Sedimentation in the Kandi extensional basin (Benin and Niger): fluvial and marine deposits related to the Late Ordovician deglaciation in West Africa

Konaté, Moussa; Guiraud, Michel; Lang, J.; Yahaya, M.

doi:10.1016/s0899-5362(03)00026-5

Cited by 18 publications

(9 citation statements)

References 22 publications

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“…This author suggested that this area can be further subdivided into a “western” area with higher 87 Sr/ 86 Sr ratios (>0.720) and lower ɛ Nd (around −15), and an “eastern” area with lower 87 Sr/ 86 Sr ratios (<0.720) and higher ɛ Nd values (around −12). This geographical variation in 87 Sr/ 86 Sr and ɛ Nd must largely reflect the fact that the “northwestern” area contains old Precambrian outcrops compared to the “southeastern” area, which is characterized by younger, Paleozoic terrains [ Konate et al , 2003]. According to this subdivision, the Sr and Nd isotope ratios measured in our samples (Figure 5b and Table 1) also support a west‐to‐east shift within the Sub‐Saharan/Sahelian regions that supplied Mbour during the March 2006 event.…”

Section: Resultsmentioning

confidence: 99%

The 7–13 March 2006 major Saharan outbreak: Multiproxy characterization of mineral dust deposited on the West African margin

et al. 2011

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Mineral dust deposits were collected at Mbour, Senegal, throughout the spring of 2006 and especially during the well‐documented March 7–13 large Saharan dust outbreak. During this 7‐day period, significant changes in mass flux, grain‐size, clay mineralogy and Sr and Nd isotopic compositions were recorded, indicating distinct provenances for the dust transported and deposited during and outside the event. All these terrigenous proxies, as well as freshwater diatom taxa, also showed significant temporal variations during the outbreak, implying contributions from at least two different provenance regions. Tri‐dimensional back‐trajectories and satellite imaging enabled us to link those distinct signatures to regions increasingly to the southeast within a large area covering Mauritania, Mali and southern Algeria, identified by the Total Ozone Mapping Spectrometer (TOMS) as the main source of the prominent winter/spring plume over the tropical Atlantic. The multiproxy characterization of the March 7–13 dust fall therefore enables us to typify the terrigenous signature of two different regions supplying dust off West Africa, and provide valuable clues for the interpretation of Northeastern Tropical Atlantic Ocean dust sedimentary records in terms of changes in provenance regions and transport systems. Additionally, because dust deposition data are scarce, flux and grain size data obtained in this study, among other parameters such as clay assemblages, provide important constraints for atmospheric transport models and dust deposition budget estimates in this area.

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Section: Resultsmentioning

confidence: 99%

The 7–13 March 2006 major Saharan outbreak: Multiproxy characterization of mineral dust deposited on the West African margin

et al. 2011

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“…Ice flows are generally centrifugal from ice-sheet centre and so flowed from south to north in Saharan areas. A great deal of evidence of this glaciation has been reported from north and west African basins [1,14,15,16,10,17,18]. The present work concerns the Murzuq-Djado Basin, located on the north-Gondwanan continental shelf.…”

Section: Introductionmentioning

confidence: 94%

Hirnantian glacial and deglacial record in SW Djado Basin (NE Niger).

et al. 2007

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Pluridisciplinary fieldwork highlights features generated by an extended ice-sheet in the Djado Basin during the Hirnantian. Two glacial palaeovalley systems associated with glacial pavements and separated by thin glaciomarine interstadial series are revealed. Rigid glacial pavements characterised by abrasion erosion are differentiated from soft glacial pavements characterised by soft-bed deformation. Glacial pavements are associated with subglacial bedforms such as megaflutes, flutes and meltwater channels. They are also associated with clastic dykes and glaciotectonic structures such as deformed flutes, subglacial folds and duplex structures. This record demonstrates that ice was warm-based and flowed rapidly on the highfluid-pressure soft substrate, as for ice streams. The erosional glacial landscape is typical of areal scouring, and the depositional sediment-landform assemblage corresponds to subglacial processes. These data afford a reconstruction of glacial events which is consistent with the two polyphased low-frequency glacial cycles inferred in previous studies. During interstadial and postglacial stages, grabens, normal faults, radial extensional microfaults and extensional dihedrons were generated by extensional tectonics during glacio-isostatic rebound. In sectors highly affected by this tectonics, doleritic dykes reflect a basal crust fusion increase induced by adiabatic decompression.

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“…Guiraud and Bosworth (1999). (A) Reconstruction at 445 Ma (latest Ordovician), black star shows the South Pole position (after Konate et al, 2003); (B) reconstruction at 400 Ma (Early Devonian), wavy line is the Acadian collision; (C) reconstruction at 220 Ma (Late Triassic), dotted lines correspond to major Karoo rifts in Africa-Arabia; (D) reconstruction at 115 Ma (Late Aptian), dotted line represent major Late Jurassic-Early Cretaceous rifts and fault zones in Africa-Arabia; (E) reconstruction at 46 Ma (Lutetian), with major Late Senonian to Early Eocene rifts in Africa-Arabia; (F) present-day, with major Oligocene to Recent rifts and fault zones in Africa, wavy line is the Alpine fold-thrust belt. Guiraud et al (2000).…”

Section: Late Pan-african Fault Networkmentioning

confidence: 99%