Devara Anil, M. Devi, J. Blinkhorn, V. Smith, Satish Sanghode, Vrushab Mahesh, Zakir Khan, P. Ajithprasad, N. Chauhan
Abstract The eruption of Toba ca. 75 ka was the largest volcanic eruptive event during the Quaternary, and evidence for this eruption is widespread in terrestrial sediment sequences in South Asia as primary and reworked distal ash deposits. Youngest Toba Tuff horizons (YTT) have been widely employed as isochrons to understand and link regional sediment sequences and the evidence for environmental and cultural change in the archaeological records preserved within them. We identify the YTT deposits at Retlapalle, Andhra Pradesh, India, and present the optical ages of the K-feldspar grains recovered from sediments immediately underlying and overlying the tephra horizon. We combine these results with particle size and magnetic susceptibility analyses to establish the depositional conditions of YTT, which indicate that accumulation and reworking ceased by ca. 64 ka. We explore the role of YTT deposits as an isochron for examining the effect of the 75 ka Toba super-eruption, highlighting the need for an independent chronological assessment of YTT before using it as a Late Pleistocene chronological marker in reconstructing South Asian paleo-landscapes and hominin adaptations. Further, our findings support the regional continuity of human occupations within South Asia, spanning the eruption of Toba and the enduring utility of Middle Paleolithic tools.
摘要托巴约75ka的火山喷发是第四纪最大的火山喷发事件，这种喷发的证据在南亚的陆地沉积物序列中广泛存在，作为原始和改造的远端火山灰沉积物。最年轻的托巴-塔夫层位（YTT）已被广泛用作等时线，以了解和联系区域沉积物序列以及保存在其中的考古记录中环境和文化变化的证据。我们确定了印度安得拉邦Retlapalle的YTT矿床，并提供了从直接位于和覆盖于火山灰层的沉积物中回收的钾长石颗粒的光学年龄。我们将这些结果与粒度和磁化率分析相结合，以确定YTT的沉积条件，这表明堆积和改造在约64ka时停止。我们探索了YTT矿床作为等时线的作用，以检查75 ka Toba超级喷发的影响，强调在将YTT用作重建南亚古景观和人类适应的晚更新世时间标记之前，需要对其进行独立的时间评估。此外，我们的发现支持了南亚人类职业的区域连续性，涵盖了托巴火山爆发和旧石器时代中期工具的持久使用。
{"title":"Youngest Toba Tuff deposits in the Gundlakamma River basin, Andhra Pradesh, India and their role in evaluating Late Pleistocene behavioral change in South Asia","authors":"Devara Anil, M. Devi, J. Blinkhorn, V. Smith, Satish Sanghode, Vrushab Mahesh, Zakir Khan, P. Ajithprasad, N. Chauhan","doi":"10.1017/qua.2023.13","DOIUrl":"https://doi.org/10.1017/qua.2023.13","url":null,"abstract":"Abstract The eruption of Toba ca. 75 ka was the largest volcanic eruptive event during the Quaternary, and evidence for this eruption is widespread in terrestrial sediment sequences in South Asia as primary and reworked distal ash deposits. Youngest Toba Tuff horizons (YTT) have been widely employed as isochrons to understand and link regional sediment sequences and the evidence for environmental and cultural change in the archaeological records preserved within them. We identify the YTT deposits at Retlapalle, Andhra Pradesh, India, and present the optical ages of the K-feldspar grains recovered from sediments immediately underlying and overlying the tephra horizon. We combine these results with particle size and magnetic susceptibility analyses to establish the depositional conditions of YTT, which indicate that accumulation and reworking ceased by ca. 64 ka. We explore the role of YTT deposits as an isochron for examining the effect of the 75 ka Toba super-eruption, highlighting the need for an independent chronological assessment of YTT before using it as a Late Pleistocene chronological marker in reconstructing South Asian paleo-landscapes and hominin adaptations. Further, our findings support the regional continuity of human occupations within South Asia, spanning the eruption of Toba and the enduring utility of Middle Paleolithic tools.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48317211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Felix C. Pym, F. Franco-Gaviria, Ismael G. Espinoza, D. Urrego
Abstract Examining the ecological consequences of the late Quaternary megafaunal extinctions within biodiversity hotspots is crucial for our understanding of the potential consequences of contemporary extinctions. We present the first multi-species record of spores of coprophilous fungi (SCF) from Monquentiva and the high-Andean forests of Colombia to reconstruct Late Pleistocene and Holocene megafaunal abundance. Fossilised pollen and charcoal are used to examine the consequences of megafaunal declines on the surrounding vegetation and fire activity. Our SCF record indicates the presence of Pleistocene megafauna at least since 30,290 BP, with two waves of megafaunal decline at ca. 22,900 BP and 10,990 BP. At Monquentiva, megafaunal decline in the Early Holocene resulted in transitional non-analogue vegetation, loss of some herbivore-dispersed plant taxa, an encroachment of palatable and woody flora, and a rise in fire activity. Differences with other published South-American records suggest that ecological consequences of megafaunal declines were habitat-specific. Overall, we show that ecosystems in the eastern Colombian Cordillera were highly sensitive to the decline of megafaunal populations. Under the current biodiversity crisis, management and conservation efforts must account for the effects of local herbivore declines on plant dispersal, on fire activity, and the potential loss of ecosystem services.
{"title":"The timing and ecological consequences of Pleistocene megafaunal decline in the eastern Andes of Colombia","authors":"Felix C. Pym, F. Franco-Gaviria, Ismael G. Espinoza, D. Urrego","doi":"10.1017/qua.2022.66","DOIUrl":"https://doi.org/10.1017/qua.2022.66","url":null,"abstract":"Abstract Examining the ecological consequences of the late Quaternary megafaunal extinctions within biodiversity hotspots is crucial for our understanding of the potential consequences of contemporary extinctions. We present the first multi-species record of spores of coprophilous fungi (SCF) from Monquentiva and the high-Andean forests of Colombia to reconstruct Late Pleistocene and Holocene megafaunal abundance. Fossilised pollen and charcoal are used to examine the consequences of megafaunal declines on the surrounding vegetation and fire activity. Our SCF record indicates the presence of Pleistocene megafauna at least since 30,290 BP, with two waves of megafaunal decline at ca. 22,900 BP and 10,990 BP. At Monquentiva, megafaunal decline in the Early Holocene resulted in transitional non-analogue vegetation, loss of some herbivore-dispersed plant taxa, an encroachment of palatable and woody flora, and a rise in fire activity. Differences with other published South-American records suggest that ecological consequences of megafaunal declines were habitat-specific. Overall, we show that ecosystems in the eastern Colombian Cordillera were highly sensitive to the decline of megafaunal populations. Under the current biodiversity crisis, management and conservation efforts must account for the effects of local herbivore declines on plant dispersal, on fire activity, and the potential loss of ecosystem services.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41304544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract African rodents of the genus Arvicanthis are presently restricted to sub-Saharan savannas and to the Nile Valley. In contrast, their distribution during the Quaternary included most of northern Africa, leading to the emergence of local fossil species. To date, there have been no comprehensive studies of Arvicanthis populations in northern Africa, neither to clarify their taxonomy nor their paleoecology. The present study aims to explore both morphology and diet of modern and fossil Arvicanthis species using geometric morphometric and dental microwear analyses on first upper molars. The geometric morphometric analysis efficiently discriminates the studied extant and fossil Arvicanthis species and allowed for the identification of probable geographical variations within the A. niloticus group. Although all extant species of the genus Arvicanthis are predominantly grass-eaters, microwear analyses also highlighted diet differences in various modern populations of A. niloticus, as well as paleodiet inferences in the A. arambourgi fossil species, but no clear link between molar size or shape and diet can be established. This work helps set the stage for a complete revision of the fossil remains of Arvicanthis from northern African Quaternary deposits, and for a better understanding of the geographical and temporal morphological variability of this genus in Africa.
{"title":"Towards a better knowledge of the molar morphology and ecology of extant and fossil grass rats (Muridae: Arvicanthis Lesson, 1842)","authors":"E. Stoetzel, Helder Gomes Rodrigues, R. Cornette","doi":"10.1017/qua.2023.7","DOIUrl":"https://doi.org/10.1017/qua.2023.7","url":null,"abstract":"Abstract African rodents of the genus Arvicanthis are presently restricted to sub-Saharan savannas and to the Nile Valley. In contrast, their distribution during the Quaternary included most of northern Africa, leading to the emergence of local fossil species. To date, there have been no comprehensive studies of Arvicanthis populations in northern Africa, neither to clarify their taxonomy nor their paleoecology. The present study aims to explore both morphology and diet of modern and fossil Arvicanthis species using geometric morphometric and dental microwear analyses on first upper molars. The geometric morphometric analysis efficiently discriminates the studied extant and fossil Arvicanthis species and allowed for the identification of probable geographical variations within the A. niloticus group. Although all extant species of the genus Arvicanthis are predominantly grass-eaters, microwear analyses also highlighted diet differences in various modern populations of A. niloticus, as well as paleodiet inferences in the A. arambourgi fossil species, but no clear link between molar size or shape and diet can be established. This work helps set the stage for a complete revision of the fossil remains of Arvicanthis from northern African Quaternary deposits, and for a better understanding of the geographical and temporal morphological variability of this genus in Africa.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41419819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Urban, T. Kasper, Kim J. Krahn, T. van Kolfschoten, Bent Rech, Marco Holzheu, Mario Tucci, A. Schwalb
Abstract Detailed sedimentological, geochemical, palynological, and aquatic-microfossil analyses on a new composite profile (Para-Reference Profile Schöningen 13 II and Zeugenblock 13 II [2018]) exposed at the archaeological excavation site of Schöningen 13 II reflect several phases of newly recorded lake level fluctuations and vegetation changes. A pronounced deforestation and the expansion of grasses and herbal plant communities characterize the first steppe (open woodland) phase, which follows the interglacial forest communities. A succeeding tripartite woodland phase predominantly marked by Betula and Pinus is followed by another rather dry steppe phase and a second woodland period, which includes the famous archaeological “spear horizon” 13 II-4ab. Transition into a cold period is indicated by progressive desiccation of the lake and a shift to a steppe/tundra vegetation. Novel 3D images of the 10 most characteristic phases of the Reinsdorf sequence have been constructed based on the botanical data (macro remains as well as palynomorphs), terrestrial vertebrate faunal, geochemical, sedimentological, and previously established data from aquatic microfossils. In addition, a tentative correlation between the post-interglacial phases of the Reinsdorf sequence and Marine Isotope Substages 9d–9a, based on biostratigraphical as well as sedimentological data, is proposed.
{"title":"Landscape dynamics and chronological refinement of the Middle Pleistocene Reinsdorf Sequence of Schöningen, NW Germany","authors":"B. Urban, T. Kasper, Kim J. Krahn, T. van Kolfschoten, Bent Rech, Marco Holzheu, Mario Tucci, A. Schwalb","doi":"10.1017/qua.2022.65","DOIUrl":"https://doi.org/10.1017/qua.2022.65","url":null,"abstract":"Abstract Detailed sedimentological, geochemical, palynological, and aquatic-microfossil analyses on a new composite profile (Para-Reference Profile Schöningen 13 II and Zeugenblock 13 II [2018]) exposed at the archaeological excavation site of Schöningen 13 II reflect several phases of newly recorded lake level fluctuations and vegetation changes. A pronounced deforestation and the expansion of grasses and herbal plant communities characterize the first steppe (open woodland) phase, which follows the interglacial forest communities. A succeeding tripartite woodland phase predominantly marked by Betula and Pinus is followed by another rather dry steppe phase and a second woodland period, which includes the famous archaeological “spear horizon” 13 II-4ab. Transition into a cold period is indicated by progressive desiccation of the lake and a shift to a steppe/tundra vegetation. Novel 3D images of the 10 most characteristic phases of the Reinsdorf sequence have been constructed based on the botanical data (macro remains as well as palynomorphs), terrestrial vertebrate faunal, geochemical, sedimentological, and previously established data from aquatic microfossils. In addition, a tentative correlation between the post-interglacial phases of the Reinsdorf sequence and Marine Isotope Substages 9d–9a, based on biostratigraphical as well as sedimentological data, is proposed.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42568477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Coastal dunes along Lake Michigan's eastern shoreline are a unique system comprising perhaps the largest complex of freshwater coastal dunes in the world. Here, we examine the blowouts in this region and determine how they have evolved since the 1930s. We conducted a spatiotemporal analysis of 435 blowouts by comparing repeat aerial images of the coast beginning in 1938. Using an unsupervised machine learning classification known as iso-clustering, we mapped blowout morphologies at three timestamps: 1938, 1986–1988, and 2018. We then compared the blowout geographies through a technique known as a spatial-temporal analysis of moving polygons (STAMP) model, which allowed us to analyze how each blowout changed in time and space. Results show blowouts have contracted ~37% in size since 1938, mostly at the expense of vegetation, with many fragmenting. These findings comport with other regional and global studies detailing a trend in coastal dune stabilization from vegetation and suggest that an increase in precipitation or other environment drivers could be responsible. Moreover, we detected no new blowouts since 1938 along the ~500 km shoreline or on any of the Lake Michigan islands. This suggests blowouts here are artifacts of premodern conditions, perhaps the result of prior stormier or drier eras.
{"title":"The geography and progression of blowouts in the coastal dunes along the eastern shore of Lake Michigan since 1938","authors":"K. McKeehan, A. Arbogast","doi":"10.1017/qua.2023.10","DOIUrl":"https://doi.org/10.1017/qua.2023.10","url":null,"abstract":"Abstract Coastal dunes along Lake Michigan's eastern shoreline are a unique system comprising perhaps the largest complex of freshwater coastal dunes in the world. Here, we examine the blowouts in this region and determine how they have evolved since the 1930s. We conducted a spatiotemporal analysis of 435 blowouts by comparing repeat aerial images of the coast beginning in 1938. Using an unsupervised machine learning classification known as iso-clustering, we mapped blowout morphologies at three timestamps: 1938, 1986–1988, and 2018. We then compared the blowout geographies through a technique known as a spatial-temporal analysis of moving polygons (STAMP) model, which allowed us to analyze how each blowout changed in time and space. Results show blowouts have contracted ~37% in size since 1938, mostly at the expense of vegetation, with many fragmenting. These findings comport with other regional and global studies detailing a trend in coastal dune stabilization from vegetation and suggest that an increase in precipitation or other environment drivers could be responsible. Moreover, we detected no new blowouts since 1938 along the ~500 km shoreline or on any of the Lake Michigan islands. This suggests blowouts here are artifacts of premodern conditions, perhaps the result of prior stormier or drier eras.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45677665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Intense aeolian processes in arid and semi-arid environments play an essential role in the preservation and destruction of archeological sites. This is especially the case in the lower basin of the Colorado River at the eastern Pampa-Patagonia Transition of Argentina, as is illustrated by geoarchaeological and chronostratigraphic studies at a mid-Holocene hunter-gatherer site, La Modesta, where aeolian processes strongly influence the archeological record in dune sediments. At La Modesta, surface archaeological materials are numerous and well preserved, although the stratigraphic record is incomplete. Optically stimulated luminescence (OSL) dating of sediments that contain cultural material provides a chronology dating from ca. 8.2 ka but shows one or more hiatuses from ca. 6–2 ka in the sedimentary succession. Intense morphogenesis related to arid climates likely caused gaps in sedimentation, affecting the integrity and resolution of the archaeological record. This study helps explain mid-Holocene archaeological discontinuities throughout central Argentina and highlights the importance of considering taphonomic and geologic biases when dealing with the absence or reduction of the archaeological record in dryland regions.
{"title":"Human occupation, site formation, and chronostratigraphy of a mid-Holocene archaeological site at the eastern Pampa-Patagonia transition, Argentina","authors":"G. Martínez, G. Martínez, L. Owen","doi":"10.1017/qua.2023.8","DOIUrl":"https://doi.org/10.1017/qua.2023.8","url":null,"abstract":"Abstract Intense aeolian processes in arid and semi-arid environments play an essential role in the preservation and destruction of archeological sites. This is especially the case in the lower basin of the Colorado River at the eastern Pampa-Patagonia Transition of Argentina, as is illustrated by geoarchaeological and chronostratigraphic studies at a mid-Holocene hunter-gatherer site, La Modesta, where aeolian processes strongly influence the archeological record in dune sediments. At La Modesta, surface archaeological materials are numerous and well preserved, although the stratigraphic record is incomplete. Optically stimulated luminescence (OSL) dating of sediments that contain cultural material provides a chronology dating from ca. 8.2 ka but shows one or more hiatuses from ca. 6–2 ka in the sedimentary succession. Intense morphogenesis related to arid climates likely caused gaps in sedimentation, affecting the integrity and resolution of the archaeological record. This study helps explain mid-Holocene archaeological discontinuities throughout central Argentina and highlights the importance of considering taphonomic and geologic biases when dealing with the absence or reduction of the archaeological record in dryland regions.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45065072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yiru Wang, Yu Gao, Zhengwei Zhang, Zhengquan Gu, Jishuai Yang, Yanren Wang, Q. Sun, Wei He, Yang Tsho, W. Shargan, Chunmei Ma, J. Peters, Xiaoyan Yang
Abstract In this paper, we apply standard zooarchaeological methods and novel osteological approaches to analyse faunal remains from five Middle–Late Holocene sites in the southern Tibetan Plateau (STP). Framed by direct radiocarbon dates on taxonomically classified bioarchaeological remains and compared with published palaeoclimate data, our findings revealed a three-stage process of agro-pastoral development in the STP ca. 5.5 to 1.0 ka. In the first phase, habitation was restricted to the lower southeastern part of the plateau and human subsistence essentially based on foraging and low-level pig–millet farming. With the onset of colder and drier climatic conditions ca. 3.8 ka, the study area witnessed a growing human presence at higher elevations in its central and western parts, together with a shift towards bovid husbandry and barley cultivation, that is, agricultural practices that originated in west Asia; these were likely introduced to the STP following the eastern margin of the TP and/or arrived by sub-Himalayan transfer. Climate and ecological degradation might have contributed to the decline of local game in favour of cold-and-dry-tolerant pastoral livestock and crops. Our work shows that Middle–Late Holocene climate change, ecological change, human subsistence shifts, and prehistoric cultural transmissions are intimately connected.
{"title":"Human–animal–environment dynamics and formation of pastoralism in the southern Tibetan Plateau during the Middle–Late Holocene","authors":"Yiru Wang, Yu Gao, Zhengwei Zhang, Zhengquan Gu, Jishuai Yang, Yanren Wang, Q. Sun, Wei He, Yang Tsho, W. Shargan, Chunmei Ma, J. Peters, Xiaoyan Yang","doi":"10.1017/qua.2023.6","DOIUrl":"https://doi.org/10.1017/qua.2023.6","url":null,"abstract":"Abstract In this paper, we apply standard zooarchaeological methods and novel osteological approaches to analyse faunal remains from five Middle–Late Holocene sites in the southern Tibetan Plateau (STP). Framed by direct radiocarbon dates on taxonomically classified bioarchaeological remains and compared with published palaeoclimate data, our findings revealed a three-stage process of agro-pastoral development in the STP ca. 5.5 to 1.0 ka. In the first phase, habitation was restricted to the lower southeastern part of the plateau and human subsistence essentially based on foraging and low-level pig–millet farming. With the onset of colder and drier climatic conditions ca. 3.8 ka, the study area witnessed a growing human presence at higher elevations in its central and western parts, together with a shift towards bovid husbandry and barley cultivation, that is, agricultural practices that originated in west Asia; these were likely introduced to the STP following the eastern margin of the TP and/or arrived by sub-Himalayan transfer. Climate and ecological degradation might have contributed to the decline of local game in favour of cold-and-dry-tolerant pastoral livestock and crops. Our work shows that Middle–Late Holocene climate change, ecological change, human subsistence shifts, and prehistoric cultural transmissions are intimately connected.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44291131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amin Ghafarpour, F. Khormali, H. Tazikeh, M. Kehl, C. Rolf, M. Frechen, C. Zeeden
Abstract We present stratigraphic, magnetic, diffuse reflectance spectrophotometric analyses, and chronologic data for the Chenarli loess–paleosol sequence in northeastern Iran. Eight loess units (LU) are identified, described, and constrained in time based on relative stratigraphy and luminescence dating from >130 ± 9.1 ka to ~9.8 ± 0.7 ka. Our data indicate that pedogenic magnetite/maghemite formation gives rise to magnetic enhancement in modern soil and paleosols. The top of LU 7 is demarcated by the well-developed last interglacial soil in which magnetic depletion occurred. We infer that magnetic depletion in this paleosol was produced by reducing conditions in a seasonally waterlogged soil during a warm and wet phase within Marine Isotope Stage (MIS) 5e. Units LU 6 to 1 record several episodes of dust accumulation and soil formation during the last glacial and Holocene. Increased dust accumulation rates occurred during middle-late MIS 3 and lasted into the late MIS 2, with a peak during the last glacial maximum (LU 2). These findings could be applicable to understanding magnetic enhancement/dissolution mechanism in the loess–paleosol sequences in study area. We infer paleoenvironmental changes in northeastern Iran relative to northern Iran, Eurasia, and China.
本文介绍了伊朗东北部Chenarli黄土-古土壤序列的地层、磁性、漫反射分光光度分析和年代学数据。根据相对地层和发光时间(约130±9.1 ka ~9.8±0.7 ka)对8个黄土单元(LU)进行了识别、描述和时间约束。我们的数据表明，成土磁铁矿/磁赤铁矿的形成导致了现代土壤和古土壤的磁性增强。LU 7顶部以发育良好的末次间冰期土壤为界，其中发生了磁衰竭。我们推测，该古土壤的磁耗损是在海洋同位素阶段(MIS) 5e温暖湿润阶段季节性涝渍土壤条件减少的结果。LU 6至LU 1单元记录了末次冰期和全新世期间的几次尘埃积累和土壤形成。沙尘积累速率的增加主要发生在第3期中后期，并持续到第2期晚期，在末次盛冰期(LU 2)达到峰值。这些结果可用于研究区黄土-古土壤序列的磁增强/溶解机制。我们推断伊朗东北部相对于伊朗北部、欧亚大陆和中国的古环境变化。
{"title":"Geophysical sediment properties of a late Pleistocene loess–paleosol sequence, Chenarli, northeastern Iran","authors":"Amin Ghafarpour, F. Khormali, H. Tazikeh, M. Kehl, C. Rolf, M. Frechen, C. Zeeden","doi":"10.1017/qua.2023.5","DOIUrl":"https://doi.org/10.1017/qua.2023.5","url":null,"abstract":"Abstract We present stratigraphic, magnetic, diffuse reflectance spectrophotometric analyses, and chronologic data for the Chenarli loess–paleosol sequence in northeastern Iran. Eight loess units (LU) are identified, described, and constrained in time based on relative stratigraphy and luminescence dating from >130 ± 9.1 ka to ~9.8 ± 0.7 ka. Our data indicate that pedogenic magnetite/maghemite formation gives rise to magnetic enhancement in modern soil and paleosols. The top of LU 7 is demarcated by the well-developed last interglacial soil in which magnetic depletion occurred. We infer that magnetic depletion in this paleosol was produced by reducing conditions in a seasonally waterlogged soil during a warm and wet phase within Marine Isotope Stage (MIS) 5e. Units LU 6 to 1 record several episodes of dust accumulation and soil formation during the last glacial and Holocene. Increased dust accumulation rates occurred during middle-late MIS 3 and lasted into the late MIS 2, with a peak during the last glacial maximum (LU 2). These findings could be applicable to understanding magnetic enhancement/dissolution mechanism in the loess–paleosol sequences in study area. We infer paleoenvironmental changes in northeastern Iran relative to northern Iran, Eurasia, and China.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42741581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Hagemans, T. Donders, K. Nooren, Iris E.E. Scheper, M. Stekelenburg, Maud Theunissen, P. Minderhoud, A. Goldenberg‐Vilar, S. León-Yánez, Manuela Ormaza, F. Wagner-Cremer, A. Cvetkoska
Abstract A robust understanding of the impact of anthropogenic activities on high-altitude tropical aquatic ecosystems is key for the conservation and protection of the Tropical Andean biodiversity hot spot. We present the results of a multiproxy study of lake sediments from the high Andean páramo of El Cajas National Park, a UNESCO biosphere reserve in Ecuador. The main site, Laguna Pallcacocha, is well known for recording El Niño–driven clastic flood layers that are triggered by high-intensity rainfall anomalies from the eastern Pacific. The second site, Laguna El Ocho, does not contain clastic laminations, providing a control. The records show abrupt shifts in diatom assemblages ca. AD 1991 in both high-elevation Andean lakes accompanied by local changes in páramo composition that suggest a sudden nutrient enrichment of the environment. The diatom assemblages from Laguna Pallcacocha, in relation to the clastic input events, are remarkably stable and do not show evident El Niño signals at the analysed resolution. Based on comparison with the nonlaminated El Ocho record, we deduce the main source of this nutrient enrichment to be the construction of a heavily transited road that runs through the park, while climate warming played secondary role by amplifying its effects.
摘要充分了解人类活动对高海拔热带水生生态系统的影响是养护和保护热带安第斯生物多样性热点的关键。我们展示了对厄瓜多尔联合国教科文组织生物圈保护区El Cajas国家公园安第斯山脉高海拔地区湖泊沉积物的多因素研究结果。主要地点Laguna Pallacocha以记录由东太平洋高强度降雨异常引发的厄尔尼诺驱动的碎屑洪积层而闻名。第二个地点，Laguna El Ocho，不包含碎屑叠层，提供了控制。记录显示，约公元1991年，两个高海拔安第斯湖泊中的硅藻组合发生了突然变化，伴随着páramo成分的局部变化，这表明环境中的营养物质突然富集。Laguna Pallacocha的硅藻组合与碎屑输入事件有关，非常稳定，在分析的分辨率下没有显示出明显的厄尔尼诺信号。根据与未受污染的El Ocho记录的比较，我们推断出这种营养富集的主要来源是修建了一条穿过公园的交通繁忙的道路，而气候变暖通过放大其影响起到了次要作用。
{"title":"Anthropogenic activities in the páramo trigger ecological shifts in Tropical Andean lakes","authors":"K. Hagemans, T. Donders, K. Nooren, Iris E.E. Scheper, M. Stekelenburg, Maud Theunissen, P. Minderhoud, A. Goldenberg‐Vilar, S. León-Yánez, Manuela Ormaza, F. Wagner-Cremer, A. Cvetkoska","doi":"10.1017/qua.2023.9","DOIUrl":"https://doi.org/10.1017/qua.2023.9","url":null,"abstract":"Abstract A robust understanding of the impact of anthropogenic activities on high-altitude tropical aquatic ecosystems is key for the conservation and protection of the Tropical Andean biodiversity hot spot. We present the results of a multiproxy study of lake sediments from the high Andean páramo of El Cajas National Park, a UNESCO biosphere reserve in Ecuador. The main site, Laguna Pallcacocha, is well known for recording El Niño–driven clastic flood layers that are triggered by high-intensity rainfall anomalies from the eastern Pacific. The second site, Laguna El Ocho, does not contain clastic laminations, providing a control. The records show abrupt shifts in diatom assemblages ca. AD 1991 in both high-elevation Andean lakes accompanied by local changes in páramo composition that suggest a sudden nutrient enrichment of the environment. The diatom assemblages from Laguna Pallcacocha, in relation to the clastic input events, are remarkably stable and do not show evident El Niño signals at the analysed resolution. Based on comparison with the nonlaminated El Ocho record, we deduce the main source of this nutrient enrichment to be the construction of a heavily transited road that runs through the park, while climate warming played secondary role by amplifying its effects.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42917290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Leshchinskiy, V. N. Zenin, E. M. Burkanova, Y. Kuzmin
Abstract In 2020, a unique bone assemblage was found at the Late Paleolithic site Volchia Griva. Its base is made of a distal mammoth femur minus epiphysis, in which a cavity has been hollowed out. Impact notches along the edges of the cavity and holes in the metaphysis prove the human-made nature of this specimen. A portion of a polar fox cranium, half of a fox hemimandible, a fox tooth, and a large mammal rib fragment were enclosed in the cavity. The mammoth femur was previously used as a retoucher, as evinced by the impressions and cut marks. Incisions were detected on the polar fox cranium, indicating skinning. According to two 14C dates, the age of the remains is 19.3–19.1 ka BP. Palynological analysis of the cavity fill shows a forb-grass steppe at that time. The assemblage, which has no known analogues, is a reflection of prehistoric culture. This extraordinary find most likely is evidence of the ritual behavior of people who lived in the south of Western Siberia during the last glacial maximum. The assemblage was accompanied by a large number of fox remains, and lithic artifacts identical to bladelet-based Late Paleolithic industries of Siberia and the Middle Urals.
2020年，在旧石器时代晚期的Volchia Griva遗址发现了一种独特的骨骼组合。它的基部由一根远端猛犸股骨减去骨骺组成，骨骺中有一个空腔。沿空腔边缘的撞击痕和干骺端上的洞证明了这个标本是人造的。在洞穴中还发现了北极狐头盖骨的一部分、半食性狐狸的一半、一颗狐狸牙齿和一大块哺乳动物的肋骨碎片。猛犸象股骨之前被用作修图工具，这可以从印痕和切割痕迹上看出来。在北极狐头盖骨上发现了切口，表明是剥皮。根据2个14C测年，确定其年龄为19.3 ~ 19.1 ka BP。对空腔填充物的孢粉学分析表明，当时是一个杂草草原。这一组合，没有已知的类似物，是史前文化的反映。这一非凡的发现很可能是最后一次冰川高峰时期居住在西伯利亚西部南部的人们仪式行为的证据。这一组合伴随着大量的狐狸遗骸，以及与西伯利亚和乌拉尔中部旧石器时代晚期以刀片为基础的石器制品。
{"title":"The unique Late Paleolithic artifactual bone assemblage from the Volchia Griva site, Western Siberia","authors":"S. Leshchinskiy, V. N. Zenin, E. M. Burkanova, Y. Kuzmin","doi":"10.1017/qua.2023.4","DOIUrl":"https://doi.org/10.1017/qua.2023.4","url":null,"abstract":"Abstract In 2020, a unique bone assemblage was found at the Late Paleolithic site Volchia Griva. Its base is made of a distal mammoth femur minus epiphysis, in which a cavity has been hollowed out. Impact notches along the edges of the cavity and holes in the metaphysis prove the human-made nature of this specimen. A portion of a polar fox cranium, half of a fox hemimandible, a fox tooth, and a large mammal rib fragment were enclosed in the cavity. The mammoth femur was previously used as a retoucher, as evinced by the impressions and cut marks. Incisions were detected on the polar fox cranium, indicating skinning. According to two 14C dates, the age of the remains is 19.3–19.1 ka BP. Palynological analysis of the cavity fill shows a forb-grass steppe at that time. The assemblage, which has no known analogues, is a reflection of prehistoric culture. This extraordinary find most likely is evidence of the ritual behavior of people who lived in the south of Western Siberia during the last glacial maximum. The assemblage was accompanied by a large number of fox remains, and lithic artifacts identical to bladelet-based Late Paleolithic industries of Siberia and the Middle Urals.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48405081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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