Pliocene/pleistocene formations in the lower omo basin, southern Ethiopia

Journal ArticleFollowing a two month geological reconnaissance by one of us (FHB) in 1966, four seasons of fieldwork by members of the Omo Research Expedition has added greatly to our previous, scanty knowledge of the late Cenozoic history of the lower Omo basin in southern Ethiopia. Eduard Suess (in: von Hohnel et al., 1891) was the first to associate the lower Omo basin with the Eastern Rift Valley after the explorations of the Teleki-von Hohnel expedition in 1888 (von Hohnel, 1938). M. Sacchi, geologist with the Bottego expedition, subsequently noted the occurrence of flat-lying, undeformed sediments in the basin and these were reported on by Angelis d'Ossat and Millosevich (Angelis d'Ossat and Millosevich, 1900; Vannutelli and Citerna, 1899). These sediments have since proved to represent an extensive suite of later Pleistocene to recent strata deposited during major northward extensions of Lake Rudolf and of the delta and floodplain of the Omo River (Butzer and Thurber, 1969). E. Brumpt first collected fossils from older, tectonically disturbed sediments in the lower Omo basin when the Bourg de Bozas (Bourg de Bozas, 1903) expedition traversed the area at the turn of the century. Haug (1912, p. 1727) recognized that these specimens were of some importance in the study of the Pleistocene of eastern Africa. Two decades later, the late Prof. C. Arambourg (Arambourg and Jeannel, 1933) made a geological reconnaissance of a part of this area and amassed a substantial collection of vertebrate fossils from these deformed deposits, which he termed the Omo Beds. His pioneer work placed on record the richness and diversity of this fauna which he regarded as of earlier Pleistocene age

Chronology

Journal ArticleThe boundaries of the Lower Omo Basin have been mapped by Fuchs (1939) and by Butzer (1970, 1971) in a general way. The structural features and physiography of the eastern and central part of the Lower Omo Basin are best expressed on the maps of Davidson et al. (1973). Walsh and Dodson (1969) have mapped the geology of the North Turkana District of Kenya. East of Lake Turkana the geology is summarized by Vondra and Bowen (1976), and Vondra, Burggraf and White (1978). The Ilemi Triangle in southern Sudan remains poorly known geologically, but some information is presented by Fuchs (1939), and by Arambourg (1943). More recently Baker et al. (1972) and Cerling and Powers (1977) have provided general summaries of the structural evolution of this part of East Africa

The lower Omo basin

Journal ArticleThe boundaries of the Lower Omo Basin have been mapped by Fuchs (1939) and by Butzer (1970, 1971) in a general way. The structural features and physiography of the eastern and central part of the Lower Omo Basin are best expressed on the maps of Davidson et al. (1973). Walsh and Dodson (1969) have mapped the geology of the North Turkana District of Kenya. East of Lake Turkana the geology is summarized by Vondra and Bowen (1976), and Vondra, Burggraf and White (1978). The Ilemi Triangle in southern Sudan remains poorly known geologically, but some information is presented by Fuchs (1939), and by Arambourg (1943). More recently Baker et al. (1972) and Cerling and Powers (1977) have provided general summaries of the structural evolution of this part of East Africa

La vallée de l'Escaut à Pont-à-Chin

The sudden opening of a karst pipe in the abandoned bed of the Scheldt River has exposed 8 m ofHolocene deposits; their stratigraphy, archaeological contents, fossil fauna and flora are studied here. A well dated early occupation is from the First Iron Age to Early La Tène (around 650-450 B.C.), a second one from Roman times (around 50-200 A.D.); they permit a close control of the14 C dates, which are systematically too old, due to reworking in the stream. Vertebrate and molluscan assemblages are discussed separatel

Dynamic landscapes and human dispersal patterns : tectonics, coastlines, and the reconstruction of human habitats

Studies of the impact of physical environment on human evolution usually focus on climate as the main external forcing agent of evolutionary and cultural change. In this paper we focus on changes in the physical character of the landscape driven by geophysical processes as an equally potent factor. Most of the landscapes where finds of early human fossils and artefacts are concentrated are ones that have been subjected to high levels of geological instability, either because of especially active tectonic processes associated with faulting and volcanic activity or because of proximity to coastlines subject to dramatic changes of geographical position and physical character by changes of relative sea level. These processes can have both beneficial effects, creating ecologically attractive conditions for human settlement, and deleterious or disruptive ones, creating barriers to movement, disruption of ecological conditions, or hazards to survival. Both positive and negative factors can have powerful selective effects on human behaviour and patterns of settlement and dispersal. We consider both these aspects of the interaction, develop a framework for the reconstruction and comparison of landscapes and landscape change at a variety of scales, and illustrate this with selected examples drawn from Africa and Arabia