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1. Integrative geochronology calibrates the Middle and Late Stone Ages of Ethiopia’s Afar Rift

   https://doi.org/10.1073/pnas.2116329118  

   Niespolo, Elizabeth M; WoldeGabriel, Giday; Hart, William K; Renne, Paul R; Sharp, Warren D; Shackley, M Steven; Ambrose, Stanley H; Asfaw, Berhane; Beyene, Yonas; Brasil, Marianne F; et al (December 2021, Proceedings of the National Academy of Sciences)

   Significance Understanding the evolution, dispersals, behaviors, and ecologies of early AfricanHomo sapiensrequires accurate geochronological placement of fossils and artifacts. We introduce open-air occurrences of such remains in sediments of the Middle Awash study area in Ethiopia. We describe the stratigraphic and depositional contexts of our discoveries and demonstrate the effectiveness of recently developed uranium-series dating of ostrich eggshell at validating and bridging across more traditional radioisotopic methods (¹⁴C and⁴⁰Ar/³⁹Ar).Homo sapiensfossils and associated Middle Stone Age artifacts are placed at >158 and ∼96 ka. Later Stone Age occurrences are dated to ∼21 to 24 ka and ∼31 to 32 ka, firmly dating the upper portion of one of the longest records of human evolution. 

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2. Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling

   https://doi.org/10.1146/annurev-earth-031920-081947  

   Cohen, Andrew S.; Campisano, Christopher J.; Arrowsmith, J. Ramón; Asrat, Asfawossen; Beck, Catherine C.; Behrensmeyer, Anna K.; Deino, Alan L.; Feibel, Craig S.; Foerster, Verena; Kingston, John D.; et al (May 2022, Annual Review of Earth and Planetary Sciences)

   Paleoanthropologists have long speculated about the role of environmental change in shaping human evolution in Africa. In recent years, drill cores of late Neogene lacustrine sedimentary rocks have yielded valuable high-resolution records of climatic and ecosystem change. Eastern African Rift sediments (primarily lake beds) provide an extraordinary range of data in close proximity to important fossil hominin and archaeological sites, allowing critical study of hypotheses that connect environmental history and hominin evolution. We review recent drill-core studies spanning the Plio–Pleistocene boundary (an interval of hominin diversification, including the earliest members of our genus Homo and the oldest stone tools), and the Mid–Upper Pleistocene (spanning the origin of Homo sapiens in Africa and our early technological and dispersal history). Proposed drilling of Africa's oldest lakes promises to extend such records back to the late Miocene. ▪ High-resolution paleoenvironmental records are critical for understanding external drivers of human evolution. ▪ African lake basin drill cores play a critical role in enhancing hominin paleoenvironmental records given their continuity and proximity to key paleoanthropological sites. ▪ The oldest African lakes have the potential to reveal a comprehensive paleoenvironmental context for the entire late Neogene history of hominin evolution. 

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3. Pleistocene climate variability in eastern Africa influenced hominin evolution

   https://doi.org/10.1038/s41561-022-01032-y  

   Foerster, Verena; Asrat, Asfawossen; Bronk Ramsey, Christopher; Brown, Erik T.; Chapot, Melissa S.; Deino, Alan; Duesing, Walter; Grove, Matthew; Hahn, Annette; Junginger, Annett; et al (September 2022, Nature Geoscience)

   Abstract Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 yearsbp(episodes 1–6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7–9 (~275,000–60,000 yearsbp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence ofHomo sapiensin eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10–12 (~60,000–10,000 yearsbp) could have facilitated the global dispersal ofH. sapiens. 

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4. Early human impacts and ecosystem reorganization in southern-central Africa

   https://doi.org/10.1126/sciadv.abf9776  

   Thompson, Jessica C.; Wright, David K.; Ivory, Sarah J.; Choi, Jeong-Heon; Nightingale, Sheila; Mackay, Alex; Schilt, Flora; Otárola-Castillo, Erik; Mercader, Julio; Forman, Steven L.; et al (May 2021, Science Advances)

   null (Ed.)

   Modern Homo sapiens engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an early, pre-agricultural anthropogenic landscape. 

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5. A marine isotope stage 11 coastal Acheulian workshop with associated wood at Amanzi Springs Area 1, South Africa

   https://doi.org/10.1371/journal.pone.0273714  

   Herries, Andy I.; Arnold, Lee J.; Boschian, Giovanni; Blackwood, Alexander F.; Wilson, Coen; Mallett, Tom; Armstrong, Brian; Demuro, Martina; Petchey, Fiona; Meredith-Williams, Matthew; et al (October 2022, PLOS ONE)

   Hart, John P. (Ed.)

   Amanzi Springs is a series of inactive thermal springs located near Kariega in the Eastern Cape of South Africa. Excavations in the 1960s exposed rare, stratified Acheulian-bearing deposits that were not further investigated over the next 50 years. Reanalysis of the site and its legacy collection has led to a redefined stratigraphic context for the archaeology, a confirmed direct association between Acheulian artefacts and wood, as well as the first reliable age estimates for the site. Thermally transferred optically stimulated luminescence and post-infrared infrared stimulated luminescence dating indicates that the Acheulian deposits from the Amanzi Springs Area 1 spring eye formed during Marine Isotope Stage (MIS) 11 at ~ 404–390 ka. At this time, higher sea levels of ~13-14m would have placed Amanzi Springs around 7 km from a ria that would have formed along what is today the Swartkops River, and which likely led to spring reactivation. This makes the Amanzi Springs Area 1 assemblage an unusual occurrence of a verified late occurring, seaward, open-air Acheulian occupation. The Acheulian levels do not contain any Middle Stone Age (MSA) elements such as blades and points that have been documented in the interior of South Africa at this time. However, a small number of stone tools from the upper layers of the artefact zone, and originally thought of as intrusive, have been dated to ~190 ka, at the transition between MIS 7 to 6, and represent the first potential MSA identified at the site. 

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