Geochemical Prospecting Methods Research Articles

Identifying Areas of High Gold Potential Using Geochemical Prospecting Methods: The Tenado Area in the Boromo Birimian Belt, West-Central Burkina Faso, West Africa

The investigation area is located in the central-western region of Burkina Faso, in a geological environment that incorporates the Paleoproterozoic formations of the Boromo greenstone belt. This zone already has several gold showings and an active zinc mine, but no major gold deposits. The aim of this study is to define target areas with high gold potential for further prospecting. To meet this objective, we mainly used total rock geochemistry and stream sediment geochemistry methods. The combination of stream sediment gold content and litho-geochemical data has enabled us to highlight two areas of gold (Au) and various metal anomalies. The gold content of stream sediments is mainly influenced by that of the parent rock from which they are derived. In fact, strong gold anomalies are more common in clay sediments than in sandy sediments. These clay sediments are derived from basic rocks (basalt) and intermediate rocks (andesite-dacite), while the gold-poor sandy sediments are derived from granitoids. Basic to intermediate rocks are fertile for primary gold. Anomaly zone one (01) in the northern part of the study area (Kelsio, Zoula, Poa and Dyoro) and anomaly zone two (02) in the southern part of the study area (Kwademan, Baguiomo, Bérédo, Bonga and Baganapou) show occurrences of mainly gold and various metals (Zn, Cu, Ni).

Geoarchaeological investigations in Artanish Peninsula, Armenia: Testing a new geochemical prospecting method for archaeology

AbstractWithin the framework of an Armenian–German research project, taking place between 2019 and 2021 on the Artanish Peninsula at Lake Sevan (Armenia), in addition to numerous (geo‐) archaeological investigations, methods of geochemical prospection have been carried out. The ancient burial grounds of Artanish 23 and Artanish 29 have served as model sites to successfully test the well‐known method of geochemical prospection and evaluation of metal deposits in geology (mineral sector). As a result, a new experimental archaeo‐geochemical prospecting and evaluation method has been developed, which has been adapted for the exploration of archaeological monuments. It is planned to use this experimental method (which we consider new and important in archaeogeochemical investigation, but not a conclusive and comprehensive work per se), which has already proven its work capacity, in archaeological research, in the prospective areas of Armenia and other countries. In addition to these investigations, research on the transformations in the landscape of the ancient tombs related to Lake Sevan fluctuations has also been carried out. The anthropogenic impact of humans on the environment (geochemical halos formed in the soil on the surface of the tombs) has been studied, as well as the problem of the impact of geological environment on human life activities, that is, the relocation of the burial grounds to more elevated areas due to the rise in the lake level. Based on the results of geochemical sampling and high‐resolution magnetometer surveys, excavations have been performed at the site. Here, we present the results of an experimental study exploring the potential of combined magnetometer prospection and chemical soil analyses to locate and characterize the burial ground of Artanish on Lake Sevan, Armenia. The results have demonstrated the capability of these analyses to detect the sites, outline hotspots and interpret the features identified in the magnetometer results.

Metallogeny and exploration indicators of Sn and Ag deposits in the Southern Great Xing'an Range, China: Application of knowledge-driven CoDA based on geology and geochemistry

There have been recent breakthroughs in exploration for tin (Sn) and silver (Ag) mineral resources in the Southern Great Xing'an Range, making this region a world-class Sn and Ag metallogenic area. However, thick surface coverage and hidden deposits make exploration difficult, and conventional geological and geochemical prospecting methods have severely limited efficacy. In order to further extract geological and geochemical information on the basis of the existing research, to serve the regional mineral exploration, the knowledge-driven CoDA method is used to identify geochemical associations for inferring matallogenic information. Meanwhile, the fractal C-A model is used to determine geochemical anomalies, the catchment basin geochemical method is used to delineate anomaly boundary. Especially, the data-driven CoDA method is employed for comparison analysis with the knowledge-driven one. As a result, seven groups of compositional balances are proposed and verified, and geological bodies closely related to Sn and Ag mineralization are identified. These occurred in Dashizhai Formation strata, being calcareous rocks and granites, especially A-type granite, which is most closely related to mineralization. Meanwhile, Sn and Ag mineralization areas were identified and found to be consistent with known deposits. Finally, this paper proposes a novel model of regional porphyry Sn–Cu metallogenic systems and delineates exploration targets for Ag–Zn–Pb–Cu deposits and Sn–polymetallic deposits based on the analysis of catchment basins.

Prospecting terrain for surface geochemical exploration of oil and gas in West Siberia

ABSTRACT The relevance of this research is necessitated by the need to advance geochemical prospecting methods for raw hydrocarbon deposits. The study aimed to design new migration models by the interpretation of surface geochemical survey data. In particular, the relationship behavior needs to be identified between the hydrocarbon migration intensity and the presence of oil-bearing reservoirs within the section. To reveal quantitative relationships between the oil show and the oil-bearing capacity of the section, a substantial body of geochemical data across different fields in West Siberia was processed herein. Field-type and in-office operations were being performed by the snow survey procedure. The СН4–С6Н14 saturated hydrocarbons were employed as the major measured parameter. No direct quantitative connection was found between the intensity of surface hydrocarbon anomalies and the section productivity. Nonetheless, the two basic factors were found to affect the structure of the surface geochemical field: first, oil-bearing reservoirs present in the section and, second, fluid-resistant properties of the above-productive strata. Despite a direct quantitative relationship between the oil-bearing capacity of the section and the intensity of surface hydrocarbon anomalies being absent, the large sample made it possible to determine quantitative measures of the surface geochemical field that credibly characterize territories whose sections hold oil-bearing horizons.

The efficiency of different soil-sampling geochemical prospecting methods in the search for pge-cu-ni ores in the landscape and geological environment of Norilsk region

The efficiency of different soil-sampling geochemical prospecting methods in the search for pge-cu-ni ores in the landscape and geological environment of Norilsk region

A Critical Analysis of Gold Prospecting Methods

Exploration and prospecting for mineral resources deposits are perceived to not be an easy process due to big deposits being discovered in early times. Numerous gold prospecting methods have been used in gold prospecting. The aim of this research is to critically analyze both traditional and modern gold prospecting methods that are being used in gold exploration. The research objective is to critically evaluate the numerous studies that focus on gold prospecting methods in an effort to provide an effective analysis of gold prospecting methods. In doing so, the study has used a qualitative method to review the existing literature. The study reviews academic journals and articles, books, and periodicals which were published between 2010 and 2019. This study has achieved to critically analyze both traditional and modern gold prospecting methods. The study finds out that the traditional gold prospecting methods include gold panning and dry washing. Additionally, the current gold prospecting methods include biological prospecting, geochemical prospecting and geophysical prospecting methods.

Geochemical Prospecting of tin Mineralization Zone at Belukar Semang Prospect, Gerik, Perak

Belukar Semang is a new prospect after geochemical exploration of tin mineralization located within the western Tin Belt of Peninsular Malaysia. The mineralization form within a thick sequence of metasedimentary rock belongs to the Baling Formation of Paleozoic age. The host rock of weakly metamorphosed argillite generally experienced strong tropical weathering that resulted in a thick sequence of light grey to light brown oxidized profiles. The mineralized veins range from simple quartz-cassiterite, quartz-tourmaline-cassiterite to complex quartzcassiterite-polymetallic sulphide veins. From historical mining view, this prospected area is closer to the Rahman Hydraulic Tin Sdn. Bhd. (RHTB) which is located at Klian Intan that is also lies within the Baling Formation. Geological Survey of Malaysia promising that Sungai Pong and Sungai Pahit which located outside the property of RHTB has a greater potential for tin mineralization and that particular area is nearer to the Belukar Semang prospect. In this paper, geochemical prospecting method is used to locate the presence of the ore in the vicinity. The normal abundance of an element in any material where the equilibrium has not been upset by the presence of a mineral deposit is commonly referred to as “background”. Tin mineralization studies at Belukar Semang Prospect need to have more detailed exploration to ensure that area are economic to do mining. The source of tin mineralization was not well known, however, it was postulated associated with the magmatism that formed Triassic biotite granite batholith within the vicinity of Klian Intan.

The discovery of the metallic particles of groundwater from the Dongshengmiao polymetallic deposit, Inner Mongolia, and their prospecting significance

In recent years, new methods for seeking concealed ore bodies have become an active area of ore prospecting. Previous studies of water geochemistry have usually been confined to the analysis of the elemental content of surface water, and performing metallogenic predictions based on high element contents. This paper represents the first use of transmission electron microscopy (TEM) to study particles of groundwater in or around the ore district. Comparing the results of the TEM characterization of well waters near the ore district with those of groundwater samples from the deep ore district (hereinafter referred to as the concept of “deep groundwater”), the particles found in both types of water samples were similar. The ore-forming metal particles, such as Fe, Cu, Pb and Zn-bearing particles, are found in both well water and deep groundwater, while the samples in the well waters of the background area (hereinafter referred to as the concept of “background water”) mainly contain only particles, such as CaCO3, Ca(OH)2, silicate, oxide of Na, K and Fe. In addition, the composition and characteristics of particles from well waters and deep groundwater revealed that they are derived from the concealed ore bodies. Faulting and oxidation are the main mechanisms of particle formation. Because well water samples are similar to the deep groundwater samples, they can be conveniently collected at ground level, and may be used to predict the presence of a deep ore resource. This research establishes a new method for geochemical prospecting using groundwater particles. These particles can reflect more abundant and accurate information regarding the concealed ore bodies than the content of elements. The discovery of metal containing particles in groundwater may improve water-based geochemical prospecting method.

Study and application of the partial extraction geochemical prospecting method for the uranium exploration in Changpai, north of Guangdong province, China

Study and application of the partial extraction geochemical prospecting method for the uranium exploration in Changpai, north of Guangdong province, China

How robust are geochemical patterns? A comparison of low and high sample density geochemical mapping in Germany

Regional geochemical mapping projects have been carried out for mineral exploration in Germany since 1954. In the early days, geochemical prospecting methods were mainly used for exploration of ore and non-metal deposits in Germany. Mapping for the first geochemical atlas of Germany was conducted in the 1980s by the Federal Institute of Geosciences and Natural Resources (BGR) with a sample density of one sample per 3km2. Parts of eastern Germany (Flechtingen Ridge, Harz Mountains, Thuringian Forest, Slate Mountains, Ore Mountains, Granulite Mountains, the Lausitz region, and along the Elbe River) were mapped by the former Central Geological Institute Berlin (ZGI) during the same period at a density of 1.3 samples per km2. Stream sediment and surface water were sampled in all of these high-density geochemical mapping projects. The first low sample density geochemical survey (one site per 380km2) was carried out for the latest geochemical atlas of Germany, which presents comprehensive information about the regional distribution of hazardous inorganic and organic substances. A density of one sample per 5000km2 was also used in Germany for the FOREGS Geochemical Mapping Project of Europe. Geochemical stream sediment and surface water data obtained at these three different scales in different geochemical mapping projects have been compared in this study for the elements Ba, Cu, Cr, Pb and U in stream sediment as well as pH, EC and U in stream water. Comparison of overlapping high and low sample density surveys conducted in the same study areas, demonstrates that the geochemical patterns produced from low sample density surveys are very nearly the same as those from the high sample density surveys, and that they can be related to natural processes. The low sample density geochemical surveys in Germany provide element background values very similar to those obtained by high sample density mapping of the same region. In unmapped terrain, low-density geochemical mapping provides a cost-effective reconnaissance technique to establish element background values.

Previous geological exploration of antimony ore occurrences Krceva Reka (eastern Serbia) in terms of the potentiality of the epithermal gold

This paper presents the results of a previous geological exploration of antimony ore occurrences in the area Krčeva river. Data analysis of geological, geophysical, geochemical prospecting and appropriate methods of laboratory testing identified a series of similarities to epithermal gold mineralization Carline type and formed a preliminary model of its creation.

Geo-microbial and light gaseous hydrocarbon anomalies in the near surface soils of Deccan Syneclise Basin, India: Implications to hydrocarbon resource potential

Deccan Syneclise Basin is considered geologically prospective for oil and gas reserves; however, a major part of the basin is covered by the Deccan Traps, hindering the exploration of Mesozoic hydrocarbon targets. Surface geochemical prospecting, based on micro-seepage of hydrocarbons from subsurface accumulations, could be advantageous in such areas. Surface geochemical prospecting method was applied in Deccan Syneclise for evaluation of hydrocarbon resource potential of the basin. The gas chromatographic analyses of adsorbed soil gasses showed the presence of C1 to C4 hydrocarbons. The concentrations of adsorbed soil gasses ranged for methane (C1)=1 to 483ppb, ethane (C2)=1 to 83ppb, propane (C3)=1 to 38ppb, butane (nC4)=1 to 60ppb and ΣC2+=1 to 129ppb, respectively. The scatter plots between C1 and C4 components depict linear trend indicating that all the gasses are derived from the same source.The carbon isotope composition of adsorbed methane was measured using Gas Chromatography–Combustion-Isotope Ratio Mass Spectrometry (GC–C-IRMS). The values for methane δ13C1 varied from −39.9 to −19.9‰ versus the Vienna PeeDee Belemnite (VPDB). The carbon isotope ratio distribution pattern represents isotopic characteristics pertaining to hydrocarbon gasses derived from thermogenic sources. The propane oxidizing bacteria (POB) ranged between 1.0×102 and 12.8×105cfu/g of soil. The adsorbed light gaseous hydrocarbons and propane oxidizing bacterial anomalies found in and around Aurangabad, Ahmednagar, Shirdi, Akola, Bhusawal and Indore areas are considered to be promising for future hydrocarbon research and exploration.

Study of the Method of Geochemical Prospecting for Gold-Silver Deposits, an Example of Mercury Indication at the Okuchi Mine

Study of the Method of Geochemical Prospecting for Gold-Silver Deposits, an Example of Mercury Indication at the Okuchi Mine

Pb isotopic ratios and elemental abundances for selective leachates from near-surface till: implications for mineral exploration

Pb isotope ratios obtained from fine-grained fractions ( < 63 and < 2 gmm from near-surface ( < 1 m depth) till surrounding ore deposits show isotopic overprinting from the underlying sulfide mineralization, and provide a new approach to mineral exploration for massive sulfide deposits (VMS) in glaciated terrains. In this study, Pb isotopic measurements, and selective leaching of 6 near-surface till samples down-ice from the Chisel Lake (Manitoba) and Manitouwadge (Ontario) VMS deposits were carried out in order to determine the location and nature of the Pb within till. Elemental abundances from selective leachates for all 6 samples display similar patterns and show that chalcophile elements (Cu, Ni, Pb and Zn), derived predominantly from the underlying VMS deposits, occur as (i) adsorbed/exchangeable metals; (ii) associated with oxyhydrous Fe and Mn; (iii) crystalline Fe oxides, and/or (iv) silicate. Despite the relative proximity of some of the till samples to the VMS deposits, only a very small component of the chalcophile elements is present as sulfide. This result is consistent with those from studies of weathered (oxidized) tills, which show that labile minerals such as sulfides have been completely destroyed and their chemical constituents reprecipitated or scavenged locally by clay-sized phyllosilicates and secondary oxides/hydroxides. Pb isotopic ratios for selective leachates from till samples with VMS-like (anomalous) signatures are similar to those from ore (galena) within the proximal VMS deposits. This indicates that the Pb is of a secondary nature and was probably scavenged and deposited after destruction of original sulfide minerals during till formation. The lack of a predominant sulfide-held Pb component within the selective leachates supports this interpretation. In contrast, Pb isotopic ratios for the same selective leachates from “background” samples are significantly higher and show that the Pb is not derived from proximal VMS deposits but from a more radiogenic source. Till samples were also leached using 2.5 M HCl (ldconventional” leaching). The Pb isotope ratios from the conventional leachates are similar to those obtained from the selective leachates, and show a large difference in Pb isotopic ratios between anomalous and background samples. We propose, therefore, that the conventional leaching rather than selective leaching or complete dissolution of a particular grain-size fraction be adopted for mineral exploration purposes using glacial sediments. The results from this study support the effective use of Pb isotope ratios from near-surface till as an exploration tool despite the weathered nature of the latter. We feel that this represents a more cost-effective technique over traditional geochemical prospecting methods, if used in conjunction with Pb abundance data.

GEOCHEMICAL PROSPECTING FOR OIL‐AND GASFIELDS IN THE NE USSR (CIS)†

The NE USSR is an area of great interest for oil and gas exploration. Geochemical prospecting methods are particularly useful in areas of permafrost, and the efficiency of these methods has been established by tests in the Anadyr and Khatyrka Basins.This paper presents data on the spatial and temporal changes in the content of methane and its gaseous homologues in seasonally‐thawed soil layers, near‐surface air and lichens. Annual freezing and thawing of the near‐surface layers has been shown to result in various geochemical processes which were previously unknown. When near‐surface layers are frozen in Winter, gases migrating upwards from the Earth's interior accumulate within them. During warmer weather in Spring, the accumulated gases diffuse into the atmosphere, and the hydrocarbons content of the near‐surface air is then tens or hundreds of times higher than at the end of Summer.Evidence has been obtained of regular alterations in methane contents. The intensity of solar radiation has been proved to influence the diurnal methane content of the atmosphere. Lichens are accepted to be accurate indices of hydrocarbon pollution at the Earth's surface.The distribution of hydrocarbon‐oxidising bacteria in tundra is described, and methods of geochemical prospecting are evaluated.

Surface geochemical methods used for oil and gas prospecting — a review

The majority of the world's oil and gas deposits have been discovered by drilling in the vicinity of natural petroleum seeps, and to date the most successful geochemical prospecting methods still rely upon the surface detection of hydrocarbons. Gas chromatographic techniques are now commonly used in the analysis of hydrocarbon gases for prospecting both onshore (analysis of soils and rocks) and offshore (analysis of near-bottom waters and sediments). Detection of helium fluxes has been partially successful as a geochemical prospecting technique. Many indirect techniques such as the determination of isotope and metal-leaching anomalies in surface rocks and the measurement of radon fluxes have not been widely used. Onshore geochemical prospecting appears to have more problems associated with it than offshore prospecting due to the more complex migration mechanism of near-surface waters containing dissolved gases. No onshore prospecting studies have been published which thoroughly consider this factor and the success of onshore prospecting remains equivocal. In offshore prospecting “sniffers” have been used to detect hydrocarbon anomalies in near-bottom waters, and coring equipment has been used for the detection of hydrocarbons in near-surface sediments. Success is claimed using these techniques. Geochemical prospecting methods are complementary to the widely used geophysical methods. Geochemical methods can provide direct evidence for the presence of petroleum accumulations and are relatively cheap and rapid. Failures in prospecting to date are attributable to the simplistic manner in which data have been interpreted; insufficient attention has been paid to the hydrological and geological factors which modify the upward migration of indicator species to the surface. As oil and gas deposits become more difficult to locate, greater attention should be paid to geochemical prospecting techniques, especially as a regional exploration tool.

Prospection géochimique en France: evolution et tendances de la dernière décennie

There has been a noticeable evolution within the last ten years in the geochemical prospecting methods, particularly with increased use of emission spectrometry; several factors favoured this evolution: In France as well as in many countries, large geochemical surveys are carried out in order to promote exploration and/or draw up an inventory of the potential mining resources of the country; such an exhaustive inventory requires the analysis of a great number of elements, and leads to the use of emission spectrometry. Geochemistry gradually proves itself as one of the most efficient tools in exploration (even the most efficient in some cases), if used with a relatively high sample density, in order to locate directly the deposits sought; the preliminary selection of favourable areas through low samples density reconnaissance surveys seems a hazardous and hardly efficient procedure. Fortunately the utilization of the computer, which geologists have become more familiar with, allows to make better interpretation: the computer makes it possible to overcome the difficulties which inevitably would have occurred in the processing of large amounts of analytical data. An important technical effort has been made to provide sufficiently accurate analyses for use in geochemical prospecting, at as low a cost as possible. The obtained data have caused a reconsideration of the usual models of secondary dispersion around ore deposits; in France and in the regions with similar climate (and paleoclimate) there is mainly a mechanical migration from weathered rocks, related to former permafrost phenomena in a tundra-type environment. The old idea of the metal fixation on clays and organic compounds must, in most cases, be given up, at least with regard to soil or stream sediment anomalies related to ore deposits.

Method of geochemical prospecting for coastal-marine placers

Method of geochemical prospecting for coastal-marine placers

Soil hydrocarbon geochemistry, a potential petroleum exploration tool in the Cooper Basin, Australia

The ethane, propane, butanes and pentanes concentrations of shallow soil samples collected in 1975 from 1070 sites over the Permian Cooper Basin have been analyzed. The samples were taken at a spacing of 300 m along two regional traverses; on a widely spaced irregular grid from above the known gas fields of Daralingie and Della; and above potential gas field areas. Geochemical anomalies appear to be associated with all the known fields traversed and with structures having petroleum potential either as anomalies directly above the gas fields or as halo anomalies. The most useful variables mapped are: (1) the sum of soil concentration of the four hydrocarbons (expressed in ppb of soil by weight), and (2) that sum divided by the percentage of acid-soluble material. Average and highest hydrocarbon concentrations measured respectively are ethane 0.59, 18.9; propane 0.34, 10.9; butanes 0.21, 4.6; pentanes 0.20, 3.8. The acid-soluble material averaged 4.2% with the highest value at 62.8% and moisture content at 60°C averaged 5.7% with a highest value of 25.7%. Some apparent anomalies are probably spurious. The soil geochemical prospecting method has a potential in petroleum exploration only if interpreted in conjunction with good structural and stratigraphic information.

Gasmap--A Method of Geochemical Prospecting: ABSTRACT

Geochemical prospecting is, theoretically, the most direct approach to oil and gas exploration. Migration End_Page 846------------------------------ of a minute amount of hydrocarbons to the surface should produce an abnormal content of hydrocarbons in soils, and therefore forecast the location of an oil or gas reservoir underneath. Several major inconveniences, however, make the hypothesis very difficult to apply, mainly, (1) the exact process of migration is not fully understood, (2) geochemical noises due to contamination, hydrocarbons being formed in the soils, etc., are superimposed on migrating hydrocarbons, and (3) different soil lithologies have different powers of retention of hydrocarbons and, conversely, a different aptitude to release the hydrocarbons retained. Gasmap introduces a method which, although following the basic theory, attempts to eliminate, solve, or bypass the problems, i.e., it attempts to cope with each of the known geochemical noises. The solution attempted in Gasmap proposes a method in which sampling and desorption of the sample are done under a definite number of principles. Its originality, however, lies basically in the method of interpretation of the results. Samples are listed according to their depths, lithology, chemical markers, and hydrocarbon contents. Through use of a computer, a statistical analysis of the Gaussian type is done and a mean value and a dispersion are derived. Samples are classified in homogeneous sets and anomalous samples are derived according to a probability threshold. Results are plotted on maps for each hydrocarbon. A composite map is produced and anomalies are classified according to their chemical composition and degree of anomaly. End_of_Article - Last_Page 847------------