西昆仑赞坎地区古元古代化学沉积岩系的地球化学及微区特征研究

赞坎铁矿是西昆仑地区典型的铁矿床之一,该矿区内存在一套共生的化学沉积岩系"铁矿层和硅质岩"。本研究对该化学沉积岩系的宏观地球化学特征和微观矿物学组构及矿物地球化学特征进行了分析和探讨,研究结果支持赞坎铁矿为遭受了改造的沉积变质型铁矿并形成于类似大陆边缘海相环境。显微镜下,富铁矿石主要包含石英、磁铁矿和硅酸盐矿物并具有明显的条带状构造,而硅质岩则表现为细-微晶石英颗粒构成的紧密堆积结构。矿石富铁条带的XRD和EBSD分析结果表明,该矿石富铁条带内的主要矿物为磁铁矿、辉石和微量磷灰石,磁铁矿颗粒的晶胞参数为a=b=c=8.394A,z=8并吻合沉积变质型铁矿的特征。LA-ICPMS分析结果表明,磁铁矿内杂质元素的氧化物平均含量按照Cr_2O_3(2764×10^(-6))、Al_2O_3(2494×10^(-6))、V_2O_5(1494×10^(-6))、SiO_2(1255×10^(-6))、TiO_2(589.7×10^(-6))、MnO(162.5×10^(-6))、MgO(114.9×10^(-6))依次降低,其地球化学示踪结果吻合沉积变质型铁矿的特征。全岩地球化学分析结果显示,硅质岩的SiO_2含量70.58%~81.78%、Ba含量平均372.4×10^(-6)、U含量平均2.21×10^(-6)、ΣREE值平均97.37×10^(-6),这些特征总体上吻合热水成因,而部分样品偏高的Al_2O_3含量和∑REE值及无明显Eu异常则指示了非热水成因陆源沉积物的贡献;硅质岩的Al/(A1+Fe+Mn)值0.68~0.96、MnO/TiO_2值0.00~0.05、Al/(Al+Fe)值0.74~0.97、Sc/Th值2.22~7.07、U/Th值0.33~0.86、Al_2O_3/TiO_2值平均32.24吻合,这些指标指示其形成于类似大陆边缘海相的沉积环境;硅质岩的Ni/Co平均3.10吻合富氧环境,Sr/Ba值平均0.23指示该硅质岩形成环境的水动力总体偏弱,这说明赞坎地区硅质岩及铁矿的原始形成环境相对富氧且水动力总体偏弱。由于遭受了后期的构造-岩浆事件改造,赞坎铁矿的矿石地球化学特征与典型BIF存在略微的差异,但其岩石学、宏观地球化学和微区矿物学特征均在总体上吻合沉积变质型BIF的特点。综上所述,赞坎铁矿属于早前寒武纪的沉积变质型BIF铁矿,该铁矿形成于类似大陆边缘海相环境并遭受了后期构造-岩浆事件的改造。

华北克拉通南缘舞阳地区太古代BIF中方解石的微区特征及地质意义研究

条带状铁建造(banded iron formation,BIF)是前寒武纪地层中广泛发育的一类富铁沉积岩,它在华北克拉通内广泛发育。在华北克拉通南缘的舞阳地区,晚太古代太华群铁山庙组BIF包含石英-磁铁矿和辉石-磁铁矿两种组合,前者的绝大部分磁铁矿颗粒均自形程度高、粒度粗大并常常紧密伴生有一定量的方解石。舞阳地区铁山庙组BIF的RAMAN,SEM,CL和EDS分析结果表明:石英-磁铁矿矿石中的磁铁矿自形程度最高、石英次之、方解石最低;方解石似条带的RAMAN分析结果指示其有序度、结晶程度沿条带的垂直方向无规律突变,明显不同于裂隙中后期热液流体沉淀形成的方解石脉;方解石发生了塑性流变并最终定位于石英和磁铁矿间的间隙内,其矿物的截面形状和展布特征明显受控于石英和磁铁矿并得到了石英颗粒间微裂隙内方解石的证实;方解石似条带的微区成份存在明显差异,这反映方解石经历了塑性流变及再次汇聚;在磁铁矿颗粒的汇聚及生长过程中,方解石充当了磁铁矿微颗粒迁移的媒介并得到了方解石中磁铁矿微颗粒局部富集现象的证实。

高钙飞灰的矿物学组成及微区特征研究

对小龙潭电厂飞灰及不同密度级的分选灰的矿物学和颗粒微区特征进行了详细研究,高钙飞灰中的含钙矿物主要包括石灰,硬石膏,钙黄长石,镁黄长石和氢氧钙石;同时含有少量斜硅钙石,方解石,钙铁石,陨硫钙石,钙铁榴石和钙铝榴石;不同密度级分选灰矿物组成和微区特征差异很大。石英、莫来石主要存在于低密度级飞灰;石灰、硬石膏在漂珠中明显富集;斜硅钙石和钙铝榴石主要存在于沉珠中;含铁矿物赤铁矿、磁铁矿以及钙铁石在重灰和沉珠中的含量明显高于漂珠和轻质灰。

铁陨石中陨磷铁镍矿的矿物学特征及微区特征研究

铁陨石中常发现有陨磷铁镍矿包体,该特征矿物镜下特征、晶体结构、物化性质、成因等特征研究较少或尚不明确。通过电子显微镜、电子探针分析,对铁陨石中陨磷铁镍矿的矿物学特征、显微形貌特征进行研究,为陨石的演化形成过程等研究工作奠定基础。结果表明:陨磷铁镍矿晶形呈四方长柱状,自形程度高,截面呈四边形或长方形,立体空间上大体呈3个方向定向平行排列,形态类似混凝土的钢筋架构,表明陨磷铁镍矿结晶早于铁纹石及镍纹石。铁陨石母体内P元素的存在,在铁陨石的母体元素演化过程中对微量元素分配系数的影响起主导作用,可能影响微量元素丰度的分配,对元素固化分析系数影响很大。

东菲律宾海多金属结核微区元素赋存特征及成因意义

多金属结核富含Mn、Fe、Co、Ni、Cu和REY(稀土元素和钇)等元素,具有巨大的潜在经济价值。东菲律宾海结核由包壳和核部岩屑(或泥团)构成,其Mn、Fe、Co、Ni和Cu含量介于南海结核和大洋结核之间,但该区域结核的微区特征尚不清楚。本文基于微区元素分析,探究了东菲律宾海结核的元素赋存特征及其成因意义。结果表明,东菲律宾海结核总体为水成成因,主要形成于氧化环境。结核包壳主要由含δ-MnO_(2)的水成型富铁层(FeO平均为28.7%,MnO平均为21.9%,Mn/Fe值平均为0.93)构成,但边部存在薄层(<100μm)的成岩型富锰层(FeO平均3.41%,MnO平均52.6%,Mn/Fe值平均为17.5),富锰层具有高NiO(2.71%)和CuO(1.45%)含量。根据Co经验公式估算,富锰层可能形成于末次盛冰期(LGM)以来。本研究还发现,结核核部气孔状岩屑中存在成岩成因的富锰矿物,其MnO含量为22.5%~64.7%,FeO含量为0.46%~7.05%,Mn/Fe值为3.96~126。相比包壳中富锰层,核部富锰矿物NiO(1.25%)和CuO(0.5%)含量明显减少。此外,核部富锰矿物具有从纹层状到纤维状的变化,且随MnO含量(43.8%→56.1%)增加,CoO(0.55%→0.02%)、NiO(2.04%→0.88%)、CuO(0.62%→0.43%)含量反而降低,指示了矿物演化过程中,Co、Ni和Cu倾向于保留在纹层状富锰矿物中。

雪宝顶白钨矿的谱学特征及主微量元素分析

白钨矿是一种稀有宝石,具粒状、块状构造,颜色为白-浅黄色,油脂光泽,荧光性明显。四川平武雪宝顶白钨矿矿床为围岩蚀变较弱的脉状热液巨晶宝石级矿床,产出白钨矿颜色饱和度较高,具完美晶型且色泽纯正,与绿柱石、锡石和白云母共生。该研究选取雪宝顶近无色-橘黄色调白钨矿为研究对象,使用X射线粉晶衍射(XRD)、傅里叶变换红外光谱分析仪、紫外-可见分光光度计、激光拉曼光谱仪、电子探针、激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)的综合分析,结合矿物学、谱学与主微量元素特征,确定近无色-橘黄色调白钨矿的矿物成分、晶体结构、特征鉴别谱带、致色离子以及主微量、稀土等化学组分含量,探讨白钨矿稀土元素含量与颜色成因关系,为雪宝顶近无色-橘黄色调白钨矿提供诊断性鉴别依据。研究结果表明,白钨矿结晶程度较好,化学成分均匀,无明显间断,矿物成分含量相对集中,共生矿物多为白云母和伊利石。样品具典型的白钨矿红外特征峰440、809和870 cm^(-1)及与Ca_(2+)有关的448 cm^(-1)特征峰,谱峰显示色调越深者吸收度越高;拉曼特征峰909 cm^(-1)和Ca—O晶格振动峰207 cm^(-1),随色调加深强度加深;紫外吸收峰表现为橙黄区强吸收,尖峰在383、570、584和804 nm附近,近无色调者仅具383 nm尖峰,黄色调较浅者近紫外区Fe^(3+)吸收度较低,黄色调较深者蓝紫区Fe^(3+)强吸收且其橘黄色调由Nd^(3+)所致;白钨矿化学组分WO_(3)和CaO质量比接近甚至超过理想值,近无色者含量相对集中;微量元素中Fe元素与色调呈正相关,黄色调越深者,含量越高;稀土总量变化范围大,轻稀土更为富集,具明显的Eu负异常,Ce异常不明显。浅黄色调受微量元素Si、Fe元素及Fe^(3+)的d—d电子跃迁影响,黄色调受微量元素Mn、Fe元素及Fe^(3+)的电子跃迁所致,橘黄色调受稀土Nd和Sm元素影响较大。

相山铀矿田东西部矿床中铀矿物微区化学特征

通过阅读大量相关文献及地质调查,深入了解相山矿田含矿断裂构造特征,选取成矿差异较大的邹家山和云际铀矿床的含矿断裂构造进行研究探讨,运用电子探针技术发现邹家山主要铀矿物为:沥青铀矿、钛铀矿、钍铀石、铀石;云际矿床铀矿物主要为:钛铀矿、铀石。对两个铀矿床同种主要铀矿物微区进行化学分析及对比,发现除U含量有起伏外,Ca、Fe、Zr的含量,邹家山矿床均低于云际矿床;受邹石断裂控制的铀矿床铀矿物中U与Zr含量成负相关,而受火山颈东部北东向断裂控制的铀矿床则相反。

胶东玲珑九曲金矿床载金黄铁矿矿物学特征及其深部找矿意义

九曲矿床位于胶东玲珑金矿田东部,属于典型的"石英脉型"金矿床。黄铁矿作为该矿床中主要的载金矿物和成矿期的贯通性矿物,其矿物学特征对该区矿床成因和找矿预测均具有重要意义。通过研究不同成矿阶段的黄铁矿矿相学发现:九曲金矿床中细粒状、破碎状和裂纹状黄铁矿对金富集具有重要的指示意义;黄铁矿中的自然金主要有晶隙金、裂隙金和包体金3种类型;浅黄色、暗黄色或黄色黄铁矿中金含量较高。不同成矿阶段的黄铁矿微区地球化学特征研究显示:黄铁矿主量元素总体表现为富铁贫硫特征,含矿流体在上升过程中硫逸度逐渐降低;第一、四阶段的微量元素总量小于第二、三主成矿阶段,指示成矿热液的温度由早期阶段到主成矿阶段总体有降低的趋势。黄铁矿复杂聚形、颜色变化、黄铁矿中脆性和塑性变形特征均可作为找矿标志。

Zonal Distribution of the Erosion-Landslide and Soil Micromorphological Features in Purple Hilly Region

In the purple hilly region, erosions and landslides are all serious, and it is of great scientific value and practical significance to study their formation mechanism and distribution features there. In this paper, soil micromorphological methods and techniques were used to study the erosion zonal distribution in the region. The results indicated: (1) According to erosion process, the spacial distribution zones of the erosions and landslides in the purple hilly region with different solums were divided into scouring erosion zone, transport-diffusion zone, rocks and soil turbulence zone and sediment-bury zone; (2) The soil micromorphologic taxonomic feature identifying different erosion-landslide zone were found by studying the soil micromorphology of erosive zone in purple hilly region; (3) As for the erosion–landslide formation in the region, besides the external factors, the internal factors were found more important and favorable for landslide formation through the studies on the micormorphological features of slide soil.

Micromorphological Features of Diagnostic Horizons in Several soils in Southwest China: Implication for Soil Taxonomic Classification

The comparative studies on micromorphological features in diagnostic horizons of Stagnic Anthrosols, Ustic Ferrosols and Ustic Vertosols in southwestern China were conducted to underpin the rationale for Chinese Soil Taxonomy. The following findings were explored: (1) Stagnic Anthrosols had the specific micromorphological features, e.g., the humic formation in anthrostagnic epipedon, the platy structures in plow subhorizon, the secondary formation of ferromanganese and the weakly optical-orientation clay domains in hydragric horizon, etc.: (2) The groundmasses of ferric horizon in Ustic Ferrosols appeared in hue of 2.5YR or redder, and had pellicular grain structure; (3) Ustic Vertosols had a crust horizon (Acr), and crack structure dominated in Acr and angular blocky structure in disturbed horizon; (4) Because of the distinct differences in micromorphological features among these three soils, the specific micromorphological features might be employed as diagnostic horizons to differentiate soils while the quantifiable micromorphological features might potentially be selected as diagnostic indices for Chinese soil taxonomic classification.

Relationship Between Vegetation Restoration and Soil Microbial Characteristics in Degraded Karst Regions: A Case Study

The mechanism of vegetation restoration on degraded karst regions has been a research focus of soil science and ecology for the last decade.In an attempt to preferably interpret the soil microbiological characteristic variation associated with vegetation restoration and further to explore the role of soil microbiology in vegetation restoration mechanism of degraded karst regions,we measured microbial biomass C and basal respiration in soils during vegetation restoration in Zhenfeng County of southwestern Guizhou Province,China.The community level physiological profiles(CLPP) of the soil microbial community to were estimated determine if vegetation changes were accompanied by changes in functioning of soil microbial communities.The results showed that soil microbial biomass C and microbial quotient(microbial biomass C/organic C) tended to increase with vegetation restoration,being in the order arboreal community stage > shrubby community stage > herbaceous community stage > bare land stage.Similar trend was found in the change of basal respiration(BR).The metabolic quotient(the ratio of basal respiration to microbial biomass,qCO 2) decreased with vegetation restoration,and remained at a constantly low level in the arboreal community stage.Analyses of the CLPP data indicated that vegetation restoration tended to result in higher average well color development,substrate richness,and functional diversity.Average utilization of specific substrate guilds was highest in the arboreal community stage.Principle component analysis of the CLPP data further indicated that the arboreal community stage was distinctly different from the other three stages.In conclusion,vegetation restoration improved soil microbial biomass C,respiration,and utilization of carbon sources,and decreased qCO 2,thus creating better soil conditions,which in turn could promote the restoration of vegetation on degraded karst regions.

Effect of Groundwater Irrigation on Soil PAHs Pollution Abatement and Soil Microbial Characteristics:A Case Study in Northeast China

To evaluate the effect of groundwater irrigation on the polycyclic aromatic hydrocarbons(PAHs) pollution abatement and soil microbial characteristics,a case study was performed in the Shenfu irrigation area of Shenyang,Northeast China,where the irrigation with petroleum wastewater had lasted for more than fifty years,and then groundwater irrigation instead of wastewater irrigation was applied due to the gradually serious PAHs pollution in soil.Soil chemical properties,including PAHs and nutrients contents,and soil microbial characteristics,including microbial biomass carbon,substrateinduced respiration,microbial quotient(qM),metabolic quotient(qCO2),dehydrogenase(DH),polyphenol oxidase(PO),urease(UR) and cellulase(CE) in surface and subsurface were determined.Total organic C,total N,total P,and available K were significantly different between the sites studied.The PAHs concentrations ranged from 610.9 to 6362.8 μg kg-1 in the surface layers(0-20 cm) and from 404.6 to 4318.5 μg kg-1 in the subsurface layers(20-40 cm).From the principal component analysis,the first principal component was primarily weighed by total PAHs,total organic C,total N,total P and available K,and it was the main factor that influencing the soil microbial characteristics.Among the tested microbial characteristics,DH,PO,UR,CE,qM and qCO2 were more sensitive to the PAHs stress than the others,thus they could serve as useful ecological assessment indicators for soil PAHs pollution.

Characteristics of pathogenic microorganisms found in 99 cases of conjunctivitis from the Qinghai Tibetan area

Morbidity associated with conjunctivitis is higher in developing countries,particularly among children,because of the poorer standards of living（Azari and Barney,2013;Yetman and Coody,1997）.Presently,little is known regarding the microorganisms that cause conjunctivitis in the remote area of Chinese Tibet.In particular,it is difficult to monitor and control the occurrence of conjunctivitis in children from this area.