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1.
Peter M. D. Bradshaw Ian Thomson Barry W. Smee Jan O. Larsson 《Journal of Geochemical Exploration》1974,3(3):209-225
This paper deals briefly with the principles of geochemical migration in the secondary (soil, sediment) environment, a knowledge of which is essential to a correct interpretation of exploration geochemical data. Examples are given which illustrate that the principles which apply in the more easily interpreted tropical areas, also apply in the more complicated glaciated regions. Any person employing exploration geochemistry in geomorphologically complicated areas, is well advised to study data from strictly residual soil areas where the fundamentals of geochemical migration are more easily observed. From this base it is easier to understand the additional complications of geochemistry in mountainous and glaciated terrain. Of the variety of exploration geochemical techniques which can be used, this paper deals specifically with two: soil profile sampling, and different strengths of acid extraction of metal from samples. Examples from the different environments are compared and contrasted. 相似文献
2.
3.
It is a worldwide challenge to explore the deeply buried deposits. Deep-penetrating geochemical exploration methods were developed to solve the problems of how to get the information of the buried deposits in the covered layer. The methods were successfully used to indicate some buried deposits, but not all kinds of deposits. What is more, a method cannot be used in all kinds of landscapes. In this paper, theories and case studies of deep-penetrating geochemical exploration methods, including mobile metal ions, enzyme leach, leaching of mobile forms of metals in overburden, electro-geochemical extraction method, biogeochemical exploration, nano-metal in geogas were reviewed. Elements migration, unloading mechanism and anomaly models are the most important parts for deep-penetrating geochemistry and need to be further investigated. From the perspective of economic efficiency and applicability, sampling and analyzing procedures should be simplified to improve the stability of all methods. 相似文献
4.
This paper summarizes advances since 1987 in the application of glacial sediment sampling to mineral exploration (drift prospecting) in areas affected by continental or alpine glaciation. In these exploration programs, clastic glacial sediments are tested by geochemical or mineralogical methods to detect dispersal trains of mineral deposit indicators that have been glacially transported from source by mechanical processes. In glaciated terrain the key sampling medium, till, is produced by abrasion, crushing and blending of rock debris and recycled sediment followed by down-ice dispersal ranging from a few metres to many kilometres. As a consequence of the mid-1980s boom in gold exploration, the majority of case studies and regional till geochemical surveys published in the past decade deal with this commodity. Approximately 30% of Canada and virtually all of Fennoscandia have been covered by regional till geochemical surveys that aid mineral exploration and provide baseline data for environmental, agricultural, and landuse planning. The most profound event in drift prospecting in the last decade, however, has been the early-1990s explosion in diamond exploration which has dramatically increased the profile of glacial geology and glacial sediment sampling and stimulated changes in sampling and analytical methods. 相似文献
5.
A comparison of selective extraction soil geochemistry and biogeochemistry in the Cobar area, New South Wales 总被引：1，自引：0，他引：1
D. R. Cohen X. C. Shen A. C. Dunlop N. F. Rutherford 《Journal of Geochemical Exploration》1998,61(1-3)
In parts of the deeply weathered and semi-arid environments of the Cobar area (NSW, Australia), detection of mineralisation using conventional soil sampling and total metal analysis is impeded. This is due to the intense leaching of trace elements within the weathered profile, discontinuous coverage of transported materials and the existence of diffuse regional geochemical anomalies of ill-defined source. Selective chemical extractions, applied to various regolith components, and biogeochemistry offer a means of isolating localised geochemical patterns related to recent dispersion of trace elements through the overburden. Lag geochemical patterns across the McKinnons deposit (Au) and Mrangelli prospect (Pb–Zn–As) reflect mechanical dispersion processes and minor hydromorphic effects. Concentrations of more mobile elements tend to be higher in the non-magnetic fraction, due to higher proportions of goethite and poorly crystalline hematite than in the magnetic fraction. The subdued soil geochemical responses for metals extractable by cold 40% hydrochloric acid (CHX) and for total element concentration reflect the leached nature of the residual profile, low grade of mineralisation, dilution by aeolian components and disequilibrium of fine fractions with coarser, relict Fe-oxides. The stronger contrast for CHX for most metals, compared with total extraction, indicates surface accumulation of trace elements derived from underlying mineralisation. Enzyme leach element anomalies are intense but generally located directly over bedrock sources or major structural breaks, irrespective of the nature of the overburden. Though mechanisms for the dispersion of trace elements extracted by enzyme leaching are not well established, the lack of lateral transport suggests vertical migration of volatile metal species (atmimorphic dispersion). The strong, multi-element response to mineralisation in cypress pine needles indicates significant metal recycling during the present erosional cycle. However, a comparison of the trace element concentrations in vegetation (cypress pine needles) and selective extractions of soils indicates that recycling by the plants is not the dominant mechanism for transportation of metals through the overburden. The vegetation may be responding to hydromorphic dispersion patterns at depth. The use of selective extractions may be useful in detecting mineralisation through deeply leached profiles, but offers even greater potential when integrated with biogeochemistry to detect targets buried by significant thickness of transported cover. 相似文献
6.
Vertical migration of elements from mineral deposits 总被引：1，自引：0，他引：1
There is currently widespread interest in the exploration community worldwide in the development of methods to locate deeply buried mineralisation. In the application of geochemical methods, some success has been achieved using the selective extraction of mobile and weakly bonded forms of elements (MWBE) in overburden. Studies in Russia commenced in the 1960s, and have continued in Russia and in other countries to the present time. This paper presents some examples of experimental and applied research carried out in Russia, specifically by members of VITR and then VIRG NPO Rudgeofizika (St. Petersburg). In particular, some characteristics of MWBE anomalies and rates of MWBE migration are illustrated, with reference to several case studies in geochemical exploration for base metal and precious metal deposits. 相似文献
7.
A case history is presented describing geochemical exploration of the porphyry Cu-Mo system at Yandera in the Bismark Ranges of Papua New Guinea. Three phases of geochemistry are discussed: (1) stream sediment, (2) ridge and spur, and (3) detailed rock and soil from contour trails. Results of each phase are presented and their relationship to drill-indicated mineralisation discussed. The effectiveness of the three techniques and various elements as geochemical guides to primary mineralisation is compared.Copper in stream sediment samples at a density of one sample per 1–2 km2 effectively delineated the porphyry Cu system. The extent of ridge and spur sampling was limited, therefore its effectiveness is uncertain. Detailed sampling along contour trails indicated that Au and Mo are the most effective geochemical tools. Copper geochemistry is of limited use as its distribution is largely a function of recent processes and dispersion from supergene mineralisation. No clear relationship exists between Ag geochemistry and mineralisation. Lead and Zn are distributed peripheral to the porphyry Cu system.The effectiveness of Au and, to a lesser extent, Mo as geochemical guides to ore in the steep mountainous terrain of the prospect area where high rainfall, deep weathering and rapid erosion prevail is due to the relatively high stability of these metals in the soils and the oxide zone. 相似文献
8.
Local and mine scale exploration models for anomaly recognition within known ore fields are discussed. Traditional geochemical exploration methods are based on multivariate statistical analysis, metallometry, vertical geochemical zonality and criteria of natural field geochemical associations, which suffer several shortcomings, including lack of a geostatistical generalised approach for separating anomalies from background. These shortcomings make the interpretation process time consuming and costly. Fuzzy set theory, fuzzy logic and neural network techniques seem very well suited for typical mining geochemistry applications. The results, obtained from applying the proposed technique to a real scenario, reveals significant improvements, comparing the results obtained from applying multivariate statistical analysis. Computationally, the introduced technique makes possible, without exploration drilling, the distinction between blind mineralisation and zone of dispersed ore mineralisation. The methodology developed in this research study has been verified by testing it on various real-world mining geochemical projects. 相似文献
9.
As geochemical appraisals of mineral regions of commercial prospectivity evolve, the organic matter associated with metal rich ores has attracted greater attention. Petroleum basin and modern seafloor hydrothermal vent studies have suggested that organic matter can have a significant influence on the behaviour of mineralising fluids. There have been many isolated reports of certain organic compositional or morphological (e.g. pyrobitumen) features showing an apparent relationships with hydrothermal fluids or minerals, raising expectations that organic based parameters might be useful to mineral exploration. However, the understanding of organic–inorganic relationships in Earth systems is far from complete. For example, the detailed mechanics of the interaction of organics with hydrothermal fluids over geological time remain largely undefined. Organic geochemistry studies have traditionally involved the measurement and interpretation of the hydrocarbon composition of sedimentary rocks. Here we review the types of aliphatic hydrocarbons, aromatic hydrocarbons and metalloporphyrins often detected from organic geochemical investigations in mineral-rich regions. Such molecular data can be particularly diagnostic of biochemical sources and the palaeo-environments at the time mineral associated organic matter was deposited. Sub-surface trends of hydrocarbon alteration may also reflect major biogeochemical processes such as thermal maturity and biodegradation. Organic geochemistry data can also occasionally provide information about the nature (e.g., origin, composition, temperatures) and migration pathways of hydrothermal fluids and can make a contribution to holistic ore genesis models. The well preserved organic matter associated with the economic “Here's Your Chance” Pb–Zn–Ag Mine (Paleoproterozoic Barney Creek Formation, McArthur Basin, Australia) and the transition metal-rich Early Permian Kupferschiefer Formation (Germany–Poland) have attracted significant attention. A more detailed summary of the organic character of these deposits is provided to highlight the contribution organic geochemistry can make to understanding mineralisation processes. Most organic geochemical studies of highly mineralised regions, however, have not adequately addressed the significance of organic matter to mineralisation. A slightly different analytical focus than traditionally used for exploration appraisal of petroleum hydrocarbons may be required to properly evaluate the significance of organic species to the mobilisation, transport and deposition of ore metals. The characterisation and subsequent thermodynamic modeling of organic substances and complexes within metalliferous hydrothermal systems will contribute to a better understanding of the nature and role of organic–inorganic fluids or other affiliated organics in ore systems. 相似文献
10.
气体地球化学测量方法由于气体的强穿透性,可将大量的与深部矿化作用有关的物质携带到地表,可直接或间接指示各种地质成矿过程,而受到勘查地球化学的重视。经历数十年的发展之后,气体地球化学测量在测量指标、方法及影响因素研究方面都取得了长足进展。特别是近年来由于分析技术提高,使得很多超微含量的气体测定成为可能,一些新的气体测量方法相继提出,在寻找隐伏矿或盲矿方面获得了较好的效果。笔者对气体测量发展史、气体测量方法、指标及影响因素进行了简单总结,并重点介绍了一种新的气体测量技术（SDP）的测量原理、使用方法及应用实例。 相似文献
11.
Vast parts of the Australian continent are prospective for precious and base metal mineralisation, but exploration is hindered by extensive cover of often deeply reaching regolith. New operational exploration methods are required that can help to characterise the cover and provide information about bedrock signatures. This paper shows how mineral mapping information from a combination of satellite multispectral Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery and drill core hyperspectral profiling data (HyLogging™) can be used to unravel the regolith stratigraphy and to describe regional variations of regolith landforms, delivering important information for mineral exploration.The case study is located in the Neale tenements in the northeastern Albany–Fraser Orogen (Western Australia), which is prospective for Tropicana-style gold mineralisation. By interpretation of indicator minerals from hyperspectral drill hole logging data the regolith stratigraphy atop a metamorphic basement, comprising saprock, ferrugineous saprolite, kaolinitic saprolite, silcrete and transported cover, is recorded in cm-detail. Important mineralogical parameters extracted from the hyperspectral subsurface data and validated by XRD and FTIR, are 1) the abundance and type of iron oxides, 2) the abundance and crystallinity of kaolinite, 3) the abundance and composition of primary minerals, such as white mica, and 4) the abundance of quartz.The HyLogging™ data served as ground control points for mineral mapping information provided by CSIRO's ASTER Geoscience Products, which are a collection of mineral maps that highlight variations in the abundance, type or chemistry of selected mineral groups. Key ASTER Geoscience Products for regolith characterisation were the Ferric Oxide and AlOH abundance and composition images. The comparison of the surface with the subsurface data suggests three major different regolith landforms, including erosional, depositional and relict areas, which were used to generate a map showing transported versus relict and erosional areas. Erosional domains were mapped out in great detail, providing important information for exploration in saprolite dominated areas. Furthermore, source areas of transported material could be identified, which may help to understand the distribution of geochemical signatures collected during, for example, geochemical soil sampling projects. 相似文献
12.
随着出露区矿产资源的日益枯竭,覆盖区已逐渐成为矿产勘查的重点。传统化探方法难以在覆盖区发挥作用,而金属活动态测量法可以提取与深部隐伏矿体有关的矿化信息。该方法在冲积平原覆盖区还缺乏相关研究。以安徽无为龙潭头隐伏硫铁矿为例,开展土壤全量和金属活动态测量的试验研究。结果显示:土壤全量测量在隐伏矿体上方无异常显示。金属活动态测量中,Cu和S元素的水溶态,Fe元素的铁锰氧化物态和吸附态均呈现出高异常值,异常衬度达到2及以上。其中S元素的水溶态异常最明显,含量峰值达14.8×10^-9,背景值为4.81×10^-9,异常衬度3.08。其次,Cu元素的有机态和S元素的铁锰氧化物态呈现较高异常,异常衬度1.5以上。金属活动态测量提取的异常均位于隐伏矿体上方,且与赋矿主断裂空间关系密切。本次试验研究表明,金属活动态测量可以有效提取与龙潭头隐伏矿床有关的地球化学异常,该方法在冲积平原覆盖区应当有着较好的应用前景,但仍需要更进一步地研究,以建立相应的方法技术流程与标准。 相似文献
13.
P. de Caritat P. T. Main E. C. Grunsky A. W. Mann 《Australian Journal of Earth Sciences》2017,64(8):1033-1043
Understanding the character of Australia's extensive regolith cover is crucial to the continuing success of mineral exploration. We hypothesise that the regolith contains geochemical fingerprints of processes related to the development and preservation of mineral systems at a range of scales. We test this hypothesis by analysing the composition of surface sediments within greenfield regional-scale (southern Thomson Orogen) and continental-scale (Australia) study areas. In the southern Thomson Orogen area, the first principal component (PC1) derived in our study [Ca, Sr, Cu, Mg, Au and Mo at one end; rare earth elements (REEs) and Th at the other] is very similar to the empirical vector used by a local company (enrichment in Sr, Ca and Au concomitant with depletion in REEs) to successfully site exploration drill holes for Cu–Au mineralisation. Mapping of the spatial distribution of PC1 in the region reveals several areas of elevated values and possible mineralisation potential. One of the strongest targets in the PC1 map is located between Brewarrina and Bourke in northern New South Wales. Here, exploration drilling has intersected porphyry Cu–Au mineralisation with up to 1 wt% Cu, 0.1 g/t Au, and 717 ppm Zn. The analysis of a comparable geochemical dataset at the continental scale yields a compositionally similar PC1 (Ca, Sr, Mg, Cu, Au and Mo at one end; REEs and Th at the other) to that of the regional study. Mapping PC1 at the continental scale shows patterns that (1) are spatially compatible with the regional study and (2) reveal several geological regions of elevated values, possibly suggesting an enhanced potential for porphyry Cu–Au mineralisation. These include well-endowed mineral provinces such as the Curnamona and Capricorn regions, but also some greenfield regions such as the Albany-Fraser/western Eucla, western Murray and Eromanga geological regions. We conclude that the geochemical composition of Australia's regolith may hold critical information pertaining to mineralisation within/beneath it. 相似文献
14.
在祁连山冻土区木里天然气水合物矿区进行了微量元素地球化学勘查有效性试验,试验面积150 km2,采样密度2个点/km2。研究表明,土壤Ba、V、Fe 、Ca等元素在水合物矿藏上方呈现顶部异常,而且异常吻合程度较高。微量元素预测天然气水合物具有较高的成功率,调查前钻探的干井(DK-4、DK-5和DK-6)位于背景区,调查前钻探的水合物井(DK-1、DK-2、DK-3、DK-7)和调查后水合物井(DK3-11、DK2-13、DK1-14)位于异常内。试验结果还预测了祁连山天然气水合物两个新的远景区。试验表明,微量元素是祁连山冻土区寻找天然气水合物的有效指示元素,它们与水合物其它化探指标结合冻土条件和地质特征综合解释,可以提高冻土区天然气水合物预测成功率。 相似文献
15.
Radiogenic isotopes have long been used in mineralisation studies, not just for geochronological determinations of mineralising events but also as tracers, providing, for example, information on the source of metals. It was also evident early on that consideration of isotopic data on a regional scale could be used to assist with metallogenic interpretation, including identification of metallogenic terranes. The large amounts of isotopic (and other) data available today, in combination with readily available graphical software, have made possible construction of isotopic maps, using various isotopic variables, at regional to continental scales, allowing for metallogenic interpretation over similarly large regions. Such interpretation has been driven largely by empiricism, but increasingly with a mineral systems approach, recognising that mineral deposits, although geographically small in extent, are the result of geological processes that occur at a variety of scales.This review looks at what radiogenic isotopes can tell us about different mineral systems, from camp- to craton-scale. Examples include identifying lithospheric/crustal architecture and its importance in controlling the locations of mineralisation, the identification of metallogenic terranes and/or favourable geodynamic environments on the basis of their isotopic signatures, and using juvenile isotopic signatures of intrusives to identify metallogenically important rock types. The review concentrates on the Sm–Nd system using felsic igneous rocks and the U–Th–Pb system using galena, Pb-rich ores and other rocks. The Sm–Nd system can be used to effectively ‘see’ through many crustal processes to provide information on the nature of the source of the rocks. For voluminous rocks such as granites this provides a potentially powerful proxy in constraining the nature of the various crustal blocks the granites occur within. In contrast, Pb isotopic data from galena and Pb-rich associated ores provide a more direct link to mineralisation, and the two systems (Pb and Nd) can be used in conjunction to investigate links between mineralisation and crustal domains.In this contribution we document: the more general principles of radiogenic isotopes; the identification of time-independent isotopic parameters; the use of such variable to generate isotopic maps, and the use of the latter for metallogenic studies. Regional and continental scale isotopic maps (and data) can be used to empirically and/or predictively to identify and target (either directly or indirectly by proxy) larger scale parts of mineral systems that may be indicative of, or form part of metallogenic terranes. These include demonstrable empirical relationships between mineral systems and isotopic domains, which can be extracted, tested and applied as predictive tools. Isotopic maps allow the identification of old, especially Archean, cratonic blocks, which may be metallogenically-endowed, or have other favourable characteristics. These maps also assist with identification of potentially favourable paleo-tectonic settings for mineralisation. These include: old continental margins, especially accretionary orogenic settings; and juvenile zones, either marginal or internal, which may indicate extension and possible rifting, or primitive arc crust. Such isotopic maps also aid identification of crustal breaks, which may represent major faults zones and, hence, fluid pathways for fluids and magmas, or serve to delineate natural boundaries for metallogenic terranes. Finally, isotopic maps also act as baseline maps which help to identify regions/periods characterised by greater (or lesser) magmatic, especially mantle input. Of course, in any exploration model, any analysis is predicated on using a wide range of geological, geochemical and geophysical information across a range of scales. Sm–Nd and U–Th–Pb isotopic maps are just another layer to be integrated with other data. Future work should focus on better constraining the 4D (3D plus time) evolution of the lithosphere, by integrating isotopic data with other data, as well as through better integration of available radiogenic isotopic systems, including the voluminous amounts of in situ isotopic analysis (of minerals) now available. This should result in more effective commodity targeting and exploration. 相似文献
16.
Geochemical data obtained during mineral exploration often are biased by systematic as well as random errors; these may result in failures when usual methods of evaluation are used. This is true particularly in soil surveys carried out in regions where a long history of prospecting and mining activity has occurred and/or where aerial chemical pollution is likely to have occurred.A satisfactory evaluation of geochemical data even in such an unfavorable case requires sampling on a relatively dense grid and utilization of all available knowledge of types of mineralization. The evaluation procedure proposed consists of five consecutive phases: (1). Dividing the area of interest into subareas of a relatively homogeneous geological nature. (2). Processing by multivariate methods (factor analysis, in particular) without consideration of geographic relations. (3). A preliminary interpretation and search for a geochemical explanation of factors. (4). Processing of individual factors in two-dimensional geographic space by directional and frequency linear filtering methods. (5). Final interpretation and construction of a geochemical model. The procedure is illustrated by an example from a geochemical exploration survey in the vicinity of Píbram (Middle Bohemia). 相似文献
17.
A study of deep penetrating geochemistry-the surface exploration techniques for finding concealed mineral deposits-was carried out over the Spence porphyry copper deposit in Chile by Australian,Canadian and Chinese laboratories using selective weak leach methods and is briefly reviewed here.Erratic and weak copper anomalies were obtained above the Spence deposit,which is concealed below a thick piedmont gravel cover.In the literature,such patterns are common in most of the weak selective leach studies carried out over known buried deposits.During exploration in unknown area,such weak leach techniques lead to some success and many dry holes.In this paper,stronger selective leaching methods are developed for oxides and sulfides,which may be the stable end products transformed and accumulated by a mobile precursor phase carried upward through the overburden by gas or water through long spans of geological time.The data obtained by the methods developed in this paper produced more significant and consistent anomalous data than previous efforts.Consequently,the leach approaches described here may increase the effectiveness of deep penetrating geochemistry in exploration for concealed ore deposits. 相似文献
18.
Vegetation sampling is an effective mineral exploration technique in areas of transported cover in the Tanami Gold Province where other techniques have been of limited success. This research tests the ability of plants to show signatures of mineralisation as well as the optimum scale of sampling for first-pass mineral exploration surveys. The semi-arid Tanami Gold Province in northern Australia encompasses nearly 160,000 km2 and is a highly prospective yet under-explored region due to transported cover masking mineralisation. Various dominant plant species were sampled along transects across four sites of Au mineralisation in the Tanami (Larranganni, Hyperion, Coyote and Titania). Snappy gum (Eucalyptus brevifolia) gave a geobotanical (plant distribution) and lithological (S and Zn) signature of an underlying geological structure known to host Au mineralisation at the Coyote Prospect. Soft spinifex (Triodia pungens) provided an Au, As, ± Zn, ± S, and ± Ce expression of buried Au mineralisation at Coyote and Titania. At the Hyperion prospect, mineralisation is located at the contact between granite and dolerite, and biogeochemical signatures from snappy gum and dogwood (Acacia coriacea) show elevated ± Au, Ce, S and Zn that corresponded to the contact. Biogeochemistry is able to determine the location of mineralisation at each site, except at Hyperion where the sample density was too low. It is able to identify underlying substrate differences, however, background knowledge relating to regolith, geology, hydrology and geophysics are important in aiding the interpretation of the elemental data. It was found that having too few samples (at Hyperion) there was insufficient useful information for mineral exploration. Grid coverage of an area (at Titania) provided information on mineralisation and groundwater dispersion plumes; however, in this case a single transect over the same area would have been sufficient for a first-pass mineral exploration survey. 相似文献
19.
A 2D prospectivity model of epithermal gold mineralisation has been completed over the Taupo Volcanic Zone (TVZ), using the weights of evidence modelling technique. This study was used to restrict a 3D geological interpretation and prospectivity model for the Ohakuri region. The TVZ is commonly thought of as a present-day analogue of the environment in which many epithermal ore deposits, such as in the Hauraki Goldfield, Coromandel Volcanic Zone, are formed. The models utilise compiled digital data including historical exploration data, geological data from the Institute of Geological and Nuclear Sciences Ltd. Quarter Million Mapping Programme, recent Glass Earth geophysics data and historic exploration geochemical data, including rock-chip and stream sediment information. Spatial correlations between known deposits and predictive maps are determined from the available data, which represent each component of the currently accepted mineral system model for epithermal gold. The 2D prospectivity model confirms that the TVZ has potential for gold mineralisation. However, one of the weaknesses of this weights of evidence model is that the studies are carried out in 2D, with an approximation of 3D provided by geophysical and drilling data projected to a 2D plane. Consequently, a 3D prospectivity model was completed over the Ohakuri area, constrained by the results of the 2D model and predictive maps. The 3D model improved the results allowing more effective exploration targeting. However, the study also highlighted the main issues that need to be resolved before 3D prospectivity modelling becomes standard practise in the mineral exploration industry. The study also helped develop a work flow that incorporates preliminary 2D spatial data analysis from the weights of evidence technique to more effectively restrict and develop 3D predictive map interpretation and development. 相似文献
20.
The nature of secondary geochemical dispersion of As, Sb, Hg and Bi in soil and ground water of the semi-arid, tropical, Archaean, auriferous, Hutti-Maski greenstone belt has been investigated for identification of appropriate geochemical techniques for Au exploration in similar terrains.Results indicate that the <180 μm size-fraction of C-horizon soil is an appropriate sampling medium for delineating pedogeochemical anomalies of As, Sb, Hg and Bi related to gold mineralisation. These pedogeochemical anomalies along with anomalous values of alkalinity, chloride, sulphate, As and Sb in groundwater are controlled significantly by primary mineralisation located along shear zones in the greenstone belt. Arsenic anomalies in soil are broad, whereas, those of Sb and Bi are restricted to narrow zones directly over mineralised areas. In contrast, Hg anomalies around known mineralised areas are irregular and do not clearly demarcate the mineralised areas. The study indicates that anomalies of As, Sb and Hg in soil are principally hydromorphic, whereas those of Bi are clastic.The study recommends use of groundwater sampling at 2–3 km spacing with routine analysis of chloride, sulphate and alkalinity along with As and Sb in the first phase. This may be followed up with sampling of C-horizon of soils on a 1 km square grid for As-anomalies. Arsenic-anomalous areas may be sampled for As, Sb, Hg and Bi on a 500 m square grid for detailed exploration. 相似文献