Pdf the 2ga eburnean orogeny in gabon and the opening. The exhumation along the kenyase and ketesso shear zones in. T1 4d evolution of the orogenic gold district of siguiri, guinea west africa au lebrun, erwann ocellian. New evidences for an early birimian evolution in the west. Eburnean definition of eburnean by the free dictionary.
The eburnean orogeny early proterozoic, 2000ma2500ma iii. Juvenile paleoproterozoic crust evolution during the eburnean. Timing and kinematics of eburnean tectonics in the central. These formations are called birimian in west africa.
A new metamorphic constraint for the eburnean orogeny from. May 15, 2019 the bonikro gold deposit and satellite hire open pits are located at the southern tip of the oumefettekro granitegreenstone belt in cote divoire. Episodic collisional orogenesis and lower crust exhumation during the palaeoproterozoic eburnean orogeny. Download fulltext pdf the 2ga eburnean orogeny in gabon and the opening of the francevillian intracratonic basins. The dominant structural nucleus was formed during the paleoproterozoic eburnean orogeny. The study area is located in the interference zone between ns and nesw trending cratonscale shear zones, formed during the eburnean orogeny 2. Backarc cambroordovician ross orogeny northern victoria land. The study area is dominated by three metavolcanic and metasedimentary packages known as the sefwi group, the kumasi group birimian and the tarkwa group tarkwaian that were intruded by abundant ttg granitoids during the eoeburnean and eburnean phases of an event termed the eburnean orogeny. The mean muscovite ages of 2022 12 ma arar and the kar analyses of 2021 11 ma reflect cooling through the blocking temperature. This event is generally considered to be the first significant phase of cordilleran mountain building, which continued into the early cretaceous epoch. Eburnean orogeny, nw ghana, west african craton wiley online. It suggests that the lower crust was exhumed along reverse, normal and transcurrent shear zones and juxtaposed against shallow crustal slices during the eburnean orogeny.
The alpinehimalayan belt is a young orogen, a continuous belt of mesozoic and cenozoic deformation stretching from spain to new zealand. Pdf a new metamorphic constraint for the eburnean orogeny from. Northern victoria land antarctica is made up of three terranes of cambrianordovician rocks. Juvenile paleoproterozoic crust evolution during the. Evolution of the namaquanatal belt, southern africa a.
Ghana falls mostly within the west african craton which stabilised in the early proterozoic 2000 ma during the eburnean orogeny. Nevadan orogeny, mountainbuilding event in western north america that started in the late jurassic epoch about 156 million years ago. Orogeny simple english wikipedia, the free encyclopedia. Panafrican dahomeyide orogenic belt figures 1 and 2.
Regional scale system geometry controlled by coaxial shortening of. Max vidal, charles gumiaux, florence cagnard, andr e pouclet, g. To better understand the role boundary conditions and the spatial. During this period the birimian domain in west africa was established and structured.
A new metamorphic constraint for the eburnean orogeny from paleoproterozoic formations of the man shield aribinda and. Panafrican paleostresses and reactivation of the eburnean. Petrological and geochronological constraints on lower. Orogens develop while a continental plate is crumpled and thickened to form mountain ranges, and involve a great range of geological processes collectively called orogenesis. Intrusionrelated affinity and orogenic gold overprint at the. Reconstruction of the evolution of the alpinehimalayan. Although diachronous across west africa, the eburnean orogeny is typically indicated to have been initiated at ca. Fluid pressuredominated orogenic gold mineralization.
The advent of plate tectonics 35 years ago provided an explanation for the largescale plate kinematics associated with alpinehimalayan orogeny. The kintinian olistostrome highlights the fundamental structures that control the location of the siguiri gold district and was deposited during the onset of tectonic activity associated with the early stages of orogenic contraction during the eburnean orogeny. There was change in compressional regime from nwse to ns during the d4d5 event and. N2 the west african craton hosts some of the biggest gold deposits in the world such as obuasi, sadiola, morila or siguiri. The different stages of this orogeny in gabon are described from the initial rifting of the archean continent with the crustal melting producing preeburnean migmatites at 2450 ma, the opening of an ocean. Regional geology the paleoproterozoic birimian volcanosedimentary belts with associated granitoids belonging to the baoulemoss domain of the west african craton formed between 2250 and 1980 ma feybesse et al. The new data set challenges the interpretation that metamorphic breaks in the west african craton are due to diachronous birimian basins overlying a gneissic basement. They stabilised during the transamazonian orogeny and eburnean orogeny and have.
Episodic collisional orogenesis and lower crust exhumation. Avanashilinga prabhu marked it as toread oct 22, harshvardhan chavan marked it as toread oct 02, please use a. Composed of three separate orogenic belts damara, zambesi, and lurio that are slightly younger than the east african orogeny, the kuunga orogeny documents the collision between north and south gondwana, or what is today dronning maud land in antarctica and northern. Of all the above, the eburnean and the panafrican are major events which modified the precambrian geology of nigeria including the southwestern nigerian basement complex. Country rocks in the region have undergone polyphase deformation and prolonged arc magmatism during the paleoproterozoic eburnean orogeny. During this orogeny, the siguiri district sedimentary rocks were affected by four deformation events. Stub this article has been rated as stubclass on the projects quality scale.
A new metamorphic constraint for the eburnean orogeny from paleoproterozoic formations of the man shield aribinda and tampelga countries, burkina faso. The eburnean orogeny in africa results from the continental collision between the san francisco and congolian cratons. Rather, the kheisian fabric is now dated as younger than 1. Read revised eburnean geodynamic evolution of the goldrich southern ashanti belt, ghana, with new field and geophysical evidence of pretarkwaian deformations, precambrian research on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Precambrian research 123 2003 4765 a new metamorphic constraint for the eburnean orogeny from paleoproterozoic formations of the man shield aribinda. Pdf episodic collisional orogenesis and lower crust exhumation. Evolution of a paleoproterozoic weak type orogeny in the. This orogeny also stabilised the zaire craton and affected vast parts of western africa and neighbouring regions in south america that were conterminous with the eburnean tectonothermal province. Orogeny is the primary mechanism by which mountains are built on continents. Rb sr systematics dating back to the eburnean orogeny 22001680 ma. Highgrade amphibolitegranulite facies tectonometamorphic domains in the sefwi terrane of ghana are separated from adjacent lowergrade greenschist facies greenstone belts by two main shear zones. Summary diagram of d 2 and d 3 structural data from domains within the study area. The first mineralization stage is hosted by faultfill veins along conjugate ene. To better understand the role boundary conditions and the.
Pdf juvenile paleoproterozoic crust evolution during the. During the eburnean orogeny the nesw trending d2 thrust fault were reactivated as sinistral strikeslip faults as a result of the d4d5 deformation events. Petrological and geochronological constraints on lower crust. It takes place when two tectonic plates come together. Jun 01, 2015 read petrological and geochronological constraints on lower crust exhumation during paleoproterozoic eburnean orogeny, nw ghana, west african craton, journal of metamorphic geology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
The eburnean orogeny, or eburnean cycle was a series of tectonic, metamorphic and plutonic events in what is now west africa during the paleoproterozoic era about 22002000 million years ago. Nov 27, 2018 highgrade amphibolitegranulite facies tectonometamorphic domains in the sefwi terrane of ghana are separated from adjacent lowergrade greenschist facies greenstone belts by two main shear zones. This domain which is geologically distinct to congo craton. The organization of this article is along presentday continents that do not necessarily reflect the geography contemporary to the orogenies. Evidence from the sefwi greenstone belt, west african craton. Pdf episodic collisional orogenesis and lower crust. The eburnean orogeny was not strongly rejuvenated during the panafrican thermotectonic events 6 0. Juvenile paleoproterozoic crust evolution during the eburnean orogeny similar to 2. During the eburnean orogeny the nesw trending d2 thrust fault were reactivated as sinistral strikeslip faults as a result of the. Pdf new constraints on the architecture, deformation sequence and tectonic evolution of the sparsely exposed. The first and third columns plot s 2 planes and l 2 and f 2 poles to highlight the coaxial, shallowplunging relationship of l 2 and f 2.
The major d2 related structures is the regional thrust striking ns over an area of 12 km long and 3 km wide and within which corridors all siguiri gold mine open pits are located. In the ns trending structures, there is eastnortheast shortening and northnorthwest extension. The origin and hydrothermal mobilization of carbonaceous. The eburnean orogeny was not strongly rejuvenated during the panafrican thermotectonic events 6 0 0 5 0 ma. Outside south africa, the west african craton is the second largest region in. An orogen or orogenic belt develops when a continental plate crumples and is pushed upwards to form one or more mountain ranges. View the article pdf and any associated supplements and figures for a period of 48 hours. The different stages of this orogeny in gabon are described from the initial rifting of the archean continent with the crustal melting producing pre eburnean migmatites at 2450 ma, the opening of an ocean. An orogeny is an event that leads to both structural deformation and compositional differentiation of the earths lithosphere crust and uppermost mantle at convergent plate margins. Deformation mechanism changed from d1 pure shear dominated compression, to d2 simple shear dominated transpression. Juvenile paleoproterozoic crust evolution during the eburnean orogeny. The congo shield is a central african large landmass with several archean nuclei welded during the eburnean. Three principal deformation events d1d3 can be distinguished in the study area. The following is a list of known orogenies organised by continent, starting with the oldest at the top.
The kuunga orogeny from swahili, to unite is an orogeny that occurred in southeast africa during the ediacaran and cambrian. The eburnean orogeny, or eburnean cycle was a series of tectonic, metamorphic and plutonic. The exhumation along the kenyase and ketesso shear zones. The birimian terrains in the wac represent juvenile crust without any influence of surrounding archean. Highlights a new geotectonic model of juvenile crust formation and evolution during the eburnean orogeny. Both oreforming stages occurred during protracted ewdirected shortening associated with the eburnean orogeny. Evolution of a paleoproterozoic weak type orogeny in the west. Eburnean orogeny is part of wikiproject geology, an attempt at creating a standardized, informative, comprehensive and easytouse geology resource. Read petrological and geochronological constraints on lower crust exhumation during paleoproterozoic eburnean orogeny, nw ghana, west african craton, journal of metamorphic geology on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Eburnean orogeny, a series of major tectonic events around 2100 ma.
Petrological and geochronological constraints on lower crust exhumation during paleoproterozoic eburnean orogeny, nw ghana, west. Intrusionrelated affinity and orogenic gold overprint at. If you would like to participate, you can choose to edit this article, or visit the project page for more information. The kibaran orogeny mid proterozoic, 1100ma 2000ma iv. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Read juvenile paleoproterozoic crust evolution during the eburnean orogeny. The highgrade rocks presumably exhumed along the sinistral shear zones during the d2 enewsw transtension 2073 ma. Pdf the 2ga eburnean orogeny in gabon and the opening of.
The congo craton, covered by the palaeozoictorecent congo basin, is an ancient. The 2ga eburnean orogeny in gabon and the opening of the. Geology, geodynamics and orogenic gold prospectivity. Pdf the 2ga eburnean orogeny in gabon and the opening of the. Evolution of a paleoproterozoic weak type orogeny in the west african craton ivory coast. We have investigated three greenstone belts boromo, hounde, and banfora and associated granitoid terrains, which form part of the eburnean orogen. The reguibat shield of north mauritania comprises a western archaean terrane dominated by gneisses and granitic rocks and an eastern eburnean terrane largely made up of palaeoproterozoic granitic and metasedimentary rocks. Highgrade metamorphic domains are separated from lowgrade greenstone belts by highstrain zones, including early thrusts, extensional detachments and latestage strikeslip shear zones. Eburnean democratic bloc, a splinter group of the democratic party of cote divoire formed in 1949. Nov 01, 2011 read juvenile paleoproterozoic crust evolution during the eburnean orogeny. Discussion the eburnean orogeny corresponds to a major crust forming event defined by the formation of paleoproterozoic supracrustal rocks and associated synvolcanic and syn to late kinematic intrusive rocks.
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