First heat flow determination from the central Sahara: relationship with the Pan-African belt and Hoggar domal uplift

Lesquer, A.; Bourmatte, Amar; Ly, Saïdou; Dautria, Jean-Marie

doi:10.1016/0899-5362(89)90006-7

Cited by 37 publications

(18 citation statements)

References 14 publications

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“…The first measurements in the southern part (Leo Rise) revealed low values (Chapman and Pollack, 1974;Beck and Mustonen, 1972) confirmed by later measurements (Sass and Behrendt, 1980;Brigaud et al, 1985). Measurements in the northern part of the WAC (Brigaud et al, 1985;Rimi and Lucazeau, 1987;Lesquer et al, 1989;Takherist and Lesquer, 1989;Lesquer et al, 1991) have conversely shown values 15-20 mW m −2 higher. The Pan-African border also shows higher values in the north (Brigaud et al, 1985;Rimi and Lucazeau, 1987;Latil-Brun and Lucazeau, 1988;Lesquer et al, 1989;Takherist and Lesquer, 1989) than the western border (Latil-Brun and Lucazeau, 1988;Lesquer et al, 1991).…”

Section: Previous Heat-flow Measurementsmentioning

confidence: 49%

“…Measurements in the northern part of the WAC (Brigaud et al, 1985;Rimi and Lucazeau, 1987;Lesquer et al, 1989;Takherist and Lesquer, 1989;Lesquer et al, 1991) have conversely shown values 15-20 mW m −2 higher. The Pan-African border also shows higher values in the north (Brigaud et al, 1985;Rimi and Lucazeau, 1987;Latil-Brun and Lucazeau, 1988;Lesquer et al, 1989;Takherist and Lesquer, 1989) than the western border (Latil-Brun and Lucazeau, 1988;Lesquer et al, 1991). Lesquer and Vasseur (1992) have correlated the higher heat-flow in the north to the presence of a regional mantle anomaly that also affects the large scale gravity field and the P-waves propagation.…”

Section: Previous Heat-flow Measurementsmentioning

confidence: 87%

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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: Previous Heat-flow Measurementsmentioning

confidence: 49%

Section: Previous Heat-flow Measurementsmentioning

confidence: 87%

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

Lucazeau

Rolandone

2012

Solid Earth

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“…Domal uplift could be the isostatic response to the presence of this body . Lesquer et al (1989) present heat flow data for the area which do not reveal any large scale thermal perturbations of the lithosphere consistent with upwelling of the lithosphere/ asthenosphere boundary on a regional scale. This is consistent with the conclusions of Crough (1981) on the basis of gravity data.…”

Section: Hoggarmentioning

confidence: 80%

Magmatism and rifting in Western and Central Africa, from Late Jurassic to Recent times

Wilson¹,

Guiraud²

1992

Geodynamics of Rifting

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“…In their studies of the eastern Saharan basins, Galushkin (2003, 2005) used variable lithosphere thickness. Their basement model incorporates a total crustal thickness of 20 -55 km (12 -34 mi) and a mantle thickness of geater than or equal to 35 km (21 mi), in agreement with data from seismological and thermal studies in the Hoggar massif and other areas of north Africa (Evans and Tammemagi, 1974;Morgan et al, 1985;Lesquer et al, 1989;Nyblade et al, 1996). Proximal to the Ghadames Basin, they model lithosphere thickness of 30 -40 km (18 -25 mi) in the north.…”

Section: Basal Heat-flow Parametersmentioning

confidence: 86%

Petroleum generation and migration in the Ghadames Basin, north Africa: A two-dimensional basin-modeling study

Underdown

Redfern

2008

Bulletin

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The Ghadames Basin contains important oil-and gas-producing reservoirs distributed across Algeria, Tunisia, and Libya. Regional twodimensional (2-D) modeling, using data from more than 30 wells, has been undertaken to assess the timing and distribution of hydrocarbon generation in the basin. Four potential petroleum systems have been identified: (1) a Middle-Upper Devonian (Frasnian) and Triassic (Triassic Argilo Gréseux Inférieur [TAG-I]) system in the central-western basin; (2) a Lower Silurian (Tannezuft) and Triassic (TAG-I) system to the far west; (3) a Lower Silurian (Tannezuft) and Upper Silurian (Acacus) system in the eastern and northeastern margins; and (4) a Lower Silurian ( Tanezzuft) and Middle -Upper Devonian (Frasnian) system to the east-southeast. The Lower Silurian Tanezzuft source rock underwent two main phases of hydrocarbon generation. The first phase occurred during the Carboniferous, and the second started during the Cretaceous, generating most hydrocarbons in the eastern (Libyan) basin. The Frasnian shales underwent an initial, minor generative phase in the central depression during the Carboniferous. However, the main generation occurred during the Late Jurassic-Cenozoic in the western and central depression. The Frasnian shales are currently only marginally mature in the eastern part of the basin.Modeling indicates that the Alpine (Eocene) exhumation of the eastern (Libyan) basin margin had a significant control on the timing of hydrocarbon generation from the Lower Silurian source rock. The preferred burial-history model calibrates source rock maturity data by incorporating late exhumation and reduced subsidence

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First heat flow determination from the central Sahara: relationship with the Pan-African belt and Hoggar domal uplift

Cited by 37 publications

References 14 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)

Magmatism and rifting in Western and Central Africa, from Late Jurassic to Recent times

Petroleum generation and migration in the Ghadames Basin, north Africa: A two-dimensional basin-modeling study

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