Structure and emplacement model for late-orogenic Paleoproterozoic granitoids: the Tenkodogo–Yamba elongate pluton (Eastern Burkina Faso)

Naba, Séta; Lompo, Martin; Debat, Pierre; Bouchez, Jean‐Luc; Béziat, Didier

doi:10.1016/j.jafrearsci.2003.09.004

Cited by 70 publications

(56 citation statements)

References 34 publications

(64 reference statements)

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“…In Ghana (Harcouët et al, 2007), the average heat production of monzogranites is 1.04 ± 0.44 µW m −3 . In Burkina Faso, the Tenkodogo-Yamba granitoids have an average heat production of 1.35 ± 0.49 µW m −3 (Naba et al, 2004). Such values do not support the existence of a thick granitic layer, as the lithosphere cannot exceed 200-250 km in West Africa according to the tomographic studies (Ritsema and van Heijst, 2000;Sebai et al, 2006;Pasyanos and Nyblade, 2007;Priestley et al, 2008).…”

Section: Heat-flow and Thermal Regime Of The Wacmentioning

confidence: 92%

Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

Lucazeau

Rolandone

2012

Solid Earth

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Abstract. New temperature measurements from eight boreholes in the West African Craton (WAC) reveal superficial perturbations down to 100 m below the alteration zone. These perturbations are both related to a recent increase in the surface air temperature (SAT) and to the site effects caused by fluid circulations and/or the lower conduction in the alterites. The ground surface temperature (GST), inverted from the boreholes temperatures, increased slowly in the past (∼0.4 • C from 1700 to 1940) and then, more importantly, in recent years (∼1.5 • C from 1940 to 2010). This recent trend is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou), and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids) or conductive (lower conductivity of laterite and of highporosity sand) perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these site perturbations: all the eight borehole temperature logs can be interpreted with the same basal heatflow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous borehole measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a sub-humid zone in southern Mali. Finally, the background heat-flow is low (31 ± 2 mW m −2 ), which makes this part of the WAC more similar with the observations in the southern part (33 ± 8 mW m −2 ) rather than with those in the northern part and in the Pan-African domains where the surface heat-flow is 15-20 mW m −2 higher.

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Section: Heat-flow and Thermal Regime Of The Wacmentioning

confidence: 92%

Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

Lucazeau

Rolandone

2012

Solid Earth

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“…The area is 700 km northwest of Accra, the national capital. Underlying the area are metamorphosed lavas and pyroclastic rocks plus dolerites that are locally intruded by gabbro (Leube et al, 1990;Liegeois et al, 1991;Hirdes et al, 1992;Doumbia et al, 1998;Oberthur et al, 1998;Egal et al, 2002;Gasquet et al, 2003;Naba et al, 2004;Feybesse et al, 2006 However the Birimian rocks of southern Ghana have migmatite and granitic intrusions that have generally been classified into two broad categories (Leube et al, 1992). These are hornblende-rich varieties that are closely associated with the metavolcanic rocks and known as the 'Dixcove' or 'belt' type; and mica-rich varieties which tend to border the volcanic belt.…”

Section: Location and Geology Of The Study Areamentioning

confidence: 99%

Regolith mapping of deeply weathered terrain in savannah regions of the Birimian Lawra Greenstone Belt, Ghana

Arhin

Jenkin

Cunningham

et al. 2015

Journal of Geochemical Exploration

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ABSTRACT:A regolith map for the Lawra Belt has been developed by categorizing the regolithlandform units by processing and interpreting remote sensing data. Regolith landform units were extracted from Landsat band ratios 3/1 and 5/4 to map ferruginous saprolite and lags; band ratio 5/7 was used to identify residual regolith and band ratio 4/2 was employed to separate ferruginous units from non-ferruginous regolith.Additional regolith landform units' discrimination was provided by compiling and interpolating radiometric data particularly for Landsat TM poorly defined areas.SRTM images were used to mark out the extent of the alluvial plains. High topographical terrains were marked from DEM image to represent the residual areas.Regolith landform unit (RLU) map that showed residual (relict and erosional), ferruginous, and depositional domains of the Lawra Belt was developed by superimposing the extractions made from the remote sensed data. Interpretive map generated from the remote sensed image analysis was validated by first creating a non-genetic regolith map through ground truth survey. The non-genetic map based on A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT2 | P a g e spatial distributions of the different regolith mapping units were classified on genetic classes or regimes based on regolith-landform similarities to develop a genetic map.The interpretive and the genetic map were superimposed to develop the regolith map for the Lawra Belt. The inliers and outliers presenting compositional overlaps within broad regolith classes were rectified from the field mapping information. The combined approach of image analysis and the ground truth mapping grouped the regolith of Lawra Belt into ferruginous (F), relict (R), erosional (E) and depositional (D) regimes.

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“…6 with metamorphosed lavas and pyroclastic rocks containing basalts, andesite, rhyolites, dolerites with gabbroic intrusive particularly characterizing mostly the eastern and the southern block of the area [10][11][12][13][14]. The western block consists mainly of metasedimentary suite of rocks.…”

Section: Geologymentioning

confidence: 99%

Characterizing and Indexing Regolith Materials Using Geochemistry towards Hidden Mineral Anomaly Delineation: A Case Study of Savannah Region of NW Ghana

Arhin¹,

Zango²,

Kazapoe³

2017

ujg

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As the discovery rate of world-class gold deposits continues to decline, increased attention is focused on geochemical exploration methods designed for regolith-dominated terrains. This involves mapping the regolith and classifying the mapping units into different regolith classes on the basis of weathering and geomorphic histories. The challenges of identifying some regolith mapping units in the field by novice in regolith mapping require the characterization and indexing of regolith from major element geochemistry in the regolith profiles. XRF analytical method was used to measure the weight % of the major oxides in regolith samples. The metal weight % of Mg, K and Al were calculated from their oxides and were normalized relative to immobile Al calculated from its oxide. The plot of Mg/Al and K/Al identified the regolith of the study area to consist of 137 transported clays, 4 ferruginous sediments or ferricrete, 2 lateritic duricrust and 4 saprolites. Plot of Mg/Al and K/Al highlighted the compositional variability of the regolith samples and refute the notion of the homogeneity of all the sampled materials in the area. The study thus recognized Mg/Al versus K/Al plots to be used in supporting field identification of regolith mapping units particularly in complex regolith terrains of savannah regions of Ghana and in similar areas where geochemical exploration surveys are being carried out under cover.

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Structure and emplacement model for late-orogenic Paleoproterozoic granitoids: the Tenkodogo–Yamba elongate pluton (Eastern Burkina Faso)

Cited by 70 publications

References 34 publications

Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

Regolith mapping of deeply weathered terrain in savannah regions of the Birimian Lawra Greenstone Belt, Ghana

Characterizing and Indexing Regolith Materials Using Geochemistry towards Hidden Mineral Anomaly Delineation: A Case Study of Savannah Region of NW Ghana

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