Geochemistry of surface sediments in the southwestern East/Japan Sea

We analyzed 77 surface sediment samples collected in the southwestern East/Japan Sea from the Korea Strait through the Ulleung Basin and the Korea Plateau for grain size, calcium carbonate, organic carbon, and major (Na, Mg, Al, Fe, K, Ca, and Ti) and trace elements (P, Mn, Sr, Li, Sc, V, Cr, Co, Ni, Zn, Cu, and Pb).The chemical composition of the surface sediments was found to be highly variable spatially. Cluster analysis of surface sediment chemical compositions indicated five major geochemical sedimentary environments: basin, lower slope, coast and upper slope, inner shelf, and outer shelf. Continental-shelf sediments were rich in shell fragments and had relict and coarse-grained characteristics. Recent fine-grained sediments were only distributed in coastal, slope, and basin areas. Concentrations of Al, K, Ca, Ti, Cr, and Sc were highest in the coastal and upper slope areas and decreased with water depth. Elemental ratios using major and trace elements indicated that coastal and upper slope detrital sediments were mixtures of sediments derived from the Changjiang (Yangtze) and Nakdong Rivers. Although the concentrations of organic carbon, P, Mn, V, Co, Ni, Cu, and Pb increased with water depth, their distribution patterns indicated authigenic (V, Cu, and Pb) and diagenetic (Fe, P, Mn, Co, and Ni) origins. The distribution pattern with water depth suggested that the chemical composition of surface sediment was determined by sedimentologic and geochemical processes, such as the supply of detrital and biogenic materials, and authigenic and post-depositional diagenetic processes in sediments.     

Effects of coal fly ash amended soils on trace element uptake in plants

Variations in As, Ba, Bi, Cd, Co, Cu, Hg, Mn, Mo, Ni, Pb, Sb, Se, Sn, Th, Tl, U, W, and Zn uptake were evaluated in young, middle-aged, and mature basil, tomato, zucchini, and sunflower plants grown in soils amended with 5, 10, and 20% by weight fly ash. Elements susceptible to uptake with increasing fly ash were As and Tl, with As exceeding potentially toxic levels in basil and zucchini. Temporal variations in element uptake included (1) increasing Ba and Cd concentrations in tomato and As, Ba, Cd, and Tl in zucchini, (2) decreasing Co concentrations in tomato, zucchini, and sunflower, Ni in zucchini, and Tl in basil, and (3) increasing As and Ni concentrations in basil and Pb in zucchini and sunflower during early growth followed by decreasing concentrations at maturity. Although most of the trace elements were below reported toxic levels, the elevated concentrations of As in plant tissue suggests that fly ash treatment programs can lead to potentially toxic accumulations of As, and thus, should be carefully monitored.     

Geochemical reconnaissance survey and environmental assessment for stream sediments of Wadi Um Gier,Southeastern Desert,Egypt

The purposes of this study were to assess the influence of old mining activities on the geochemistry and quality of sediments and to identify the sites of economic elements. Thirty sites of stream sediment were sampled in the study area covered by granitic, metarhyodacitic and meta-andesitic rocks and related tuffs-hosted abandoned Au mine. The suite of chemical elements, Ag, Bi, Cd, Cu, Fe, Ga, Hg, Mn, Nb, Pb, Rb, Sb, Se, Sn, Te, Th, U, Y, Zn and Zr, pH value and total organic carbon were determined, and univariate, bivariate and multivariate statistical methods were applied. The results show that the enrichment factor (EF) is very high in the case of Te and significant also with respect to Ag, Bi, Cu, Sb, Se, Sn and Zn. Likewise, geoaccumulation indices (Igeos) varied from very highly polluted with Sn and Te, strongly to very strongly polluted with Bi and Se, and moderately polluted with Sb. The polluted sites of Ag, Bi, Sb, Se, Sn and Te were outlined using Igeos maps, and economic sites of Ag and Sn were identified by geochemical maps leading to their sources, which are likely to be mining activities and lithogenic processes. The pollutant elements may cause toxicity in stream sediments, or surface or underground water, as well as plants and animals in the area. This investigation provides an environmental baseline for future monitoring of possible human/anthropogenic, industrial and agricultural impacts on the study area and considers an attempt at re-mining Ag and Sn.     

Geochemical and Mineralogical Characteristics of Pleistocene Lignites and Associated Sediments of Marathousa Coal Field,Central Peloponnese,Greece

The mineralogy and geochemistry data are presented for thirty-seven shales,four concretions,two carbonate sediments and seven lignites from the Marathousa coal field of the Megalopolis Basin in Greece.The argillaceous rocks consist of chlorite,illite,kaolinte,albite,quartz.opal-A,calcite and dolomite;the concretions of aragonite,gypsum and pyrite;and the carbonate rocks of calcite,quartz and illite.The mineral matter in the lignites consists of gypsum,quartz,albite,chlorite,illite,opal-A,dolomite,pyrite,and rarely calcite and kaolinite Athree-factor model explains the total variaition of major and trace elements in the argillaceous sediments.The first factor is an aluminosilicate factor and involves the following elements:Al,Si,Mg,Na,K,Ti,Mn,Nb,Y,Rb,Zn,Cu,Ni,Cr,Nband V,associated with chlorite,albite and illite.The second factor involves the elements Ca,Sr,Ba,Znand Sc and is related to carbonate lithology and mainly the carbonate concretions with gypsum.The third factor involves Fe and Ce with a weak association with Mn.The diagenesis of the Marathousa sediments and lignites was not very advanced as indicated by (a) the total thickness of the sequence (500m),(b) the presence of biogenic silica(opal-A) and (c) the age of the deposit(Pleistocene).FOr these reasons the rpresence of chlorite,illite and kaolinite in the sediments and lignite is due not to diagenetic reactions but to weathering of the flysch and metamorphic rocks at the edges of the Megalopolis Basin and transport of the weathering products(illite,chlorite,kaolinite)into the basin of deposition.The diagenetic minerals of the Marathousa sequence include pyrite,gypsum,dolomite and aragonite.     

The Trace Element Distribution Patterns of Ediacaran-Early Cambrian Black Shales and the Origin of Selenium in the Guangning Area, Western Guangdong Province, South China

The Ediacaran and early Cambrian black shales are widespread across the South China Craton (Yangtze and Cathaysia blocks). However, the trace element distribution patterns of the Ediacaran and early Cambrian black shales in the Cathaysia Block are still unclear. In this study, thirty-four black shale samples in the Lechangxia Group (Ediacaran) and thirteen black shale samples in the lower Bacun Group (early Cambrian) from Guangning area, western Guangdong Province, South China, were analyzed for major and trace elements concentrations. Compared to the upper continental crust, the Ediacaran black shales exhibit strongly enriched Se, Ga, and As with enrichment factor values (EF) higher than 10, significantly enriched Bi and Rb (10>EF>5), weakly enriched Mo, Ba, Cs, V, In, Be, Tl, and Th (5>EF>2), normal U, Cr, Cd, Sc, Pb, Cu, and Li (2>EF>0.5), and depleted Ni, Zn, Sr, and Co. Early Cambrian black shales display strongly enriched Se, Ga, and As, significantly enriched Ba, Bi, and Rb, weakly enriched Mo, Cs, Cd, V, U, Be, In, and Tl, normal Sc, Th, Cr, Li, Cu, Ni, and Pb and depleted Co, Zn, and Sr. Moreover, Se is the most enriched trace element in the Ediacaran and early Cambrian black shales: concentrations vary from 0.25 to 30.09 ppm and 0.54 to 5.01 ppm, and averaging 4.84 and 1.72 ppm, with average EF values of 96.87 and 34.32, for the Ediacaran and early Cambrian shales respectively. The average concentration of Se in the Ediacaran black shales is 2.8 times higher than that of early Cambrian black shales. Se contents in the Ediacaran and early Cambrian black shales exhibit significant variation (P = 0.03). Provenance analysis showed that Se contents of both the Ediacaran and early Cambrian black shales were without detrital provenance and volcanoclastic sources, but of hydrothermal origin. The deep sources of Se and the presence of pyrite may explain the higher Se contents in the Ediacaran black shales. Similar with the Se-rich characteristics of the contemporaneous black shales in the south Qingling Mountain and Yangtze block, the Ediacaran and early Cambrian black shales in Guangning area, Cathaysia, are also enriched in Se, which may provide a clue for looking for the selenium-rich resources in western Guangdong Province.     

喀斯特断陷盆地水资源高效开发利用模式构建

在调查研究典型喀斯特断陷盆地水文地质特征、地表水文过程、“五水”转换及水资源均衡,研发地下水高效开发利用、地表水调蓄、水污染风险评估与水质修复、农田节水灌溉及土壤保墒、水资源优化调控等系列技术的基础上,以可持续发展和系统科学理论为指导,构建了喀斯特断陷盆地水资源高效开发利用模式,包括理论与技术支撑体系和开发利用工程体系两个层次。前者的基本构成及内涵为:水资源高效开发利用工作流程、理论依据及技术支撑,是模式的理论与技术内涵;后者为沿着盆地地表、地下水的形成、运动和转换过程,从上游山区到下游河谷区,逐级分区部署的水资源开发利用工程体系,工程布局做到因地制宜、科学合理,大、中、小、微型并举,集中供水与分散供水兼顾,同时系统推进水质修复、水循环利用、节约用水等措施,实现水资源的高效和可持续开发利用。      

Selenium and heavy metals content in some Mediterranean soils

The study of metal contents in industrial, agricultural or/and polluted soils compared with natural or unpolluted soils is currently necessary to obtain reference values and to assess soil contamination. Nonetheless, very few works published appear in international journals on elements like Se, Li and Sr in Spanish soils. This study determines the total levels of Se, Li, Sr, As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn, Fe, Mn and Ba in 14 natural (unpolluted) soils (Gypsisols, Leptosols, Arenosols and Acrisols), 14 agricultural soils (Anthrosols, Fluvisols and Luvisols), and 4 industrial–urban affected-surface soil horizons (Anthrosols and Fluvisols) of Eastern Spain. The geochemical baseline concentrations (GBC) and reference values (RV) have been established, and the relationships among elements and also between soil properties and elemental concentrations have been analysed. The RV obtained in this study were (mg kg⁻¹): Se 2.68, Li 115, Sr 298, Cd 0.97, Co 35, Cr 217, Cu 46, Ni 50, Pb 137, V 120, Zn 246, Fe 124,472, Mn 2691, and Ba 743. The RV for Se and Li were used as a preliminary approach to assess soil contamination in Spanish soils. The results confirm human impact on Sr, As, Cd, Cr, Cu, Ni, Pb and Zn soil concentrations, but evidence no deviation from natural Se, Li, Co, V, Fe, Mn and Ba concentrations. The results obtained from the statistical analysis reveal significant correlations between some elements and clay and soil organic matter (SOM) contents, indicating that metal concentrations are controlled by soil composition. One particularly interesting finding is the high correlation coefficients obtained between SOM and Se, Cd, Cr, V, Fe, and Mn, and between clay and Cd, Zn, V, Fe and Mn. Once again, these facts confirm the role of SOM and clay minerals in soil functions and that soil is an ecosystem element responsible for maintaining environmental quality.     

Water quality index and fractal dimension analysis of water parameters

Statistical analysis of water quality parameters were analyzed at Harike Lake on the confluence of Beas and Sutlej rivers of Punjab (India). Mean, median, mode, standard deviation, kurtosis, skewness, coefficient of variation, regression lines, correlation coefficient, Hurst exponent, fractal dimension and predictability index were estimated for each water parameter. Monthly variation of water quality index using month-wise and parameter-wise value of quality rating and actual value present in water sample was calculated and compared with World Health Organization/Environmental Protection Agency standard value of these parameters. It was observed that Brownian time series behavior exists of potential of hydrogen with total dissolved solids, hardness, alkalinity, sulfate, chloride and conductance parameters; biochemical oxygen demand with total dissolved solids, hardness, alkalinity, sulfate, chloride, conductance and calcium parameters; dissolved oxygen with total dissolved solids, hardness, alkalinity, sulfate, chloride, conductance and calcium parameters; ferrous with total dissolved solids, hardness, alkalinity, sulfate, conductance and calcium parameters; chromium with total dissolved solids, hardness, alkalinity, sulfate, chloride, conductance and zinc parameters; zinc with total dissolved solids, hardness, sulfate, chloride, conductance and calcium parameters; fluoride with total dissolved solids, hardness, alkalinity, sulfate, chloride and conductance parameters; nitrate with total dissolved solids, sulfate and conductance parameters; nitrite with potential of hydrogen, total dissolved solids, hardness, alkalinity, sulfate, chloride, conductance and calcium parameters. Also, using water quality index, it was observed that water of the lake was severely contaminated and became unfit for drinking and industrial use.     

华北地块东南缘中生代侵入杂岩中所含榴辉岩类包体矿物微量元素地球化学特征及其意义

华北地块东南缘中生代侵入杂岩中所含榴辉岩类包体中矿物的分析结果表明, 组成榴辉岩类包体的各矿物之间元素的分配在榴辉岩相变质阶段已经达到了化学平衡;石榴石中Al、Fe、Mn, 单斜辉石中Na、Mg、Ca, 角闪石中Na、Mg、Fe等主量元素含量与其全岩之间均呈良好的正相关, 受全岩成分制约;石榴石明显富集HREE、贫LREE, 单斜辉石相对富集LREE、MREE、贫HREE, 两者轻、重稀土含量呈相互消长的互补关系, 石榴石和单斜辉石中分别富集Y、Sr, Ga和过渡族元素Sc、Ti、V、Cr、Co等含量较高, 其含量受全岩成分控制;金红石中稀土元素的含量很少, Fe、Al、Mg、Ca、Mn、Nb、Ta、Cr和Zr含量相对较高, Rb、Sr、Ba含量极低, 部分微量元素(如Nb、Cr、Fe、V、W等)含量与其原岩有继承和对应关系;部分原生或/和退变角闪石的REE配分模式分别与单斜辉石和石榴石相似, 过渡族金属元素等的含量与石榴石、单斜辉石和全岩具有一定的相关性, 角闪石容纳Na、K、Sr、Rb、Ba等元素的能力较强, 其成分除受全岩成分的制约外, 石榴石、单斜辉石对其形成也有影响。榴辉岩类包体与其寄主中生代侵入杂岩中部分高价态/高场强元素(HFSE)和重稀土元素(HREE)呈相互消长的关系。榴辉岩的形成与扬子地块和华北地块之间的俯冲-碰撞作用有关。     

论油气勘探开发中的水文地质,工程地质方法技术

油气勘探开发涉及水文地质,工程地质许多领域及其方法技术,油气水烃类,矿化度等有机,无机地球化学信息是判别油气成藏与油气运移的重要依据,通过对此类地化参数的检测可有效地指导油气勘探,如塔中,松南。油田水文地质直接关系到油田开发方案的合理设计与顺利实施－对油田水文地质条件前期分析,开采中水文地质参数的跟踪监测,选择合适的注水方式,时机及注水量,是油田稳产增产的关键;钻井,试采工程技术受不同工区（地表,     

行星矿产及行星资源地质学初论

了解并利用行星矿产资源、可持续永久开发太空成为行星科学与深空探测的一项重要研究任务。而行星矿产资源的开发利用,需要运用行星科学与地质学特别是矿床学的基础理论,利用行星观测、探测及开发技术方法,研究行星矿产资源形成演化规律,查明行星矿产资源的类型、特征、储量和分布规律;进行行星矿产资源的地质调查、岩石-矿石成分、结构与性能、元素赋存状态、开发利用条件评价与预测,为行星矿产资源开发与太空的可持续永久开发建设提供基础理论与关键技术方法。因此,行星矿产资源学是研究行星矿产资源的品种、类型与分布规律、行星矿产资源成因演化与比较行星成矿学、行星矿产资源勘查评价技术与开采利用工程学的交叉学科。笔者从行星资源地质学的视角,从地球与月球的层圈结构、演化历史、岩石组成与表生环境,研判月球可能产出的矿产资源类型。认为与月海玄武岩、月幔(柱)和陨石撞击成因的层状岩体与镁铁-超镁铁质小岩体有关的铬铁矿-铜镍钴硫化物-铂族元素-钒钛磁铁矿-金刚石矿产,KREEP岩以及月幔柱熔融上覆岩石圈所产生碱性岩相伴的铌-钽-铍-铀等稀有-稀土矿产,具有形成条件与产出可能,从而拓展可能的矿产类型、品种,从更宽广的视角研究月球矿产并规划月球基地建设资源供给。火星上由于水(以及可能存在的板块构造)的存在,除岩浆矿床之外,火星可能具备发育与化学风化沉积、次生富集作用以及变质作用有关矿产的形成条件,具有形成金属与非金属资源的禀赋,可与地球矿产相媲美。未来行星资源地质学应加强地质学、行星化学、行星地质学、行星物理学、矿业工程、冶金工程和材料学的交叉融合及理论应用,发展行星地质勘探方法与智能机器人工程技术,发展高/低温、高/低压、高辐照、低/微重力环境条件下样品采集、加工、多尺度测试分析理论与方法,培养行星资源地质资源与开发工程学科人才。     

当代世界的矿产资源

论述了最近５０年来世界矿产资源供求关系的变化和现状,着重讨论了独联体国家、北美地区西欧国家、中欧和东欧国家、日本、澳大利亚和南非共和国、欧佩克国家的矿产资源情况。俄罗斯仍是矿产资源大国,但矿山开采工业每况愈下,许多矿种没有清楚的探明储量。独联体一些国家某些矿种储量大,但没有维持经济正常发展的其它矿种。美国的某些矿种储量大,但其它矿种不足,例如石油、天然气、煤、铝、铜、铅、锌、锡、镍、钴、钨等需求量     

沉积岩石学的室内研究方法综述*

为了正确、高效地完成沉积岩石学的研究内容,势必要求沉积岩石学的研究方法具多样性和先进性,并可在实践中不断完善和发展。作者着重阐述了沉积岩石学的室内研究方法,旨在为沉积岩石学研究者系统介绍合适的技术和手段。室内研究方法主要包括矿物成分与结构分析、无机与有机地球化学分析和其他实验方法。矿物成分与结构分析主要包括薄片鉴定、粒度分析、重矿物分析、激光拉曼光谱和荧光光谱分析、微区矿物识别和元素分析、阴极发光分析,以及X射线衍射、红外光谱和热谱分析。无机地球化学分析主要包括元素地球化学、风化强度的量化、稳定同位素分析和测年分析。有机地球化学分析主要包括总有机碳、岩石热解分析、镜质体分析、气相色谱分析和生物标志物色谱—质谱分析、非生物标志化合物和有机化合物稳定同位素组成分析等。此外,沉积岩石学的室内研究方法还包括磁性矿物学、物理和数值模拟、岩石地球物理方法和地质大数据方法等。新技术、新方法的应用和发展,是促进沉积岩石学发展的重要原因之一。     

平阴县土壤地球化学基准值与背景值研究

平阴县土壤地球化学调查是按每1km^2采集1件表层样,4km^2组合成1件分析样,每4km2采集1件深层样,16km^2组合成1件分析样,分析测试Ag,As,Au,B,Ba,Be,Bi,Br,C,Cd,Ce,C1,Co,Cr,Cu,F等54元素或指标;统计了这些元素或指标的土壤地球化学基准值与背景值等参数;研究了区内土壤地球化学基准值、背景值与全国、黄河下游流域土壤及平原区、丘陵区土壤的差异;对比区内土壤地球化学基准值与背景值变化,认为区内大部分元素或指标在表层土壤中的含量继承了土壤母质,后期人类活动对其影响较小,但C,Cd,C1,Hg,P,N,S,Se,Corg等元素或指标在表层土壤中已明显富集,表明表生作用和人类活动等因素已对这些元素或指标的含量变化与分布分配产生明显影响。     

江西修水地区中元古界双桥山群修水组内波内潮汐沉积

详细论述了江西修水地区中元古界双桥山群修水组中的深水牵引流内波内潮汐的沉积特征及形成环境。深水牵引流内波内潮汐沉积具双向递变、单向递变和对偶层递变层序；其岩相可划分为双向交错层理砂岩相，单向交错层理砂岩相，砂岩、板岩薄互层相，波状、脉状、透镜状细砂岩、粉砂岩、板岩相；发育双向和单向交错层理、曲线型和干涉波痕及波状、脉状、透镜状层理；在综合分析的基础上，进一步建立了该区水道型和非水道型内波内潮汐沉积模式。     

现代岩溶学学科体系

作为现代地球科学学科体系重要组成部分的岩溶学一直以来都被认为是地质学、地理学、环境科学、生态学之间的交叉、边缘学科,并未建立起自己独立的学科体系。面对全球岩溶地貌分布广泛、生态环境脆弱及问题复杂多样且同经济社会发展密切相关等情况,文章在简要回顾国内外岩溶学发展历程的基础上,通过对近三十年国内外岩溶研究相关学科发展情况的分析,以地球系统科学、岩溶动力学理论为指导,讨论构建现代岩溶学学科体系这一重要问题。文章围绕岩溶动力系统的四大功能和岩溶区资源环境生态问题的实际,从地质学、地理学、地球化学、生态学、环境学、水文学等与现代岩溶学研究相关的学科出发,尝试构建现代岩溶学学科体系,其主要的学科分支包括岩溶地质学、岩溶地貌学、岩溶水文地质学、岩溶环境学、岩溶工程地质学、岩溶生态学、岩溶资源学、全球变化岩溶学、洞穴学等九个分支学科,并简要阐述了各分支学科的科学内涵和定位。分支学科的构建,体现了国际岩溶科学研究中相关研究方向和学科发展独立性和交叉性的统一,体现了国际岩溶学发展的现状和趋势,对于国际岩溶科学的发展具有较为重要的意义。      

祁连山黑河上游不同退化草地土壤理化性质及养分和酶活性的变化规律

为了揭示草地退化过程中土壤理化性质及养分和酶的变化规律,在祁连山黑河上游俄博岭研究了4种草地土壤理化性质及养分和酶活性的变化规律.结果表明:未退化草地与退化草地、中度退化草地和重度退化草地比较,0~60 cm土层有机碳、有机碳密度、有机碳储量随退化程度加剧呈显著减少趋势;土壤理化特性的总孔隙度、团聚体、物理性粘粒、饱和蓄水量、田间持水量随土壤退化加剧呈减少趋势,同时CEC、碱解氮、速效磷、速效钾、脲酶、蔗糖酶、磷酸酶、多酚氧化酶、过氧化氢酶等养分和酶活性也随土壤退化加剧呈明显减少变化.随着土壤退化加剧,容重、物理性砂粒、石砾、pH值以及CaCO3含量均有明显的增长.4种草地0~60 cm土层孔隙度、团聚体、物理性粘粒、饱和蓄水量、田间持水量、土壤有机碳、速效氮磷钾和酶活性均值由大到小的变化顺序为:未退化草地轻度退化草地中度退化草地重度退化草地;容重、物理性砂粒、石砾、pH、CaCO3均值由小到大的变化顺序为:未退化草地轻度退化草地中度退化草地重度退化草地.不同层次孔隙度、团聚体、物理性粘粒、饱和蓄水量、田间持水量、土壤有机碳、速效氮磷钾和酶活性均值随着土层垂直深度的增加而递减,而容重、物理性砂粒、石砾、pH、CaCO3均值随着土层垂直深度的增加而递增.     

微生物岩研究的发展与展望

概述了微生物岩的定义、研究范围和实用意义；划分了早期启蒙阶段、古生物学派与现实主义（沉积）学派对立阶段、比较现实主义（沉积学）阶段和微生物沉积学阶段等４个研究发展阶段（涉及微生物岩的岩石、微生物、生态系、环境、分类和演化）；介绍了微生物礁丘、热泉沉积和磷铁锰微生物岩等研究热点；指出在构造类型、沉积环境、组成岩石和成因标志等方面的发展趋势；提出当前任务是要分析鉴定微生物岩的细菌化石，微生物成因的结构构造和矿物，标志元素、同位素和生物标志物，以及微生物生态系统和成岩成矿机理.     

Commingling and mixing of S-type peraluminous, ultrapotassic and basaltic magmas in the Cayconi volcanic field, Cordillera de Carabaya, SE Peru

The Cayconi district of the Cordillera de Carabaya, SE Peru, exposes a remnant of an upper Oligocene–Lower Miocene (22.2–24.4 Ma) volcanic field, comprising a diverse assemblage of S-type silicic and calc-alkaline basaltic to andesitic flows, members of the Picotani Group of the Central Andean Inner Arc. Basaltic flows containing olivine, plagioclase, clinopyroxene, ilmenite and glass, and glassy rhyolitic agglutinates with phenocrystic quartz, cordierite, plagioclase, sanidine, ilmenite and apatite, respectively exhibit mineralogical and geochemical features characteristic of medium-K mafic and Lachlan S-type silicic lavas. Cordierite-bearing dacitic agglomerates and lavas, however, are characterized by dispersed, melanocratic micro-enclaves and phenocrysts set in a fine-grained quartzo-feldspathic matrix. They contain a bimodal mica population, comprising phlogopite and biotite, as well as complexly zoned, sieve-textured plagioclase grains, sector-zoned cordierite, sanidine, quartz, irregular patches of replaced olivine, clinopyroxene and orthopyroxene and accessory phases including zircon, monazite, ilmenite and chromite. The coexistence of minerals not in mutual equilibrium and the growth/dissolution textures exhibited by plagioclase are features indicative of magmatic commingling and mixing. Trachytic-textured andesite flows interlayered with olivine+plagioclase–glomerophyric, calc-alkaline basalts have a phenocrystic assemblage of resorbed orthopyroxene and plagioclase and exhibit melanocratic groundmass patches of microphenocrystic phlogopite, Ca-rich sanidine, ilmenite and aluminous spinel. The mineralogical and mineral chemical relationships in both the dacites and the trachytic-textured andesites imply subvolcanic mixing between distinct ultrapotassic mafic melts, not represented by exposed rock types, and both the S-type silicic and calc-alkaline mafic magmas. Such mixing relationships are commonly observed in the Oligo-Miocene rocks of the Cordillera de Carabaya, suggesting that the S-type rocks in this area and, by extension, elsewhere derive their unusually high K₂O, Ba, Sr, Cr and Ni concentrations from commingling and mixing with diverse, mantle-derived potassic mafic magmas.     

浙北地区土壤元素有效量及其影响因素研究

浙江省北部地区调查研究表明,受成土母质来源、土壤类型及其理化性质等因素的影响,土壤元素全量、有效量及其有效度表现为:1)低山丘陵岗地土壤中As,Cd,Mo,Pb和Se全量较高,As,Cd,Fe,Pb,Se和Zn有效量较高;而山前平原区土壤中Hg,Pb和Zn元素全量较高,由地表向深部的下降递度较小,显示为原始沉积成因特点。2)中酸性、富含有机质的红壤和水稻土中As,Cd,Cu,Fe,Mn,Pb,Se,Zn等元素有效度较高,水稻土Hg有效度最低;弱碱性或碱性、贫有机质的潮土和滨海盐砂土中As,Cd,Cu,Fe,Mn,Pb,Se,Zn等元素有效量较低,但B有效量及有效度均较高。3)统计分析表明,土壤中Mn,Cu,Zn,Mo,Cd,Pb,Se等元素全量与有效量间具显著正相关性,表明全量是有效量的重要影响控制因素;有机质含量与Fe,Cu,Zn,Cd,As和Pb有效度间为显著正相关,说明有机质较高有利于土壤元素活化;Fe,Cu,Zn,Cd,As,Pb和Se有效度与pH值为显著负相关,表明土壤酸性增强(酸化)会增加这类元素的生物有效性。