Spatial distribution and trace element geochemistry of laterites in Kunche area: Implication for gold exploration targets in NW, Ghana

Kunche area is located in NW Ghana within the Wa-Lawra greenstone Birimian belt and is composed mainly of volcaniclastics, metasediments and some intrusive granitoids. The area is covered with laterites making it difficult to identify exploration targets. In this study, we describe a new methodology based on statistical tools and trace element geochemistry to map the pathfinder elements of gold deposits in lateritic context. However, the results of this study are specific to a particular context and cannot be extrapolated without supplementary studies to all the lateritic areas. In this respect, a total of 67 lateritic samples were collected from residually weathered materials and their spatial distribution was determined by means of the GIS-based kriging interpolation method. The samples collected vary from detrital to residual laterites/duricrusts and are hosted in volcaniclastic rocks. ICP-MS and XRF techniques were used to determine the element concentrations of the samples. The trace element geochemical data were analyzed using bivariate and multivariate geostatistical analysis to establish relationships among elements. Fe-oxides such as goethite and hematite and clay minerals like kaolinite are the main secondary minerals of the concretionary reddish lateritic samples. All the analyzed elements showed asymmetrical distribution rather than normal distribution. Spearman correlation shows that Cu, Pb, S, As, and Ag have moderate to strong positive correlation with Au. From the multivariate geostatistical analysis, three element associations; a) Fe, Pb, S, Co, Cr; b) Ni, Y, Rb, Sr, Zn, and c) Ca, Cu, Mn, Ti, Zr, As, Au, Ag were observed. Threshold values of selected elements were determined using the median absolute deviation (MAD) method, which indicates possible anomalous concentrations in the laterites for Pb (?48 ppm), Cu (?46 ppm), As (?134.2 ppm), and Ag (?0.42 ppm). Multi-element mapping indicates that Pb + Cu + As + Ag is the most ideal association in the exploration of gold deposits. It reveals ellipsoidal anomalies comparable to the Au distribution map that suggest dispersion and accumulation of the pathfinder elements in the area. The geochemical anomalies are mainly restricted to the environment of the residual laterites in the Kunche area and we recommend that exploration programs should be focused in such areas. © 2019 Elsevier LtdUniversity of Electronic Science and Technology of ChinaAzumah Resources Limited, Ghana is acknowledged for the support during the period of this research. Special thanks goes to Assoc. Prof. Emmanuel ARHIN at the University for Development Studies, Ghana for his useful comments. The first author thanks TÜBİTAK, BIDEB 2215 Graduate Scholarship Program for International Students for the continuous support as a doctoral research fellow in Turkey. The second author also acknowledges the support from the Graduate Scholarship Program for International Students of the University of Electronic Science and Technology of China . The Editor-in-Chief (Dr. Damien Delvaux), Dr. David Baratoux and other anonymous reviewers are greatly acknowledged for their useful comments that improved the quality of the paper. Appendix