Geology, geodynamics and orogenic gold prospectivity modelling of the Paleoproterozoic Kumasi Basin, Ghana, West Africa

Chudasama, Bijal; Porwal, Alok; Kreuzer, Oliver P.; Butera, Kris

doi:10.1016/j.oregeorev.2015.08.012

Cited by 39 publications

(14 citation statements)

References 47 publications

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“…our D2; e.g. Pigois et al, 2003;Chudasama et al, 2016;Traoré et al, 2016;Le Mignot et al, 2017). Our analysis results indicate strong and systematic correlation between Au and both D1 and D2 structures in Côte d'Ivoire.…”

Section: Discussionmentioning

confidence: 50%

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A geostatistical approach to analyzing gold distribution controlled by large-scale fault systems – An example from Côte d’Ivoire

Murray

Torvela

Bills³

2019

Journal of African Earth Sciences

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Geostatistical approaches can help to understand the general characteristics of an area, to suggest feasible geological models, and to quantify overall patterns in the occurrence of economic mineralisation. We use such an approach to demonstrate the relationships between large-scale faults of various ages and kinematics, lithologies, and gold mineralisation to facilitate understanding of crustal-scale structural controls of gold deposits. Our example comes from Côte d'Ivoire, which is known to have undergone at least three major phases of deformation, two of which produced transpressional faults resulting from ESE-WNW and, later, NE/ENE-SW/WSW, compression. Using aeromagnetic and surface geological data, we interpret these faults and suggest a multiphase Riedel model for the region, taking fault reactivation into consideration. With the help of this simplified model, the spatial relationships between the faults, lithology, and 909 known gold occurrences, including 554 artisanal mining sites, are analysed within a GIS. Using geostatistical methods, gold mineralisation was found to probably be a two-stage process, with the later D2 stage potentially being the peak mineralization event. Gold occurrences are most abundant within c. 3 km of both newly formed and reactivated NE-SW faults, most importantly P1 and Y2 faults, in areas of low-intermediate fault density, and close to lithological contacts within the greenstone sequences.

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Section: Discussionmentioning

confidence: 50%

“…Reports do exist of the strong control of the D2 faulting, including reactivation of D1 structures, of gold deposition in the Birimian: e.g. Chudasama et al (2016) discuss the reactivation of the D1 NE-SW striking thrusts during D2 in the Kumasi Basin in Ghana.…”

Section: Discussionmentioning

confidence: 99%

A geostatistical approach to analyzing gold distribution controlled by large-scale fault systems – An example from Côte d’Ivoire

Murray

Torvela

Bills³

2019

Journal of African Earth Sciences

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“…Thereafter, the As concentration increased progressively to about 1.2 ± 0.18 mg/kg in the 2010s, with occasional declines within the 2000 and 2010 periods. The geology of the Ashanti Region, and most parts of the mining belts in Ghana, is dominated by arsenopyrites, the mineralization of which liberates As (Chudasama, Porwal, Kreuzer, & Butera, ). It is also known that excavation activities might expose and liberate heavy metals from soils and rocks (Katsumi, ).…”

Section: Resultsmentioning

confidence: 99%

Sedimentation and sediment core profile of heavy metals in the Owabi reservoir in Ghana

et al. 2019

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Tropical reservoirs are important for numerous socioeconomic and ecological reasons, including water supply, fishing and flood control. These functions are easily compromised, however, when reservoirs undergo accelerated sedimentation with increased inputs of chemical contaminants. The present study applied the concept of sediment core analysis to evaluate the sedimentation rate in Owabi Reservoir, which has served as a source of drinking water supply in Kumasi, Ghana, for nearly a century. The temporal variation of contamination from heavy metals was also assessed over this period. The sedimentation rate for Owabi Reservoir was estimated to be 6.82 mm/year, suggesting a relatively low rate of sedimentation, which is ecologically healthy in preventing a rapid loss of reservoir water volume. Heavy metal concentrations in the sediment cores taken from the reservoir reflected varying degree of contamination from the 1930s to 2010s. The concentration of iron (Fe) (1,560–1,770 mg/kg) was found to be the highest among the metals in the sediment core, while mercury (Hg) concentration (0.01–0.04 mg/kg) was the lowest. Lead (Pb) contamination peaked in the 1980s. Arsenic (As) and mercury (Hg) contamination exhibited more recent peaks in the 2000s, coinciding with recent widespread issues of artisanal and small‐scale gold mining (ASGM) in Ghana. Thus, even though ASGM activities are known to occur in remote districts, releases from such activities might eventually contaminate reservoirs designated as urban drinking water supplies.

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“…The underlying geology consists of the Paleoproterozoic Birimian metasedimentary rocks, within about an 80km wide anticlinal basin and intruded by granite-granodiorite suites (Chudasama, Porwal, Kreuzer, & Butera, 2015). The basin is dissected by a 10-20km wide NE-SW trending shear systems permeated by hydrothermal fluid flow and gold mineralisation (Chudasama et al, 2015), with associated sulphide minerals dominated by arsenopyrite and pyrite (Oberthur, Vetter, Mumm, Weiser, Amanor, Gyapong, Kumi, & Blenkinsop, 1994). The sulphide minerals decompose to release trace metals such as copper (Cu), arsenic (As), lead (Pb), nickel (Ni) and zinc (Zn) into soils (Foli & Gawu, 2017.…”

Section: The Study Areamentioning

confidence: 99%

“…Appelo & Postma, 2005;Foli & Nude, 2012). The dominance of As in the environment may be due to redistribution of elements from mineralised zones associated with deep-seated shear zones flanking the Paleo-Proterozoic Kumasi basin (Chudasama et al, 2015).…”

Section: Parameter Distributions In Water and Sediment Samplesmentioning

confidence: 99%

Geochemical Assessment of Trace Metals in Peri-Urban Drainage and Bioaccumulation in Selected Food Crops in the Kumasi Metropolis, Ghana

Foli¹,

Gawu²,

Brako³

et al. 2019

ENRR

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This paper evaluates some geochemical properties of trace metals in peri-urban drainage and bioaccumulation in cassava, plantain, lettuce and sugarcane in the Kumasi metropolis in Ghana, West Africa. The aim is to establish water quality and food safety. Water, sediment and the food crops were sampled along the profiles of Wiwi and Subin rivers for analysis. T-test statistic shows that pH, HCO3, Cl, Cu, As, Pb and Ni are significant in water and sediment. Mean concentrations of Cu, As, Pb and Ni in water and sediment are (0.01mg/l; 3.2mg/kg), (3.08mg/l; 4.9mg/kg), (0.034mg/l; 8.7mg/kg) and (0.021mg/l; 6.1mg/kg), respectively. In water, As, Pb and Ni concentrations are above primary maximum contamination limits of 0.05 mg/l, 0.015 mg/l and 0.020mg/l with metal ratios of 61.54, 2.27 and 1.05, respectively. In sediment, As concentration is above the continental crustal background value of 1.8mg/kg with a metal ratio of 2.72. From geochemical process models: (1) As and Ni adsorbs into sediment and may lead to attenuation in water in closed systems; (2) Cu and Pd are in equilibrium and may affect water quality at higher concentrations. The food crops have trace metals concentrations below reference values and bioaccumulation factors<1. The food crops are therefore excluders, and safe for dietary intake. Members in cassava-plantain-lettuce and cassava-lettuce-sugarcane suites have translocation factors (TFs)>1 for Cu and As, respectively, while lettuce has TF>1 for Pd and Ni. Crops with TF>1 may bioaccumulate the respective trace metals in over a prolonged period.

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Geology, geodynamics and orogenic gold prospectivity modelling of the Paleoproterozoic Kumasi Basin, Ghana, West Africa

Cited by 39 publications

References 47 publications

A geostatistical approach to analyzing gold distribution controlled by large-scale fault systems – An example from Côte d’Ivoire

A geostatistical approach to analyzing gold distribution controlled by large-scale fault systems – An example from Côte d’Ivoire

Sedimentation and sediment core profile of heavy metals in the Owabi reservoir in Ghana

Geochemical Assessment of Trace Metals in Peri-Urban Drainage and Bioaccumulation in Selected Food Crops in the Kumasi Metropolis, Ghana

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