Pleistocene landscapes in central Iberia inferred from pollen analysis of hyena coprolites     

J. S. Carrin  L. Scott  A. Arribas  N. Fuentes  G. Gil‐Romera  E. Montoya 《第四纪科学杂志》2007,22(2):191-202

New pollen data from hyena coprolites from central Spain are presented. The fossil faecal material has been recovered from two karstic systems in different localities, Villacastín and Los Torrejones, which are both around 1000 m a.s.l. The combined findings of bone remains and coprolites in both locations suggest the following chronology: late Middle Pleistocene for Villacastín and early Upper Pleistocene for Los Torrejones. The environments inferred from pollen are broadly in keeping with evidence from associated vertebrate fossil remains, and include a shifting mosaic of open and wooded habitats with abundant pine and juniper species, steppe‐grassland areas with composites and chenopods, and enclaves with mixed oak forests. However, Los Torrejones appears to have been less forested than Villacastín. The abundance of oaks in Villacastín may imply the presence of refugia within an interconnected network of several enclaves during the glacial stages in the Upper Pleistocene. A possible explanation for the patchiness of the landscape may be in the role of herbivores, although the long distances and variety of habitats that hyenas had to roam through could be another explanation for the heterogeneous pollen contents in their dung. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Holes in the spinous processes of woolly mammoth vertebrae: spatial and temporal distribution,and the causes of pathology formation     

Sergey V. Leshchinskiy  Yaroslav V. Kuzmin  Mathieu Boudin  Leeli Amon 《第四纪科学杂志》2021,36(7):1254-1267

The latest data on holes in the spinous processes of the vertebrae of woolly mammoths, a rare pathology, are presented. This was identified at 19 sites of northern Eurasia. Such destructive changes are recorded ca. 34–12k ¹⁴C a bp , and only two sites dated to >50k and >41k ¹⁴C a bp. The main hypotheses about hole formation are: vertebral abnormalities; bone infections; genetic traits; and unfavourable geochemical environment. The pathology occurred in mammoths of all age groups, and could have arisen at the embryonic stage. There are two types: classic holes associated with osteolytic changes; and very rarely tumour-like lesions. The most likely cause of the lesions is alimentary osteodystrophy caused by chronic mineral starvation. The aetiology of this disease is usually associated with a deficiency or excess of macro- and microelements in the geochemical landscape, and through forage and water this leads to a severe metabolic disorder. Analysis of palaeopathological data shows two waves of geochemical stress in animals, ca. 26–18k and ca. 16–12k ¹⁴C a bp. Therefore, the woolly mammoth extinction can be viewed as a non-linear function, with two peaks of high mortality corresponding to the Last Glacial Maximum and the Lateglacial.  相似文献   

Distribution of n-alkan-2-ones in Qionghai Lake sediments,southwest China,and its potential for late Quaternary paleoclimate reconstruction     

Gen Wang  Yongli Wang  Zhifu Wei  Wei He  Ting Zhang  Xueyun Ma  Xiaoli Yu 《第四纪科学杂志》2021,36(2):288-297

Studies on long-chain n-alkan-2-ones from lake sediments remain sparse. In this study, we present an n-alkan-2-one record from Qionghai Lake, southwest China, to assess the paleoclimate significance of variations in their compositions. A homologous series of n-alkan-2-ones ranging from C₂₁ to C₃₅ were identified, with maximum concentrations of the C₂₉ or C₃₁ chain lengths and a strong odd-over-even predominance. This type of n-alkan-2-one is considered to derive mainly from microbial oxidation of the corresponding n-alkanes, and partial inputs from plants. The n-alkan-2-one-derived average chain length (ACL) and carbon preference index (CPI) values changed significantly over the past 28k cal a bp , consistent with the sediment grain size and n-alkane proxies from the same core. Generally, the high CPI_27-33-ket and low ACL_27-33-ket values indicated cold and dry climates such as for the Last Glacial Maximum (23.2–19.7k cal a bp ), Heinrich 1 event (17.6–15.6k cal a bp ) and Younger Dryas (12.8–11.6k cal a bp ), but low CPI_27-33-ket and high ACL_27-33-ket values denoted a warm and humid Holocene Climatic Optimum (7.0–4.3k cal a bp ). Therefore, n-alkan-2-ones have great paleoclimatic potential and can be applied together with other biomarkers to reconstruct a reliable paleoclimate record in lake sediments.  相似文献   

Preliminary investigation of Late Pleistocene fauna from Ryonggok Cave No. 1, Sangwon County,North Hwanghae Province,Democratic People's Republic of Korea     

Rye Sun Choe  Kum Sik Han  Se Chan Kim  Myong Hyok Ri  Jae Nam Ri 《第四纪科学杂志》2021,36(6):1137-1142

The investigation of a limestone cave on the Ryonggok-ri of Sangwon County, North Hwanghae Province, DPRK, has yielded many faunal remains including Late Pleistocene deer, brown bears and horses. Uranium series dating of fossil teeth yielded dates of ~72ka at the base of Layer 2 – the bone-bearing unit – and ~44ka at the top. The rich and diverse mammal remains of Ryonggok Cave No. 1 are indicative of warm and humid temperate conditions during the Late Pleistocene, and reflect the presence of both dense forests and open grassland. In addition, pollen and spores from the site include two families and 24 genera of trees, six families and a genus of grasses and herbs, and two families and six genera of ferns, corroborating the environments inferred from the faunal remains.  相似文献   

The use of iron chemical analysis of podzols to date the Late Pleistocene–Holocene deglaciation history of the Central Italian Alps     

Alessandro Longhi  Damiano Monticelli  Mauro Guglielmin 《第四纪科学杂志》2020,35(8):1021-1035

Podzols that have developed on glacial and periglacial features provide the opportunity to reconstruct glacial evolution after the Last Glacial Maximum (LGM) using different soil indices. Analysing 17 soils classified as podzol, we used the crystallinity ratio of free iron oxides (CRF) on both the A and Bs horizons, and absolute ages for the same landforms containing the soil profile, to create dating curves. Two equations were generated: age = 4566.9 × ln (CRF) + 1760 (1), and age = 3907 × ln (CRF) + 3508.2 (2). The reliability of the curves was evaluated with the Fe_o/Fe_d ratio, and with the difference of ages calculated using both equations. Equation (2) is considered more reliable because the A horizon may be influenced by new pedogenesis on the pre-existing podzol, leading to the development of a new type of soil. By dating the soils, we reconstructed the glacial history of the three main upper branches of the LGM Adda Glacier in the Central Italian Alps, specifically the Stelvio Pass area (ST), Gavia Pass area (GV), and the Val Viola valley (VV). Seven glacial advances were identified at 16.7–14.7 ka (phase I), 12.3 ka (phase II), 11 ka (phase III), 10–9.7 ka (phase IV), 9 ka (phase V), 7.5 ka (phase VI) and 5.3 ka (phase VII). The first five phases are chronologically similar to the main Late Pleistocene–Early Holocene phases recorded in the Central European Alps. The last two Holocene phases, which are both longer in duration than the Little Ice Age, are recorded in ST and GV. Interestingly, these phases generally are not recorded in the rest of the Central European Alps, where the late Holocene glaciers were smaller than their present size.  相似文献   

New insights into a late-Pleistocene human occupation in America: The Vale da Pedra Furada complete chronological study     

《Quaternary Geochronology》2015

Within the framework of the studies focusing on the Pleistocene peopling of the Americas, our French-Brazilian team has undertaken a pluridisciplinary research on different archaeological sites, inside and in the neighborhood of the Serra da Capivara National Park, in Brazilian Nordeste. The present study regards an archaeological site, Vale da Pedra Furada, situated in the Piauí state in Brazil. The results of technological and functional studies suggest the existence of different successive human occupations during the Pleistocene in this region. Moreover, the geological and geomorphological studies shed new light on our understanding of sedimentary processes and confirm that the levels were not subject to any significant post-depositional processes. This is also confirmed by macro- and micro-analysis of quartz artefact surfaces. The chronological study has recently been completed employing both radiocarbon and luminescence techniques; radiocarbon dates were obtained on charcoal, multi-grain and single-grain OSL ages on sedimentary quartz grains. The results obtained with the different methods are consistent with each other: the most recent archaeological level is dated to around 8 ka and the oldest to 24 ka, indicating the open-air site of Vale da Pedra Furada to be a succession of human occupations beginning from OIS 2. These results are discussed in the context of some archaeological sites studied in the Serra da Capivara National Park of the last few decades.  相似文献   

Magnetostratigraphy of the Plio‐Pleistocene carbonate section of the Great Australian Bight     

M. Fuller  R. Molina-Garza  M. Antretter  F. Lichowski 《Australian Journal of Earth Sciences》2013,60(3):447-466

ODP Leg 182 drilled two north‐south transects in the western Great Australian Bight close to longitude 128°E. These transects penetrated a remarkably thick section of uppermost Pliocene and Pleistocene carbonate sediments, which are separated from Miocene sections by a major hiatus. In the eastern transect, at sites 1129, 1131 and 1127, the Brunhes‐Matuyama boundary (onset of C1n) was found at 343 m, between 280 and 300 m, and at 343 m below the sea floor, respectively. In the western transect, at sites 1132 and 1130, it was found between 170 and 181 m, and at 200 m, respectively. Within the Brunhes chron, inclination and intensity fluctuations and correlations between susceptibility and standard δ¹⁸O records were used to give age‐depth relations. These age relations from the palaeomagnetics are broadly consistent with the biostratigraphy and the δ¹⁸O results from Leg 182, but do not provide an entirely independent dataset. Rock magnetism stratigraphy at site 1131 revealed the principal bryozoan buildup to be at the time of the last glacial lowstand, as suggested by previous workers. At all sites the sedimentation rate increases from the basal unconformity up into the thick Upper Pleistocene section. In the western transect there appears to be a partial record of most of the Late Pliocene and Early Pleistocene chron boundaries (C1r1n to C2An3n) in a condensed section, but in the eastern transect only the Jaramillo (C1r1n) is observed.  相似文献   

The Campo Felice late Pleistocene Glaciation (Apennines,central Italy)     

Carlo Giraudi 《第四纪科学杂志》2012,27(4):432-440

Study of the glacial deposits and lacustrine sediments of Campo Felice (Apennines, central Italy) has enabled the glacial phases of the last 40 ka to be dated more precisely, and has demonstrated that the maximum glacial advance did not occur in correspondence with the last global glacial maximum and with the coldest and most arid phase suggested by the pollen, but in a period dated between about 33 and 27 ka, characterized by a less extreme climate. Furthermore, a glacial expansion took place also in the period prior to 35 ka. Correlation with the Alpine glacial variations has shown that the Apennine last glacial maximum occurred before that of the southern slope of the Alps. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

雅鲁藏布江中游晚更新世古堰塞湖群的时空关系探讨     

胡海平  冯金良  刘金花  陈锋 《冰川冻土》2022,44(4):1298-1305

雅鲁藏布江中游堵江事件多发,探索堵江事件之间的关系对理解河流地貌演化有着重要作用。在中游宽谷地区,众多河流堆积阶地中保存着古堰塞湖相沉积物。前人对林芝地区、泽当宽谷和日喀则宽谷的古湖相沉积进行了较为深入的研究,三个宽谷在晚更新世均发育过古堰塞湖,但三个地区古堰塞湖之间的时空关系仍未可知。在上述基础上,对雅鲁藏布江中游不同河段古堰塞湖的坝体位置、成因、海拔及发育年代等进行总结分析。归纳出在雅鲁藏布江中游宽谷河段分别发育着3个独立的古堰塞湖,成因多为冰川/冰碛物堵江。晚更新世不同河段降水和地貌条件差异,冰川规模变化速率不同,可能导致冰川前进壅塞河道时间不一致;但3个古堰塞湖的消亡时间较为接近,其溃决过程可能存在关联。  相似文献   

A Middle Pleistocene Glaciation Record from Lacustrine Sediments in the Western Tibetan Plateau and Discussion on Climate Change     

ZHAO Zhenming  JI Wenhu  FU Chaofeng 《《地质学报》英文版》2023,97(2):623-635

The Tibetan Plateau is an important area for studying global climate change, but the answers to many scientific problems remain unknown. Here, we present new information from the lacustrine sedimentary record in the western Tibetan Plateau, related to the third most-recent glaciations. Continuous sediment data, including sporopollen, particle size, total organic carbon, mass susceptibility, CaCO3, CaSO4, BaSO4 contents and chronological data, were reconstructed and revealed that climate and environmental conditions obviously and distinctly changed between 600 and 700 thousand years ago. In comparison, the data obtained from the Guliya ice core in this area also corresponds to the global glacial climatic characteristics recorded in basin sediments in the eastern and southeastern regions of the plateau and to the information obtained from ice cores in the Antarctic and Arctic regions. In this study, we conclude that the main reason for the glaciations and new tectonic movement must be a geomagnetic polarity reversal 774 thousand years ago (from Matuyama to Brunhes). Indeed, the results of this study suggest that the described reversal event might have influenced the current global climate pattern and will continue to impact climatic changes in the future.  相似文献