Early proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa

Milési, Jean-Pierre; Ledru, Patrick; Feybesse, Jean-Louis; Dommanget, A.; Marcoux, Éric

doi:10.1016/0301-9268(92)90123-6

Cited by 239 publications

(178 citation statements)

References 43 publications

Supporting

Mentioning

163

Contrasting

Unclassified

Order By: Relevance

“…According to Bourges et al (1998) [43], transcurrent sinistral shear has evolved towards inverse sinistral shear. As for the Diabatou gold shear zone (in Burkina Faso), it is marked by an inverse dextral movement (Milési, 1989 [44], Milési et al, 1992 [13], Klemd et al, 1997 [45]). The Harbor Lights gold deposit in Australia, on the other hand, is interpreted as a normal shear zone with a dip around 30˚ (Skwarnecki, 1987 [46] and 1988 [47]; Vearncombe, 1992 [48]) in which the deformation processes are partly similar to those of inverse shear zones containing most of the gold deposits.…”

Section: Discussionmentioning

confidence: 99%

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&ocirc;te d’Ivoire

Houssou¹,

Allialy²,

Kouadio³

et al. 2017

IJG

View full text Add to dashboard Cite

Located in the southwestern of the Oume-Fettekro greenstone belt, the Agbahou gold deposit is controlled by structural factors. Geophysics, teledetection and core data suggest the presence of NE and NW faults. However, the NEfaults define two major shear zones (ATZ: Agbahou Tectonic Zone and WTZ: West Tectonic Zone) that control the Agbahou gold mineralization. These first order structures are subparallel to the regional tectonic grain mostly north-east oriented. They seem to respectively develop on the both arms (eastern and western) of an anticline moderately plunging ~25˚ towards northeast. Each shear-zone contains several second-order shear-zones or lenses of variable direction and of 50˚ -80˚ dip. NW-faults however correspond to strike-slip faults and their development should be related to transcurrent tectonics. They acted as control channels on the distribution of gold mineralizations. The ductile-brittle character of shear-zones favored the ascent of hydrothermal fluids and the formation of multiple auriferous quartz veins: veins Type IIa and veins Type IIb relating respectively to the shear-veins and extensional veins. However, Agbahou also shows the existence of a disseminated sulphides-bearing mineralization within host-rocks. At Agbahou, the precipitation of gold probably occurred in a post to late ductile-brittle deformation period.

show abstract

Section: Discussionmentioning

confidence: 99%

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&ocirc;te d’Ivoire

Houssou¹,

Allialy²,

Kouadio³

et al. 2017

IJG

View full text Add to dashboard Cite

show abstract

“…1). The corridor along the flanks of this contact elsewhere in the Ashanti belt is well known for the occurrence of shear zones and associated gold mineralization (e.g., Leube et al 1990;Milesi et al 1992;Melcher and Stumpfl 1994;Yao and Robb 2000).…”

Section: Geological Settingmentioning

confidence: 99%

Petrography, geochemistry, and alteration of country rocks from the Bosumtwi impact structure, Ghana

Karikari

Ferrière

Koeberl

et al. 2007

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Abstract-Samples of the country rocks that likely constituted the target rocks at the 1.07 Myr old Bosumtwi impact structure in Ghana, West Africa, collected outside of the crater rim in the northern and southern parts of the structure, were studied for their petrographic characteristics and analyzed for their major-and trace-element compositions. The country rocks, mainly meta-graywacke, shale, and phyllite of the Early Proterozoic Birimian Supergroup and some granites of similar age, are characterized by two generations of alteration. A pre-impact hydrothermal alteration, often along shear zones, is characterized by new growth of secondary minerals, such as chlorite, sericite, sulfides, and quartz, or replacement of some primary minerals, such as plagioclase and biotite, by secondary sericite and chlorite. A late, argillic alteration, mostly associated with the suevites, is characterized by alteration of the melt/glass clasts in the groundmass of suevites to phyllosilicates. Suevite, which occurs in restricted locations to the north and to the south-southwest of the crater rim, contains melt fragments, diaplectic quartz glass, ballen quartz, and clasts derived from the full variety of target rocks. No planar deformation features (PDFs) in quartz were found in the country rock samples, and only a few quartz grains in the suevite samples show PDFs, and in rare cases two sets of PDFs. Based on a total alkali element-silica (TAS) plot, the Bosumtwi granites have tonalitic to quartz-dioritic compositions. The Nb versus Y and Ta versus Yb discrimination plots show that these granites are of volcanic-arc tectonic provenance. Provenance studies of the metasedimentary rocks at the Bosumtwi crater have also indicated that the metasediments are volcanic-arc related. Compared to the average siderophile element contents of the upper continental crust, both country rocks and impact breccias of the Bosumtwi structure show elevated siderophile element contents. This, however, does not indicate the presence of an extraterrestrial component in Bosumtwi suevite, because the Birimian country rocks also have elevated siderophile element contents, which is thought to result from regional hydrothermal alteration that is also related to widespread sulfide and gold mineralization.

show abstract

“…Ces différentes unités gréso-conglomératiques contiennent des minéralisations uranifères mais aussi des minéralisations aurifères, témoignant ainsi de leur énorme potentiel métallifère à travers le monde. Boher et al, 1992, Taylor et al, 1992) durant l'orogenèse éburnéenne qui prenait place entre 2,1 et 2,0 Ga (Bonhomme, 1962, Liégeois et al, 1991 et était contemporaine avec la mise en place des grands plutons de granitoïdes (Leube et al, 1990, Pons et al, 1995, Naba et al, 2004 (Junner, 1940, Milési et al, 1992 alors que d'autres proposaient l'inverse (Bassot, 1969, Vidal et al, 1996. Quant à (Bonkoungou, 1994 alors que d'autres la réfutent (Mikhailov, 2006 , Baratoux et al, 2011 Le contact fragment-ciment ou fragment-fragment (figure 2.…”

Section: Le Bouclier Guyanaisunclassified

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Sinare¹

2013

View full text Add to dashboard Cite

JANVIER 2013 RÉSUMÉLe présent projet d'étude a été financé par SEMAFO Inc. et la Fondation SEMAFO. Son but principal est : 1) établir les processus de formation du gisement aurifère de Yaho à travers sa caractérisation pétrographique, structurale et métallogénique ; 2) établir des bases de comparaison avec certains gisements aurifères proximaux et 3) proposer des guides d'exploration afin de rendre l'exploration minière plus efficace.Le gisement aurifère de Yaho est localisé au sein des roches vertes de la ceinture birimienne de Houndé, à environ 320 km à l'ouest de Ouagadougou, la capitale du Burkina Faso. Une différence notable est observée entre les spectres en terres rares des clastes de PQF et l'intrusion felsique à phénocristaux de feldspath et de quartz, dénotant ainsi l'absence d'une relation génétique entre eux. Le bassin de Yaho a donc été formé par un apport externe, continu ou ponctuel, de produits d'érosion. Les données de la géochimie sur roche totale montrent une source mafique pour les pélites et une source mixte à dominance felsique pour les wackes lithiques. Les différentes intrusions présentent les caractéristiques de granitoïdes d'îles-en-arc volcaniques et sont des témoins indirects d'un contexte tectonique d'une zone de subduction.Les gisements aurifères de Yaho et de Wona sont localisés sur un même couloir de déformation ductile-cassant orienté NNE au nord et NNW au sud. Les structures observées sur le terrain sont compatibles avec deux déformations superposées D1 et D2 qui impriment le grain tectonique globalement N340. La D1 serait principalement le résultat d'une déformation coaxiale tandis que la D2 serait liée à une déformation dominante non-coaxiale. Cette dernière produit une zone de cisaillement qui est reconnue à l'échelle de la ceinture comme la principale structure hôte des minéralisations aurifères. La D3 est un mouvement compressif N-S qui génère le clivage de crénulation (Sp+1 = N270) particulièrement bien développé dans les pélites.

show abstract

Early proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa

Cited by 239 publications

References 43 publications

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&ocirc;te d’Ivoire

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&ocirc;te d’Ivoire

Petrography, geochemistry, and alteration of country rocks from the Bosumtwi impact structure, Ghana

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Contact Info

Product

Resources

About

Early proterozoic ore deposits and tectonics of the Birimian orogenic belt, West Africa

Cited by 239 publications

References 43 publications

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&amp;ocirc;te d’Ivoire

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, C&amp;ocirc;te d’Ivoire

Petrography, geochemistry, and alteration of country rocks from the Bosumtwi impact structure, Ghana

Métallogénie du gisement aurifère de Yaho, ceinture birimienne de Houndé, Burkina Faso /

Contact Info

Product

Resources

About

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, Côte d’Ivoire

Structural Control of Auriferous Mineralization in the Birimian: Case of the Agbahou Deposit in the Region of Divo, Côte d’Ivoire