Vol.:(0123456789) 1 3 Environmental Earth Sciences (2019) 78:268 https://doi.org/10.1007/s12665-019-8265-5 ORIGINAL ARTICLE Geochemical and pathfnder elements assessment in some mineralised regolith profles in Bole‑Nangodi gold belt in north‑eastern Ghana Eric E. Bayari 1  · Gordon Foli 1  · Simon K. Y. Gawu 1 Received: 28 December 2018 / Accepted: 11 April 2019 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract This study presents gold mineralisation and pathfnder elements characteristics in fve surfcial regolith profles, with the aim of enhancing exploration strategies in the north-eastern Bole-Nangodi Gold Belt in Ghana. Samples were collected from mature soils and bedrocks in exploration pits and prepared for chemical and soil particle size analysis. 13 major ele- ments, mineral forms and ffty-one trace elements were analysed using XRF, XRD and ICP-MS devices, respectively. SiO 2 , Fe 2 O 3 –MnO and Al 2 O 3 are elevated in the A, B and C horizons, respectively, while Na 2 O–K 2 O–MgO–CaO–P 2 O 5 systems dominate the bedrocks. Gold pathfnder element suites of As–Mo–Ag–Sn–Sb–Te–W–Hg–Bi are above Primitive Mantle values by a factor of > 5, while the mean chemical index of alteration (CIA) values are above 80%. Profles contain > 70% quartz with stable mineral concentrations of 53, 18 and 29% in the A, B and C, horizons, respectively. The B horizon is the most altered horizon based on CIA, loss on ignition and Fe/Al ratios; the horizon accounts for 52% of the material and 76% of elements in the > 2 mm particle size. Mass balance and principal component analysis shows that Au exploration targets and the associated pathfnder element suites are the following: (1) horizon A with Sr–Ca–Ge–Sn–Th in the amphibolite and biotite gneiss profles (2) horizons A and B with S–K–Zr–Tl–Ge in the volcaniclastic and (3) the bedrocks with Cu–Pb–Sb– Ag–Mo and Mn–Cr–Ba–V–Ce–Bi–Fe–Co–Sb–As–Se of the metavolcanic and phyllite profles, respectively. The regolith models summarise the mineralogical and structural framework of the profles and may largely infuence exploration designs. Keywords Horizon · Weathering · Exploration · Saprolite · Lithophile · Pisoliths · Models Introduction Background The fast depletion of lucrative gold ore targets located in easily accessible metalliferous environments has shifted the attention of prospectors towards the highly under-explored and often problematic areas between lat. 35°N and 35°S. As noted in a study by Afam and Arhin (2013) in the northern part of Ghana, West Africa, such areas as defned above are characterized by complex regolith covers. According to Anand and Paine (2002), regolith environments contain numerous minerals derived from primary sources which are transformed through various forms of weathering to form secondary minerals, mainly quartz, Al–Fe–Mn-oxides/ hydroxides, phosphates, element suites and resistant min- erals. These authors further noted that, from the primary sources, the liberated mineral components migrate along various pathways and are disseminated by complex mecha- nisms into the receptor soil horizons available. The regolith mineralogical characteristics of the target areas, therefore, control the availability of pathfnder ele- ments, which are very useful and relevant indicators for efective mineral exploration planning and implementation (Cairns et al. 2001). Identifying specifc regolith minerals and pathfnder elements can be challenging because most of the minerals are amorphous and fne-grained, especially in mature profles, but can be determined by chemical analyses (Cairns et al. 2001). The major task, therefore, is to ensure that the most efec- tive horizons are selected using chemical index of alteration * Eric E. Bayari ericbayari@gmail.com 1 Department of Geological Engineering, College of Engineering, Kwame Nkrumah University of Science and Technology (KNUST), Ashanti Region, Kumasi, Ghana