Seminar – Hydro-Climatic Changes & Paleolandscape Evolution (ARCCH/CFEE)

SEMINAR

The Role of Hydro-Climatic Changes on Paleolandscape Evolution and on Prehistoric Settlement During the Last Humid-Arid Cycle in the Horn of Africa

By Carlo Mologni

With an introduction of the VAPOR-Afar research program by Lamya Khalidi

Tuesday 29th March, 3 PM

@ ARCCH – Meeting Hall

Carlo Mologni is a geomorphologist, actually postdoc researcher in the laboratories CEPAM (Nice) & TRACES (Toulouse) into the frame of the ANR Nilafar and the program VAPOR-Afar. He is working on the relationship between climates and humans during the Quaternary in the Horn of Africa. Carlo Mologni had successfully defended his PhD in February 2021 and will present these results.

During the last fourteen thousand years, East Africa was the locus of significant climatic and cultural changes, which highly affected landscape evolution and prehistoric ways of life. Enhanced monsoonal precipitations over the tropics, mainly driven by Earth’s precessional and eccentricity orbital parameters, were the primary causes of the African Humid Period (AHP; ~14 – ~6 ka). This humid period led to the transgression of continental lacustrine waterbodies, the increase of fluvial discharge and the spread of vegetation cover over present-day desertic regions. This highly variable environmental scenario was the theatre of one of the most important socio-economic changes in human history, that of the transition between the last hunter-gatherers and the first herding societies. The concomitance of such cultural transformations and climatic disruptions raises the question of the role of changing environmental conditions on the distribution patterns of new socio-economic practices, namely herding. Comparing past hydrological fluctuations of the Blue Nile and of paleolake Abhe with newly published chrono-cultural sequences from the Vapor-Afar program in the Central Afar Region allow us to estimate the interactions between climate-induced landforms dynamics and human occupations.

This study improves our understanding of the spatial and temporal patterns of the Holocene hydro-climate in East Africa. More precisely we have identified a strong and stable monsoonal regime between ~11 and ~9 ka BP, followed by stepwise aridification until the end of the AHP. Early Holocene Lake Abhe waters and environments were strongly exploited by hunter-fishers-gatherers until the last lake dropped around ~4.5 ka BP, when herding practices were integrated into pre-existing lifeways in this region. Associations between prehistoric settlements and Holocene hydrological variations demonstrate how humans were extremely reactive to fluctuating lake environments and how new socio-economic models were often adapted to specific local to regional environmental trajectories.

Heading picture: Loma active rift segment, Afar Region, Ethiopia © E. Soteras.