrate mixed with 5.0% calcined alum had very good activating action on hydraion. 28 days later, the hydration rate reached 74.32%.

Abstract:This paper studied the mineralogical characteristics of kaolin from Longyan by means of chemical analysis, mineral examination, SEM, XRD, IR and DTA-TG. It is shown that the content of Al2O3 and SiO2 is very close to the theoretical value, with tiny content of Fe and Ti. The content of K2O is higher because of residual mica. The results also show that Longyan kaolin is made up of kaolinite with minor mica and a very small amount of quartz, and its natural whiteness varies from 83% to 92%. The SEM photographs of Longyan kaolin show clear layer structure 0.1～5 μm in size, and a small amount of rod-shaped kaolinite. The laser particle size analyzer measurement results of Longyan kaolinite shows that 83.2% particles are between 1.00 and 5.00 μm in size, with an average of 3.16 μm. The main bands of XRD pattern of Longyan kaolinite are 1.004 nm， 0.722 nm，0.447 nm，0.359 nm，0.335 nm，0.257 nm，0.250 nm and 0.235 nm. A comparison with the standard spectrum shows that kaolin is the main mineral component of Longyan kaolin. The 1.004 nm band is attributed to halloysite or mica. Combined with SEM results, these data indicate that Longyan kaolinite contains small amounts of halloysite, and the 0.335 nm band is attributed to quartz. Its lower crystallinity index (HI=0.42) suggests that Longyan kaolinite is a relatively disordered kaolinite. FT-IR spectra imply that the functional groups of kaolinite layer structure remain perfect, but the intensity of 3695.39 cm-1 band (inner surface hydroxyl stretching vibration) is 1.10 times that of 3620.26 cm-1 band (inner hydroxyl stretching vibration), which indicates that the crystallinity of Longyan kaolinite is relatively low. TG results show that the weighloss at 100～800℃ is 11.33%, almost equal to the theoretical water content (10.8%). This also proves that the content of impurities of Longyan kaolinite is tiny. In the present experiments, the Kln-KAc intercalates were investigated to study the relationship between the microstructure and the intercalation. XRD data show that potassium acetate could directly insert between the inner layers of kaolinite. As a result, the c-axis spacing (d001) of Kln-KAc intercalation composite increased from 0.7223 nm to 1.3929 nm of kaolinite, and the intercalation rate could reach over 90%. There were four new bands, 1605.22 cm-1, 1566.33 cm-1, 1416.57 cm-1 and 1344.99 cm-1, on the FT-IR spectrum of Kln-KAc, which indicated that potassium acetate inserted the inner layers of kaolinite. IR analysis showed that the band of inner surface hydroxyl and inner hydroxyl stretching vibration became greatly weaker, and moved towards low wavelength. Synchronously, the appearance of the band at 3604.68 cm-1 was corresponding to the hydrogen bond formed between acetate ions and the inner surface hydroxyl of kaolinite. DTA curves of Kln-KAc indicate the endothermic peak was at 562.05℃, which was attributed to the fact that dehydroxylation became obviously weaker. These data indicated that the microstructure of hydroxyl was destroyed to a certain extent because of the insert of acetate ions. These results indicate that acetate ions insert between the inner layers of kaolinite under the participation of water, and different intensities and types of hydrogen bonds exist between acetate ions and the inner surface hydroxyl of kaolinite.

Abstract:Using classical gemological methods, UV-Vis-NIR, FTIR, LA-Raman spectra, cathode luminescence images, and LA-ICP-MS gemological properties, this paper systematically studied spectroscopic features, melt inclusions, trace elements and U-Pb radioactive ages of gem-quality zircon megacrysts found in alluvia of Tertiary alkali basalt deposits associated with Cenozoic basalts from Muling in Heilongjiang Province, which are distributed along the middle-northern section of Dunhua-Mishan fault, the northern branch of Tanlu fault between Xing-Meng orogenic belt and Pacific subduction zone. These normal zircons are generally colorless to reddish brown, transparent to semitransparent, and some of them are up to 17 mm long with euhedral to subhedral shapes which have clear surface melting features. Refractive indexes are higher than 1.78 and SG values vary from 4.7 to4.9. The tetragonal prism and bipyramid constitute the most developed crystal forms. According to the classifica-tion of gem-quality of zircons, these samples are superior quality gemological material which can be used directly. The polarized UV-Vis absorption spectral analysis shows that the coloration mechanism of the zircon megacrysts are attributed to REE f-f and V4+ d-d charge transitions. Raman and IR spectral features confirm the viewpoint that these zircon megacrysts have undergone low extent of radiation damage and contain common melt inclusions of apatite, zircon and hematite. However, zircon megacrysts display obvious oscillatory zoning in CL images typical of igneous zircon, which suggests that they were crystallized from a melt or fluid surroundings. LA-ICP-MS analysis shows that they have distinct positive Ce anomalies and negative Eu anomalies, and are enrichedin P, HREEs and HFSEs; most of Th/U ratios are higher than 1 with one exception, and (Yb/Sm)N ratios are 21～63. ΣREE concentrations vary from 1765×10-6 to 2374×10-6, and are much higher than those in kimberlitic zircons but similar to things of zircons from basic igneous rocks. In general, the shapes and trends of their REE patterns are similar to those of zircons from such areas of eastern China as Wenchang in Hainan Province, Mingxi in Fujian Province, and Changle in Shandong Province as well as to things of other zircon megacrysts associated with Cenozoic alkali basalts all over the world in spite of different absolute REE concentrations, thus suggesting similar origins. Pronounced positive Ce anomalies, negligible Eu anomalies and magnetite inclusions suggest crystallization from relatively oxidized conditions. Uptake of titanium in zircon is sensitive to temperature. In situ titanium analysis shows that model Ti-in-zircon temperatures at TiO2 and SiO2 activities=1 range from 646 to 737℃. The weight mean of the remaining six points yields a U-Pb age of 9.39±0.4 Ma(MSWD=0.22) , which is interpreted as the crystallization age of these zircon megacrysts. Based on this study in combination with data obtained by other authors, the authors hold that Muling Cenozoic alkali basalt-related megacryst zircons might have originated from depleted metasomatized lithospheric mantle related to the oxidization conditions of CO2 fluid enrichment and resulted from retrogression of lithospheric thinning.

Abstract:Lantian Jade is one of the most famous jades in Chinese history， but there still exists controversy among researchers in recognition of the difference between modern Lantian Jade and ancient Lantian Jade, and hence the research on mineralogical characteristics of modern Lantian Jade is of great importance in the archaeological study of Lantian Jade. In this paper, the techniques of proton induced X-ray emission (PIXE), X-ray diffraction (XRD) and laser Raman spectroscopy (LRS) were employed to analyze the chemical composition and mineral structure of modern Lantian Jade from Shaanxi Province. The proportions of several samples were estimated. The results indicate that the specimens can be divided into two kinds. The major mineral of the first kind is serpentine, the major mineral of most specimens is antigorite whose Raman characteristic peaks occur at 231, 373, 458, 527, 648, 681 and 1045 cm-1, and the formula of specimen LT2 is Na0.30(Mg5.08, Al0.14, Fe0.26)(Si4.06O10)(OH)8. However, one of the specimens belongs to lizardite whose Raman characteristic peaks occur at 226, 344, 379, 462, 623, 690 and 1098 cm-1, with lizardite being found in Lantian Jade for the first time. The major minerals of the second kind are serpentine, calcite or augite, together with minor dolomite, talc and tremolite. The formation mechanism of Lantian Jade seemed to be regional metamorphism together with contact metasomatic metamorphism. The formation process is as follows: dolomitic marble generated low temperature metamorphic mineral serpentine by magmatic hydrothermal metasomatism at low temperature, with two kinds of specimens corresponding to different serpentinization levels. There are no other minerals in the first kind, because the calcium was moved away by hydrothermal SiO2. The existence of dolomite and calcite in the second kind suggests incomplete serpentinization. In trace elements, the content of Mn, Zn and Zr is higher than that of other rocks. Both Lantian Jade and Xiuyan Jade belong to serpentine jade, but they can't be distinguished from each other by available technologies. These characteristics can provide useful data for the study of archaeology and civilization of Lantian Jade.

Abstract:Quartz, one of the most abundant minerals in the earth crust and also a very important mineral, occurs in large quantities in igneous, sedimentary and metamorphic rocks as well as in some hydrothermal systems. Petrogenesis, oxygen-isotope and trace element geochemistry, physical properties and defect microstructures of quartz and chalcedony have been studied by mineralogists and geologists in the past two decades, but some related problems are still in controversy. Due to wide distribution and highly stable nature of quartz, a variety of petrologic, isotopic and geochemical provenance techniques have been developed over the past two decades to study the provenance of detrital quartz. Integrated scanning electron microscope CL, electron microprobe CL and optical microscopy analysis of single quartz grains are fairly simple and inexpensive techniques and are efficient methods for visualizing microtextures in minerals that are invisible in conventional transmitted-bight microscopy. Quartz cathodoluminescene is commonly applied to decipher complex histories of geological process; however, the causes of quartz cathodoluminescence remain poorly understood, which may involve the variations in trace element concentrations in quartz. Different mechanisms of trace element uptake into the quartz lattice are discussed. For example, some trace elements in quartz may generally be incorporated into the crystal structure or bound in microinclusions (fluid mineral inclusions), and only a small amount of "foreign" elements can be incorporated into the crystal lattice; the substitutional incorporation of Al, Ge, Ti, Ga, Fe, H and P into Si position is well established. Cathodoluminescene may help establish the succession of paragenetic associations in minerals and a wide variety of rocks, such as growth zoning, randomly oriented microcracks and healed microfractures, homogeneous patchy or mottled CL, deformed lamelae, grain shattering and dissolution or alteration features. The distinguishable characteristics among volcanic rock, pluton, sedimentation, metamorphism and quartz in veins are systematically summarized on the basis of the authors' recent research and literature reviews. The relationship between trace element geochemistry, cathodoluminescence texture and characteristics of cathodoluminescence are discussed. In the end of this paper, the authors attempt to provide a flow chart to illustrate theidentification of various kinds of quartz in nature.