The association of gold with calcrete

Lintern, M.J.

doi:10.1016/j.oregeorev.2014.10.029

Cited by 16 publications

(3 citation statements)

References 224 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C). The nodules are coalescent in some portions of the profile, resulting in a planar appearance and forming hardpans, similar to the characteristics described in Alonso‐Zarza & Wright (), Lintern () and Zamanian et al . ().…”

Section: Resultsmentioning

confidence: 97%

Facies and palaeosol analysis in a progradational distributive fluvial system from the Campanian–Maastrichtian Bauru Group, Brazil

et al. 2018

View full text Add to dashboard Cite

The Upper Cretaceous Bauru Group in south‐east Brazil consists of alluvial strata whose characteristics and distribution indicate a fluvial system developed in a semi‐arid to arid climate. Sections exposed within a 90 000 km2 study area in Minas Gerais State (in south‐eastern Brazil) were evaluated using facies and palaeosol analysis to formulate depositional and pedogenic models that may account for geomorphic and climate features. From east to west, the study succession records a gradual decrease in grain size, an increase in the width/thickness ratio in channels, a decrease in the lateral and vertical connectivity of channel deposits, and an increase in overbank deposits. The fluvial architecture indicates a braided channel belt, ephemeral ribbon–channels, and an unconfined fluvial facies from east to west in the study area. The lateral and vertical distribution of facies, stratigraphic architecture and palaeocurrent data suggest proximal, medial and distal portions of a progradational distributive fluvial system. The sedimentary dynamics were marked by the building and abandonment of channels related to processes of aggradation, vegetation growth and palaeosol generation. Macromorphological and micromorphological analyses have identified pedological and mineralogical features that indicate an arid to semi‐arid climate with a provenance from the north‐eastern part of the basin (Alto Paranaiba Uplift). From the proximal to the distal portions of the distributive fluvial system, the palaeosol development is different. In the proximal portion, the palaeosols are absent or poorly developed, allowing a possible general comparison with the present soil order: Inceptisols and Aridisols. In the medial portion of the fluvial system, the palaeosols are well‐developed and characterized by Bt, Btk, C and Ck horizons (Alfisols, Aridisols, Inceptisols and Entisols). Poorly drained to well‐drained palaeosols from the base to the top in the distal plain (Aridisols and Inceptisols) are associated with geomorphic and hydromorphic changes in the fluvial system due to progradational evolution. The genetic relationship between the fluvial architecture and the palaeosols enhances the understanding that the sedimentation and pedogenesis that occurs in different portions of the distributive fluvial system are related to the tectonic and climatic evolution of the basin.

show abstract

Section: Resultsmentioning

confidence: 97%

Facies and palaeosol analysis in a progradational distributive fluvial system from the Campanian–Maastrichtian Bauru Group, Brazil

et al. 2018

View full text Add to dashboard Cite

show abstract

“…High carbonate content in groundwater may be involved in calcite (CaCO 3 ) precipitation in the vadose zone, leading to hardened layers formation in soils (calcrete) (Alonso-Zarza and Wright, 2010). High gold contents are described in calcretes which are actually used for gold exploration (Lintern, 2015), confirming the potential link between such formations and orogenic gold deposit alteration. Even though the exact mechanism of calcrete formation near gold deposits remains unclear, our results indicate that Fe-carbonate dissolution at depth can generate CO 2 exhalation.…”

Section: Geomorphological Feature Formation In Association With Gas V...mentioning

confidence: 64%

Barren ground depressions, natural H2 and orogenic gold deposits: Spatial link and geochemical model

Malvoisin

Brunet

2023

Science of The Total Environment

View full text Add to dashboard Cite

“…Valley calcretes are known hosts for the U mineral carnotite (K 2 (UO 2 ) 2 V 2 O 8 .3H 2 O) with the U being derived from the weathering of granite (Mann & Deutscher 1978). Regolith carbonates, or pedogenic calcretes, are also known to be effective sampling media for exploration for gold deposits, with their Au content being the most effective vector to mineralization (Reith et al 2011;Lintern 2015). Conversely, relative to the calcrete, the marine limestone is clearly more enriched in REEs (ranks >450 v. <270) and especially chalcophile elements Pb, Cd, Sn, and Tl (ranks >840 v. <350).…”

Section: Degree Of Geochemical Similarity Map V Nullarbor Limestonementioning

confidence: 99%

An improved method for assessing the degree of geochemical similarity (DOGS2) between samples from multi-element geochemical datasets

Caritat

Mann

2018

GEEA

View full text Add to dashboard Cite

The multi-element aqua regia National Geochemical Survey of Australia (NGSA) database is used to demonstrate an improved method for quantifying the degree of geochemical similarity (DOGS2) between soil samples. The improvements introduced here address issues relating to compositional data (closure, relative scale). After removing the elements with excessive censored (below detection) values, the rank-based Spearman correlation coefficient (r s ) between samples is calculated for the remaining 51 elements. Each element is given equal weight through the rank-based correlation. The r s values for pairs of samples of known similar origin (e.g. granitoid-derived) are significantly positive, whereas they are significantly negative for pairs of samples of known dissimilar origin (e.g. granitoid-v. greenstone-derived). Maps of r s for all samples in the database against various reference samples are used to obtain correlation maps for lithological derivations. Likewise, the distribution of soils having a geochemical fingerprint similar to established mineralized provinces can be mapped, providing a simple, first order mineral prospectivity tool. Sensitivity of results to the removal of up to a dozen elements from the correlation indicates the method to be extremely robust. The new method is compliant with contemporary compositional data analysis principles and is applicable to various digestion methods.Multi-element databases, often containing in excess of 50 elements, are a common product of modern soil geochemistry programs, primarily due to the quality and quantity of data produced by modern instrumentation, in particular inductively coupled plasmamass spectrometry (ICP-MS). Presentation of informative statistical analysis derived from such datasets can be challenging and is commonly limited to one or two elements of interest, either because they are sought-after commodities or pathfinders in an exploration program or are potential contaminants in an environmental impact assessment. The alternative approach is to consider a geochemical composition as a multi-dimensional 'whole' and treat the data in a multivariate way. Correlation analysis can thus be used to define elements with common geochemical behaviour. Recently, principal component analysis (PCA) has been used to objectively 'discover' suites of elements with common characteristics (e.g. Caritat & Grunsky 2013; Zhang et al. 2014a), which can then guide follow-up interpretation. Grunsky (2010) provided a comprehensive discussion of multivariate data analysis techniques, including PCA and cluster analysis methods. The systematic and objective examination of databases for pattern recognition or inference of lithology and geology commonly requires advanced statistical and/or coding skills. The widely varying concentrations of elements in a multielement compositional database and their interdependencies present special problems for statistics-based methods of analysis (Aitchison 1986).Determining quantitatively how geological samples are similar or not based on majo...

show abstract

The association of gold with calcrete

Cited by 16 publications

References 224 publications

Facies and palaeosol analysis in a progradational distributive fluvial system from the Campanian–Maastrichtian Bauru Group, Brazil

Facies and palaeosol analysis in a progradational distributive fluvial system from the Campanian–Maastrichtian Bauru Group, Brazil

Barren ground depressions, natural H2 and orogenic gold deposits: Spatial link and geochemical model

An improved method for assessing the degree of geochemical similarity (DOGS2) between samples from multi-element geochemical datasets

Contact Info

Product

Resources

About