Skip to Main content Skip to Navigation
Theses

STRUCTURE DU BATHOLITE DE FERKESSEDOUGOU (SECTEUR DE ZUENOULA, CÔTE D'IVOIRE) : IMPLICATIONS SUR L'INTERPRETATION DE LA GEODYNAMIQUE DU PALEOPROTEROZOÏQUE D'AFRIQUE DE L'OUEST A 2.1 Ga

Abstract : In the West African Craton, the 2.1 Ga period is a major stage of leucogranite production. Because of its localization, its extension as much as its history in the geological literature, the batholith of Ferkessédougou (Côte d'Ivoire) is a main element for the interpretation of the Paleoproterozoic geodynamics. Interpreted as a typical granite of eugeosynclinal then as typical of collision of the modern type, it is in any case a NNE-SSW oriented significan crustal accident of Paleoproterozoic : the GFB (Greenville-Ferkessédougou-Bobodioulasso) lineament. Its study and its interpretation fall under the debate of the validity of plate tectonics at this period. As a matter of fact, by remote sensing, we show that this 400 km lenght batholith on about fifty broad consist in an important quantity of adjacent plutons which are petrographically relatively close. The general context of slightly deformed and epizonal metavolcanic and/or metasedimentary birimian age (2.2 Ga to 2.1 Ga) host rocks, as well as the absence of additional tangential deformations express the weakness of the crustal thickening synchronous of its genesis. Its fabric, determined by traditional structural analysis ans AMS (Anisotropy of Magnetic Susceptibility), is double. The first foliation (magmatic) is generally coaxial with varied orientation and dips. This foliation draws curved trajectories and expresses the intrusion of plutons. It is the equivalent of what was brought back to the D1 deformation around older granites. The second foliation (from magmatic to post-solidus), which is much better well-ordered and often constrictive or none coaxial, is the result of a regional strain transcurrent field which refers to the D2 deformation. This latter is well-known in the chrology of the birimian craton. The plutons of the granitic batholith of Ferké are syntectonic of the birimian main shortening (2.1 to 2.07 Ga). From the review of the various models of plutons emplacement, the analysis of the SW sector of Côte d'Ivoire showing two-micas granite dykes and metamorphic facies of higher range, a review of the Imata formations in Surinam, as well as the assessment of structural analysis, we propose a 3D model for the batholith of Ferké. This latter may correspond to a set of small plutons of laccolithic form intruded into the superficial crust between birimian epizonal metasediments known as "metasediments of basin" and gneiss and micaschists of age probably ranging between 2.2 and 2.1 Ga. The plutons may rise from dykes resulting of fracturing by pull-apart opening of the SASCA-Bandaman-Bobodioulasso sedimentary basin. The melting of the old greenstone-belts/TTG type crust (absence of traces of Archean basement), which occurs vertically compared to the subsident basin, will have incorporated material of sedimentary basin. The necessary contribution of heat for the compensation of the weakness of thickening would have been provided by the strike-slip faults of pull-aparts. The volume required for the emplacement of plutons needs a rise of these latters at the end of the extensive period thanks to many cauldron-subsidences. The conditions and modes of the two principal deformations imply a short time between the stabilization of the opening of the basins and thei closing. In addition, the variation of the structural level from North-East towards South-West, particulary towards the probable zone of the equivalent-root in Venezuela-Surinam, shows a deepening and the bringing together of an archean crust towards the SW whereas it was recognized only towards the West up to now (Guinea, Dorsale of Man) or was only suspected towards the East of Ghana.
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00834040
Contributor : Ouattara Gbele Connect in order to contact the contributor
Submitted on : Friday, June 14, 2013 - 3:21:10 PM
Last modification on : Tuesday, October 12, 2021 - 5:20:39 PM
Long-term archiving on: : Tuesday, April 4, 2017 - 9:50:13 PM

Identifiers

  • HAL Id : tel-00834040, version 1

Collections

Citation

Ouattara Gbele. STRUCTURE DU BATHOLITE DE FERKESSEDOUGOU (SECTEUR DE ZUENOULA, CÔTE D'IVOIRE) : IMPLICATIONS SUR L'INTERPRETATION DE LA GEODYNAMIQUE DU PALEOPROTEROZOÏQUE D'AFRIQUE DE L'OUEST A 2.1 Ga. Tectonique. Université d'Orléans, 1998. Français. ⟨tel-00834040⟩

Share

Metrics

Record views

781

Files downloads

3868