The early Paleogene is critical for understanding global biodiversity patterns in modern ecosystems. During this interval, Southern Hemisphere continents were largely characterized by isolation and faunal endemism following the breakup of Gondwana. Africa has been proposed as an important source area for the origin of several marine vertebrate groups but its Paleogene record is poorly sampled, especially from sub-Saharan Africa. To document the early Paleogene marine ecosystems of Central Africa, we revised the stratigraphic context of sedimentary deposits from three fossil-rich vertebrate localities: the Landana section in the Cabinda exclave (Angola), and the Manzadi and Bololo localities in western Democratic Republic of Congo. We provide more refined age constraints for these three localities based on invertebrate and vertebrate faunas, foraminiferal and dinoflagellate cyst assemblages, and carbon isotope records. We find an almost complete absence of Danian-aged rocks in the Landana section, contrary to prevailing interpretations over the last half a century (only the layer 1, at the base of the section, seems to be Danian). Refining the age of these Paleocene layers is crucial for analyzing fish evolution in a global framework, with implications for the early appearance of Scombridae (tunas and mackerels) and Tetraodontiformes (puffer fishes). The combination of vertebrate fossil records from Manzadi and Landana sections suggests important environmental changes around the K/Pg transition characterized by an important modification of the ichthyofauna. A small faunal shift may have occurred during the Selandian. More dramatic is the distinct decrease in overall richness that lasts from the Selandian to the Ypresian. The Lutetian ofWest Central Africa is characterized by the first appearance of numerous cartilaginous and bony fishes. Our analysis of the ichthyofauna moreover indicates two periods of faunal exchanges: one during the Paleocene, where Central Africa appears to have been a source for the European marine fauna, and another during the Eocene when Europe was the source of the Central Africa fauna. These data indicate that Central Africa has had connections with the Tethyian realm.
Located in
Library
/
RBINS Staff Publications 2019
The objective of the present revision is to complement the lithostratigraphy of the Ieper Group published in 2001 (Laga et al., 2001). This last publication reflected the activities in the Tertiary Subcommission at that time. The review published in 2001 framed in an initiative of the National Stratigraphic Commission and was limited to the lithostratigraphy at formation level. The Laga et al (2001) reference document has been the basis for the NCS website until now. The Ieper Group is characterised by clay−dominated sediments overlying, in most situations, the Landen Group strata and, if not outcropping, underlying the sand−dominated Zenne Group sediments. According to Laga et al. (2001) in their reference document for Paleogene and Neogene lithostratigraphy, the Ieper Group consists of the Kortrijk, Tielt and Gentbrugge Formations and ,members in these Formations are only listed. These subdivisions are also used on the 1:50 000 geological maps of Flanders, edited in the last decades of the 20th century. Especially the additional description of the members, and where possible, horizons, identified in the Formations, made the present review necessary and also modifications at the formation level itself arisen since 2001 needed to be integrated in a new synthesis. The present update is based on the earlier description of members in Maréchal & Laga (1988), Geets et al. (2000) and Steurbaut (1998) as far as appropriate. All modifications, discussions and additions are supported by the relevant literature references.
Located in
Library
/
RBINS Staff Publications 2016
