Petrography, multi-element geochemistry and multivariate statistical analysis of residual laterites from the Wa-Lawra Belt, NW Ghana: Implications for identifying pathfinder elements of gold

Abstract The Wa-Lawra greenstone belt is located in northwest Ghana and is largely dominated by Birimian metavolcanics, volcaniclastics, and metasediments with some intrusive suites. These rocks are capped by mineralized laterites in most localities, especially in the Kunche area. Previously, regolith materials such as laterites and soils from mixed sources were used to identify pathfinder elements of gold in the belt. However, in-situ (residual) laterites will better represent their underlying formations than transported laterites because transported laterites may contain extraneous sources of element enrichment caused by pollution, which is unrelated to gold mineralization. Therefore, in this study, petrographic studies of residual laterites and statistical analyses of trace element geochemical data of the residual laterites were performed to identify the pathfinder elements of gold in the Wa-Lawra greenstone belt. Six fresh residual laterite samples were used for the petrographic studies, which revealed the dominance of quartz, amphibole, clinopyroxene, hematite, goethite, magnetite, sphalerite, and pyrite. These minerals contribute Fe, S, Ca, Zn, and other elements to the laterites. The geochemical data of 12 residual laterite samples were used for statistical analysis. P-P plots revealed deviations from the normal distribution and outliers in the dataset. Spearman’s correlation revealed that Cu, Ag As, Pb, Fe, and S have moderate-strong positive correlation with Au. Hierarchical cluster analysis revealed that there are 3 multi-element associations; a) Fe, Pb, Mn, S, Co, Au, Cr, Cu, Ni, Ag; b) Ti, Zr, Sr, Ca, and c) Rb, Y, Zn, As. Factor analysis shows that the occurrence of Pb, Cu, Ag, and As is directly related to the occurrence of Au. Thus, the best multi-element association of Au for exploration purposes is Pb, Cu, Ag, and As similar to the previous findings. Single and multi-element anomaly mapping revealed that geochemical anomalies involving these elements are mainly found around the northern and southern parts of the study area on hills and ridges. The results of this study confirm what has been reported by the previous studies. However, it is recommended that gold exploration in similar terranes should be focused on areas dominated by residual laterites since they will always give a true reflection of geochemical anomalies than transported laterites..

Medienart:	Preprint

Erscheinungsjahr:	2022
Erschienen:	2022

Enthalten in:	ResearchSquare.com - (2022) vom: 20. Jan. Zur Gesamtaufnahme - year:2022

Sprache:	Englisch

Beteiligte Personen:	Sunkari, Emmanuel Daanoba [VerfasserIn] Tetteh, Samuel Edem Kodzo [VerfasserIn] Sumbobo, Moses [VerfasserIn] Demir, Yilmaz [VerfasserIn]

Links:	Volltext [kostenfrei]

doi:	10.21203/rs.3.rs-1279747/v1

funding:
Förderinstitution / Projekttitel:

PPN (Katalog-ID):	XRA035036982