围山城金银多金属矿带 成矿作用的地球化学特征及找矿标志     

蒋建强  何孝良  姚晓华  王云 《物探与化探》2005,29(2):122-127

围山城金银多金属成矿带处于秦岭造山带东段核部,其由多个形成于不同构造环境,有着各自独立的建造特征、变形变质和构造演化序列的构造地层地体,经多次聚合后拼贴并焊结为一体的复杂构造带。研究该矿带成矿作用和在不同时代岩浆岩、主要脉岩、围岩蚀变、微量元素及地球化学特征,了解元素富集变化规律,建立了地质-地球化学找矿标志。  相似文献   

Pesticide and Trace Metal Concentrations in Queensland Estuarine Crabs     

M.R Mortimer 《Marine pollution bulletin》2000,41(7-12):359-366

Trace metals, metalloids and pesticide content were quantified in intertidal burrowing crabs Australoplax tridentata and a portunid Scylla serrata sampled from estuaries on the east coast of Australia between Cairns and Brisbane. Residues of dieldrin occurred at all locations, heptachlor epoxide and DDT (principally metabolites DDD and DDE) at most, reflecting historical use. Chlordane, chlorpyrifos and endosulfan were only detected in crabs in the urban Brisbane area, and neither hexachlorobenzene (HCB) or polychlorinated biphenyls (PCBs) were quantifiable. Calculations of ambient exposures to organochlorines based on residues in crab tissues indicated that dieldrin exceeded national water quality guidelines for protection of aquatic ecosystems at all sampling locations, but exposure to DDT and its metabolites was below the threshold of concern. Concentrations of trace metals and metalloids generally reflected sediment data and likely sources.  相似文献   

Sources, input pathways, and distributions of Fe, Cu, and Zn in a Chesapeake Bay tidal freshwater marsh     

M.A. Knight  G. B. Pasternack 《Environmental Geology》2000,39(12):1359-1371

Tidal freshwater marshes exist at the interface between watersheds and estuaries, and thus may serve as critical buffers protecting estuaries from anthropogenic metal pollution. Bi-weekly samples of newly deposited marsh sediments were collected and analyzed for Cu, Zn, and Fe concentrations over 21 months from July 1995 to March 1997 in five distinct habitats at the head of Bush River, Maryland. Bi-weekly anthropogenic metal enrichments ranged from 0.9–4.7. Anthropogenic excess metal loadings averaged over 1996 ranged from 6–306 and 25–1302 μg cm⁻² year⁻¹ between sites for Cu and Zn, respectively. Based on Fe-normalized trace metal signatures, Susquehanna River sediment does not significantly contribute to upper Bush River. Organic matter was found to dilute total metal concentrations, whereas past studies suggested organics enhance labile metal content. Analysis of metal input pathways shows that marsh metals are primarily imported from nearby subtidal accumulations of historic watershed material by tidal flushing. Received: 29 April 1999 / Accepted: 7 December 1999  相似文献   

Barite concretions as evidence of pauses in sedimentation in the Marnes Bleues Formation of the Vocontian Basin (SE France)     

Jean-G. Brhret  Hans-J. Brumsack 《Sedimentary Geology》2000,130(3-4):205-228

Several intervals rich in barite nodules occur in the mid-Cretaceous marls of the Vocontian Trough (SE France). These concretions, which grew on heterogeneities in the sediment, are arranged as horizons parallel to the bedding, and are often associated with carbonate and phosphate nodules. Detailed sedimentological and stratigraphical observations suggest that they represent the consequence of short-term pauses in sedimentation during early diagenesis, but the most important occurrences of barite are below prominent discontinuities. This may be explained by the frequency of pauses in sedimentation caused by a progressive starvation, or an increase in the energy of bottom-water currents. The high number of barite occurrences on the basin margins is directly linked to the recurrence of sedimentary breaks. The geochemical data show that the host sediment corresponds to a pelagic setting, far from hydrothermal influences, but generally in a restricted, dysoxic to suboxic, depositional environment. The sulphur isotopic composition of the barite sulphate (+16 to +76‰ rel. CDT) supports the hypothesis of an early diagenetic origin of the barite nodules. Their genesis may be explained by the fixation of a diagenetic front corresponding to the penetration of a sulphate reduction zone from the seawater–sediment interface down in the sediment which is in contact with barium-rich porewaters expelled upwards as a consequence of compaction. The barium of biogenic origin, initially stored in the underlying black shale, was mobilized under strongly reducing conditions. Such fixation is normally induced by a pause or a stop in sedimentation due to starvation or renewed bottom-water circulation. Together with other concretions, the barite nodules mark condensed stratigraphic intervals and often represent major breaks. As such they shed light on variations in sedimentary activity and their importance in the sedimentology and stratigraphy of pelagic marly sequences cannot be ignored.  相似文献   

Formation of the Devonian Fengtai Hydrothermal Brine Basin and the Metallogeny of Gold and Lead-Zinc Mineralizations in Shaanxi     

ZHU Huaping  GUO Jian  LIU Ping  LI Falin  HUANG Changqing Northwest Exploration Bureau of Geology  State Bureau of Nonferrous Metals Industry  Xi ''an 《《地质学报》英文版》2000,74(3):500-503

The study of the relationships between the hydrothermal sedimentary formations and the gold andlead-zinc mineralizations in the Devonian Fengtai basin in Shaanxi shows that there was a hydrothermal brine sedimentary event which was inserted into the normal sedimentary background from the late Middle Devonian to the early Late Devonian. This event is closely related to gold and lead-zinc mineralizations in this area.  相似文献   

镇旬铅锌矿田主要矿物的标型特征研究   总被引：1，自引：1，他引：0  

侯满堂  王文昭 《陕西地质》2000,18(2):9-15,37

闪锌矿、方铅矿、黄铁矿、石英及重晶石镇旬铅锌矿田的主要矿物,不同世代的闪锌矿,其形态,颜色及矿物共生组合的差异,反映了形成条件的差异,主要矿物的化学成份。微量元素含量,反映了本区铅锌矿床与西成一凤太地区的喷流沉积改造型铅放床一样,即与国内岩浆热液型铅锌矿床有相似之处,更与典型的沉积改造型铅锌矿床类型。  相似文献   

新庄孜矿塌陷区煤矸石中重金属迁移对覆土影响   总被引：5，自引：0，他引：5  

邵群 《煤田地质与勘探》2007,35(6):34-36

针对淮南新庄孜矿覆土造地中煤矸石填充带来的重金属元素迁移污染进行了研究。结果表明:煤矸石中有毒元素Pb、As、Cd、Hg向覆土有一定迁移,且距离煤矸石越近的土壤中重金属含量明显增高;虽然覆土中重金属含量均超过淮南土壤的均值,但是该土壤中Pb、As和Cd含量均符合国家二级标准;其中土壤中Hg含量分别符合国家一级标准和二级标准。须对覆土中重金属元素进行跟踪研究。   相似文献   

大兴安岭东南段铜多金属成矿构造条件   总被引：10，自引：0，他引：10  

张永正  李秀荣  杨宏智  邵军 《地质与资源》2007,16(1):38-41

论述了大兴安岭成矿带区域构造演化特征.成矿带存在前寒武纪、古生代、中生代3个构造层,各构造层的断裂体系构成了大兴安岭东南段的等距、网格状的构造格局.铜多金属成矿受“带、块、结、点、缘”区域性构造控制.不同型式的构造控制不同成因类型矿床的形成.  相似文献   

A Routine Method for Oxide and Hydroxide Interference Corrections in ICP-MS Chemical Analysis of Environmental and Geological Samples     

Sébastien Aries  Michel Valladon  Mireille Polvé  Bernard Dupré 《Geostandards and Geoanalytical Research》2000,24(1):19-31

Inductively coupled plasma-mass spectrometry has revolutionized the field of multi-elemental analysis because of its high sensitivity and speed of analysis. However, problems with polyatomic ion interferences during routine analysis can give rise to inaccuracies. We propose a method that systematically corrects for oxide and hydroxide interferences in routine analysis, for a wide range of materials. Oxide and hydroxide production for a specified element is calculated from measurements on each sample, as levels may depend on sample composition and may also vary with time. We show that oxide and hydroxide interferences can then be calculated for other elements, by reference to a set of oxide and hydroxide ratios measured on standard solutions. Validity of correction is controlled by internal tests involving two isotopes of one element with respect to experimental errors. The limits and validity of this approach are demonstrated with the analysis of selected reference materials.  相似文献   

中国铂族金属矿床找矿方向初探     

刘凤山  王登红 《地质通报》2000,19(4):434-439

根据 2 0世纪 90年代铂族金属矿床勘查的新发现 ,提出铂族金属矿床成因分类 ,探讨中国铂族金属找矿方向 ,提出“以绿找铂”、“以黄找铂”和“以黑找铂”的找矿原则 ,即在蛇绿混杂岩或基性—超基性岩分布区寻找基性—超基性岩浆岩型、岩浆热液型铂族金属矿以及与之有关的砂铂矿床 ,在金矿田中寻找伴生铂族金属矿床 ,在黑色页岩分布区寻找黑色页岩型铂族金属矿床。  相似文献