Gulf of Guinea continental slope and Congo (Zaire) deep-sea fan: Sr–Pb isotopic constraints on sediments provenance from ZaiAngo cores

U-Pb single zircon grain dating of Present fluvial and Cenozoic aeolian sediments from Gabon: consequences on sediment provenance, reworking, and erosion processes on the equatorial West African margin

“…Such values of denudation are consistent with the high values gradient for the coastal rivers (such as the Ogooué) compared with the low gradient characterizing the Congo tributaries . High strontium isotopic ratios from Pleistocene sediments, cored off the Ogooué mouth [Bentahila et al, 2006], are in agreement with a sedimentary source mostly derived from the Archaean craton underlying the Ogooué drainage, and in strong contrast with the much lower values characterizing the strontium isotopic ratio of the rivers draining the Batéké sands. Accordingly, low radiogenic values from the Batéké sands indicate that they have a much younger source, or includes a significant proportion of a younger component.…”

“…1) . Discussions on the mass balance bear on 1) long-term geodynamics of continental margins, allowing renewed uplift of the hinterland , 2) tracing the respective contribution of major, versus numerous small rivers [Bentahila et al, 2006], and 3) on the temporal evolution of sediment flux to the margin, due to the interaction of climate and tectonics [Lavier et al, 2001;Séranne and Anka, 2005].…”

Accelerated Contribution of the Paleo–Congo River to Global Seawater 87Sr/86Sr Change Following Eocene‐Oligocene Collapse of the African Surface

“…The red beds and boulders of silcrete in the Congo Basin have Sr concentrations between 6 and 54 ppm (23 ppm in average), and 87 Sr/ 86 Sr between 0.727 and 0.746 (0.736 in average). The latter value is indistinguishable from measured 87 Sr/ 86 Sr of suspended sediments in the Lower Congo River near Kinshasa (0.736; Allègre et al, ) and is also in the same range of those reported from the offshore sediments of the Congo Delta Fan cored at 0.1–0.9 m below seafloor (0.721–0.741; Bentahila et al, ). This suggests that the red beds and silcretes are the dominant sources of both the river and submarine fan sediments.…”

“…Hydrochemistry from the main river systems of the modern Congo Basin shows that dissolved loads are dominated by silicates (Gaillardet et al, , ). The dominance of silicate weathering is also evident in the 87 Sr/ 86 Sr composition of suspended river sediments, which is distinctively higher in the Upper Congo and Kasaï Rivers (0.747 and 0.734, respectively), compared to the RBT and Oubangui (0.723–0.732; Allègre et al, ), as well as from the 87 Sr/ 86 Sr composition of offshore sediments in the Congo Fan (0.721–0.741; Bentahila et al, ). In the dissolved river loads, the highest recorded radiogenic Sr signature is from the Kasaï, dominated by the Jurassic‐Cretaceous red beds (Figure a and Table ).…”

The effect of river-delta system on the formation of the source rocks in the Baiyun Sag, Pearl River Mouth Basin

“…A large scale delta is likely to form below the estuary of a large scale river, which can provide abundant terrestrial organic matter to form high quality source rocks. For example, the famous Niger Delta Basin and the Congo Basin are both affected by the inflow of fresh water and develop certain scale of delta (Tong, 2002;Hou et al, 2005;Bentahila et al, 2006;Zhou et al, 2007;Deng, 2010).…”