Multiproxy reconstruction of the ecological context of the Plio-Pleistocene transition and early Middle Pleistocene in Morocco

Identifier:  TDX:4524

Handle: https://hdl.handle.net/20.500.11797/TDX4524

Authors:  Ramírez Pedraza, Iván

Abstract:
The discovery of archaeological sites with hominin presence dated to the Early Pleistocene to the Middle Pleistocene has conferred a significant role to North Africa, especially Morocco and Algeria, integrating this territory into the global discussions of human evolution alongside eastern and southern Africa. A better understanding of the dynamics of the Green Sahara Events has allowed the identification of multiple humid episodes that could have favoured the dispersal of various species, including hominins. However, despite this diachronic occupation of the Maghreb area, there is limited knowledge about the ecological context in which these different occupations occurred. For this thesis, various archaeological and palaeontological sites in Morocco dated to the Plio-Pleistocene transition (Guefaït-4.2 and Ahl al Oughlam) and to the early Middle Pleistocene (Oued Rabt, Grotte à Hominidés, and Grotte des Rhinocéros) have been selected, located, on the one hand, on the Atlantic coast of the present-day city of Casablanca (western Morocco), and the other hand, in the Maghreb depression of the Intra-Atlas in the Aïn Beni Mathar – Guefaït basin (eastern Morocco). This work aims to reconstruct the landscape of these sites and their surroundings and to characterise the diet of the large vertebrates. To achieve this, different methods with different temporal resolutions have been used: dental microwear (buccal and occlusal surfaces), dental mesowear, analysis of carbon and oxygen isotopes in the dental enamel of mammals (bulk and sequential analysis of the crown), and finally, isotopic analysis of carbon of n-alkane chains found in plant waxes recovered from sediments. Overall, the results indicate a predominantly arid environment in both the Plio-Pleistocene transition sites and those of the early Middle Pleistocene. On the Atlantic coast, the data show a similar pattern between 2.5, 0.77, 0.7 and 0.5 million years, with a predominance of open spaces dominated by C3 grasslands and shrubs, where forested environments might be very residual. The type of landscape and climate are similar regardless of whether hominins are present. In eastern Morocco, during the Plio-Pleistocene, the defined landscape is much more diverse, including forests, wetlands, shrubs, and C3 and C4 grasslands.