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Agatova  A. R.  Nepop  R. K.  Khazin  L. B.  Zhdanova  A. N.  Uspenskaya  O. N.  Ovchinnikov  I. Yu.  Moska  P. 《Doklady Earth Sciences》2019,488(1):1134-1136
Doklady Earth Sciences - One of the debated problems in Pleistocene paleogeography of the Altai region is the extent and time of existence of the last glacier-dammed lakes. For the first time...  相似文献   
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In this work we present luminescence analyses of material taken from a Neolithic hearth in the Sahara Desert in Egypt. The sample was taken from a beach sand layer which contained traces of charcoal. The sample was dated using quartz luminescence, and its luminescence properties were investigated to find whether it had been heated by fire. In doing so we established a procedure to distinguish heated and unheated quartz at single grain level.The OSL age estimate of the sample is 10.6 ± 0.4 ka. Luminescence properties were measured using about 40,000 individual grains. Using an approach similar to that used to measure thermal activation characteristics (TAC), we compared the distribution of OSL sensitivity of single grains following different thermal treatments. It was found that higher temperatures and longer treatment times change the sensitivity distributions systematically from that observed using the natural sample. We conclude that the grains examined in our dating study were not heated by fire prior to burial, and that the hearth is not older than the OSL age.  相似文献   
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Pronounced climatic warming associated with the Late Weichselian Pleniglacial‐to‐Lateglacial transition caused considerable environmental changes throughout the former periglacial zones (in Europe ~53°–46°N). During permafrost degradation and subsequent ground subsidence (i.e. thermokarst processes), the landscape changed rapidly. In this study we investigated a flat mid‐altitude area in south Bohemia, Czech Republic, lying close to the southern limit of the Weichselian permafrost. We discovered palaeo‐lake basins with sedimentary infillings up to 11 m in depth. According to radiocarbon and palynostratigraphical dating, these basins were formed at the onset of the Late Pleniglacial‐to‐Lateglacial transition, whereas the smaller depressions were formed later. We suggest that the basins resulted from thermal and fluvio‐thermal erosion of the former permafrost and represent remnants of discontinuous gullies and possibly collapsed frost mounds (pingo/lithalsa scars). The formation of this a fossil thermokarst landscape was climatically driven and multiple phased, with the major phase during the climatic warming and wetting at the onset of GI‐1e (Bølling) and the minor phase during GI‐1c (Allerød). This study enhances knowledge of the palaeogeography of the former European periglacial zone by showing that Late Pleistocene thermokarst activity could have had a significant impact on the evolution of the landscape of at least some regions of central Europe along the southern limit of the continuous permafrost zone. The research also points to a similar history for the physical transformation of the landscape of the former European periglacial zone and current thermokarst landscapes and could be a valuable source of information with respect to the future transformation of the Arctic under conditions of ongoing global warming.  相似文献   
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The sedimentary succession exposed in the Gorzów Wielkopolski area includes Eemian Interglacial (MIS 5e) or Early Weichselian (MIS 5d–e) deposits. The sedimentary sequence has been the object of intense interdisciplinary study, which has resulted in the identification of at least two palaeolake horizons. Both yielded fossil remains of large mammals, alongside pollen and plant macrofossils. All these proxies have been used to reconstruct the environmental conditions prevailing at the time of deposition, as well as to define the geological context and the biochronological position of the fauna. Optically stimulated luminescence dating of the glaciofluvial layers of the GS3 succession to 123.6 ± 10.1 (below the lower palaeolake) and 72.0 ± 5.2 ka (above the upper palaeolake) indicate that the site formed during the Middle–Late Pleistocene (MIS 6 – MIS 5). Radiocarbon-dating of the lacustrine organic matter revealed a tight cluster of Middle Pleniglacial Period (MIS 3) ages in the range of ~41–32 ka cal bp (Hengelo – Denekamp Interstadials). Holocene organic layers have also been found, with 14C ages within a range of 4330–4280 cal bp (Neolithic). Pollen and plant macrofossil records, together with sedimentological and geochemical data, confirm the dating to the Eemian Interglacial.  相似文献   
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