Imaging the Architecture of Mineral Systems and the Pathways of Ore-forming Fluids across Mongolia with Magnetotellurics

In the framework of a mineral system approach,a combination of components is required to develop a mineral system.This includes the whole-lithosphere architecture,which controls the transport of ore-forming fluids,and favorable tectonic and geodynamic processes,occurring at various spatial and temporal scales,that influence the genesis and evolution of ore-forming fluids(Huston et al.,2016;Groves et al.,2018;Davies et al.,2020).Knowledge of the deep structural framework can advance the understanding of the development of a mineral system and the emplacement of mineral deposits.Deep geophysical exploration carried out with this aim is increasingly important for targeting new ore deposits in unexplored and underexplored regions(Dentith et al.,2018;Dentith,2019).

Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(< 200 ℃) compatible with boiling conditions. Such results open up perspectives for the development of precious metal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.

Diversity and Adaptations of Immature Diptera in Semiaquatic Habitats at Shorelines of Hypersaline Lakes in the Crimea,with a Brief Review of Diptera in Mineralized Bodies of Water

The order Diptera(Insecta)is one of animal groups most successful in the colonization of mineralized shallow aquatic and semiaquatic environments.At the same time,the taxonomic composition of Diptera,their role in

Quantitative analysis of geological ore-controlling factors and stereoscopic quantitative prediction of concealed ore bodies

To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of field analysis. By dint of solving the field models through transferring the continuous models into the discrete ones, the relationship between the geological ore-controlling effect field and the mineralization distribution field was analyzed, and the quantitative and located parameters were extracted for describing the geological factors controlling mineralization enrichment. The method was applied to the 3-dimensional localization and quantitative prediction for concealed ore bodies in the depths and margins of the Daehang mine in Guangxi, China, and the 3-dimensional distribution models of mineralization indexes and ore-controlling factors such as magmatic rocks, strata, faults, lithology and folds were built. With the methods of statistical analysis and the non-linear programming, the quantitative index set of the geological ore-controlling factors was obtained. In addition, the stereoscopic located and quantitative prediction models were set up by exploring the relationship between the mineralization indexes and the geological ore-controlling factors. So far, some concealed ore bodies with the resource volume of a medium-sized mineral deposit are found in the deep parts of the Dachang Mine by means of the deep prospecting drills following the prediction results, from which the effectiveness of the predication models and results is proved.

Approaches to location prognosis of concealed ore deposits (bodies) of productive mines

This paper demonstrates the channels and methods for location prognosis of concealed ore deposits (bodies) in the deep seated and surrounding districts of productive mines in accordance with their special features. The system frame map is built, from quick exploration in the field to the rapid building of a model indoors. The main research points of location prognosis are also discussed in the paper, which include: 1) integrating the location with the surrounding geological areas, microscopic with macroscopic; 2) analyzing and synthesizing all geological information of different levels, depths and aspects; 3) laying stress on mineralization series; 4) paying attention to the study of the distribution law of ore bodies; 5) introducing the theory of nonlinear dynamics of ore forming processes to ordinary static prognosis; 6) the necessity of the geophysical me thod in recovering information of concealed ore bodies; 7) the combination of all kinds of geology, geophysics, geochemistry and remote sensing methods.

Lithium extraction from hard rock lithium ores(spodumene,lepidolite,zinnwaldite,petalite):Technology,resources,environment and cost

Lithium production in China mainly depends on hard rock lithium ores,which has a defect in resources,environment,and economy compared with extracting lithium from brine.This paper focuses on the research progress of extracting lithium from spodumene,lepidolite,petalite,and zinnwaldite by acid,alkali,salt roasting,and chlorination methods,and analyzes the resource intensity,environmental impact,and production cost of industrial lithium extraction from spodumene and lepidolite.It is found that the sulfuric acid method has a high lithium recovery rate,but with a complicated process and high energy consumption;alkali and chlorination methods can directly react with lithium ores,reducing energy consumption,but need to optimize reaction conditions and safety of equipment and operation;the salt roasting method has large material flux and high energy consumption,so require adjustment of sulfate ratio to increase the lithium yield and reduce production cost.Compared with extracting lithium from brine,extracting lithium from ores,calcination,roasting,purity,and other processes consume more resources and energy;and its environmental impact mainly comes from the pollutants discharged by fossil energy,9.3-60.4 times that of lithium extracted from brine.The processing cost of lithium extraction from lepidolite by sulfate roasting method is higher than that from spodumene by sulfuric acid due to the consumption of high-value sulfate.However,the production costs of both are mainly affected by the price of lithium ores,which is less competitive than that of extracting lithium from brine.Thus,the process of extracting lithium from ores should develop appropriate technology,shorten the process flow,save resources and energy,and increase the recovery rate of related elements to reduce environmental impact and improve the added value of by-products and the economy of the process.

Location Prediction of Blind Ore bodies in Shuijingtun Gold Mine, Zhangjiakou, China

By analyzing the metallogenic conditions and prospecting marks of F 8 fault belt in Shiujingtun Gold Mine, the geochemical samples were collected along F 8 fault belt and prospecting profile normal to the F 8 fault belt. Gold and its indicator elements were tested with X ray fluorescence spectrometry and the content distribution diagram of Au, Ag, Hg and As along the F 8 fault belt was performed. The geochemical primary halo model and the Grey system model of F 8 fault belt are established. With these element distribution features and models, the blind ore bodies in the F 8 fault belt were predicted. Engineering prospect shows that the industrial orebodies have been discovered and the prediction results are dependable.

Combined Geoelectrical Approach DC and IP Methods in the Identification of the Mineralized Bodies Parallel to the NE-SW Tectonic Line of Kadei River: Case of Quartz or Pegmatite Gold Bearing Veins of Ngoura Subdivision (East Cameroon)

A geophysical investigation of subsurface structures using the Syscal Junior 48 resistivity-meter was conducted in Ngoura subdivision (East Cameroon) following a combined geoelectrical direct current (DC) approach involving Resistivity and IP methods. This investigation was allowed to collect data on forty-five (45) profiling lines at three acquisition levels (AB = 100 m, MN = 10 m;AB = 200 m, MN = 20 m and AB = 500 m, MN = 50 m) and two electric panels L1 and L4, using the Schlumberger array. Processing, modeling and interpretation of data collected using the Winsev, Res2Dinv and Surfer software helped in highlighting a conductive and strongly mineralized discontinuity in granite formations, which lined up with the NE-SW Kadei tectonic line. It extends beyond 100 m depth over an average width of 600 m. The mineralization associated with this discontinuity is identified by a high concentration of disseminated metalliferous minerals in quartz or pegmatite veins. The mining reconnaissance works in the study area and those of several authors have characterized this anomaly to a lode gold quartz or large pegmatite. The results of this study correlate with geological and tectonic data for the region marked by NE-SW Kadei tectonic line. Therefore, they confirm the reliability of a geoelectrical DC investigation method combining Resistivity and IP to the identification of ore bodies.

Ground subsidence mechanism of a filling mine with a steeply inclined ore body

Long-term field monitoring finds that serious surface subsidence can still occur even if the high strength cemented fill method is adopted.Combining the results of numerical simulations with global position system(GPS)monitoring,we took a typical filling mining mine with a steeply inclined ore body as an example,and explored its ground subsidence mechanism.The results show that the ground subsidence caused by the mining of steep ore body is characterized by two settlement centers and a significantly uneven spatial distribution,which is visibly different from ground subsidence characteristic of the coal mine.The subsidence on the hanging wall is much larger than that on the footwall,and the settlement center tends to move to the hanging wall with the increase of mining depth.The backfill improves the strength and surrounding rock bearing capacity,which leads to a lag of about 3 years of the subsidence.However,under the actions of continuous and repeated mining disturbances,the supporting effect of the backfill can only reduce the amplitude of the deformation,but it cannot prevent the occurrence of settlement.

Study on Epithermal Gold Mineralization System at Shwebontha Prospect,Monywa Copper-Gold Ore Field,Central Myanmar

The Shwebontha prospect area is situated in the Central Volcanic Belt,central Myanmar,where the well-known Sagaing Fault serves as its eastern boundary.This study aims to document key the mineralogy,host rock geochemistry and ore mineralizing fluids.The mineralization,hosted by Upper Oligocene to Middle Miocene rhyolites,displays a strong lithological control.Mineralization is characterized by gold-bearing silicified massive ore and chalcedonic quartz veins in which sulfides are clustered and disseminated not only in quartz gangue but also in rhyolite host rocks.The significant ore minerals in the mineralized veins include pyrite,sphalerite,galena,chalcopyrite,and gold.Common hydrothermal alterations such as silicic,argillic and propylitic alteration types are recognized.According to the fluid inclusion data and interpretation,ore mineralizing fluids in the research area are characterized by formation temperatures of 260-280℃ and salinity of 0.35-2.41%wt.NaCl eq.respectively.Mixing of hydrothermal fluids was generally considered to be an effective mechanism for ore transport and deposition.

河南银洞坡金矿“三位一体”找矿预测地质模型及应用示范

河南银洞坡金矿位于河南省桐柏县朱庄镇,为一特大型金矿床,同体共生银、铅锌。运用勘查区找矿预测方法与理论,构建成矿地质体、成矿构造与成矿结构面和成矿作用特征标志为主的“三位一体”找矿预测地质模型。野外调查和矿床学研究认为,矿床成因为与早白垩世岩浆作用有关的中低温岩浆热液矿床,主成矿阶段温度介于200~350℃之间,碳、氢、氧、硫同位素研究表明,成矿物质和成矿流体主要来源于岩浆。确定成矿地质体为矿区深部隐伏早白垩世花岗岩体;成矿结构面为岩性界面(硅/钙面)、褶皱成矿构造系统结构面、沉积成岩结构面;成矿作用特征标志主要为矽卡岩化、钾化、黄铁绢英岩化、硅化、铁白云石化、萤石矿化、碳酸盐化。由此建立了银洞坡金矿找矿预测地质模型,圈定了找矿靶区,施工的钻孔见矿率达到85%,对该地区及邻区进一步找矿具有现实的指导意义。

热液脉型萤石矿床隐伏矿体定位预测综合技术方法

萤石是国家战略性新兴产业发展中不可或缺的关键支撑原材料,被国际社会普遍列为“关键矿产”,随着萤石露头矿的发现殆尽,急需开展隐伏矿体的深部定位预测研究。文章简要论述了断裂构造控制的热液脉型萤石矿床地质特征、分带模式和成矿规律,评述了萤石找矿中常用的勘查技术方法。结合找矿标志和控矿要素分析,总结了隐伏-半隐伏萤石矿体定位预测的找矿模型,提出了“分带型”和“掩埋型”两种类型隐伏萤石矿体及相应的找矿技术方法组合。笔者建立了隐伏萤石矿体定位预测的地质-物探-化探-遥感综合找矿模型及其四步勘查技术流程,这对指导隐伏萤石矿床(体)的找矿勘查具有重要的理论和实践意义。

贵东复式岩体中东部晚期花岗质小岩体的SHRIMP锆石U-Pb年龄及其地质意义

贵东复式岩体由多期次、多类型的岩体组成,且东部盛产铀矿床,因此精确厘定该复式岩体的时代及其时序,查明复式岩体东部与中西部岩浆活动的差异性及其与铀成矿的关系,不仅有利于深入研究区域岩浆活动,而且有利于深刻认识铀的成矿规律。现有研究认为,以龟尾山断裂带为界,贵东复式岩体中西部岩基属燕山早期、东部岩基属印支早期,东部广泛发育的燕山期中基性脉岩与铀成矿关系密切。但对复式岩体中东部呈岩枝、岩株广泛出露的晚期花岗质小岩体的成岩地质时代及其分布规律尚存在争议,也有待进一步查明花岗质小岩体与铀矿床的时空关系。文章选择贵东复式岩体中东部晚期花岗质小岩体为研究对象,采用SHRIMP锆石U-Pb法厘定其成岩时代,并分析它们的时空分布及其与铀成矿的关系。测试结果显示,贵东复式岩体中东部晚期花岗质小岩体普遍存在高铀锆石,这可能是对同一岩体不同学者所获得的^(206)Pb/^(238)U加权平均年龄差别较大的主要原因。剔除高铀锆石的年龄数据,龟尾山断裂带以西的隘子、司前、陈洞岩体锆石^(206)Pb/^(238)U加权平均年龄分别为163.0±1.6 Ma、163.1±1.6 Ma、160.7±1.9 Ma,属燕山早期岩浆活动的产物;而以东的帽峰、分水坳、龟尾山岩体锆石^(206)Pb/^(238)U加权平均年龄分别为230.0±2.7 Ma、225.9±2.9 Ma和232.6±3.1 Ma,属印支期岩浆活动的产物。所以,龟尾山断裂以西和以东晚期花岗质小岩体的时代不同。且龟尾山断裂带以东的印支期花岗质小岩体空间上与铀矿化、尤其是与燕山早期的绢英岩化型等中高温热液铀矿化关系密切,是主要的储矿围岩;结合元素地球化学研究结果,该区产出的印支期花岗质小岩体也可为铀成矿提供铀源。

氧化石墨烯辅助仿生矿化原位合成羟基磷灰石

羟基磷灰石(HAp)是一种与人体骨骼成分类似的无机材料,具有良好的生物相容性。本文以氧化石墨烯(GO)为模板,通过模拟体液(SBF)仿生矿化原位合成了HAp纳米粒子。通过SEM、XRD、EDS和拉曼光谱等测试分析研究了矿化时间、SBF/GO体积比对矿化产物物相组成、形貌和结构的影响。结果表明,矿化处理后的GO表面形成了大量均匀分布的类骨HAp。随着矿化时间延长和SBF体积占比增大,矿化产物的尺寸及数量增大,GO层间距逐渐扩大。本研究验证了GO辅助合成HAp的可行性,拓展了仿生矿化法的应用领域。

利用DXA评估系统性红斑狼疮患者中肌少症的现患率

目的评估系统性红斑狼疮(systemic lupus erythematosus,SLE)患者中肌少症的现患率,分析SLE共病肌少症患者的体成分变化,探讨SLE患者肌少症发生的危险因素。方法共纳入114例SLE患者(病例组)和114例健康对照者(对照组)。采用双能X线吸收法(dual energy X-ray absorptiometry,DXA)测量两组的肌肉质量,通过握力和步速分别评估患者的肌力和体能。根据欧洲老年人肌少症工作组及亚洲肌少症工作组诊断标准对SLE患者进行肌少症诊断及分期,将SLE患者分为肌少症组及非肌少症组,比较组间患者的体成分及骨密度等指标的差异,分析SLE患者共病肌少症的影响因素。结果SLE患者的平均病程为(79.6±72.8)个月。45.6%(n=52)的SLE患者共病肌少症,其中22.8%(n=26)的患者为肌少症前期,16.7%(n=19)的患者为肌少症期,6.1%(n=7)的患者为严重肌少症期。肌少症组患者的体重、体质指数、脂肪质量指数、全身瘦组织含量、瘦质量指数、全身去脂体重、去脂体重指数均低于非肌少症组和对照组。肌少症组的骨矿物质含量、腰椎和股骨骨密度明显低于对照组。多因素回归分析显示,体质指数(OR=0.61,P<0.001,95%CI:0.49~0.75)和职业劳动强度(OR=2.0,P=0.009,95%CI:1.19~3.34)是SLE患者共病肌少症的影响因素。结论SLE患者中约半数共病肌少症,共病肌少症SLE患者的脂肪、肌肉含量和重要部位骨密度下降,其中体质指数和职业劳动强度是SLE患者出现肌少症的影响因素。

绝经后2型糖尿病患者BMI、腰围与骨密度的相关性及其骨密度的影响因素

目的:探讨绝经后2型糖尿病(T2DM)患者BMI、腰围与骨密度的相关性及其骨密度的影响因素。方法:选取我院内分泌科2022年11月至2024年2月收治的130例绝经后T2DM患者为研究对象,根据BMI分级标准将患者分为肥胖组、超重组、正常组;根据腰围大小分为腹型肥胖组及腰围正常组。比较不同BMI及腰围组间临床资料及骨密度差异,研究BMI、腰围与骨密度的相关性,分析骨密度的影响因素。结果:BMI与腰围、体重及各部位骨密度均呈正相关(P<0.05)。腰围与年龄、体重及各部位骨密度均呈正相关(P<0.05)。多元线性回归分析显示,仅体重是各部位骨密度的影响因素(P<0.05)。结论:绝经后T2DM患者BMI及腰围与骨密度呈正相关,其骨密度受体重的影响,体重低者,骨密度也低,故T2DM患者在绝经后需避免体重过轻。

松辽盆地南部砂岩型铀矿储层结构与铀成矿作用

以松辽盆地南部DL地区砂岩型铀矿为目标,在沉积学背景研究的基础上,开展铀储层结构与铀成矿作用研究。通过钻孔数据统计及系统的取样分析并编制铀储层非均质性图件,精细地刻画了姚家组铀储层的几何形态和复杂结构,充分展示了铀储层的定量非均质性。结果显示,区内灰色砂体多为原生灰色砂体,而下氧化带在沉积期后经历了较强的表生流体改造,为后生氧化带,矿体主要分布于河道砂体分岔处,以及从无隔挡层到隔挡层突然变厚的河道砂体边缘而非河道中央,其形态受氧化还原界面控制以板状为主。综合分析认为,表生流体成矿作用经历了晚白垩世姚家组含矿主岩预富集与表生流体叠加改造成矿2个阶段。通过对比DL地区储层结构对铀成矿的控制作用,在BL地区优选出3片找矿靶区,为下一步的勘查工作提供理论依据。

准噶尔盆地黄花沟地区下白垩统吐谷鲁群上段沉积特征与铀矿找矿潜力

黄花沟地区位于准噶尔盆地北部,随着近年来铀矿勘查的投入,发现层间氧化带型铀矿化,主要产于下白垩统吐谷鲁群上段辫状河三角洲平原辫状河道砂体中。通过对大量钻孔岩心、野外露头的观察,结合剖面对比等手段,研究了吐谷鲁群上段砂体沉积特征及铀成矿潜力。结果显示,吐谷鲁群上段主要发育辫状河三角洲平原亚相,砂体连通性好、厚度大,为含铀含氧水的自蚀源区向盆地径流提供了先决条件;层间氧化带自北西向南东发育,受岩性岩相控制明显,揭露到的铀矿化主要产于氧化带翼部,表明氧化还原作用是该地区铀沉淀富集的主要控制因素;吐谷鲁群上段砂体总体存在后生氧化程度及砂体还原容量低的缺陷,于铀成矿不利,但局部富集有机质地段仍存在形成小型铀矿床的可能,下一步铀资源勘查应关注有机质的分布特征。

人体成分与跟骨骨密度因果关联:一项孟德尔随机化研究

目的采用孟德尔随机化方法研究人体成分与跟骨骨密度的因果关系。方法利用全基因关联分析数据,暴露因素为全身脂肪量、全身水分量和去脂体质量,结局变量为跟骨骨密度。采用IVW法、MR-Egger法、加权中位数法、简单模式法、加权模式法进行孟德尔随机化分析,并行异质性、敏感性、多效性分析以检验结果可靠性。结果IVW法显示全身脂肪量与跟骨骨密度存在正向因果关系(β=1.10,95%CI 1.05~1.15,P<0.001),MR-Egger法、加权中位数法、加权模式法与IVW法结果一致,敏感性分析显示单核苷酸多态性无异质性和水平多效性;IVW法显示全身水分量与跟骨骨密度因果关系无统计学意义(β=0.96,95%CI 0.91~1.02,P>0.05);IVW法显示去脂体质量与跟骨骨密度之间因果关系无统计学意义(β=0.97,95%CI 0.91~1.03,P>0.05)。结论人体全身脂肪量与跟骨骨密度存在正向因果关系。

肌少症病人超声参数与体质指数、骨密度及骨骼肌质量指数的关系

目的:探究肌少症病人超声参数与体质指数、骨密度及骨骼肌质量指数的关系。方法:选取山西医科大学第二医院2023年1月1日—2024年1月1日收治的60例肌少症病人为研究组,选取同期来院体检的50名性别、年龄匹配的健康志愿者为对照组。两组均接受超声检查,记录腓肠肌肌肉厚度、肌肉最大横截面积、肌肉硬度(收缩及舒张时杨氏模量值)及双能X线吸收法检查,记录骨密度、四肢肌肉量并计算骨骼肌质量指数及体质指数。对比两组上述指标差异,使用Logistic回归分析筛选肌少症影响因素,使用受试者工作特征(ROC)曲线分析超声参数对肌少症诊断效能,使用Pearson相关系数分析研究组超声参数与体质指数、骨密度及骨骼肌质量指数的相关性。结果:Logistic回归分析结果显示:腓肠肌肌肉厚度、肌肉最大横截面积、收缩及舒张时杨氏模量值、体质指数、骨密度及骨骼肌质量指数是肌少症的独立影响因素(P<0.05);腓肠肌肌肉厚度、肌肉最大横截面积、收缩、舒张时杨氏模量值诊断肌少症ROC曲线下面积分别为0.908,0.958,0.909,0.932;Pearson相关分析结果显示,肌少症病人腓肠肌肌肉厚度、肌肉最大横截面积、收缩及舒张时杨氏模量值与体质指数、骨密度及骨骼肌质量指数均呈正相关(P<0.05)。结论:超声参数有助于筛查诊断肌少症,超声参数、腓肠肌肌肉厚度、肌肉最大横截面积、肌肉硬度与体质指数、骨密度及骨骼肌质量指数存在明显关联。