Author

Kelsey Boyd

Year

2020

Degree Name

Honours degree of Bachelor of Science

Department

School of Earth, Atmospheric and Life Sciences

Advisor(s)

Chris Ames, Alexander Mackay

Abstract

Recent evidence suggests Homo sapiens dispersed out of Africa and through the Levant during the late Middle Pleistocene to early Late Pleistocene. This window coincides with fluctuating climatic conditions over the Levant associated with glacial/interglacial cycles, including increasingly hot and dry conditions over the Middle to Late Pleistocene transition. Inland palaeohydrological features, such as the Azraq Wetlands of northeast Jordan, across the region would have been crucial to hominin survival during this time, providing concentrated freshwater and biotic resources. This thesis aims to establish the palaeoecological context of the Shishan Marsh, in the southern Azraq Wetlands, over the late Middle Pleistocene to early Late Pleistocene (~300-110ka) using biogenic silica microfossils, and considers the implications for early hominins occupying the landscape. Phytoliths, diatoms, and sponge spicules were extracted from 17 bulk sediment samples from the lower layers of five stratigraphic sequences over the Shishan Marsh. Using modern phytolith assemblages from the Azraq Wetland Reserve and Shaumari Reserve, past ecological communities in the study area have been reconstructed. Overall, biogenic silica data illustrates a mosaic of terrestrial and aquatic communities experiencing significant ecological succession and boundary shifts over the Middle to Late Pleistocene. Evidence suggests the presence of a shallow perennial lake environment during the late Middle Pleistocene, undergoing a northeast-wards recession as a result of regionally rising aridity, with associated marsh development due to spring flow during the Middle to Late Pleistocene transition. This marsh was surrounded by open steppe-grassland, representing an attractive, resource-rich habitat for hominins in an otherwise arid region. Such an environment potentially acted as a desert refugium under regionally hot and dry conditions at the onset of the Late Pleistocene. The results presented in this study represent a substantial contribution to the understanding of local palaeoenvironmental changes in the Azraq Wetlands, providing direction for future research into early human dispersal and occupation of the Levant. This thesis suggests that, based on biogenic silica data, hominins may have followed receding freshwater and biotic resources to the northeast.

FoR codes (2008)

040606 Quaternary Environments

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.