TY - JOUR A1 - Foerster, Verena A1 - Asrat, Asfawossen A1 - Ramsey, Christopher Bronk A1 - Brown, Erik T. A1 - Chapot, Melissa S. A1 - Deino, Alan A1 - Düsing, Walter A1 - Grove, Matthew A1 - Hahn, Annette A1 - Junginger, Annett A1 - Kaboth-Bahr, Stefanie A1 - Lane, Christine S. A1 - Opitz, Stephan A1 - Noren, Anders A1 - Roberts, Helen M. A1 - Stockhecke, Mona A1 - Tiedemann, Ralph A1 - Vidal, Celine M. A1 - Vogelsang, Ralf A1 - Cohen, Andrew S. A1 - Lamb, Henry F. A1 - Schaebitz, Frank A1 - Trauth, Martin H. T1 - Pleistocene climate variability in eastern Africa influenced hominin evolution JF - Nature geoscience N2 - 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 similar to 620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (similar to 275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in 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 (similar to 60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens. KW - Evolutionary ecology KW - Limnology KW - Palaeoclimate Y1 - 2022 U6 - https://doi.org/10.1038/s41561-022-01032-y SN - 1752-0894 SN - 1752-0908 VL - 15 IS - 10 SP - 805 EP - 811 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Lu, Honghua A1 - Cheng, Lu A1 - Wang, Zhen A1 - Zhang, Tianqi A1 - Lu, Yanwu A1 - Zhao, Junxiang A1 - Li, Youli A1 - Zheng, Xiangmin T1 - Latest Quaternary rapid river incision across an inactive fold in the northern Chinese Tian Shan foreland JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - This work focuses on the incision process over the Tuostai anticline, a fold of the proximal structure Belt I in the northern Chinese Tian Shan foreland, where the Sikeshu River has incised deeply into the alluvial gravels and the fold's underlying bedrock strata. Field investigation and geomorphic mapping define five terraces of the Sikeshu River (designated as T1 to T5 from oldest to youngest) preserved within the Tuostai anticline. 10Be surface exposure dating and optically stimulated luminescence dating constrain stabilization of the highest three terrace surfaces at about 80 ka (T1), 16 ka (T2), and 15 ka (T3), respectively. Around 16 ka, the calculated river incision rates significantly increase from <2 mm/yr to >6 mm/yr. Undeformed longitudinal profiles of terraces T2, T3 and T4 over the Tuostai anticline suggest that this structure may have been tectonically inactive since stabilization of these three terraces. We thus think that the observed rapid river incision over the Tuostai anticline has not been largely forced by tectonic uplift. Instead, the progressively warmer and wetter palaeoclimatic condition within the Tian Shan range and its surrounding area during the period of ∼20–10 ka may have enhanced river incision across the Tuostai anticline. A reduced sediment/water ratio might have lowered the gradient of the Sikeshu River. KW - River incision KW - Fluvial terrace KW - Palaeoclimate KW - Late Quaternary KW - Tian Shan Y1 - 2017 U6 - https://doi.org/10.1016/j.quascirev.2017.10.017 SN - 0277-3791 VL - 179 SP - 167 EP - 181 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Nazarova, Larisa B. A1 - Bleibtreu, Annette A1 - Hoff, Ulrike A1 - Dirksen, Veronika A1 - Diekmann, Bernhard T1 - Changes in temperature and water depth of a small mountain lake during the past 3000 years in Central Kamchatka reflected by a chironomid record JF - Quaternary international : the journal of the International Union for Quaternary Research N2 - We investigated chironomid assemblages of a well-dated sediment core from a small seepage lake situated at the eastern slope of the Central Kamchatka Mountain Chain, Far East Russia. The chironomid fauna of the investigated Sigrid Lake is dominated by littoral taxa that are sensitive to fluctuations of the water level. Two groups of taxa interchangeably dominate the record responding to the changes in the lake environment during the past 2800 years. The first group of littoral phytophilic taxa includes Psectrocladius sordidellus-type, Corynoneura arctica-type and Dicrotendipes nervosus-type. The abundances of the taxa from this group have the strongest influence on the variations of PCA 1, and these taxa mostly correspond to low water levels, moderate temperatures and slightly acidified conditions. The second group of taxa includes Microtendipes pedellus-type, Tanytarsus lugens-type, and Tanytarsus pallidicornistype. The variations in the abundances of these taxa, and especially of M. pedellus-type, are in accordance with PCA 2 and correspond to the higher water level in the lake, more oligotrophic and neutral pH conditions. Water depths (WD) were reconstructed, using a modern chironomid-based temperature and water depth calibration data set (training set) and inference model from East Siberia (Nazarova et al., 2011). Mean July air temperatures (T July) were inferred using a chironomid-based temperature inference model based on a modern calibration data set for the Far East (Nazarova et al., 2015). The application of transfer functions resulted in reconstructed T July fluctuations of approximately 3 degrees C over the last 2800 years. Low temperatures (11.0-12.0 degrees C) were reconstructed for the periods between ca 1700 and 1500 cal yr BP (corresponding to the Kofun cold stage) and between ca 1200 and 150 cal yr BP (partly corresponding to the Little Ice Age [LIA]). Warm periods (modern T July or higher) were reconstructed for the periods between ca 2700 and 1800 cal yr BP, 1500 and 1300 cal yr BP and after 150 cal yr BP. WD reconstruction revealed that the lake level was lower than its present level at the beginning of the record between ca 2600 and 2300 cal yr BP and ca 550 cal yr BP. Between ca 2300 and 700 cal yr BP as well as between 450 and 150 cal yr BP, the lake level was higher than it is today, most probably reflecting more humid conditions. (C) 2016 Elsevier Ltd and INQUA. All rights reserved. KW - Kamchatka KW - Chironomids KW - Palaeoclimate KW - Late Holocene KW - Temperature KW - Water depth Y1 - 2017 U6 - https://doi.org/10.1016/j.quaint.2016.10.008 SN - 1040-6182 SN - 1873-4553 VL - 447 SP - 46 EP - 58 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Nazarova, Larisa B. A1 - Grebennikova, Tatiana A. A1 - Razjigaeva, Nadezhda G. A1 - Ganzey, Larisa A. A1 - Belyanina, Nina I. A1 - Arslanov, Khikmat A. A1 - Kaistrenko, Victor M. A1 - Gorbunov, Aleksey O. A1 - Kharlamov, Andrey A. A1 - Rudaya, Natalia A1 - Palagushkina, Olga A1 - Biskaborn, Boris A1 - Diekmann, Bernhard T1 - Reconstruction of Holocene environmental changes in Southern Kurils (North-Western Pacific) based on palaeolake sediment proxies from Shikotan Island JF - Global and planetary change N2 - We investigated a well-dated sediment section of a palaeolake situated in the coastal zone of Shikotan Island (Lesser Kurils) for organic sediment-geochemistry and biotic components (diatoms, chironomids, pollen) in order to provide a reconstruction of the palaeoenvironmental changes and palaeo-events (tsunamis, sea-level fluctuations and landslides) in Holocene. During the ca 8000 years of sedimentation the changes in organic sediment-geochemistry and in composition of the diatoms and chironomids as well as the shifts in composition of terrestrial vegetation suggest that the period until ca 5800 cal yr BP was characterized by a warm and humid climate (corresponds to middle Holocene optimum) with climate cooling thereafter. A warm period reconstructed from ca 900 to at least ca 580 cal yr BP corresponds to a transition to a Nara-Heian-Kamakura warm stage and can be correlated to a Medieval Warm Period. After 580 cal yr PB, the lake gradually dried out and climatic signals could not be obtained from the declining lacustrine biological communities, but the increasing role of spruce and disappearance of the oak from the vegetation give evidences of the climate cooling that can be correlated with the LIA. The marine regression stages at the investigated site are identified for ca 6200-5900 (at the end of the middle Holocene transgression), ca 5500-5100 (Middle Jomon regression or Kemigawa regression), and ca 1070-360 cal yr BP (at the end of Heian transgression). The lithological structure of sediments and the diatom compositions give evidences for the multiple tsunami events of different strengths in the Island. Most remarkable of them can be dated at around ca 7000, 6460, 5750, 4800, 950 cal yr BP. The new results help to understand the Holocene environmental history of the Southern Kurils as a part of the Kuril-Kamchatka and Aleutian Marginal Sea-Island Arc Systems in the North-Western Pacific region. KW - Kurils KW - North-Western Pacific KW - Palaeoclimate KW - Sea level KW - Diatoms KW - Chironomids KW - Pollen Y1 - 2017 U6 - https://doi.org/10.1016/j.gloplacha.2017.10.005 SN - 0921-8181 SN - 1872-6364 VL - 159 SP - 25 EP - 36 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Bougeois, Laurie A1 - de Rafelis, Marc A1 - Reichart, Gert-Jan A1 - de Nooijer, Lennart J. A1 - Dupont-Nivet, Guillaume T1 - Mg/Ca in fossil oyster shells as palaeotemperature proxy, an example from the Palaeogene of Central Asia JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - Fossil oyster shells are well-suited to provide palaeotemperature proxies from geologic to seasonal timescales due to their ubiquitous occurrence from Triassic to Quaternary sediments, the seasonal nature of their shell growth and their relative strong resistance to post-mortem alteration. However, the common use to translate calcitic oxygen isotopes into palaeotemperatures is challenged by uncertainties in accounting for past seawater delta O-18, especially in shallow coastal environment where oysters calcify. In principle, the Mg/Ca ratio in oyster shells can provide an alternative palaeothermometer. Several studies provided temperature calibrations for this potential proxy based on modem species, nevertheless their application to palaeo-studies remains hitherto unexplored. Here, we show that past temperature variability in seawater can be obtained from Mg/Ca analyses from selected fossil oyster species and specimens. High-resolution Mg/Ca profiles, combined with delta O-18, were obtained along 41 fossil oyster shells of seven different species from the Palaeogene Proto-Paratethys sea (Central Asia) found in similar as well as different depositional age and environments providing comparison. Suitable Mg/Ca profiles, defined by continuous cyclicity and reproducibility within one shell, are found to be consistent for specimens of the same species but differ systematically between species, implying a dominant species-specific effect on the Mg/Ca signal. Two species studied here (Ostrea (Turkostrea) strictiplicata and Sokolowia buhsii) provide an excellent proxy for palaeoclimate reconstruction from China to Europe in Palaeogene marine sediments. More generally, the protocol developed here can be applied to identify other fossil oyster species suitable for palaeoclimate reconstructions. (C) 2015 Elsevier B.V. All rights reserved. KW - Palaeoclimate KW - Oyster KW - Mg/Ca KW - Sclerochronology KW - Palaeogene KW - Central Asia Y1 - 2016 U6 - https://doi.org/10.1016/j.palaeo.2015.09.052 SN - 0031-0182 SN - 1872-616X VL - 441 SP - 611 EP - 626 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Maslin, Mark A. A1 - Pancost, Richard D. A1 - Wilson, Katy E. A1 - Lewis, Jonathan A1 - Trauth, Martin H. T1 - Three and half million year history of moisture availability of South West Africa evidence from ODP site 1085 biomarker records JF - Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences N2 - Ocean Drilling Program Site 1085 provides a continuous marine sediment record off southern South West Africa for at least the last three and half million years. The n-alkane partial derivative(13) C record from this site records changes in past vegetation and provides an indication of the moisture availability of SW Africa during this time period. Very little variation, and no apparent trend, is observed in the n-alkane delta C-13 record, suggesting stable long-term conditions despite significant changes in East African tectonics and global climate. Slightly higher n-alkane delta C-13 values occur between 3.5 and 2.7 Ma suggesting slightly drier conditions than today. Between 2.5 and 2.7 Ma there is a shift to more negative n-alkane delta C-13 values suggesting slightly wetter conditions during a similar to 0.2 Ma episode that coincides with the intensification of Northern Hemisphere Glaciation (iNHG). From 2.5 to 0.4 Ma the n-alkane delta C-13 values are very consistent, varying by less than +/- 0.5 parts per thousand and suggesting little or no long-term change in the moisture availability of South West Africa over the last 2.5 million years. This is in contrast to the long-term drying trend observed further north offshore from the Namib Desert and in East Africa. A comparison of the climate history of these regions suggests that Southern Africa may have been an area of long-term stability over the last 3.5 Myrs. KW - Plio-Pleistocene KW - Aridity KW - SW Africa KW - Biomarkers KW - Palaeoclimate KW - Human evolution Y1 - 2012 U6 - https://doi.org/10.1016/j.palaeo.2011.12.009 SN - 0031-0182 VL - 317 SP - 41 EP - 47 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Nazarova, Larisa B. A1 - de Hoog, Verena A1 - Hoff, Ulrike A1 - Dirksen, Oleg A1 - Diekmann, Bernhard T1 - Late Holocene climate and environmental changes in Kamchatka inferred from the subfossil chironomid record JF - Quaternary science reviews : the international multidisciplinary research and review journal N2 - This study presents a reconstruction of the Late Holocene climate in Kamchatka based on chironomid remains from a 332 cm long composite sediment core recovered from Dvuyurtochnoe Lake (Two-Yurts Lake, TYL) in central Kamchatka. The oldest recovered sediments date to about 4500 cal years BP. Chironomid head capsules from TYL reflect a rich and diverse fauna. An unknown morphotype of Tanytarsini, Tanytarsus type klein, was found in the lake sediments. Our analysis reveals four chironomid assemblage zones reflecting four different climatic periods in the Late Holocene. Between 4500 and 4000 cal years BP, the chironomid composition indicates a high lake level, well-oxygenated lake water conditions and close to modern temperatures (similar to 13 degrees C). From 4000 to 1000 cal years BP, two consecutive warm intervals were recorded, with the highest reconstructed temperature reaching 16.8 degrees C between 3700 and 2800 cal years BP. Cooling trend, started around 1100 cal years BP led to low temperatures during the last stage of the Holocene. Comparison with other regional studies has shown that termination of cooling at the beginning of late Holocene is relatively synchronous in central Kamchatka, South Kurile, Bering and Japanese Islands and take place around 3700 cal years BP. From ca 3700 cal years BP to the last millennium, a newly strengthened climate continentality accompanied by general warming trend with minor cool excursions led to apparent spatial heterogeneity of climatic patterns in the region. Some timing differences in climatic changes reconstructed from chironomid record of TYL sediments and late Holocene events reconstructed from other sites and other proxies might be linked to differences in local forcing mechanisms or caused by the different degree of dating precision, the different temporal resolution, and the different sensitive responses of climate proxies to the climate variations. Further high-resolution stratigraphic studies in this region are needed to understand the spatially complex pattern of climate change in Holocene in Kamchatka and the surrounding region. KW - Kamchatka KW - Holocene KW - Chironomids KW - Palaeoclimate KW - Temperature Y1 - 2013 U6 - https://doi.org/10.1016/j.quascirev.2013.01.018 SN - 0277-3791 VL - 67 IS - 9 SP - 81 EP - 92 PB - Elsevier CY - Oxford ER -