Two generations of Birimian (Paleoproterozoic) volcanic belts in northeastern Côte d'Ivoire (West Africa): consequences for the ‘Birimian controversy’

Hirdes, W.; Davis, Donald W.; Lüdtke, G.; Konan, G N'Zi

doi:10.1016/s0301-9268(96)00011-3

Cited by 184 publications

(148 citation statements)

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“…These results and the geochemical data reveal the juvenile nature of these rocks reinforcing the interpretation that this region may be part of the Rhyacian juvenile continental magmatic arc, that extends through other parts of São Luís Craton with correspondence in the northeast portion of the Amazonian Craton and in West Africa (Abouchami et al 1990, Boher et al 1992, Wright et al 1995, Hirdes et al 1996.…”

Section: U-pb Geochronologysupporting

confidence: 73%

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

et al. 2017

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ABSTRACT:The São Luís Cráton comprises an area between northeast Pará state and northwest Maranhão that exposes Paleoproterozoic granitic suites and meta-volcanosedimentary sequences. In the east of this geotectonic unit, about 70 km south of São Luís, there is a portion of the São Luís Craton, represented by the intrusive Rosario Suite (RS). This work is focused on rocks of this suite, including petrographic, lithochemical and geochronological studies to understand the crustal evolution of these granitoid rocks. The rock spectrum varies from tonalitic to granodioritic, quartz dioritic and granitic compositions, and there are partial structural and mineralogical changes related to deformation along transcurrent shear zones. The geochemical studies show granitic metaluminous compositions of the calc-alkaline series with I-type affinity typical of magmatic arc. Rare earth elements show marked fractionation and slight Eu positive or negative anomalies (Eu/Eu* = 0.82 to 1.1). Zircon U-Pb data provided consistent ages of 2165 ± 7 Ma, 2170 ± 7 Ma, 2170 ± 7 Ma, 2161 ± 4 Ma and 2175 ± 8 Ma, dating emplacement of these granitoids as Paleoproterozoic (Rhyacian). Sm-Nd isotopic data provided model ages (T DM ) of 2.21 to 2.31 Ga with positive values of εNd +1.9 to +3.2 (t = 2.17 Ga), indicating predominantly Rhyacian crustal sources for the parental magmas, similar to those ones found in other areas of the São Luís Craton. The data, integrated with published geological and geochronological information, indicate the occurrence of an important continental crust formation event in this area. The Paleoproterozoic evolution between 2.17 and 2.15 Ga is related to the Transamazonian orogeny. The granitoids of the Rosario Suite represent the main phase of continental arc magmatism that has continuity in other parts of the São Luís Craton and can be correlated with Rhyacian accretionary magmatism in the northwestern portion of the Amazonian Craton that amalgamated Archean terrains during the Transamazonian orogeny.KEYWORDS: Rosário Suite; São Luís Craton; Petrology; U-Pb geochronology; Sm-Nd T DM . RESUMO: O Cráton INTRODUCTIONIn models of global supercontinent reconstruction, the São Luís Craton and the northeastern portion of the Amazonian Craton (to the east of the Guayana Shield) have been considered remnants of the West African Craton preserved in the northern South American Platform after the breakup of the Pangea Supercontinent (Hurley et al. 1967, Torquato & Cordani 1981, Lesquer et al. 1984, Brito Neves et al. 2000.On the African side, several studies based on structural, geochemical, geophysical and geochronological data demonstrate the existence of Archean and dominantly juvenile Paleoproterozoic crust (Abouchami et al. 1990, Boher et al. 1992, Gasquet et al. 2003. On the Brazilian side, the northern part of the Amazonian Craton and São Luís Craton have demonstrated geochronological and evolutionary similarities. In this part of the Amazonian Craton, the ancient continental crust stabilized in the Archean is bordered by...

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Section: U-pb Geochronologysupporting

confidence: 73%

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

et al. 2017

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“…Ils peuvent être regroupés sous deux grandes générations selon l'environnement géologique et la période de mise en place : les granitoïdes associés aux ceintures de roches vertes comprenant des granodiorites, des tonalités et des trondhjémites mis en place entre 2200 et 2150 Ma (Lemoine, 1988 ;Liégeois et al, 1991 ;Hirdes et al, 1992Hirdes et al, , 1996Boher et al, 1992 ;Siméon et al, 1994 ;Delor et al, 1995aDelor et al, , 1995bKouamélan et al, 1996 ;Doumbia, 1997 ;Yao, 1998), et les granitoïdes des rides volcanosédimentaires comprenant des tonalités, des monzogranites, des granodiorites et des leucogranites mis en place entre 2150 et 1800 Ma (Caen-Vachette, 1986 ;Liégeois et al, 1991 ;Hirdes et al, 1992Hirdes et al, ,1996Delor et al, 1994 ;Siméon et al, 1994 ;Doumbia, 1997 ;Yao, 1998).…”

Section: -Les Granitoïdes Birimiens De La Côte D'ivoireunclassified

Facteurs paramètres dynamique de distribution et genèse des dépôts de columbo-tantalite d Issia centre-ouest de la Côte d Ivoire

Allou

2005

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(1) les trois principaux granites de la région ont été produits par des processus profonds ayant généré une fusion partielle de la croûte, (2) ils ont été formés par cristallisation fractionnée pendant la période syn-à tardi-D2 de l'orogenèse Ébuméenne, et ( Du point de vue de l'évolution supergène, il est montré que les processus naturels superficiels dans les milieux tropicaux humides ne génèrent ni croissance, ni changements chimiques dans les minéraux de Nb-Ta. Toutefois, même si la qualité chimique du minéral est préservée, la qualité physique, quant à elle, se dégrade progressivement des zones éluviales aux zones alluviales sous l'effet des corrosions mécaniques. Columbite-tantalite deposits in humid tropical areas are generally supergene deposits associated with gravel. These deposits have been poorly studied and are mined only by small developers. This is attributed, on one hand to the small scale and the short life of the individual deposits and, on the other hand to the great thickness of the alteration overburden in zones of high concentration.This study has a triple objective: (1) establish a geodynamic model for the Issia columbite-tantalite primary mineralization and associated minerals; (2) define the factors controlling the secondary redistribution of the mineralization in detrital environments through integrating pedo-geomorphologic and geostatistical studies; and (3) determine the mineralogical species of niobium, tantalum and other associated ore minerals.The study area includes three granitic massifs intruding sedimentary rocks: the oriented two-mica granite (Lobo granite), the oriented muscovite granite (Bitapia granite) and the non-oriented, porphyritic muscovite granite (Issia granite). Field observations and whole rock analyses show that: (1) the three main granites of the region are produced by deep seated processes which generated partial melting of the crust; (2) they were formed by fractional crystallization during the syn to late-D2 period of the Ebumean orogenesis; and (3) the Issia type granite was the last to be formed at 2106±78 My. Variographic analyses and kriging give satisfactory results for the columbite-tantalite supergene deposits prospecting. This approach defines prospecting grids for the deposit types in the studied areas and it brings to evidence very weak variation on a small scale and a great continuity of the mineralization following the direction of pegmatites. The kriging results indicate that lognormal kriging is the best tool for estimation of the reserves because this method better minimizes the bias and the variance of estimation. VIThis study has a direct implication for the prospecting of columbite-tantalite detrital deposits in Issia as well as at the global scale. Indeed, it shows that in a columbite-tantalite pegmatite environment located in humid tropical areas, eluvial and colluvial gravels are more favourable to mining than alluvial gravels. Enfin, je remercie tout le personnel du module des sciences de la terre, les professeurs, les techniciens, les é...

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“…In the reconstruction proposed by Ledru et al (1994) the Guaianese belts probably align with central and eastern belts of the West African Craton (Figure 8), though the alignment is not straight. In the African belts, the medium-grade Dabakalian metamorphic complex and lower-grade volcano-sedimentary associations of a similar age are found (Boher et al, 1992;Taylor et al, 1992;Hirdes et al, 1996;Hirdes and Davis, 1998).…”

Section: Eburnean Greenstone-granite Belts In the West African Cratonmentioning

confidence: 76%

“…A major apparent difference, however, is the presence of 2.20 Ga felsic metavolcanic rocks in the oldest dated unit (Hirdes et al, 1996), in which mafic metavolcanic rocks usually predominate. Chondritenormalized REE patterns and N-MORB-normalized spidergrams (Abouchami et al, 1990) are as diverse as those found for Guyana Shield rocks.…”

Section: Eburnean Greenstone-granite Belts In the West African Cratonmentioning

confidence: 99%

Paleoproterozoic greenstone-granite belts in Northern Brazil and the former Guyana Shield - West African Craton province

McReath

Faraco

2006

Geol. USP, Sér. cient.

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The mainly meta-volcano-sedimentary Vila Nova Group and associated granites constitute separate belts, which form part of a large paleoproterozoic (mainly rhyacian) province in the Guyana Shield of which northern Brazil forms a part, and the West African Craton. In Brazil the southwestern Serra do Ipitinga and Serra Tumucumaque-Serra do Navio belts have no obvious geometrical extensions in the Guyanas or Venezuela, and may represent deposits formed at penecontemporaneous passive continental margins and ocean floor spreading centres. To the Northeast the Serra Lombarda-Tartarugalzinho and Oiapoque belts are continuations of Guianese belts. In the former the igneous rocks have geochemical characteristics of suprasubduction environments. Belts in the Guyana Shield and West African Craton have many similar features. The megaprovince evolved in a number of stages, which may have started at about 2.3 Ga, and continued with diminished activity after 2.11 Ga. Both major juvenile additions and (possibly minor) reworking of earlier crust contributed to the growth of the province. The major transcurrent deformation, responsible for the present structure of the belts, probably occurred during the later stages of evolution of the province, but metamorphism and deformation are registered even in the oldest rocks.Palavras-chave: terrenos paleoproterozóicos de greenstones e granitos; Escudo das Guianas; Norte brasileiro; Craton Oeste-Africano. RESUMOO Grupo Vila Nova, predominantemente meta-vulcanossedimentar e os granitos associados constituem cinturões que formam parte de uma grande província paleoproterozóica (predominantemente riaciana) localizada no Escudo Guianense do qual o Norte brasileiro faz parte, e no Craton Oeste-Africano. No Brasil identificam-se ambientes tectônicos diferenciados para os diferentes cinturões. No sudoeste da província os cinturões da Serra de Ipitinga, e da Serra de Tumucumaque ao Serra do Navio não encontram extensões geometricamente claras nas Guianas e Venezuela, e talvez representem depósitos penecontemporâneos formados em margens continentais passivas e bacias oceânicas. Seguindo para nordeste, os cinturões da Serra Lombarda até Tartarugalzinho e Oiapoque são continuações de cinturões presentes nas Guianas. Naquele, as características geoquímicas, tanto das rochas máficas metavulcânicas como das félsicas plutônicas posteriores, apontam para origens em zonas de supra-subducção. Os cinturões guianenses e oeste-africanos apresentam muitas feições e características semelhantes. A evolução da megaprovíncia ocorreu por etapas, desde talvez 2,3 Ga com atividade em diminuição depois de 2,11 Ga. Adições crustais, tanto juvenis quanto por retrabalhamento de crosta antiga, contribuíram para o crescimento da megaprovíncia. É provável que a deformação maior de transcorrência, responsável pela estrutura atual dos cinturões, ocorresse em fase tardia da evolução, embora mesmo as unidades mais antigas sejam deformadas e metamorfizadas.

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Two generations of Birimian (Paleoproterozoic) volcanic belts in northeastern Côte d'Ivoire (West Africa): consequences for the ‘Birimian controversy’

Cited by 184 publications

References 16 publications

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

Rhyacian evolution of the eastern São Luís Craton: petrography, geochemistry and geochronology of the Rosário Suite

Facteurs paramètres dynamique de distribution et genèse des dépôts de columbo-tantalite d Issia centre-ouest de la Côte d Ivoire

Paleoproterozoic greenstone-granite belts in Northern Brazil and the former Guyana Shield - West African Craton province

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