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1. Cave and rock shelter sediments of southern Africa: a review of the chronostratigraphic and palaeoenvironmental record from Marine Isotope Stage 6 to 1

   https://doi.org/10.25131/sajg.124.0052  

   Stratford, D. ; Braun, K. ; Morrissey, P. ( December 2021 , South African Journal of Geology)

   Abstract Caves and rock shelters contribute important records to local, regional and sub-continental reconstructions of environment and climate change through the southern African Quaternary. Against a backdrop of pronounced climate change, the archaeological record of the Marine Isotope Stage 6 to 1 period in southern Africa documents a remarkable time in the behavioural and technological evolution of anatomically modern humans. Significant evidence of this evolution is represented in diverse components of the sedimentary record in caves and rock shelters in the region. We present a catalogue of published caves and rock shelters in southern Africa that preserve temporally-relevant clastic and chemical palaeoclimatic proxies in order to: (1) facilitate the integration of cave and rock shelter sedimentary data into broader, regional chronostratigraphically-correlated palaeoclimatic sequences; and (2) identify possible areas and proxies that require focused research in the future. To demonstrate the complexity of the Marine Isotope Stage 6 to 1 stratigraphic record and use of palaeoenvironmental proxies, we present three case studies representing interior and coastal contexts: Border Cave, Klasies River Mouth and Pinnacle Point. These examples aptly demonstrate the challenges of these contexts, but also the opportunities for palaeoenvironmental research in southern Africa when conducted through integrated, multidisciplinary approaches. Published records of palaeoenvironmental research from cave and rock shelter sequences in southern Africa are heavily biased to the South African coastal areas and the record is temporally and spatially fragmented. However, there are interesting patterns in the chronostratigraphic record and in the distribution of sites within the context of the geology and vegetation ecology of southern Africa that require further exploration. There are also promising techniques in stable isotope analysis that can be applied to abundant sedimentary components found in the region’s caves and rock shelters, and in its museums. 

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2. A globally relevant stock of soil nitrogen in the Yedoma permafrost domain

   https://doi.org/10.1038/s41467-022-33794-9  

   Strauss, Jens ; Biasi, Christina ; Sanders, Tina ; Abbott, Benjamin W. ; von Deimling, Thomas Schneider ; Voigt, Carolina ; Winkel, Matthias ; Marushchak, Maija E. ; Kou, Dan ; Fuchs, Matthias ; et al ( December 2022 , Nature Communications)

   Abstract Nitrogen regulates multiple aspects of the permafrost climate feedback, including plant growth, organic matter decomposition, and the production of the potent greenhouse gas nitrous oxide. Despite its importance, current estimates of permafrost nitrogen are highly uncertain. Here, we compiled a dataset of >2000 samples to quantify nitrogen stocks in the Yedoma domain, a region with organic-rich permafrost that contains ~25% of all permafrost carbon. We estimate that the Yedoma domain contains 41.2 gigatons of nitrogen down to ~20 metre for the deepest unit, which increases the previous estimate for the entire permafrost zone by ~46%. Approximately 90% of this nitrogen (37 gigatons) is stored in permafrost and therefore currently immobile and frozen. Here, we show that of this amount, ¾ is stored >3 metre depth, but if partially mobilised by thaw, this large nitrogen pool could have continental-scale consequences for soil and aquatic biogeochemistry and global-scale consequences for the permafrost feedback. 

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3. Yedoma Permafrost Genesis: Over 150 Years of Mystery and Controversy

   https://doi.org/10.3389/feart.2021.757891  

   Shur, Yuri ; Fortier, Daniel ; Jorgenson, M. Torre ; Kanevskiy, Mikhail ; Schirrmeister, Lutz ; Strauss, Jens ; Vasiliev, Alexander ; Ward Jones, Melissa ( January 2022 , Frontiers in Earth Science)

   Since the discovery of frozen megafauna carcasses in Northern Siberia and Alaska in the early 1800s, the Yedoma phenomenon has attracted many Arctic explorers and scientists. Exposed along coastal and riverbank bluffs, Yedoma often appears as large masses of ice with some inclusions of sediment. The ground ice particularly mystified geologists and geographers, and they considered sediment within Yedoma exposures to be a secondary and unimportant component. Numerous scientists around the world tried to explain the origin of Yedoma for decades, even though some of them had never seen Yedoma in the field. The origin of massive ice in Yedoma has been attributed to buried surface ice (glaciers, snow, lake ice, and icings), intrusive ice (open system pingo), and finally to ice wedges. Proponents of the last hypothesis found it difficult to explain a vertical extent of ice wedges, which in some cases exceeds 40 m. It took over 150 years of intense debates to understand the process of ice-wedge formation occurring simultaneously (syngenetically) with soil deposition and permafrost aggregation. This understanding was based on observations of the contemporary formation of syngenetic permafrost with ice wedges on the floodplains of Arctic rivers. It initially was concluded that Yedoma was a floodplain deposit, and it took several decades of debates to understand that Yedoma is of polygenetic origin. In this paper, we discuss the history of Yedoma studies from the early 19th century until the 1980s—the period when the main hypotheses of Yedoma origin were debated and developed. 

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4. A million year vegetation history and palaeoenvironmental record from the Lake Magadi Basin, Kenya Rift Valley

   https://doi.org/10.1016/j.palaeo.2021.110247  

   Muiruri, Veronica M. ; Owen, R. Bernhart ; Lowenstein, Tim K. ; Renaut, Robin W. ; Marchant, Robert ; Rucina, Stephen M. ; Cohen, Andrew ; Deino, Alan L. ; Sier, Mark J. ; Luo, Shangde ; et al ( April 2021 , Palaeogeography, Palaeoclimatology, Palaeoecology)

   null (Ed.)
5. Middle to late Wisconsinan climate and ecological changes in northern Alaska: Evidences from the Itkillik River Yedoma

   https://doi.org/10.1016/j.palaeo.2017.08.006  

   Lapointe E., Lyna ; Talbot, Julie ; Fortier, Daniel ; Fréchette, Bianca ; Strauss, Jens ; Kanevskiy, Mikhail ; Shur, Yuri ( November 2017 , Palaeogeography, Palaeoclimatology, Palaeoecology)