Abstract:The Xiahe-Hezuo Mining area in Gansu Province is one of the important gold deposit dense areas in the West Qinling orogen.The Zaozigou gold deposit is the most famous giant gold deposit in this area.The veined intermediate to acid magmatic rocks are commonly developed in the Zaozigou gold mining area,which are closely related to mineralization.Based on the field investigation of the geological characteristics of the Zaozigou giant gold deposit,the electron microprobe analysis of the biotite was carried out on the veined intermediate to acid magmatic rocks in the mining area.The detailed results show that the FeO_t contents of biotites range from 19.71% to 29.84%,and the MgO contents range from 9.54% to 13.51%.They show the characteristics of both magnesian biotite and iron biotite.The crystallization temperatures of biotite are 776.61℃ to 799.65℃,the crystallization pressures range from 131 MPa to 283 MPa,and the oxygen fugacity lg f_O2 are-14.85 to-13.11.The biotites are characterized by high temperature,low pressure and relatively high oxygen fugacity.The geochemical composition characteristics of biotites show that the veined magmatic rocks in the Zaozigou gold deposit belongs to calc-alkaline granite,which is derived from mixed crust and mantle origin.The mineral chemical characteristics of biotite of the veined magmatic rocks of Zaozigou gold mine and the geological background revealed that the magmatism which the Zaozigou veined magmatic rocks represented contribute to the mineralization of the giant gold hydrothermal deposit.

Abstract:Provenance analysis is of great significance to the study of sedimentation,tectonic evolution and reservoir characteristics in an area.In order to find out the provenance characteristics of the Paleogene Gonjo Formation sandstones in Gonjo Basin,Tibet,this paper analyzes the characteristics of heavy mineral assemblages in the study area,and reveals the provenance direction of the Paleogene Gonjo Formation sandstones in the study area in combination with the previous data.It is believed that the provenance directions of Youzha,Xingda,Banna and other places are from southeast to northwest,and the provenance of Hajiaxiang is not only from the Youzha direction,but also from the adjacent Paleozoic and Triassic igneous rock units in the upper wall of the eastern thrust fault.The characteristics of heavy mineral assemblage and the indexes of ATi and GZi indicate that there are many types of genetic rocks in the provenance area of the Paleogene Gonjo Formation with different contents,mainly intermediate volcanic rocks and less sedimentary rocks.According to the facies mineral characteristics,it is judged that the Paleogene Gonjo Formation sandstone was formed in a shallow-water oxidation environment with different oxidation degree.The oxidation in the southeast is stronger than that in the northwest,the water in Banna is shallower than that in Youzha,and the oxidation degree is stronger.

Abstract:The Ediacaran Doushantuo Formation in South China was deposited in a key period of the transition from the original earth-life system to the modern earth-life system.This set of strata recorded the first large-scale phosphorus event in the Earth's history.However,there are still many controversies about the source of phosphorus.The phosphorus in the shallow sea area mainly comes from the riverine weathering products of phosphate minerals on the land surface and the upwelling deliver of phosphorus-bearing water-masses in other sea areas.These two sources can be distinguished by the content and distribution characteristics of whole rock detrital elements and rare earth elements.Based on the comprehensive analysis of the major and trace element of Doushantuo Formation in Xiangdangping and Sidouping sections in the upper Yangtze region,the provenance system and regional weathering have been recovered in this paper.The high correlation of P₂O₅-Al₂O₃ and P₂O₅-Fe₂O₃ indicates that the source of phosphorus is terrestrial weathering input rather than upwelling.The lower Th/Co,La/Sc,Th/Cr ratios,TiO₂-Zr correlation and ternary plots of (Th-Hf-Co and La-Th-Sc) indicate that the major source rock of Doushantuo Formation is basalt.The higher chemical alteration index (CIA) and the lower Sr/Cu ratio indicate that the provenance area was dominated by warm and humid climate at that time and experienced moderate chemical weathering.The big data analysis of phosphorus content in different types of volcanic rocks shows that the phosphorus content in mafic volcanic rocks is much higher than that of felsic volcanic rocks.Therefore,the relatively strong basalt weathering during the deposition of Doushantuo Formation greatly increased the phosphorus deposition flux and marine concentration of phosphorus in the shallow sea shelf area,which offered mass of phosphorus to widespread phosphorus burial,improved the circulation of phosphorus in early oceans,and promoted the global phosphorus event and the radiation of large metazoans.

Abstract:The Bayan Obo associated fluorite deposit in Inner Mongolia is a super-large deposit attracting worldwide attention,but the genesis of the deposit is still controversial.Based on the systematic study of the geological characteristics and the distribution of fluorite-bearing ores in the western Bayan Obo mine,the geochemical study of major,trace and rare earth elements of fluorite ore and ore-bearing H8 dolomite was carried out in this paper.The results show that the fluorite deposit in the west mine belongs to the dolomite-type ore.The REE characteristics of both fluorite and dolomite are relatively enriched in LREE and depleted in HREE.The REE distribution patterns of fluorite and dolomite have similar synchronization.The contents of Ba,Th,Sm and Ce in all samples are relatively high,especially the contents of Ba and Th are obviously high.The δEu values of fluorite ores in the mining area range from 0.93 to 1.14,with both positive and negative anomalies.The δCe values range from 1.15 to 2.11,with an average of 1.51,showing positive anomalies of Ce.Based on the geological characteristics of fluorite deposit,trace and rare earth elements and plots of (Y+La)-Y/La,Y/Ho-La/Ho and Tb/Ca-Tb/La,combined with previous studies on metallogenic fluid in fluorite,it is concluded that the associated fluorite deposit in the west Bayan Obo mine belongs to medium-high temperature,hydrothermal metasomatism type fluorite deposit.Different from typical sedimentary-reworked and hydrothermal filling fluorite deposits in China,the genesis of the deposit has nothing to do with intrusive granite,and the main ore-forming materials of F and Ca elements are derived from the metasomatism of early dolomite rocks by medium-high temperature fluids derived from Caledonian calcareous carbonate rocks.

Abstract:Paleoflood sediment is an important carrier to study extreme precipitation events and paleoenvironmental evolution in geological history.The study of paleoflood reconstruction based on geological records can provide basis for revealing the historical process and mechanism of regional flood,and has important practical significance for water resources utilization and engineering construction.In this paper,the Lidicheng village profile,which is well exposed on the north bank of the ancient channel of Caohe River,is taken as the research object.Based on the analysis of stratigraphic sequence,field sedimentary characteristics,sedimentary structure and sediment grain size,the ancient flood events recorded by the ancient channel of Caohe River in Baiyangdian area are identified.It is found that the profile has the following main characteristics:there are obvious scouring and erosion surfaces between the paleoflood sedimentary layers and the underlying strata,and the sedimentary body is lenticular in shape,which is composed of muddy gravel,charcoal fragments,bivalves and grayish black silt-fine sand,and medium-and small-sized cross-bedding is developed;The grain size indexes of flood sediment (median grain size,sand content,clay/silt and Q90) have high values,with fine sand as the dominant component,mixed silt and a small amount of clay,and poorly sorted;Ancient trees and bivalves are intensively buried in the paleoflood sediments in a directional arrangement,and the direction is consistent with that of ancient river channels revealed by remote sensing images.Based on the sedimentary characteristics of the profile and AMS ¹⁴C age analysis,it is determined that four paleoflood events occurred in Caohe at about 10.8~9.6 ka BP in the early Holocene,which can be compared with other paleoflood events in North China during this period.It is inferred that the paleoflood events in Baiyangdian area were the product of the climate in the early Holocene.At that time,the East Asian summer monsoon was strengthened,with frequent fluctuations in temperature and precipitation.

Abstract:Mahai Salt Lake is a dry salt lake rich in low-grade solid potash ore formed in the Holocene in the Qai-dam Basin,with great potential for water-soluble exploitation of potash.In this paper,the lithology of sedimentary rhythm of salt-bearing strata,the distribution characteristics of potash minerals and ore beds are studied by using the rock and mineral identification method.The results show that in the main sedimentary center of the northern mining area of the Mahai Salt Lake,a set of sedimentary strata dominated by clay,silt,rock salt,silty rock salt was deposited,while a secondary sedimentary center was formed in the southeast;The potash minerals in the study area are mainly halogenite,carnallite and potash salt;The results of sedimentary rhythm analysis show that the potash deposits are mainly distributed at the top of the Ⅳ₂ rhythmic layer and the Ⅳ₃ to Ⅳ₄ rhythmic layer,and the occurrence pattern is stratified and lenticular in the vertical direction,and is distributed in the NE-SW direction in the plane with weak continuity.The distribution of potash minerals and ore beds is closely related to the sedimentary evolution,indicating that the sedimentary characteristics have an important influence on the water solution mining of potash ore in the study area,which provides some references for the mining of the same type of low-grade potash ore.

Abstract:Heavy metals are non-degradable,they exist in the soil environment for a long time,seriously affecting the safety of crops.The sulfhydryl-modified attapulgite (ATP-SH) was added to the soils with different Cd pollution levels to conduct potted rape experiments,and the available Cd in soil and Cd in different parts of rape were determined by graphite furnace atomic spectrometry.The correlation among the addition amount of ATP-SH,the available Cd in soil,and Cd in different parts of rape were discussed by SPSS.The bioconcentration factors and translocation factors of Cd in rape were calculated,the passivation effect of ATP-SH on soil Cd and its effect on the bioconcentration and translocation of Cd in rape were studied.After adding ATP-SH,the available Cd in soil and Cd in different parts of rape significantly reduce,variation range of available Cd reduction rate in soil are 40.65%~74.27%,and variation range of available Cd reduction rate in rape root,stem,limb and rapeseed were 29.36%~79.46%,41.44%~88.45%,43.19%~95.89% and 38.02%~95.81%,respectively.The addition of ATP-SH has significant or extremely significant negative correlation with available Cd in soil and the content of Cd in all parts of rape.There are significant or extremely significant positive correlation between soil available Cd and the content of Cd in all parts of rape.There are significant positive correlation among the content of Cd in all parts of rape.In the control group,the bioconcentration factors of Cd in rape roots,stems,limbs and rapeseed respectively are 1.42~4.87 times,1.71~8.66 times,1.92~24.43 times and 1.61~23.76 times higher than that of the experimental group.The order of translocation factors of Cd in rape is sti>limb>rapeseed,the translocation factors of Cd in stem are 3.5~25 times higher than that in limb and rapeseed.ATP-SH can reduce the activity of soil Cd and effectively prevent the migration of Cd from soil to rape.

Abstract:More than 15 million tons of copper tailings are produced in China each year,and the continuous stockpiling of them will cause serious environmental harm,while the recycling treatment can usually make full use of the resources in the copper tailings and reduce the environmental harm to some extents.This article analyzes the environmental impacts of the process of making autoclaved bricks from copper tailings and by-product copper concentrate,iron concentrate and dense medium by life cycle assessment method.The results show that the most important environmental impact of the technical scheme is human toxicity (33 886 kg 1,4-DCB eq./1 000 tons of recycled copper tailings).The environmental load of cement production stage is the highest,and it has the highest contribution among the seven environmental impact categories.The most significant contribution of the key substance is nitrogen oxide,which contributes 94.1%,42.0% and 24.3% to eutrophication,acidification and photochemical pollution respectively.Considering the offset of the products of autoclaved bricks and the by-products of copper concentrate,iron concentrate and dense medium,the recycling of copper tailings can achieve obvious environmental benefits.

Abstract:In order to overcome the shortage of absorbability loss for HCHO-saturated sepiolite,static adsorption experiments were applied to evaluate the effects of heating temperature on absorbing traces of gaseous HCHO for sepiolite,and scanning electronic microscopy,X-ray diffraction,infrared absorption spectroscopy,thermogravimetry and BET specific surface area analysis were adopted to investigated the related mechanisms.It was resulted that silica-gel desiccant elevated the ability for sepiolite to absorb traces of gaseous HCHO and reduced the HCHO concentration lower than the legal safety upper limit.The sepiolite heated at temperature ≤ 400℃ held favorable HCHO absorption properties,while those heated at temperature ≥ 500℃ showed significantly reduced HCHO absorption properties.Under comprehensive characteristics,it is proposed that the crystalliferous water in sepiolite could chemically absorb HCHO and the structural microholes,basically composed of zeolite holes,could be occupied by HCHO through physical absorption.After heated at temperature ≥ 450℃,sepiolite lose the crystalliferous water irreversibly and the zeolite holes collapse that make the absorbability reduce drastically.The research supports sepiolite to regenerate absorbability by heating at temperature below 450℃ at which the escaped HCHO could be eliminated by burning,so sepiolite could enduringly remove traces of HCHO in the air by intermittently thermal regeneration.

Abstract:The paper is a systematic collection of 128 new minerals approved by the Commission on New Minerals,Nomenclature and Classification (CNMNC) of the International Mineralogical Association (IMA) in 2018,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 128 new minerals have been examined and revised under the authority of Chinese Commission of New Minerals and Mineral Names.As a part of the comprehensive introduction to discovery and research of new minerals in the world,this paper will provide reference for the work of discovering,researching and naming new minerals in China and promote the standardization of Chinese names of mineral species.