Mineral Exploration Applications Research Articles

Three-Dimensional Geological Modelling in Earth Science Research: An In-Depth Review and Perspective Analysis

This study examines the development trajectory and current trends of three-dimensional (3D) geological modelling. In recent years, due to the rising global energy demand and the increasing frequency of regional geological disasters, significant progress has been made in this field. The purpose of this study is to clarify the potential complexity of 3D geological modelling, identify persistent challenges, and propose potential avenues for improvement. The main objectives include simplifying the modelling process, improving model accuracy, integrating different data sources, and quantitatively evaluating model parameters. This study integrates global research in this field, focusing on the latest breakthroughs and applications in mineral exploration, engineering geology, geological disaster assessment, and military geosciences. For example, unmanned aerial vehicle (UAV) tilt photography technology, multisource data fusion, 3D geological modelling method based on machine learning, etc. By identifying areas for improvement and making recommendations, this work aims to provide valuable insights to guide the future development of geological modelling toward a more comprehensive and accurate “Transparent Earth”. This review underscores the global applications of 3D geological modelling, highlighting its crucial role across various sectors such as mineral exploration, the oil and gas industry, urban planning, geological hazard assessment, and geoscientific research. The review emphasizes the sector-specific importance of this technology in enhancing modelling accuracy and efficiency, optimizing resource management, driving technological innovation, and improving disaster response capabilities. These insights provide a comprehensive understanding of how 3D geological modelling can significantly impact and benefit multiple industries worldwide.

Characterization of heavy minerals and stream sediment from Bidjouka area, Nyong Complex south Cameroon: implications for gold mineralization

The stream sediment geochemistry has a wide application in mineral exploration. In this study, we applied the stream sediment geochemistry to decipher the primary source of gold mineralization, determine the mineralogy of heavy mineral concentrate and also to ascertain the provenance, depositional environment, intensity of weathering as well as determine the tectonic setting. To investigate heavy mineral in stream channel, 20 placer materials from Bidjouka area were assessed by thin plate using polarized microscope. The powder was further characterized by ICP-MS using aqua regia. Results show that placers displayed minerals such as magnetite, zircon and gold. Majors geochemical base metal point out low grade of iron (< 5 wt.%), titanium (< 1.05 wt.%) and alumina (< 0.60 wt.%). The following metallic trace elements used for industrial technology are identified in the samples. It mainly concerns manganese and thorium with content less than 328 and 200 ppm respectively as well as mercury (< 550 ppb). Precious metals are also present in the chemical composition of Bidjouka sediments. The main substances identified is gold with the grade above 2 g/tone, which is an important target in mining exploration. Also the mean value of rare earth elements varying between 1256.6 and 3626.8 ppm are so speculative, with negative and positive Eu and Ce anomaly respectively. Gold is bound with sulfide mineral (Au-Bi), suggesting a sulfidation event during sediments deposition. Factor 4 (Co, Mn, Sc, Au, Bi) refers to the mineralization factor and Co, Mn, Sc, Bi serve as pathfinder of gold. Sediments were deposited under humid, oxic and oxidizing conditions; intermediate intensity of weathering processes of the source rocks had prevailed during deposition, and sediments were rich in plagioclase. These continental sediments have quartzose sedimentary provenance, they were originated from metamorphic sources and were deposited in an active continental margin. The results of this study serve as guide for gold exploration and exploitation in the Bidjouka area.

Auto encoder generative adversarial networks - based mineral prospectivity mapping in Lhasa area, Tibet

When conducting Mineral Potential Mapping (MPM) using multiple sources of data such as geology, geochemistry, and geophysics, it often encounters the challenges of complex and diverse data distributions within these datasets. Enhancing the capability to extract nonlinear data features and further uncover metallogenic information is a crucial research objective. This study utilizes the C-A multifractal approach to extract anomalous information related to metallogenic elements, employs compositional data analysis methods for quantitatively extracting geochemical associations of mineralization, and utilizes GIS spatial analysis techniques to quantitatively extract predictive indicators from various data sources, including geology, geophysics, and remote sensing, to construct an MPM prediction dataset. Building upon the foundation of AutoEncoder (AE), this study introduces a discriminator and employs the AEGAN (Auto Encoder Generative Adversarial Network) algorithm, which combines AutoEncoder and Generative Adversarial Network (GAN), for metallogenic prospectivity prediction in the Lhasa region. Compared to AE algorithms, AEGAN combines the strengths of AE and GAN, significantly improving the model's ability to reconstruct input data through the interaction between the generator and discriminator. Additionally, this study designs comparative experiments with AE, and the results demonstrate that the AEGAN model can more accurately identify the correlation between high anomaly areas and polymetallic deposits, providing a more precise delineation of anomalous extents. The Area Under the Receiver Operating Characteristic Curve (AUC) further validates the superior performance of the AEGAN model. These findings indicate that the AEGAN model exhibits outstanding capabilities in learning the internal connections and features among multiple data sources, holding significant potential for practical applications in mineral exploration.

Editorial for Special Issue “Novel Methods and Applications for Mineral Exploration, Volume II”

As already exemplified by the highly successful first volume of this Special Issue, both the theoretical understanding of mineral exploration and its practical application in the field are undergoing a profound and significant transformation [...]

Characters and Metallogenetic Significance of Organic Matter in Coal from the Daying Sandstone-Hosted Uranium Deposit in the Northern Ordos Basin, China

Coal is usually found in many sandstone-hosted uranium deposits in western China. However, it remains unclear whether coal organic matter is related to the mineralization of uranium in sandstone. In this study, the organic matter of coal containing lenticular carbon plant strips and carbon clastics was analyzed in different alteration zones in the Daying sandstone-hosted uranium deposit located in the northern Ordos Basin. According to geological and geochemical characters, Daying sandstone can be classified into three alteration zones: the oxidation zone, the transition zone, and the reduction zone. The results are as follows. Firstly, the maceral organic matter of the coal at Daying is mostly vitrinite, indicating the characters of humic coal. The maturity of the organic matter is low, which is in the transitional evolution stage of immature lignite or lignite-long-flame coal. Secondly, the kerogen is mainly type III (humic type), which can be easily transformed into humic acid with a strong adsorption capacity for uranium. Thirdly, the vitrinite reflectance (Ro) of the coal organic matter in the transition zone is higher than that of the other alteration zones. Meanwhile, there are bright white bands in the microscopic components of the organic matter of the coal in the transition zone (mineralized zone) and a certain composition of the sapropelite has strong fluorescence. All three aforementioned phenomena are related to the radioactivity of uranium, and each of them possesses the potential for application in mineral exploration. Fourthly, the extraction and separation of humic substances indicates that humic acid plays a key role in organic matter-related uranium mineralization. In the transition zone, uranium can co-precipitate as a humate, and the transition zone’s organic carbon content increases. Therefore, the organic matter in coal contributes to sandstone-hosted uranium mineralization, providing a further guide to prospecting methodologies.

Editorial: Accessory mineral geochemistry and its application in mineral exploration

Editorial: Accessory mineral geochemistry and its application in mineral exploration

The radiation shielding competence and imaging spectroscopic based studies of Iron ore region of Kozhikode district, Kerala

Hyperspectral data and its ability to explore the minerals and their associated rocks have a remarkable application in mineral exploration and lithological characterization. The present study aims to explore the radiation shielding aspects of the iron ore in Kerala with the aid of the Hyperion hyperspectral dataset. The reflectance-spectra obtained from the laboratory conditions as well as from the image show various absorptions. The results from the spectra are validated with geochemical data and GPS points. The Monte Carlo simulation employed to evaluate the radiation shielding ability. Raising the oxygen ions caused a noteworthy decrease in the μ values of the studied rocks which is accompanied by an increase in Δ0.5 and Δeq values. The Δ0.5 and Δeq values increased by factors of approximately 77 % with raising the oxygen ions between 44.32 and 47.57 wt.%. The μ values varies with the oxygen concentrations, where the μ values decreased from 2.531 to 0.925 cm−1 (at 0.059 MeV), from 0.381to 0.215 cm−1 (at 0.662 MeV), and from 0.279 to 0.158 cm−1 (at 1.25 MeV) with raising the oxygen ions from 44.32 to 47.43 wt.%.

A review on theory, modeling, inversion, and application of self-potential in marine mineral exploration

The self-potential (SP) method is one of the passive geophysical exploration techniques, which employs measurements of naturally occurring electric potential differences on the ground surface and in boreholes or (sea-)water due to causative sources from electrochemical, electrokinetic, and thermoelectric mechanisms. SP signals are directly related to groundwater flow and (electro-)chemical gradient. There has been increasing interest in the application of SP measurements in mineral exploration, environmental surveys, and hydrogeophysical problems. This review focuses primarily on the theory concerning the causative source mechanism, numerical modeling, and inversion and interpretation of SP signals related to ore bodies and applications in mineral exploration. Three field examples focusing on seafloor sulfide deposits exploration are summarized to show the application effect of SP measurements in marine mineral exploration. This study would be helpful to investigating the use of SP surveys in ore prospecting, especially in marine environments.

Introduction to the thematic collection: applications of innovations in geochemical data analysis

Geochemistry: Exploration, Environment, Analysis (GEEA) as the scientific journal of the AAG focuses on the use of geochemistry in mineral exploration/resource development. Since the first issue of GEEA was published in 2001, there have been hundreds of papers regarding methodologies for geochemical data analysis. In 2017, a thematic issue: analysis of exploration geochemical data for mapping of anomalies (Carranza and Zuo, 2017) was published on the development of methods and techniques for exploration geochemical data analysis. As a successor, this current thematic set of papers introduces some new progress and advancements in geochemical data analysis, e.g., nonlinear, fractal/multifractal, multi-statistical, machine learning methods and their applications in mineral exploration. Twelve papers from Professor Qiuming Cheng's colleagues in China and Canada are organized in this thematic set in honor of his Gold Medal Award. Thematic collection: This article is part of the Applications of Innovations in Geochemical Data Analysis collection available at: https://www.lyellcollection.org/topic/collections/applications-of-innovations-in-geochemical-data-analysis

A review of geospatial technology-based applications in mineral exploration

A review of geospatial technology-based applications in mineral exploration

Automated Analysis of Reflection Mode Terahertz Hyperspectral Images

A suite of algorithms and associated procedures, originally developed for mineral exploration applications, are adapted for application to terahertz hyperspectral images measured in reflection mode. Such data are often quite noisy due to the low reflectivity of many materials at terahertz frequencies. The algorithms and procedures are based on an extended linear mixture model consisting of two parts. The first part, called the “foreground”, models the distinguishing parts of the spectra of materials (including mixtures) of interest (especially their diagnostic absorption features). The second part, called the “background”, models parts of the spectra that are typically of lesser interest, such as variation in low frequencies and water vapor. The model and procedures are exemplified with a spectral library of six materials and are applied to three hyperspectral images, one consisting only of pure pellets, some of which are not in the library, and two of which contain both pure and mixed pellets of three of the materials in the library. The associated procedures include the following: estimating the number of materials in the mixture at each pixel; identifying pixels with materials that are well modeled by the background terms only; identifying pixels with materials not in the library; and identifying pixels containing metal. Finally, this article concludes with a discussion of some outstanding issues.

Controls on groundwater selenium, arsenic and base metals in groundwater around a selenium-bearing volcanogenic massive sulfide deposit: constraints from stable isotopes, trace elements and redox controls

Understanding the controls on the behaviour of metalloids (Se, As) and metals (Cu, Zn, Pb) in natural aqueous systems is vital to interpreting hydrogeochemical data in environmental and mineral exploration applications. Geochemical, isotopic and redox measurements of a suite of groundwaters sampled from around the ABM zone of the Kudz Ze Kayah (KZK) volcanogenic massive sulfide (VMS) deposit in the Yukon, Canada are presented and contrasted with other case studies from a variety of mineral deposit types. This deposit has atypically high As (up to 4.3 wt%, average 2457 ppm) and Se (up to 2620 ppm, average 157 ppm) contents in the sulfide mineralization. As a relatively undisturbed deposit (unmined), it is an ideal site to study the mobility and solubility of trace metals in groundwaters. Herein we present field measurements (pH, dissolved oxygen, specific conductance, oxidation–reduction potential and temperature), major ion, trace element, anion (Cl, Br, SO4, PO4), and stable isotope (δ2H, δ13CDIC, δ18O, δ18OSO4, δ34S) data.Waters are dominantly low-salinity HCO3 to HCO3–SO4-type waters with variable sulfate (4.83 to 601 mg l−1), Ca (23–235 mg l−1) Mg (3.1–96.8 mg l−1), Na (0.30–66.9 mg l−1) and K (0.55 to 6.25 mg l−1) concentrations. These waters also have variable trace element concentrations that include As (0.01 to 148 µg l–1), Se (&lt;0.02 to 1.01 µg l–1), Fe (0.01 to 3.84 mg l−1), Zn (&lt;0.2 to 1070 µg l–1), Pb (&lt;0.01 to 8.4 µg l–1), Cu (0.03 and 24.5 µg l–1) and Sb (0.01 to 54.4 µg l–1). Some waters also have elevated concentrations (compared to most meteoric waters) of Nb (up to 0.3 µg l–1), Y (up to 1.42 µg l–1), Zr (up to 18 µg l–1), and the rare-earth elements (REEs) (ΣREE up to 2.04 µg l–1). The δ18O (−22.8 to −20.9 ‰) and δ2H (−174 to −158 ‰), together with the δ13CDIC (−10.6 to +1.9 ‰), δ34S (+10 to +12 ‰) and δ18OSO4 (15.5 to −4.75 ‰) all suggest that local meteoric water has interacted with massive sulfide mineralization at the ABM zone. Our results demonstrate the requirement for the use of multiple techniques in hydrogeochemical studies, with dissolved concentrations of major and trace elements coupled with a suite of stable isotopes that help define a larger geochemical footprint for the KZK deposit. Water–mineral interaction between groundwater aquifers and VMS deposits like the ABM zone are distinctly different from dispersion halos described from other deposit types (i.e. Cu porphyry, unconformity U).Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at: https://www.lyellcollection.org/cc/hydrochemistry-related-to-exploration-and-environmental-issues

Tellus regional stream water geochemistry: environmental and mineral exploration applications

Regional stream water geochemistry acquired as part of the Tellus programme in Ireland has been analysed to assess its potential for application to environmental assessment and mineral exploration. Interpolated geochemical maps and multivariate statistical analysis, including principal component analysis and random forest classification, demonstrate broad geogenic control of stream water chemistry, with both bedrock and subsoil contributing to the patterns observed. Surface water regulations set Environmental Quality Standard values for individual Priority Substances and Specific Pollutants that may depend on background concentrations and/or water hardness. The high resolution of Tellus stream water data and their location on low-order streams have allowed estimation of background concentrations and water hardness in the survey area, with significant implications for water monitoring programmes. Anthropogenic inputs to stream water in the survey area come mainly from agricultural sources and Tellus data suggest few catchments are unaffected. Comparison of Tellus stream water geochemistry with stream sediment and topsoil geochemistry suggest that stream water geochemistry has strong potential for use in mineral exploration, with the same base metal and gold pathfinder anomalies apparent in all three data sets. Cluster analysis indicates that base metals in stream water are associated with organic matter but statistical analysis may be employed to distinguish mineralization-related signatures.Supplementary material: Comparison of cation/anion associations using Piper plots and principal component analysis is available at https://doi.org/10.6084/m9.figshare.c.5683094Thematic collection: This article is part of the Hydrochemistry related to exploration and environmental issues collection available at: https://www.lyellcollection.org/cc/hydrochemistry-related-to-exploration-and-environmental-issues

Advanced Methods of Joint Inversion of Multiphysics Data for Mineral Exploration

Different geophysical methods provide information about various physical properties of rock formations and mineralization. In many cases, this information is mutually complementary. At the same time, inversion of the data for a particular survey is subject to considerable uncertainty and ambiguity as to causative body geometry and intrinsic physical property contrast. One productive approach to reducing uncertainty is to jointly invert several types of data. Non-uniqueness can also be reduced by incorporating additional information derived from available geological and/or geophysical data in the survey area to reduce the searching space for the solution. This additional information can be incorporated in the form of a joint inversion of multiphysics data. This paper presents an overview of the main ideas and principles of novel methods of joint inversion, developed over the last decade, which do not require a priori knowledge about specific empirical or statistical relationships between the different model parameters and/or their attributes. These approaches are designated as follows: (1) Gramian constraints; (2) Gramian-based structural constraints; (3) localized Gramian constraints; and (4) joint focusing constraints. We provide a short description of the mathematical foundations of each of these approaches and discuss the practical aspects of their applications in mineral exploration.

Feature extraction for hyperspectral mineral domain mapping: A test of conventional and innovative methods

Hyperspectral (HS) imaging holds great potential for the mapping of geological targets. Innovative acquisition modes such as drone-borne or terrestrial remote sensing open up new scales and angles of observation, which allow to analyze small-scale, vertical, or difficult-to-access outcrops. A variety of available sensors operating in different spectral ranges can provide information about the abundance and spatial location of various geologic materials. However geological outcrops are inherently uneven and spectrally heterogeneous, may be covered by dust, lichen or weathering crusts, or contain spectrally indistinct objects, which is why classifications or domain mapping approaches are often used in geoscientific and mineral exploration applications as a means to discriminate mineral associations (e.g. ore or alteration zones) based on overall variations in HS data. Feature extraction (FE) algorithms are prominently used as a preparatory step to identify the first order variations within the data and, simultaneously, reduce noise and data dimensionality. The most established FE algorithms in geosciences are, by far, Principal Component Analysis (PCA) and Minimum Noise Fraction (MNF). Major progress has been conducted in the image processing community within the last decades, yielding innovative FE methods that incorporate spatial information for smoother and more accurate classification results. In this paper, we test the applicability of conventional (PCA, MNF) and innovative FE techniques (OTVCA: Orthogonal total variation component analysis and WSRRR: Wavelet-based sparse reduced-rank regression) on three case studies from geological HS mapping campaigns, including drone-borne mineral exploration, terrestrial paleoseismic outcrop scanning and thermal HS lithological mapping. This allows us to explore the performance of different FE approaches on complex geological data with sparse or partly inaccurate validation data. For all case studies, we demonstrate advantages of innovative FE algorithms in terms of classification accuracy and geological interpretability. We promote the use of advanced image processing methods for applications in geoscience and mineral exploration as a tool to support geological mapping activities.

Deposit Location Identification Based on Feature Decomposition of High-Resolution Remote Sensing Images

In modern mineral exploration applications, remote sensing technologies have been widely used and affirmed by engineering and mineral industries due to their unique technical advantages. With the advancement of remote sensing technologies, multiple geological remote sensing-derived prospecting methods have been developed. With the development of more accurate sensors, the detection band has not been segmented, and the spectral resolution of such sensors is constantly being improved. Thus, the accuracy of remote sensing geological prospecting methods has improved, and geological prospecting results have shifted from being qualitative to quantitative in nature. In this article, high-resolution remote sensing images are used to extract the ore controlling factors of deposits. The color, shape, texture and other image shapes produced by high-resolution remote sensing images are fully exploited to comprehensively mine the available data utilizing mathematics, image processing methods and other technologies to systematically identify prospective target areas. Based on an analysis of the metalloorganic geological characteristics detected in the study area, combined with multisource data such as geophysical and geochemical exploration-derived observations, the proposed remote sensing model describing the deposits in the study area is summarized. The research results show that deposit location identification technologies based on high-resolution remote sensing image feature decomposition have the potential to provide a reliable basis for peripheral exploration and deposit positioning in geological and mineral exploration studies.

Editorial for Special Issue “Novel Methods and Applications for Mineral Exploration”

The mineral exploration industry is [...]

Long baseline LTS SQUID gradiometers with sub-μm sized Josephson junctions

In this paper, we present new integrated on-chip planar-type superconducting quantum interference device (SQUID) first order gradiometers, which are manufactured by a new mix and match fabrication technology combining sub-μm sized Josephson junctions (JJs) with cm-scale pickup loops. The fabrication technology is described and the design is schematically shown. These sensors have high voltage swing and low flux noise and provide thus the best so far reported gradient resolution of about These gradiometers were developed and implemented in instruments for applications in mineral exploration. They allow a better system dynamic range (ratio of maximal to minimal detectable signals) and a more effective use of the chip area. The gradiometer performance in terms of gradient resolution is compared against state of the art planar-type SQUID based gradiometers. Two models predicting a gradient noise limit as a function of the chip area and baseline of the gradiometer are discussed. The small geometric dimensions of the gradiometers are very important for future miniaturized instruments in mineral exploration. The comparison of our results with those models highlights the importance of a smaller JJs size for the reduction of the intrinsic gradiometer noise and geometrical dimensions.

High‐resolution unmanned aerial vehicle aeromagnetic surveys for mineral exploration targets

ABSTRACTRecent advancements in geophysical exploration have been realized through reliably integrating unmanned aerial vehicle platforms with lightweight, high‐resolution magnetometer payloads. Unmanned aerial vehicle aeromagnetic surveys can provide a contemporary data product between the two end‐members of coverage and resolution attained using manned airborne and terrestrial magnetic surveys. This new data product is achievable because unmanned aerial vehicle platforms can safely traverse with magnetometer payloads at flight elevations closer to ground targets than manned airborne surveys, while also delivering an increased coverage rate compared to walking conventional terrestrial surveys. This is a promising new development for geophysical and mineral exploration applications, especially in variable terrains. A three‐dimensional unmanned aerial vehicle aeromagnetic survey was conducted within the Shebandowan Greenstone Belt, northwest of Thunder Bay, Ontario, Canada, in July 2017. A series of two‐dimensional grids (∼500 m × 700 m) were flown at approximate elevations of 35, 45 and 70 m above ground level using a Dà‐Jiāng Innovations multi‐rotor unmanned aerial vehicle (S900) and a GEM Systems, Inc., Potassium Vapour Magnetometer (GSMP‐35U). In total, over 48 line‐km of unmanned aerial vehicle aeromagnetic data were flown with a line spacing of 25 m. The collected aeromagnetic data were compared to a regional heliborne aeromagnetic survey flown at an elevation of approximately 85 m above the terrain, with a line spacing of 100 m, as well as a follow‐up terrestrial magnetic survey. The first vertical derivative of the gathered unmanned aerial vehicle total magnetic field data was calculated both directly between each of the different flight elevations, and indirectly by calculating the values predicted using upward continuation. This case study demonstrates that low flight elevation unmanned aerial vehicle aeromagnetic surveys can reliably collect industry standard total magnetic field measurements at an increased resolution when compared to manned airborne magnetic surveys. The enhanced interpretation potential provided by this approach also aided in delineating structural controls and hydrothermal fluid migration pathways (a pair of adjacent shear zones) related to gold mineralization on site. These structural features were not clearly resolved in the regional manned airborne magnetic data alone, further demonstrating the utility of applying high‐resolution unmanned aerial vehicle aeromagnetic surveys to mineral exploration applications. The conclusions and interpretations drawn from the unmanned aerial vehicle aeromagnetic data, coupled with historical data, were applied to make a new gold mineralization discovery on the site, assayed at 15.7 g/t.

Chemical weathering of garnet in Banded Iron Formation: Implications for the mechanism and sequence of secondary mineral formation and mobility of elements

Abstract The chemical weathering of rocks and minerals on the Earth’s surface leads to the mobilization and redistribution of elements and has (a) significant control on the chemistry of the soil-hydrosphere-atmosphere system, (b) a profound effect on the bioavailability and toxic effects of elements, and (c) applications in mineral exploration among others. In this study, we describe the sequential weathering of spessartine- and pyrope-bearing almandine garnet in metamorphosed banded magnetite quartzite from the Khetri Copper Belt, western India. Based on detailed microtextural relations the following sequence of garnet weathering is proposed: garnet → alumo-goethite1 → alumo-goethite2 → kaolinite ± (monazite + xenotime ± thorite) → haematite. Our study thus reports for the first time the presence of alumo-goethite, kaolinite, monazite, xenotime, and thorite in weathering assemblage of garnet. The sequential chemical weathering of garnet was both grain boundary-controlled and fracture-controlled. Tectonic fractures (developed during exhumation), reaction-induced fractures (developed due to volume expansion), and secondary porosity (developed due to volume reduction) collectively controlled the propagation of weathering. Integrating multiple lines of evidence, e.g., corrugated contact between the weathering phases, presence of pores, relative molar volume changes, and high mobility of most elements it is argued that the weathering progressed through an interface-coupled dissolution-precipitation process. In situ major and trace element measurements and mass balance calculations show that several major (Fe, Na, K, P) and trace elements (Cl, F, alkalis, alkaline earth elements, and first series transition and base metals) were added while Si, Al, Ca, Mg and Mn were lost during the garnet to alumo-goethite transformation. During kaolinitization, all the major elements except Si and Al were lost to the weathering fluid. The alkali and alkaline earth, first series transition elements, base metals excepting Cr were lost during this weathering stage. Phosphorous, REEs, and Th were locally immobilized as monazite, xenotime, and thorite. In the more advanced stages of weathering, kaolinite was replaced by haematite. This stage involved re-addition of several major (except Al and Si) and trace elements. It is seen that although alumo-goethite, kaolinite, and haematite can host significant quantities of several trace elements, alumo-goethite and haematite have a much better potential of immobilizing most trace elements including toxic ones compared to kaolinite in the weathering profile.