New insights on proterozoic tectonics and sedimentation along the peri-Gondwanan West African margin based on zircon U–Pb SHRIMP geochronology

Waele, Bert De; Lacorde, Mathieu; Vergara, F; Chan, Gavin H.-N.

doi:10.1016/j.precamres.2014.08.008

Cited by 33 publications

(27 citation statements)

References 31 publications

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“…The northern part of the craton is known as the Reguibat Shield. The southern portion has been referred to by various alternative names, but recent usage has settled on the Leo-Man Shield (or Leo-Man rise) (de Waele et al, 2015;Rollinson, 2016;Parra-Avila et al, 2016). The outcrop of the Leo-Man Shield extends more than 1500 km, from Senegal, Guinea, Sierra Leone and Mali in the west to Ghana and Niger in the east.…”

Section: Regional Geology Of West Africamentioning

confidence: 99%

“…Recent dating shows that Palaeoproterozoic protoliths are present in the Rokelides, but they have been affected by metamorphism and magmatism of Neoproterozoic age (de Waele et al, 2015;Villeneuve et al, 2015). A major, crustal-scale shear zone separates these belts from the Archaean Kénéma-Man Domain (de Waele et al, 2015).…”

Section: Regional Geology Of West Africamentioning

confidence: 99%

“…This belt comprises metasedimentary and mafic meta-igneous rocks. In Liberia these units are interpreted to be equivalent to the lower Rokelide metamorphic units of Archaean and Palaeoproterozoic age, deformed in the Pan African orogeny at about 550 Ma (Deynoux et al, 2006;De Waele et al, 2015). Phanerozoic rocks in Liberia include: numerous north-west-trending Jurassic-age dolerite dykes extending over much of the south-western part of the country (Wahl, 2007); kimberlites within the Kénéma-Man domain (Haggerty, 1982); and minor Palaeozoic and Cretaceous sandstones and unconsolidated Quaternary deposits (Wahl, 2007).…”

Section: Geology Of Liberiamentioning

confidence: 99%

“…The Goe Range (or Goe Fantro) is located approximately 60 km south-east of Monrovia in a zone of northwestsoutheast-trending metasedimentary rocks known as the Goe Range Series (Berge, 1971). These rocks are poorly known but may correlate with the Rokelide units recognised along strike in Sierra Leone (de Waele et al, 2015). The regional strike of the Goe Range Series, comprising metasedimentary schists, quartzites and BIFs, is north-west, which contrasts with the north-east orientation of all other iron ore deposits in Liberia.…”

Section: Wologizi Range the Large Low Grade Deposit In The Wologizimentioning

confidence: 99%

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A review of the mineral potential of Liberia

Gunn

Dorbor

Mankelow

et al. 2018

Ore Geology Reviews

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The Republic of Liberia in West Africa is underlain mostly by Precambrian rocks of Archaean (Liberian) age in the west and of Proterozoic (Eburnean) age in the east. By analogy with similar terranes elsewhere in the world, and in West Africa in particular, the geology of Liberia is favourable for the occurrence of deposits of a wide range of metals and industrial minerals, including gold, iron ore, diamonds, base metals, bauxite, manganese, fluorspar, kyanite and phosphate.Known gold deposits, mostly orogenic in style, occur widely and are commonly associated with north-easttrending regional shear zones. Gold mining commenced at the New Liberty deposit in western Liberia in 2015, while significant gold resources have also been identified at several other sites in both Archaean and Proterozoic terranes. Liberia has large resources of itabirite-type iron ores, most of which are located in the Liberian terrane, and was the largest producer in Africa prior to the onset of civil war in 1989. Production of iron ore is currently restricted to a single mine, Yekepa, in the Nimba Range. Other important deposits, some of them previously mined, include Bong, the Western Cluster, Putu and Goe Fantro. There is a long history of alluvial diamond production in western and central Liberia, together with more than 160 known occurrences of kimberlite. Most of the known kimberlites occur in three clusters of small pipes and abundant dykes, located at Kumgbor, Mano Godua and Weasua, close to the border with Sierra Leone. Many of these are considered to be part of a single province that includes Jurassic age diamondiferous kimberlites in Sierra Leone and Guinea.Deposits and occurrences of a wide range of other metals and industrial minerals are also known. Several of these have been worked on a small scale in the past, mainly by artisanal miners, but most are poorly known in detail with sub-surface information available at only a few localities. By comparison with most other countries in West Africa, the geology of Liberia is poorly known and there has been very little systematic exploration carried out for most commodities other than gold, iron ore and diamonds since the 1960s and 1970s. Further detailed field and laboratory investigations using modern techniques are required to properly evaluate the potential for the occurrence of economic deposits of many minerals and metals in a variety of geological settings. Digital geological, geochemical, geophysical and mineral occurrence datasets, including new national airborne geophysical survey data, provide a sound basis for the identification of new exploration targets, but in almost every part of the country there is a need for new and more detailed geological surveys to underpin mineral exploration.

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Section: Regional Geology Of West Africamentioning

confidence: 99%

Section: Regional Geology Of West Africamentioning

confidence: 99%

Section: Geology Of Liberiamentioning

confidence: 99%

Section: Wologizi Range the Large Low Grade Deposit In The Wologizimentioning

confidence: 99%

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A review of the mineral potential of Liberia

Gunn

Dorbor

Mankelow

et al. 2018

Ore Geology Reviews

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“…The southern expression of the West African Archaean Craton outcrops over an area of about 300,000 sq km and is variably known as the 'Sierra Leone Ivory Coast nucleus' (Clifford, 1970), the 'Liberian age province' (Hurley et al, 1971), the 'Leo Rise', the 'Kenema-Man Domain' (Thieblemont et al, 2001), the 'Man Craton' (Skinner, 2004), the 'Man Shield' (Barth et al, 2002) and the 'Leo-Man shield' (De Waele et al, 2015). A new synthesis of the regional geology is presented in Figure 2.…”

Section: Craton Boundariesmentioning

confidence: 99%

Archaean crustal evolution in West Africa: A new synthesis of the Archaean geology in Sierra Leone, Liberia, Guinea and Ivory Coast

Rollinson

2016

Precambrian Research

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A new synthesis of the geology and geochronology of the little-known Archaean rocks in Sierra Leone, Liberia, Guinea and Ivory Coast is presented in order to better understand the processes of Archaean crustal evolution in this region, and to attempt to interpret these data in the light of our current understanding of Archaean crustal evolution. In addition, this study seeks to identify those aspects of Archaean crustal evolution which are currently not known in this area and which need to become the subject of future studies, given the economic importance of this region in terms of the mineral deposits hosted in the Archaean rocks. These include greenstone-belt hosted iron ore, lode gold, chromite and columbite-tantalite and younger diamondiferous kimberlites intrusive into Archaean felsic gneisses.The new results show that this cratonic nucleus comprises of four main geological units: 1. The oldest crust is made up of 3.5-3.6 Ga TTG (tonalite-trondjemite-granodiorite) gneisses. These only outcrop in the east of the craton in Guinea but their presence is indicated elsewhere in the central part of the craton though xenocrystic zircon cores in younger rocks. 2. The major rock type found throughout the craton is 3.26-2.85 Ga TTG gneiss. In detail these magmas are thought to have formed in two episodes one between 3.05-3.26 Ga and the other between 2.85-2.96 Ga. The presence of inherited zircons in the younger suite indicate that this event represents the partial reworking of the older gneisses. 3.4 Ga eclogite xenoliths in kimberlite derived from the sub-continental lithospheric mantle are thought to be the restite after the partial melting of a basaltic protolith in the production of the TTG magmas. 3. Supracrustal rocks form linear belts infolded into the TTG gneisses and metamorphosed to amphibolite and granulite grade. They are of different sizes, contain a variety of lithological sequences and may be of several different ages. The larger supracrustal belts in Sierra Leone contain a thick basalt-komatiite sequence derived by the partial melting of two different mantle sources, unconformably overlain by a sedimentary formation. They are seen as an important resource for gold, iron-ore, chromite and columbite-tantalite. 4. A suite of late Archaean granitoids formed by the partial melting of the TTG gneisses in a craton wide deformation-metamorphic-partial melting event at 2800 +/-20 Ma. This thermal event is thought to be responsible for the stabilisation of the craton.This new synthesis highlights major geological and geochronological similarities between the Archaean rocks of Sierra Leone, Liberia, Guinea and Ivory Coast and those in the Reguibat Shield in the northern part of the West African Craton suggesting that the two regions were once more closely related.

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