Abstract:The Beiling gold deposit, located in western Henan Province, is mainly hosted in the Majiahe Formation. The rocks are composed of basaltic andesites and andesties. In this paper, the petrological and geochemical characteristics of the volcanic rocks were studied to constrain the petrogenesis. The result shows that the volcanic rocks of the Majiahe Formation are rich in alkali, especially in K₂O. The mafic-intermediate rocks are characterized by a relatively low abundance. Their total amount of rare earth elements (ΣREE) is 154.60×10^-6~200.60×10^-6. They forms a LREE-enriched distribution[(La/Yb)_N=6.72~8.22] with the existence of weak negative Eu anomaly. In addition, the rocks display LILE enrichment (such as U, K, Pb and Nd) and HFSE depletion (such as Th, Nb, Ta, Ce, Zr and Ti). The chemical data presented in the paper show that the Majiahe Formation rocks had a modified mantle source with ancient subduction belt materials. It is suggested that these volcanic rocks experienced a crystal fractionation process during the magmatic evolution. Comprehensive research shows that the Majiahe Formation was formed under a continental rifting environment.

Abstract:The Zhaojinggou Nb-Ta deposit has close relationship with granite. Zircon LA-ICP-MS U-Pb dating indicates that the age of biotite K-feldspar granite in the mining area is 125±1 Ma. Geochemical data show that the Late Palaeozoic magmatic rock is characterized by metaluminous alkaline rock, high potassium and alkali, enrichment of LREE with strong negative Eu anomaly and enrichment of LILE (Rb, Th and U), and strong negative anomalies of Hf and Y in primitive mantle-normalized spidergrams. It thus belongs to A1 subtype of A type granites, and has ¹⁷⁶Hf/¹⁷⁷Hf ratios in the range of 0.000 5~0.003 0, εHf(t) values in the range of -15.42~-5.55 and corresponding model ages (t_DM2) between 2 247 and 1 640 Ma. Granite was formed in a post-orogenic setting, mainly derived from the partial melting of crustal materials.

Abstract:The Dahutang tungsten-copper deposit, located in the east of the Jiuling polymetallic ore concentration area of Jiangnan orogenic belt, is one of the largest tungsten deposits in the world. The Yanshanian granites in this area have various lithologies, and there are still disputes and deficiencies in the study of magmatic succession and source characteristics. Two phases of porphyritic granitic magmatism have been found in this area, which are por-phyry biotite-like granite (150.0 Ma) in Shimensi (northern area) and porphyry muscovite-like granite (144.2 Ma) in Shiweidong (southern area). The authors discovered porphyritic two-mica granite in the southern area and carried out detailed U-Pb dating of monazite and zircon as well as petrogeochemical and Hf isotopic study of zircon. The crystallization ages of zircons and monazites are 130.0~128.6 Ma and 128.3 Ma, respectively, indicating that the porphyritic two-mica granite in the southern area was formed in the early Cretaceous and resulted from the third stage porphyritic magmatism in this area. Petrogeochemical characteristics show that the third stage porphyry-like granites are S-type granites with high potassium as well as calc-alkaline content and the second stage porphyry-like granites in the southern area have similar geochemical characteristics. The peraluminous degree of porphyritic granite in southern area (A/CNK=1.16~1.24) is higher than that of the northern area. The total REE content of rocks in the south and north areas are low, and there are obvious negative Eu anomalies. The fractionation of light and heavy rare earth elements in the north area[(La/Yb)_N=11.17~26.67]is more significant than that in the south area[(La/Yb)_N=7.72~19.0]. The values of εHf(t) in the southern and northern sections are -7.31~0.58 and -8.6~-3.1 respectively, indicating that porphyry granites were mainly derived from the remelting of the ancient lower crust, with the addition of a small amount of new materials. The lower CaO/Na₂O ratio indicates that the source rock of the Shiweidong porphyry granite is more muddy than that of the Shimensi. Comprehensive research shows that the porphyritic granite in the south and north of Dahutang is the product of at least three stages of magmatism, which was formed by evolution after the partial melting of the muddy or argillaceous sandstones in the Shuangqiaoshan Group in the post-orogenic extension environment. This study enriches and improves the magmatic sequence and genetic significance of porphyritic granites in the Dahutang area.

Abstract:With the progress in the research on global volcanoes, geologists have discovered volcanoes of Maars type with special genesis in most volcanic groups. Maars, characterized by low-relief, broad volcanic crater and low flat cone, are mainly composed of base surges with climbing bedding, parallel bedding, large low-angle cross-bedding and some other structures, thus being an important object for studying the evolution process of volcanic eruption. Many Maars with typical base surges have recently been discovered from Nuominhe, Arshan-Chaihe and Abaga volcanic clusters in eastern Inner Mongolia. Based on comprehensive field survey and available researches both in China and aboard, the authors summarized the geological features of the late Quaternary Maars in eastern Inner Mongolia by theories of volcanology and volcanic geology, including their distribution, products and typical structures. The activity of the volcano is divided into three stages:phreatomagmatic eruption stage dominated by base surges, magma eruption stage represented by fall-spatter deposits, and magma overflow stage with alkaline olivine basalt. These composite volcanoes were active in the late Pleistocene, whereas the Maars mainly erupted at early to middle stage stated above. The unique strata, volcanic product and regional tectonic structure all indicate that phreatomagmatic eruption was generated at the shallow depth. Based on the discussion of the genetic mechanism and evolution simulation, the authors infer that there exists an inherited relationship between Maars and other volcanoes, such as Strombolian and Hawaiian.

Abstract:The rare earth elements characteristics of detrital zircons and the U-Pb age of detrital zircons of fine-grained sandstone from Fengping Formation were investigated by the LA-ICP-MS analytical technique. The detrital zircons have a good oscillatory zones and Th/U ratios of most zircons are higher than 0.1, indicating that they are of magmatic origin. The content of REE varies in a large range. The ratios of(La/Yb)_N (0~0.29) and LREE/HREE (0.003×10^-6~0.977×10^-6) show the relative enrichment of HREE. The distribution pattern of rare earth elements in detrital zircons exhibits mainly low content of LREE and high content of HREE as well as Eu negative anomaly and Ce positive anomaly. The result shows that the majority of zircons originated from magmatic source, whereas some other zircons originated from metamorphic activity. The youngest U-Pb age of detrital zircon is 193 Ma, indicating that its diagenetic age is not later than 193 Ma. The data suggest that zircons are mainly composed of 4 age stages, including 2 461~1 743 Ma, 887 Ma, 435 and 422 Ma, 330~193 Ma, respectively, corresponding to the known tectonic-magmatic thermal events (Lüliang Movement, Jinning Movement, Caledonian Movement, Indosinian-Hercynian Movement). The result reveals that the tectonic magmatism in this area is consistent with the tectonic activity in China, and it has the characteristics of continuous development. Through the systematic analysis of the U-Pb dating data of detrital zircons from the sedimentary rock of Fengping Formation and chronology of possible provenances, it is shown that the materials for sedimentation was from surrounding rock mass of Zhongtiao Movement and the Indosinian granite body in southeastern Zhejiang.

Abstract:The reservoir features, organic geochemical characteristics and gas-bearing property of the shale from Jianshi area in western Hubei Province were studied, and the factors associated with gas content of the shale were preliminary discussed. Some conclusions have been reached:① Quartz and clay minerals seem to be the major minerals in the shale, the pores of the reservoir are mainly organic pores, mineral dissolution pores and intergranular pores, and the reservoirs are characterized by low porosity and ultra-low permeability with a rock porosity of 0.2%~4.5% and a permeability of 0.081 0×10^-3 μm²; ② They are high in organic matter and thermal evolution degree, and have an average TOC content of 7.63% and an average Ro value of 3.29%, with the organic matter belonging mainly to type Ⅱ; ③ The gas content of the shale is higher with an average of 1.32 m³/t, which exhibits a positive correlation with porosity, organic matter abundance and maturity, and a weak positive correlation with the content of clay minerals. The research on shale gas reservoir could provide certain reference for the subsequent shale gas exploration and development of Jianshi in western Hubei Province.

Abstract:The Longhupao uranium mineralization area, which is located in the north of Longhupao-Da'an terrace and adjacent to Taikang uplift and Western overlap in the west, is one of the important new achievements in northern Songliao Basin based on the secondary development and drilling verification of Daqing Oilfield wells. Based on detailed field work and using experimental means such as polarizing microscope, electron probe energy spectrum, backscattering, chemical analysis and distribution analysis of elements, the authors aimed to explore the relation-ship between the Fe-Ti oxides represented by ilmenite and sandstone-hosted uranium mineralization in Longhupao area. The study shows that the assemblage of altered minerals represented by U-rich Fe-Ti oxide-titanium oxide-pyrite has recorded the important information about ore-forming fluid and metallogenic environment in the process of sandstone-hosted uranium mineralization. The comparative analysis of different occurrences and assemblages for ilmenites and other altered minerals as U-rich Fe-Ti oxide, titanium oxide and pyrite reveals that the uranium mineralization in the Longhupao area was affected by the later oxidative fluid including U/Fe and the reductive fluid including H₂S, and the metallogenic environment was strongly reductive. These strongly altered and Mg-rich ilmenites were closely related to the uranium mineralization, and the U-rich Fe-Ti oxides were formed in the redox reaction between these altered ilmenites and the later ore-bearing fluid. The corrosion fissures in these altered ilmenites provided favorable space for further alteration by ore-bearing fluid and uranium precipitation. The altered ilmenite offered a profitable mineral-scale oxidation barrier, and the pyrite offered a reduction barrier for uranium precipitation. During the fluid mixing of ore-forming and H₂S-rich fluid, the uranium precipitated near the interface of reduction oxidation between altered ilmenites and pyrites.

Abstract:In this paper, the technological mineralogical characteristics of representative lead oxide ores in the Mawengen ore district of Qinghai Province were systematically studied by means of optical microscope identification, scanning electron microscope, X-ray energy spectrum probe and sieving analysis. The results show that the main valuable elements of ores are lead (2.76%) and silver (204.4×10^-6). The modes of occurrence of lead in ores are complex, mainly occurring in lead-iron jarosite and other insoluble lead, followed by lead oxide and lead sulfate. The lead minerals in ores are mainly lead jarosite, leucite and arsenopyrite, with a small amount of galena and arsenopyrite. The modes of occurrence of silver are more complex, and the independent silver mineral is sulfur-copper-silver ore, whose content is very small. Some silver isomorphism occurs in other metal sulfides. Through polarizing microscope and scanning electron microscope analysis, it is found that the main lead minerals such as lead jarosite and cerussite are seriously intergrown and fine-grained, which is consistent with the results of screening test. At the same time, the content of arsenic in ores is high, reaching 5.43%. The arsenic-bearing minerals, except arsenopyrite and scallion, underwent X-ray diffraction. Energy spectrum analysis shows that some lead minerals are closely related to arsenic, and complex arsenic-lead minerals such as arsenopyrite and arsenopyrite are formed. Therefore, it is predicted that arsenic will be enriched synchronously with lead minerals in the mineral processing. The independent silver minerals of silver are mainly pyrite, copper and silver minerals with fine dissemination size. Most of silver minerals occur in silicates or oxides such as quartz and limonite in the form of micro-particles. Based on the above research results, it can be concluded that the lead-silver oxide ore is very difficult to be separated. It is suggested that the flotation-chemical separation process should be adopted to recover lead and silver metals.

Abstract:Laos Northern Yellow Stone is bright yellow to dark brown in color, and the color distribution is uneven. Short thin turnip grains and wave-like texture are commonly seen. It has certain similarities with the appearance characteristics of Tian Huang in Chinese seal stone. In this paper, X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (LRM), scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and whole-iron chemical analysis were used to study the mineral composition and trace element characteristics of Laos Northern Yellow Stone. According to the results of X-ray powder diffraction test and FTIR test, Laos Northern Yellow Stone is usually composed of pure dickite, which is disordered dickite. The Raman spectroscopic test shows that other minerals contained in Laos Northern Yellow Stone include barite, anatase, diaspore and hematite, in the form of impure minerals. The micromorphology of Laos Northern Yellow Stone observed by SEM indicates that the dickite in Laos Northern Yellow Stone is arranged in plate shape with a flat and sharp edge as well as a smooth surface. The turnip vein is mainly in the form of dendritic and short veins in the substrate of Laos Northern Yellow Stone. EPMA test and whole-iron chemical analysis show that Fe³⁺ causes the yellow color of Laos Northern Yellow Stone. The iron ion content shows a trend from high to low with the color changing from dark to light. The trace elements content of Laos Northern Yellow Stone was test by LA-ICP-MS. The content of Cr, Rb and Sr in Laos Northern Yellow Stone is lower than that of Tian Huang, and the content of Ga is higher than that of Tian Huang. Discriminant analysis method can effectively distinguish these two groups of similar species from Laos and China respectively. The correctness rate of the unknown sample in Laos Northern Yellow Stone and Tian Huang can reach 92.9% and the reliability of the model is high. According to the rare earth element distribution pattern, it is easy to distinguish Laos Northern Yellow Stone from Tian Huang.

Abstract:Using FTIR, SEM and EDS, the authors systematically studied the mineral composition, micro-characteristics and the variation of chemical composition of the weathered layer of Changhua secondary dickite stone, which is usually called Changhua Tianhuang. The result indicates that the main mineral composition of the weathered layer is kaolinite-group minerals, consisting of some Fe, Ca, Mg-bearing accessory minerals. Compared with those of the inner layer, the mineral crystals of the surface weathered layer have a blurred boundary and shape, due to the dissolution and the filling of Fe-bearing minerals. The difference of micro-characteristics between inner and surface layer as well as the decreasing of Fe, Ca from weathered layer to unweathered layer demonstrates the weathered progress of the Changhua secondary dickite stone. The appearance of quartz in the weathered layer and the attachment of the Mn-bearing mineral can help identify the origin of Changhua and Shoushan Tianhuang stone.

Abstract:The high ammonia nitrogen wastewater in the landfill leachate RO concentrate contains high potassium and sodium ions, but the effect of potassium and sodium ions on the crystallization of struvite remains unknown. In this paper, the addition of magnesium salts and phosphates to the simulation of different potassium and sodium concentrations and the actual RO concentrate promotes the crystallization of struvite. The concentrations of ammonia nitrogen, phosphate, potassium and sodium ions in the solution before and after crystallization were determined. The structure and morphology of the crystallized products were analyzed by XRD and SEM. The effects of potassium and sodium ions on the crystallization and ammonia recovery of struvite were discussed. The results showed that, with the increase of potassium ion concentration, the ammonia nitrogen removal rate decreased from 96.5% to 83.0%, and the mass percentage of potassium ions in the precipitated product gradually increased from 2.4% to 6.4%. The characteristic peak of struvite is shifted to a high angle, indicating that potassium ions enter the lattice position of struvite and form a K-struvite; due to the competition between potassium ions and ammonium ions, the removal rate of ammonia nitrogen is reduced under the same magnesium, ammonia nitrogen and phosphorus ratio conditions. However, potassium ions have little effect on the crystal size and morphology of struvite. Sodium ion has no significant effect on ammonia nitrogen recovery, but it will affect the crystal morphology of struvite. Experiments with the actual landfill leachate RO concentrate show that the competition of potassium ions is considered in the water treatment of the recovery of ammonia nitrogen from struvite crystals, and the ratio of magnesium salt, ammonia nitrogen and phosphate is increased by 1.8:1:1.5. The recovery rate of ammonia nitrogen is ensured and, at the same time, the potassium ion is partially recovered as a nutrient component of the slow-release fertilizer.

Abstract:The effects of dissolution medium, liberation time, adsorption temperature and Fe³⁺ addition amount on the determination results were discussed in this paper. The best determination conditions were determined, and the role of Fe³⁺ in ore dissolution and adsorption was discussed in detail. A trace amount of valence gold was separated and adsorbed by polyurethane foam. Gold was directly determined by graphite furnace atomic absorption spectrometry with thiourea solution to remove gold. The method is suitable for the determination of trace valence gold in stream sediments, soil and rocks. The detection limit of the method is 0.01 ng/g, the determination range is 0.03~300 ng/g, the recovery rates of valence gold are Au³⁺97.3%, Au⁺95.8%, Au⁰ 98.9%, respectively, and the separation precision (RSD, n=12) of valence gold is 7.3%~18.8%. Determination of valence gold by graphite furnace atomic absorption spectrometry can not only effectively inhibit interference of coexisting elements, but also reduce detection limit and improve sensitivity and accuracy. Automatic sample introduction reduces labor intensity and improves analysis and testing efficiency, thus suitable for testing large quantities of samples.