Bacterial contribution to sedimentary organic matter; a comparative study of lipid moieties in bacteria and Recent sediments     

H. Goossens  W. Irene  C. Rijpstra  R.R. Düren  J.W. De Leeuw  P.A. Schenck 《Organic Geochemistry》1986,10(4-6)

A systematic study of the lipid composition of thirteen bacterial species and three Recent sediments (methanogenic sediment, cyanobacterial mat and evaporative gypsum crust) was undertaken in an attempt to recognize bacterial organic matter in sediments. A sequential method, which distinguishes between three different modes of occurrence of lipid moieties (free, OH⁻- and H⁺-labile), was applied. The acid-labile fractions are discussed.The three main groups of bacteria, archaebacteria, gram-positive eubacteria and gram-negative eubacteria, are easily distinguished. Methanogenic and extremely halophilic archaebacteria are characterized by the presence of diphytanyl glyceryl ether and the absence of fatty acids. The gram-positive eubacteria contain primarily iso- and anteiso-branched fatty acids whereas the gram-negative bacteria and sediments are dominated by β- and α-hydroxy fatty acids. A wide variety of H⁺-labile hydroxy fatty acids was observed which included several, as yet unknown, structures.β-Hydroxy fatty acids in this H⁺-labile mode of occurrence are exclusively present in bacteria. Their distribution patterns in sediments are considered “fingerprints” of past and present bacterial populations. The specific differences in β -hydroxy fatty acid compositions observed in the different bacteria and the three sediments investigated, suggest that amide-linked β-hydroxy fatty acid patterns are useful as markers of bacterial populations and therefore of environmental conditions.  相似文献   

安徽沙溪斑岩铜矿床中伴生金的赋存状态     

季汝清  周文雅  张仕兰 《岩石矿物学杂志》1987,6(1):64-71

矿体赋存于燕山早期形成的石英闪长斑岩及闪长玢岩中。矿石的主要金属矿物有:黄铜矿、黄铁矿、斑铜矿、自然金、银金矿等。黄铁矿、黄铜矿是金的主要载体矿物。通过矿相鉴定、单矿物化学研究、物相分析,电子探针分析、透射电镜分析等,查明了金的赋存状态。显微金呈包体状态包含于黄铜矿之中,粒径为5—20微米。次显微佥呈球状、链状及不规则状分布于黄铁矿晶体边缘及微裂隙中。经探针分析,金的成色为790—850,平均成色为815。经物相分析,金的矿物量为85%—95%,表明金是以矿物态存在。我国玉龙、德兴、多宝山等地的斑岩铜矿都有不同程度金的显示,查明金的富集规律及赋存状态,对于综合开发斑岩铜矿,提高矿床利用价值将会开拓新的前景。  相似文献   

高密度电阻率法在东安金矿床勘探中的应用     

张海心  杨言辰 《吉林地质》2005,24(4):76-79

本文论述了高密度电阻率法在逊克县东安岩金矿床勘探中的应用效果;阐明了该方法在地质勘查中解决高阻脉状金矿体产状及埋深的技术手段.  相似文献   

中国煤中的氟   总被引：9，自引：0，他引：9  

陈萍  唐修义 《中国煤田地质》2002,14(Z1):25-28

氟是煤中所含微量元素中丰度较高的少数几种元素之一。对我国581个煤样分析数据的统计表明,多数样品氟含量处于20～300mg/kg,平均40mg/kg,个别超过1000mg/kg。氟在煤中赋存状态有:①独立的氟矿物;②以类质同象存在于矿物晶格内;③被矿物吸附;④以F-离子形式溶于水中。在煤中所含微量元素中,氟是对植物、动物和人体健康的影响面最大的元素。  相似文献   

从有机包体特征探讨油气运移时间—以东海盆地西湖坳陷花港组储层为例     

叶素娟  姜亮 《矿物岩石》2001,21(2):38-41

通过对西湖坳陷花港组砂岩成岩作用过程中捕获的有机包裹体研究，表明不同成岩阶段形成的自生矿物中有机包裹体的类型，产状和组分特征各不相同。本研究采用激光拉曼光谱技术测定包裹体有机组分以及α石英ESR测年技术，通过包裹体有机组分的成熟度特征，结合区域埋藏史和烃源岩有机质成熟史，确定了砂岩成岩史与有机质成熟史，并探讨了油气运移时间的关系。本区存在两期油气运移；一期与砂岩晚成岩A阶段的石英加大发育期一致，年龄约为24Ma以后，另一期则与N1末期的龙井运动引起的挤压所造成的裂隙有关。  相似文献   

The　relationships　between　earthquakes　and　positions　of　the　sun　and　moon（Ⅱ）——Sometemporalcharacteristicsoftheaftershocksequencesofstrongearthquakes     

高伟  刘蒲雄  许绍燮  彭克银  吕晓健 《地震学报(英文版)》1996,(3)

Ｔｈｅｒｅｌａｔｉｏｎｓｈｉｐｓｂｅｔｗｅｎｅａｒｔｈｑｕａｋｅｓａｎｄｐｏｓｉｔｉｏｎｓｏｆｔｈｅｓｕｎａｎｄｍｏｏｎ（Ⅱ）——Ｓｏｍｅｔｅｍｐｏｒａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅａｆｔｅｒｓｈｏｃｋｓｅｑｕｅｎｃｅｓｏｆｓｔｒｏｎｇｅ...  相似文献   

The relations between modulus of elasticity and temperature in the context of the experimental simulation of rock weathering by fire     

A. S. Goudie  R. J. Allison  S. J. McLaren 《地球表面变化过程与地形》1992,17(6):605-615

Fires occur frequently in many biomes and generate high temperatures on the ground surface. There are many field examples of fire causing rock disintegration. The simulation of fire in the laboratory (using a furnace) and the monitoring of changes in rock modulus of elasticity (with a Grindosonic apparatus), reveal that different rocks respond differently to heating. Significant decreases in elasticity occur at temperatures as low as 200°C and granites display particularly marked reductions. Extended periods of heating are not required for significant reductions to occur. It is postulated that the degree of change in elasticity as a result of simulated fire is such that rock outcrops subjected to real fires are likely to be sufficiently modified as to increase their susceptibility to erosion and weathering processes.  相似文献   

Estimation of exploration potential of a metallogenic unit by parametric modeling of the distribution of mineral occurrences when exploration is incomplete. Case study: Walker Lake quadrangle of Nevada and California     

Tetevi B. Wilson  DeVerle P. Harris 《Mathematical Geology》1992,24(7):789-805

Analysis of the distribution of ore-bodies in space can be useful generally in the estimation of mineral resources or the management of exploration. This study is directed to analysis of the undiscovered potential of well known areas of mining district size, referred to as metallogenic units (MUs). The analysis employs an effort-adjusted and truncated probability model for number of occurrences within a subdivision (quadrat) of a MU and Monte Carlo sampling to generate an approximation to the probability distribution for number of occurrences and number of mines within an MU when it is totally explored. Exploration potential for Monitor, Bodie, Aurora, and Camp Douglas MUs (Walker Lake quadrangle of Nevada and California) are estimated to be 9, 4, 7, and 4 mines, respectively.  相似文献   

GIS支持下森林火场蔓延的空间模拟     

朱启疆  高峰  张振威 《遥感学报》1995,(2)

林火扩展具有时间和空间特征。对火场模拟必须建立在空间背景数据库之上，即在地理信息系统和遥感技术的辅助下完成。森林火灾的发生发展有内在和外在因素的影响，内在因素包括了可燃物类型、可燃物湿度、地形，考虑这些因素形成了像元尺度植被燃烧基本历时图；外在因素主要是气候的影响，文中利用生成的植被起火概率图控制像元是否起火。在火场扩展中将Ｒｏｔｈｅｒｍｅｌ模型和经验模型结合使用，并考虑了坡度和风向带方向的因素的影响。最后利用迷宫算法在计算机上实现了火场在地理信息系统支持下的空间蔓延动态模拟。  相似文献   

砷、汞、锑、金矿床铊的赋存状态、成矿模式与找矿标志   总被引：6，自引：2，他引：6       下载免费PDF全文

张忠  龙江平  张宝贵 《地质论评》1995,41(4):63-370

研究表明,在砷、汞、锑、金矿床中普遍含有较高的铊,并发现富铊雄黄矿和铊单矿物。铊亲硫和亲石地球化学性质决定铊赋存形式。在岩矿石中铊主要呈单矿物,分散状态铊占次要地位。根据富铊雄黄矿床成矿特点,铊赋存状态,岩矿石中铊含量及其与砷、汞、锑、金相关关系,尝试性提出成矿模式和找矿标志。岩矿石中铊含量>10×10~(-6),5×10~(-6)—10×10~(-6),1×10~(-6)—5×10~(-6),分别为矿床、矿田和矿带的找矿标志。  相似文献