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As a contribution towards a regional environmental context of human-climate interactions, the ICDP co-funded Chew Bahir Drilling Project, a part of the HSPDP (Hominin Sites and Paleolakes Drilling Project), recovered ~280-m long cores of sedimentary strata through continental scientific drilling in southern Ethiopia. The fluvio-lacustrine coring locality in the Chew Bahir basin is situated near key archaeological and paleoanthropological sites, such as the Omo-Kibish where the Omo 1 and 2 Homo sapiens fossils were recovered.Here we present the 620,000-year environmental record from Chew Bahir that provides an extraordinary opportunity to examine the potential influence of climate variability on hominin evolution, cultural innovation and dispersal during the Middle to Late Pleistocene. The near-continuous Chew Bahir record documents 13 environmental episodes that differ in length and character, potentially inducing habitat changes influencing hominin biological and cultural transformation. We infer that long-lasting and relatively stable humid conditions from ~620,000–275,000 years BP (Episodes 1–6) were interrupted by several abrupt and extreme hydroclimatic oscillations. This phase coincided with the appearance of high anatomical diversity in hominin groups. During Episodes 7–9 (~275,000–60,000 years BP), a pronounced pattern of climatic cyclicity was paralleled by the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of H. sapiens in eastern Africa, and a key phase of human social and cultural innovation. Episodes 10–12 (~60,000–10,000 years BP), marked by high-frequency climate oscillations, is contemporaneous with the global dispersal of H. sapiens, facilitated by continued technological innovation and the alignment of humid pulses between eastern Africa and the eastern Mediterranean.Prospectively, the Chew Bahir record represents a crucial component for the Middle and Late Pleistocene in the ongoing efforts of the scientific community (future and upcoming ICDP-funded projects) to address questions in Africa across four topical core areas: paleoclimate, paleoenvironment, basin evolution, and modern lake systems.

In this study, we synthesize terrestrial and marine proxy records, spanning the past 620,000 years, to decipher pan-African climate variability and its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to El Niño Southern Ocean oscillation (ENSO) variability, a manifestation of the Walker Circulation, that was most likely driven by changes in Earth’s eccentricity. Our results demonstrate that low-latitude insolation was a prominent driver of pan-African climate change during the Middle to Late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation as well as mammals in eastern and western Africa by increasing resource-rich and stable ecotonal settings thought to have been important to early modern humans.

Dendi Lake Rockshelter is situated about 100 km west of Addis Ababa on the west-central part of the Ethiopian Plateau in the Ginchi woreda of Ethiopia’s Oromiya regional state. In October 2012, a t...

Reconstructions of climatic and environmental conditions can contribute to current debates about the factors that influenced early human dispersal within and beyond Africa. Here we analyse a 200,000-year multi-proxy paleoclimate record from Chew Bahir, a tectonic lake basin in the southern Ethiopian rift. Our record reveals two modes of climate change, both associated temporally and regionally with a specific type of human behavior. The first is a long-term trend towards greater aridity between 200,000 and 60,000 years ago, modulated by precession-driven wet-dry cycles. Here, more favorable wetter environmental conditions may have facilitated long-range human expansion into new territory, while less favorable dry periods may have led to spatial constriction and isolation of local human populations. The second mode of climate change observed since 60,000 years ago mimics millennial to centennial-scale Dansgaard-Oeschger cycles and Heinrich events. We hypothesize that human populations may have responded to these shorter climate fluctuations with local dispersal between montane and lowland habitats.

In this study, we synthesize terrestrial and marine proxy records, spanning the past 620 ky, to decipher pan-African climate variability and its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to El Niño Southern Ocean oscillation (ENSO) variability, a manifestation of the Walker Circulation, that was most likely driven by changes in Earth's eccentricity. Our results demonstrate that low-latitude insolation was a prominent driver of pan-African climate change during the Middle to Late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation as well as mammals in eastern and western Africa by increasing resource-rich and stable ecotonal settings thought to have been important to early modern humans.

Middle Stone Age humans in high-altitude Africa Recent archaeological research has produced evidence of the earliest human occupation of high-altitude habitats in the Andes and the Tibetan Plateau. Ossendorf et al. now present the oldest evidence of human settlement and adaptation to areas above 4000-meter elevation in Africa (see the Perspective by Aldenderfer). Their excavations at a rock shelter in the Bale Mountains of Ethiopia reveal obsidian artifacts and faunal remains, including abundant burnt bones, mostly of giant mole-rats. The findings reveal the environmental conditions and show how Late Pleistocene humans adapted to the harsh environments of these glaciated high-altitude African landscapes. Science , this issue p. 583 ; see also p. 541

In this study we synthesize terrestrial and marine proxy records spanning the last 620,000 years, to decipher pan-African climate variability, its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to Walker and Hadley Circulation variability that were most likely driven by changes in Earth´s eccentricity. Our results demonstrate that low latitude insolation rather than glacial-interglacial cyclicity was the predominant driver of pan-African climate change during the mid to late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation, as well as mammals, in eastern and western Africa, ultimately by increasing resource-rich and stable ecotonal settings that have long thought to have been the preferred habitats of hominins.

Rock shelter and cave sites can be suitable archives for archaeological remains and environmental records if the right conditions are complied with. There are a few sediment stratigraphies in the Horn of Africa that preserved information about human occupation during the Upper Pleistocene and Holocene. Unfortunately, little is known about human settlement in Ethiopia during the period corresponding to MIS 2 due to discontinuous archaeological records. The project A1, within the framework of the Collaborative Research Centre 806 (CRC 806 – “Our Way to Europe”), focuses on Late Pleistocene stratigraphies and paleoenvironments of northeast African sites. In this context, during excavations at the Sodicho Rockshelter in the southwestern Ethiopian Highlands, a complex stratigraphy with evidence of several human occupation phases was exposed.This poster presents the latest research results of the Sodicho Rockshelter. It displays first radiocarbon ages and the site formation processes according to a selection of sedimentological and geochemical methods to understand human settlement history in this tropical environment. A multi-proxy approach has been chosen to detect possible rapid or gradual changes in depositional conditions in the rock shelter. The sedimentological records suggest that the depositional and post-depositional processes varied significantly over time in response to external environmental changes and the use of the shelter by humans. For instance, lithic assemblages in anthropogenic influenced layers alternate with thick volcanic ash layers. In addition, a sterile, clayish horizon refers to a period of increased precipitation and could thus provide evidence for an African Humid Period. The Sodicho Rockshelter could validate the current state of research and possibly close the chronostratigraphic gap.

Although high-altitude mountain habitats are often regarded as unfavorable for human occupation (e.g. Aldenderfer 2014); on the other hand tropical highlands in Africa are suggested as potential refugia during times of environmental stress (e.g. Basell 2008; Brandt et al. 2012). Archaeological investigations on Mount Damota (2908 m a.s.l.), located on the boundary between the Southwest Ethiopian Highlands to the west and the southern Main Ethiopian Rift valley to the east, yielded a large number of archaeological sites from the Middle Stone Age period until historical times. In this paper we try to reconstruct settlement models for the late Pleistocene and Holocene occupation in this area and speculate about potential land use patterns. Such complex topics demand a landscape archaeological approach that includes open-air sites and rock-shelters. The results from our excavations at Mochena Borago Rock-shelter and evidence from open-air-sites that were recorded during intensive surveys on the slopes and plateau of the mountain, allow a first reconstruction of the settlement history of the area.

This first survey of rock shelters and settlements in the Bale Mountains in Ethiopia is a baseline assessment for further research into the settlement history of Africa’s largest alpine highlands. Extensive GPS-based mapping and interviews resulted in two detailed maps, a catalogue of profiles, and complete photographic documentation. In total, 331 rock shelters (four permanently inhabited, 51 seasonally inhabited, and 276 currently uninhabited) and 870 settlements (207 permanently inhabited, 449 seasonally inhabited, 214 uninhabited) were recorded together with information about the activities and livelihoods of the inhabitants of the current settlements. This 2015 study was part of the Ethiopian-European research project “The mountain exile hypothesis – how humans benefited from and re-shaped African high-altitude ecosystems during Quaternary climate changes” (DFG FOR 2358). It was designed to support future management plans in this internationally important conservation area that has recently faced increasing land-use pressure and the threat of degradation.

With excavated layers spanning a period from > 49 ka to ~ 36 ka, Mochena Borago Rockshelter reveals a complex sequence of Late Pleistocene human occupation punctuated by volcanic events. Fifty-nine radiocarbon ages make Mochena Borago one of the best-dated Late Pleistocene archaeological sites in eastern and northeastern Africa. However, complex site formation processes, dramatic stratigraphic differences between non-contiguous excavation areas, and “outlier” dates that appear in various parts of Mochena Borago's sequence, complicate efforts to develop a secure and detailed chronology for local and regional behavioral changes. This article focuses on contiguous squares within the Block Excavation Area (BXA) trench at the northern end of the shelter. Bayesian modeling of thirty-seven dates from six major lithostratigraphic units within the BXA yields a revised series of age ranges; these differ from the previous age model (derived from weighted means) in subtle but important ways. Perspectives gained through Bayesian analysis stimulate more careful consideration of the complex site formation processes operating at Mochena Borago, the contextual integrity of the site's robust and distinctive flaked stone artifact assemblages (lithics), and potential correlations between lithic changes and environmental events that occur on local, regional, and global scales. As these factors come into focus, Mochena Borago can serve as an important chronological benchmark to better understand human behavior in eastern and northeastern Africa around the time of the second major dispersal of Homo sapiens.

As an unambiguous indication of complex cognitive capacity, representational art presents explicit evidence for modern and symbolic human behaviour. The only examples of African figurative art dating to the Late Pleistocene comprise seven stone plaques recovered from Apollo 11 Cave in the Huns Mountains, southern Namibia. The plaques derive from a single anthropogenic layer dated by radiocarbon ( 14 C) accelerator mass spectrometry (AMS) and optically simulated luminescence (OSL) methods to c. 30 000 years ago. We present the results of digital (CIE) L*a*b* colourimetric and portable energy dispersive X-ray fluorescence (ED-XRF), Raman spectroscopic and Fourier transform infrared reflectance (FT-IR) analyses of the pigments present on the plaques. These results provide the earliest direct evidence, in Africa, for the preparation of pigment-based paint-like mixtures and their application to create prehistoric art. Our research shows that in the creation of the depictions on the plaques, the artists used black pigments derived from manganese and charcoal, red pigments likely derived from ocherous shale and white pigments possibly derived from ostrich eggshell. Additionally, these plaques provide unique evidence for the combined use of mineral- and carbon-based pigment ‘crayons’ during the African Middle Stone Age.

Our understanding of the impact of climate-driven environmental change on prehistoric human populations is hampered by the scarcity of continuous paleoenvironmental records in the vicinity of archaeological sites. Here we compare a continuous paleoclimatic record of the last 20 ka before present from the Chew Bahir basin, southwest Ethiopia, with the available archaeological record of human presence in the region. The correlation of this record with orbitally-driven insolation variations suggests a complex nonlinear response of the environment to climate forcing, reflected in several long-term and short-term transitions between wet and dry conditions, resulting in abrupt changes between favorable and unfavorable living conditions for humans. Correlating the archaeological record in the surrounding region of the Chew Bahir basin, presumably including montane and lake-marginal refugia for human populations, with our climate record suggests a complex interplay between humans and their environment during the last 20 ka. The result may contribute to our understanding of how a dynamic environment may have impacted the adaptation and dispersal of early humans in eastern Africa. (C) 2015 Elsevier Ltd. All rights reserved.

The extent of racemization (total hydrolysable amino acids) of aspartic acid, glutamic acid and valine provide a geochronological framework to assign relative and numeric ages, and examine the taphonomy of the sedimentary infill of Apollo 11 Rockshelter, Namibia. Based on the analysis of 37 ostrich ( Struthio camelus ) eggshell samples from the rockshelter sedimentary succession, three aminogroups are identified and may be correlated with oxygen isotope records from marine and ice cores. Aminogroup A spans the interval from 80,000 ± 12,000 years ago [late Marine Isotope Stage (MIS) 5a] through to the late Holocene (2000 ± 300 years). A significant diastem is identified below − 65 cm separating the lower portion of the rockshelter sediments (that were deposited predominantly by natural depositional processes), from the overlying succession. Although a human presence is generally evident throughout the whole succession, the post-diastem succession records an increasing influence of humans on sediment accumulation. Two aminogroups were identified in the sediments beneath the diastem based on contrasting extents of racemization. Pooled mean ages (representing minimum ages) for aminogroups B and C are 180,000 ± 10,000 years and 236,000 ± 18,000 years respectively, and are significantly different at the 2-sigma level. The amino acid derived numeric ages indicate an early Middle Stone Age (MSA) for the lower portion of the sedimentary succession within the rockshelter. Collectively, these ages attest to a long, but punctuated record of sediment accumulation within Apollo 11 Rockshelter. At several levels within the anthropogenically-dominated succession (layers A to T), fragments of ostrich eggshell show a disproportionately high extent of racemization in relation to their depth of burial and signify the combined effects of heating and their reworking. The reworked eggshell fragments represent a small component of the assemblage, and the overall results for aminogroup A indicate that the sedimentary succession shows a high degree of stratigraphical integrity. Reworking of sedimentary constituents is not evident in aminogroups B and C. The age for the basal layers Y and Z from Apollo 11 is one of the oldest dates for an Early MSA inventory without Acheulean elements in Southern Africa, a period that is otherwise poorly known.

This paper presents new information obtained from a recent excavation and reassessment of the stratigraphy, chronology, archaeological assemblages and environmental context of the Apollo 11 rockshelter, which contains the longest late Pleistocene and Holocene archaeological sequence in Namibia. The Middle Stone Age (MSA) industries represented at the site include an early MSA, Still Bay, Howieson’s Poort and late MSA. Optically stimulated luminescence (OSL) dating of individual quartz grains yielded numerical ages for the Still Bay and Howieson’s Poort, and indicated the presence of a post-Howieson’s Poort phase. OSL dating also verified conventional and accelerator mass spectrometry radiocarbon ages for a further two later MSA phases. The timing of the transition from the MSA to the early Later Stone Age was also investigated. Improved resolution of the excavation and a more detailed stratigraphy revealed the presence of near-sterile cultural layers, which in some cases assisted in subdividing the MSA cultural phases. Such information, in combination with the new radiocarbon and OSL chronologies, helps address questions about the duration and continuity of MSA occupation at the site. Analyses of the faunal and archaeobotanical remains show some differences between the occupation phases at the site that may be associated with changing environmental conditions.

The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa—the Still Bay and Howieson's Poort industries—that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, and coeval with genetic estimates of population expansion and exit times. Comparison with climatic records shows that these bursts of innovative behavior cannot be explained by environmental factors alone.

Item does not contain fulltext The African origin of our species has essentially been accepted as a scientific fact, but evolutionary advantages connected with the reasons and circumstances of modern human dispersal remain widely unexplained or controversial. Consequently, this paper provides an overview of the natural and cultural context of earliest AMH (Anatomically Modern Humans). According to the locations and dating of AMH fossils, the focus is on E-Africa, NE-Africa and the Middle East within a time range from 200 ka to 70 ka. At least three different “contextual areas” appear to have existed at the time, two of them in E-Africa and NE-Africa, dominated by “Bifacial-plus-Levallois” technology, and the third one in the Middle East, mostly connected with an “only-Levallois” technology. A comparison with some non-AMH sites from Eurasia displays similarity of technological principles between artifact assemblages from African AMH sites and Eurasian non-AMH (early Neanderthal) sites on the one hand, and dissimilarity between African AMH sites and Middle Eastern AMH sites on the other hand. This is particularly surprising if environmental contexts are taken into account – tropical in Africa and glacial in Eurasia. Thus, compared to their archaic neighbors (particularly early Neanderthals), earliest modern humans currently seem to lack any specific “cultural fingerprint” and their demographic success may not be explained by behavioral superiority alone. The idea of a small group of early AMH people migrating out of Africa, enabled by cultural superiority over their neighbors appears highly questionable in the light of archaeological evidence. Moreover, the concept of virtual “migration routes” deserves a revision if ethnodemographic evidence about spatial behavior of hunter-gatherers is taken into account. The proposed concept of “contextual areas” serves as a methodological alternative, comprising linked cultural and environmental features.

International audience; Between 70 and 50 ka BP, anatomically modern humans dispersed across and out of Africa to eventually populate all inhabitable continents. Knowledge of paleoenvironments and human behavioral patterns in Africa prior to and during these dispersals is crucial for understanding how and why hunter-gatherers were able to adapt rapidly to the new environments they encountered. However, few well-dated sites from this time period are known from the Horn of Africa, one of the purported staging areas for population movements into southern Arabia and Asia. Excavations at Mochena Borago Rockshelter, situated on the western slopes of a dormant volcano where the SW Ethiopian Highlands meet the Ethiopian Rift, have yielded the first securely dated archaeological sequence for later periods of the dispersal. Three major lithostratigraphic groups incorporating occupational episodes have yielded charcoal radiocarbon ages w53e38 ka calBP; deeper deposits have been tested but remain undated. Archaeological assemblages consist mainly of obsidian flaked stone artifacts manufactured from small, minimally prepared, single-to multi-platform flake cores; radially prepared cores are rare and blade cores are absent. Small unifacial to bifacial points from non-radial cores dominate the earliest shaped tool assemblages, and backed pieces first appear by w45 ka calBP. By w43 ka calBP, scrapers and backed pieces are predominant , rather than points. However, there is little evidence for technological change other than the appearance of bipolar technology. Mochena Borago's archaeological sequence thus cannot be neatly classified as Middle Stone Age, Later Stone Age or "transitional" and calls into question some of the principles by which archaeologists have attempted to classify African toolmaking traditions.

During this study, the recent relations between the hydrological systems and the distribution of archaeological sites and obsidian raw material outcrops within the catchment of the Bisare River, around Mt Damota, and around Mt Sodicho in the southwestern Ethiopian Highlands were investigated. To do so, we combined geomorphological–hydrological analyses with field surveys and GIS mapping. The aim was to try to transfer these recent interrelations into the past to better understand the factors that influenced prehistoric human settlement activity. The natural geomorphodynamics in landscapes such as the southwestern Ethiopian Highlands were and still are characterized by the interplay between endogenous processes (tectonics, volcanism) and climatic fluctuations and, during the recent past, also by human activity. In the considered region, protective and potentially habitable rock shelters are found at the volcanic slopes of Mt Damota and Mt Sodicho at high elevations. In addition, in some areas recent morphodynamic processes make obsidian raw material available near the surface. However, archaeological and terrestrial paleoenvironmental archives that allow an understanding of the interplay between prehistoric settlement activity and paleoenvironmental conditions are still rare. Therefore, the surroundings of formerly occupied rock shelters were investigated to illustrate the effect of the recent fluvial morphodynamics (erosion and accumulation) on surface visibility and preservation of archaeological obsidian raw material. This recent information can be used to make assumptions about the former hydrological system and to thereby get answers to research questions such as those about the past accessibility of obsidian raw material for prehistoric humans. The results suggest that the study area is currently affected by a highly dynamic hydrological system, which is indicated by phenomena such as the formation of swamps due to sedimentation in natural depressions. In addition, wide areas of the Bisare River catchment are affected by gully erosion, which leads to land degradation but also to the exposure of the above-mentioned lithic raw material outcrops. Human influence strongly increased during the Holocene until today, especially on the mountain flanks. This in turn increased soil loss and erosion of archaeological sites, which complicates the transfer of the current morphodynamics into the past. Although it cannot be finally confirmed that prehistoric hunters and gatherers systematically used fluvially exposed raw material, based on our results it can be assumed that humans frequented this area, due to the local availability of such kind of material.