Age constraints of the Wassa and Benso mesothermal gold deposits, Ashanti Belt, Ghana, West Africa

Parra‐Avila, Luis A.; Bourassa, Yan; Miller, John; Perrouty, Stéphane; Fiorentini, Marco L.; McCuaig, T. Campbell

doi:10.1016/j.jafrearsci.2015.05.017

Cited by 27 publications

(8 citation statements)

References 26 publications

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“…This is somewhat later than what is suggested for the neighbouring countries, where the first Au-mineralizing event is interpreted at 2.19-2.15 Ga (e.g. Allibone et a., 2002;Parra-Avila et al, 2015). It is also clear that the mineralization continued for some time after the main Eburnean phase, although the exact ages, extent and conditions of this late mineralization are debated: for example, Camus et al (2008) propose three phases of hypogenic gold mineralisation in Côte d'Ivoire, each with generally lower grades than the previous: Au1 (2.17-2.12 Ga), Au2 (2.1-2.097 Ga), and Au3 (age unknown).…”

Section: Style Of Gold Mineralisationmentioning

confidence: 69%

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: Style Of Gold Mineralisationmentioning

confidence: 69%

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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“…Sedimentary rocks of these series largely comprise conglomerates and cross-stratified to planar-bedded sandstones, with subordinate siltstones and rhyolitic volcanic r o c k s a l s o o c c u r r i n g l o c a l l y i n s o m e s e r i e s . Conglomerates are typically polymict and include clasts of granite, Eoeburnean supracrustal rocks, vein, and metamorphic quartz, and locally Archean detritus (Milési et al 1989;Feybesse and Milési 1994;Parra-Avila et al 2015;Lebrun et al 2016). The Tarkwa (Sestini 1973;Pigois et al 2003), Safane-Téhini (Simeon et al 1995;Bossière et al 1996), and Kintinian (Lebrun et al 2016) series are consistently younger in age than the deep water sedimentary rock sequences described above (Davis et al 2015;Grenhölm et al 2019).…”

Section: Deformation and Metamorphism Of The Deep Water Sedimentary Series During The Onset Of The Eburnean Orogeny (Ca 2110-2095 Ma)mentioning

confidence: 91%

Paleoproterozoic gold events in the southern West African Craton: review and synopsis

Masurel

Eglinger²,

Thébaud³

et al. 2021

Miner Deposita

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The southern part of the West African Craton includes the Baoulé-Mossi Domain, the world's premier Paleoproterozoic gold province (~10,000 metric ton gold endowment). Structural, metamorphic, and geochronological data suggest gold mineralisation occurred during three episodes that span much of the Eoeburnean and Eburnean orogenic cycles. Eoeburnean orogenic and rare skarn-hosted gold deposits formed between ca. 2200 and 2135 Ma during repeated episodes of volcanism, plutonism, and shortening, which thickened the Paleoproterozoic crust. Early Eburnean orogenic and placer gold deposits formed between ca. 2110 and 2095 Ma during inversion, metamorphism, and subsequent oblique shortening of intra-orogenic basins filled after ca. 2135 Ma. This episode of mineralisation terminated when the Baoulé-Mossi Domain docked with the Archean Kénéma-Man Domain at ca. 2095 Ma. Late Eburnean orogenic and less common intrusion-related gold deposits formed between ca. 2095 and 2060 Ma during strike-slip to oblique-slip tectonics, post-collisional high-K plutonism and crustal reworking across the western and southern Baoulé-Mossi Domain. Eoeburnean gold deposits include ca. 10 % of the gold endowment of the Baoulé-Mossi Domain, whereas the Early Eburnean and Late Eburnean deposits include ca. 50-70% and 20-40%, respectively. Here, we highlight the favourable confluence of accretion-collision tectonics, involving juvenile crust formation as well as protracted magmatic, metamorphic, and deformation histories that resulted in diachronous gold events spread over at least 100 myr throughout the Baoulé-Mossi Domain.

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“…The area is underlain by rocks of Birimian System and lies within the southern portion of the Ashanti Greenstone Belt, along the eastern margin within a volcano-sedimentary assemblage located close to the Tarkwaian formation contact. A fault zone to the east separates the Tarkwaian Formation of rock units from the Volcano-sedimentary rocks of the Sefwi group (Parra-Avila et al, 2015). The lithological sequence of the study area is characterized by a sequence of meta-volcanic (basaltic to andesitic protoliths) flows intercalated with metasedimentary rocks such as greywacke, magnetite-rich argillite and rare black shale layers, micaschists and felsic porphyry.…”

Section: Physiographic and Geological Settingsmentioning

confidence: 99%

Determination of local background and baseline values of elements within the soils of the Birimian Terrain of the Wassa Area of Southwest Ghana

Kazapoe

Arhin

2019

Geology, Ecology, and Landscapes

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Age constraints of the Wassa and Benso mesothermal gold deposits, Ashanti Belt, Ghana, West Africa

Cited by 27 publications

References 26 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

Paleoproterozoic gold events in the southern West African Craton: review and synopsis

Determination of local background and baseline values of elements within the soils of the Birimian Terrain of the Wassa Area of Southwest Ghana

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