Claude Hillaire‐MarcelPaul G. MyersShawn MarshallLev Tarasov...
9页
查看更多>>摘要：ABSTRACT The Arctic Ocean is one of the last frontiers on Earth with many unknowns about its geological and climate history and considerable speculation on its role in the Earth's climate and ocean system. It has been proposed recently that it was occupied by a freshwater body of more than 9.5 × 106 km3 underneath a thick ice mass during part of glacial isotopic stages 6 and 4. We argue that such a dramatic scenario, implying replacement of marine waters by freshwater throughout the entire Arctic Ocean and Nordic Seas, is physically implausible. The very low 230Th excesses (230Thxs) observed in sediments from these intervals were used as evidence for the presence of a U‐depleted overlying freshwater column. We show here that they may simply result from short, sporadic sedimentary pulses, below multiyear sea ice or ice shelves, linked to deglacial ice streaming and surging events interrupting long‐duration sedimentary gaps. Due to this sporadic sedimentation regime, interpolating time from 230Thxs data or between benchmark ages in sedimentary sequences would simply be erroneous.
查看更多>>摘要：ABSTRACT Hillaire‐Marcel et al. bring forward several physical and geochemical arguments against our finding of an Arctic glaciolacustrine system in the past. In brief, we find that a physical approach to further test our hypothesis should additionally consider the actual bathymetry of the Greenland–Scotland Ridge (GSR), the density maximum of freshwater at 3–4°C, the sensible heat flux from rivers, and the actual volumes that are being mixed and advected. Their geochemical considerations acknowledge our original argument, but they also add a number of assumptions that are neither required to explain the observations, nor do they correspond to the lithology of the sediments. Rather than being additive in nature, their arguments of high particle flux, low particle flux, export of 230Th and accumulation of 230Th, are mutually exclusive. We first address the arguments above, before commenting on some misunderstandings of our original claim in their contribution, especially regarding our dating approach.
查看更多>>摘要：ABSTRACT The buried soil above the Goodwood‐Slindon Raised Beach running along the foot of the South Downs (Sussex) is one of the most extensive Lower Palaeolithic land surfaces known. It extends for 16?km but exposures are limited to Boxgrove, the focus of archaeological excavations since the 1980s, and Valdoe, 4.8?km to the west. The palaeosol yielded vertebrates suggesting attribution to Marine Isotope Stage (MIS) 13 and land snails important in the reconstruction of local environments. Important differences exist between the molluscan assemblages from Valdoe and Boxgrove. An extinct land snail Retinella (Lyrodiscus) elephantium, previously known in Britain only from MIS 11, occurred at Valdoe at unusually high frequencies in assemblages poor in woodland species, prompting a reappraisal of its stratigraphical and ecological significance. Conversely, Spermodea lamellata, a woodland species present at Boxgrove, was absent at Valdoe. This lateral variability results both from the original heterogeneity of the environment, and from differential preservation resulting from decalcification and erosion. Calcitic slug plates are over‐represented (>50% of the molluscan fauna) in decalcified sediments where shells composed of aragonite are rare. These considerations, and comparisons with modern and fossil assemblages, have led to more nuanced reconstructions of the landscape occupied by early humans in southern England ~500?ka ago.
查看更多>>摘要：Abstract Megacarnivore behaviours shape ecological dynamics between their prey and competitors and therefore play a key role in structuring ecosystems. In Late Pleistocene Eurasia, hominins and hyenas were sympatric predators. Since the first discoveries of Crocuta c. spelaea in the 19th century, this ‘bone‐crushing’ species has been identified at most Palaeolithic sites and has inspired many taphonomic studies. Nonetheless, there is still very little known about its reproductive, social and spatial behaviours. We believe that exploring the complexity of the cave hyena's ethology is a way to better understand spatial relationships and niche sharing/partitioning between hominins and other top predators in Pleistocene ecosystems. This paper focuses on the study of Caverne Marie‐Jeanne Layer 4 (Hastière, Belgium), one of the best‐preserved palaeontological sites in the region. The exceptional number of hyena neonates in this assemblage (minimum number of individuals >300) has led us to describe, for the first time, a Late Pleistocene hyena birth den that was reused over a long period of time around 47.6–43k a bp. By bridging the gap between archaeology and palaeontology, we explore the potential of carnivore socio‐spatial organisation and denning habits as an ecological proxy and discuss how these new unique data could help us further understand hominins’ spatial strategy in southern Belgium.
Nimrod MaromIgnacio A. LazagabasterRoee ShafirFilipe Natalio...
27页
查看更多>>摘要：ABSTRACT The Middle Pleistocene archaeological record of the southern Levant has proven key to understanding human evolution and intercontinental faunal biogeography. Knowledge of archaeological sites of that period in the southern Levant is biased, with most Middle Pleistocene localities in the Mediterranean areas in the north, despite the mosaic of environments that mark the entire region. A key Middle Pleistocene location in the Judean Desert – on the eastern margin of the Mediterranean zone – is the site of Oumm Qatafa, excavated in the early 1900s, which yielded a faunal collection spanning an estimated time period of 600–200?kya. Here, we present a revised taxonomy of the macromammalian fauna from the site, discuss the palaeoenvironmental implications of this assemblage, and relate the finds to other Pleistocene sites from the Levant. These data enable a more precise palaeoenvironmental reconstruction which attests to an open landscape, but with the addition of a mesic Mediterranean component close by. In addition, detailed taphonomic observations on butchery marks and Fourier transform infrared spectroscopy analysis of burnt bone link the fauna for the first time to anthropogenic activities in the cave.
查看更多>>摘要：ABSTRACT We studied Viperidae remains from Qafzeh Cave, Israel, to understand past dispersal timing and range expansion of Afro‐Arabian taxa to the Southern Levant during the early Late Pleistocene (Marine Isotope Stage 5). A total of 62 African adder (Bitis) snake remains were retrieved from multiple layers at Qafzeh Cave, alongside five non‐Bitis ‘Oriental viper’ taxa vertebrae. These are the only available specimens of Bitis ever reported in the Southern Levant. The morphology of the maxilla and vertebrae corresponds well to that of the Bitis arietans complex. Qafzeh Cave thus becomes the northernmost boundary of the B. arietans complex expansion ever recorded outside Africa. The unprecedented occurrence of Bitis at Qafzeh Cave, in conjunction with other archaeozoological evidence at the site, attest to exceptional climatic and environmental conditions in the surroundings of the cave during the Mousterian Homo sapiens occupations. It reinforces previous evidence for taxa expanding from sub‐Saharan Africa to the Mediterranean biome of the Southern Levant through the now hyper‐arid Saharo‐Arabian desert belt. The environmental conditions following deposition of the early Late Pleistocene layers were probably not favourable for the establishment of the snake, and eventually the B. arietans complex became locally extirpated.
Ignacio A. LazagabasterNatalia égüezMicka UllmanRoi Porat...
13页
查看更多>>摘要：ABSTRACT Long temporal records of Holocene wild mammal communities are essential to examine the role of human impacts and climatic fluctuations in the configuration of modern ecosystems. We show that such records can be assembled through extensive radiocarbon dating of faunal remains obtained from biogenic cave deposits. We dated 110 mammalian remains from 19 different cave sites in the Judean Desert. We use the dates in combination with archaeological survey data and bone collagen/apatite δ13C values to study faunal succession in the context of Holocene climate change and human settlement history in the region. Our results suggest a change in the late Holocene, expressed in fewer observations of Arabian leopard (Panthera pardus nimr) and gazelle (Gazella spp.), and an increase of Syrian striped hyena (Hyaena hyaena syriaca), fox (Vulpes spp.), Nubian ibex (Capra nubiana) and rock hyrax (Procavia capensis); suids (Sus scrofa) appear for the first time. According to the data distribution, however, the probability of finding a bone diminishes exponentially with time, which implies that the Judean Desert cave paleozoological record is temporally biased. The weight of evidence ultimately favors an explanation of the observed patterns as the consequence of a combined anthropogenic and climatic impact on local food webs.
Charlotte HoniatDaniela FestiPaul S. WilcoxR. Lawrence Edwards...
13页
查看更多>>摘要：Abstract In the European Alps, the Last Interglacial (LIG, ~129–116?ka) has been primarily studied using pollen preserved in mires and lake sediments. These records document the vegetation succession across the LIG, but are poorly constrained chronologically. Here, we present a precisely dated stable isotope record for the early LIG (129.6?±?0.4 to 125.0?±?0.8?ka) based on two stalagmites from Katerloch, a cave located on the south‐eastern side of the Alps. The onset of the interglacial is marked by a sharp rise in the oxygen isotope values at 129.4?±?0.4?ka, consistent within dating uncertainty with the timing of Termination II as recorded by other Alpine speleothems. Carbon isotope values show an equally prominent drop at Termination II and the establishment of a forest ecosystem. Although concentrations are low, pollen from these stalagmites provide insights into how the local vegetation changed across the first five millennia of the LIG. The spectra indicate a vegetation optimum recorded by the occurrence of warm‐demanding taxa typical of the Eemian mesocratic phase. By combining stable isotopes and pollen data, we propose an absolutely dated chronological framework for peri‐Alpine pollen successions from lacustrine sediments covering the first half of the LIG.
Andreas W?lflerAndrea HampelArmin DielforderRalf Hetzel...
11页
查看更多>>摘要：Abstract Compared with the western European Alps, the ice extent during the Last Glacial Maximum (LGM) and the subsequent deglaciation history of the eastern Alps east of the Tauern Window remain less well constrained. Also, considerable discrepancies exist between the mapped LGM ice margin and the ice extent predicted by ice‐sheet models. Here we present the first 10Be surface exposures ages from two regions east of the Tauern Window (the Gurktal and Lavantal Alps), which provide constraints on the LGM ice extent and the deglaciation history. Our results show that the deglaciation of the Gurktal Alps occurred between 16 and 14 ka, which agrees with the predictions from ice‐sheet models. In contrast, the 10Be ages from the Lavantal Alps located farther east are either LGM in age or predate the LGM, indicating that these regions were ice free or only partially covered by LGM ice. This finding suggests that ice‐sheet models may have overestimated the LGM ice extent in the easternmost Alps. In conclusion, our study highlights the need for more age data from the eastern Alps to refine the location of the LGM ice margin and the deglaciation history, which is also crucial for climate‐evolution and postglacial‐rebound models.
Canh Tien Trinh NguyenPatrick MossRobert J. WassonPhilip Stewart...
13页
查看更多>>摘要：Abstract Our examination of pollen, microcharcoal, and sediment material in Nee Soon Freshwater Swamp Forest in Singapore revealed the following regarding its more than 20 000‐year history: (1) the pollen record supports the presence of a savanna corridor in this part of South‐East Asia during the Last Glacial Maximum (LGM); (2) a high abundance of charcoal at depths greater than 1.5?m supports the existence of a dryer climate and/or more frequent fires until about 18 000?cal? bp; (3) missing sedimentary material in the upper 30–40?cm, ranging in age from 64 to 7500?cal? bp, was likely removed during recent construction work in the 1950s; (4) there is evidence of sea‐level influences on the site from the presence of mangroves from 9000?cal? bp to present but it is difficult to determine whether this impacted the site because of the missing sediments; and (5) the low organic carbon content throughout the stratigraphy indicates that the swamp is not a peatland. The results indicate that the forest in this protected area of Singapore developed from a grassland‐dominated landscape after the LGM as the climate warmed and became wetter, and therefore, may not be as resilient to long‐term drought conditions as previously believed. Further, the stratigraphy contains evidence that the swamp and stream system have been highly dynamic, both naturally and in response to anthropogenic disturbance.
NSTL
Wiley