From dust devils to lipid biomarkers: a planetary perspective of the Makgadikgadi Pans, Central Botswana

The Makgadikgadi Basin in Botswana hosts a system of salt lakes, which developed from the Upper Pleistocene onwards due to gradual shrinking of the giant Lake Palaeo-Makgadikgadi in the last 2 million years. This lake, in the central Kalahari is the key to understand the climatic variability in southern Africa in the Quaternary and holds important role for the evolution of numerous taxa. Stratigraphic and palaeoclimatic studies of this area are complicated by the influence of several factors, such as a complex history of regional tectonic activities, as well as climatic changes coupled with dryland diagenetic processes. In the Makgadikgadi Pans, in fact, there is an overlap of processes linked to groundwater upwelling, seasonal flooding and dry climate pedogenesis (including formation of calcretes and silcretes), all shaped by an intense aeolian activity.

It is the overlap of these morphological and geological factors that create a unique terrestrial analogue for the exploration of Mars where scientists can study adaptation strategies of extremophiles, diagenesis of biomarker, but also test sensors that were built to study the atmosphere of Mars and need calibration under certain environmental conditions.

 

Here we introduce the new frontiers of research conducted in the Makgadikgadi Pans and we provide a new background on the geology of the basin and the evolution of the sedimentary system in the Makgadikgadi. In particular, we provide detailed sedimentological analyses of the shallow sub-surface of the Makgadikgadi Pans combining physical and geochemical properties of the pan sediments with the first comprehensive study of paleontological proxies (ostracods) in order to establish trends in the environmental changes in the area from the Late Quaternary.

The research activities of the last few years in the Makgadikgadi Pans provided new benchmarking data that will not only shed light on one of the largest evaporitic basins in the world but also support further investigations in the field of planetary sciences and astrobiology.