New inventoried Karst systems in Central Africa and preliminary paleoclimate proxies analysis applied on speleothems from Central Africa.
Authors
Arfaoui, I.
Bazebizonza, N.
Thijenira, A.
Ngala, N.
Lutete, J.
Samba, P.
Nkodia, H.
Boudzoumou, F.
Kakule, R.
Delvaux, D.
Lahogue, P.
Discipline
Earth and related Environmental sciences
Subject
Geodynamics and mineral resources
Audience
Scientific
Date
2022Metadata
Show full item recordDescription
Although knowledge of Karst is of great importance in terms of water resources, risks it can generate for populations and infrastructures, and paleoclimate changes reconstruction, it is currently little studied in central Africa from a geoscientific point of view. In Kongo-Central, the Karst system is developed in carbonate rocks, which is part of the Neoproterozoic schisto-limestone subgroup. It extends from southwest Gabon to northwest Angola over 1400 km. They cross the DRC and RC from NW to SE over nearly 500km with a width of up to 180 km. The various layers of this system are mainly sub-horizontal. The total thickness of carbonate rocks can reach more than 1000 m. Currently, multidisciplinary research is underway in this limestone area in the DRC and the Republic of Congo, within the framework of the GeoRes4Dev project (DEA and Ph.D.), funded by the Belgian cooperation. As part of this work, following the compilation of data from bibliographical sources, information obtained from local scientists, observations on satellite images, and new fieldwork, we now arrive at a compilation of 285 caves, some of which may, however, still be redundant. Only about 145 of them could be located with varying degrees of precision, and of these, 11 were mapped. The longest known cave has nearly 10 km of galleries. Caves generally develop in a subhorizontal way, on 2 or 3 levels. The current studies are mainly focused on the caves evolution, the hydrogeological network and the structural context affecting the karst system and the speleothems. All of this data will provide a better understanding of the evolution of the karst affecting these areas. In particular, the study of speleothems, which present high quality climatic records, should inform us about paleoclimatic changes. It should be mentioned that the Holocene paleoclimate is so far little studied in DRC and RC and new data will be of immediate interest for understanding climate change in the Intertropical Convergence Zone (ITCZ). Two main research ideas are in progress: - U-Th dating has already been applied without success for a sample of stalagmite taken from Mbuji-May (Kasaï, DRC). As our study area is located in the same geological context, we believe that this method is probably also inappropriate due to the low U-Th content in the area. We therefore wish to apply alternative methods to trace the growth chronology of stalagmites in Kongo-Central, DRC and in RC (Radiocarbon, measurement of the isotope O, and trace elements, Mg, Sr, and Ba as well in drop of drop by drop than in calcite stalagmites). - In Central Africa, there is a considerable lack of knowledge on climate records.
Citation
Arfaoui, I.; Bazebizonza, N.; Thijenira, A.; Ngala, N.; Lutete, J.; Samba, P.; Nkodia, H.; Boudzoumou, F.; Kakule, R.; Delvaux, D.; Lahogue, P. (2022). New inventoried Karst systems in Central Africa and preliminary paleoclimate proxies analysis applied on speleothems from Central Africa.. , Climate Change, The Karst Record IX (KR9),Identifiers
Type
Conference
Peer-Review
No
Language
eng