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Late Pleistocene (late + pleistocene)
Selected AbstractsGenetic diversity of endangered brown bear (Ursus arctos) populations at the crossroads of Europe, Asia and AfricaDIVERSITY AND DISTRIBUTIONS, Issue 5 2009Sébastien Calvignac Abstract Aim, Middle East brown bears (Ursus arctos syriacus Hemprich and Ehrenberg, 1828) are presently on the edge of extinction. However, little is known of their genetic diversity. This study investigates that question as well as that of Middle East brown bear relationships to surrounding populations of the species. Location, Middle East region of south-western Asia. Methods, We performed DNA analyses on 27 brown bear individuals. Twenty ancient bone samples (Late Pleistocene to 20th century) from natural populations and seven present-day samples obtained from captive individuals were analysed. Results, Phylogenetic analyses of the mitochondrial sequences obtained from seven ancient specimens identify three distinct maternal clades, all unrelated to one recently described from North Africa. Brown bears from Iran exhibit striking diversity (three individuals, three haplotypes) and form a unique clade that cannot be linked to any extant one. Individuals from Syria belong to the Holarctic clade now observed in Eastern Europe, Turkey, Japan and North America. Specimens from Lebanon surprisingly appear as tightly linked to the clade of brown bears now in Western Europe. Moreover, we show that U. a. syriacus in captivity still harbour haplotypes closely linked to those found in ancient individuals. Main conclusion, This study brings important new information on the genetic diversity of brown bear populations at the crossroads of Europe, Asia and Africa. It reveals a high level of diversity in Middle East brown bears and extends the historical distribution of the Western European clade to the East. Our analyses also suggest the value of a specific breeding programme for captive populations. [source] A comparative analysis of the habitat of the extinct aurochs and other prehistoric mammals in BritainECOGRAPHY, Issue 2 2008Stephen J. G. Hall The present study tests the hypothesis that the habitat of the globally extinct aurochs Bos primigenius was primarily riverine flat-lands. Landscape features in Britain were analyzed for sites with Late Pleistocene and postglacial finds of aurochs (n=188), and, for comparison, wolf (101), brown bear (96), red deer (73), beaver (68), roe deer (46) and moose (23). Find sites were defined as Ordnance Survey 1 km map squares containing 1 or more finds. For each, spot height above sea level, heights of contour lines, flatness of terrain, total length of watercourses, and presence of woods, rock and water features were noted. Comparisons of find sites among species (Kruskal-Wallis test) show significant differences that accord with knowledge of present-day habitat preferences at the landscape level. Considering the species separately each find site was then compared with a randomly selected control map square within 10 km. Compared with their respective control squares, find sites of beaver have, today, a stronger association with presence of lakes; those of brown bear and wolf with presence of cliffs and rock outcrops; and those of aurochs with absence of woodland and with lower elevation and greater flatness. The concordance of these findings with the present-day habitats of the extant species suggests valid inferences can be made about the habitat preference of the extinct aurochs. On this basis the aurochs appears, as hypothesized, to have selected low-lying, flat ground, which (indicated by its present-day use for purposes other than woodland) was relatively fertile. [source] Rockshelter sedimentation in a dynamic tropical landscape: Late Pleistocene,Early Holocene archaeological deposits in Kitulgala Beli-lena, southwestern Sri LankaGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2009Nikos Kourampas Kitulgala Beli-lena, a rockshelter in gneiss in humid tropical southwestern Sri Lanka, was inhabited by Late Pleistocene,Early Holocene (>31,000,7880 B.P.) hunter-gatherers who made geometric microliths and exploited rainforest resources. Micromorphological analysis of a ca. 3-m-thick succession of diamictic loams, clays, and breccia with cultural content suggests that relative contribution of episodic colluviation and roof fall, water seepage through joints and diverse human activity varied through time. Facies changes across the profile reflect monsoon weakening ca. 20,000,16,000 cal B.P. and abrupt intensification ca. 15,700 cal B.P., on the wane of the global Last Glacial Maximum (LGM). Post-depositional modification included clay, sesquioxide, and minor phosphate translocation; termite and other arthropod bioturbation; and clast weathering on the rockshelter floor. Human input (tools and tool-making refuse, reworked charcoal and associated combustion by-products) is markedly higher in sediments younger than ca. 15,700 cal B.P., suggesting intensification of site use immediately after the LGM. © 2009 Wiley Periodicals, Inc. [source] Late Pleistocene and Early Holocene lake-level fluctuations in the Lahontan Basin, Nevada: Implications for the distribution of archaeological sitesGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 5 2008Kenneth D. Adams The Great Basin of the western U.S. contains a rich record of Late Pleistocene and Holocene lake-level fluctuations as well as an extensive record of human occupation during the same time frame. We compare spatial-temporal relationships between these records in the Lahontan basin to consider whether lake-level fluctuations across the Pleistocene-Holocene transition controlled distribution of archaeological sites. We use the reasonably well-dated archaeological record from caves and rockshelters as well as results from new pedestrian surveys to investigate this problem. Although lake levels probably reached maximum elevations of about 1230,1235 m in the different subbasins of Lahontan during the Younger Dryas (YD) period, the duration that the lakes occupied the highest levels was brief. Paleoindian and Early Archaic archaeological sites are concentrated on somewhat lower and slightly younger shorelines (_1220,1225 m) that also date from the Younger Dryas period. This study suggests that Paleoindians often concentrated their activities adjacent to large lakes and wetland resources soon after they first entered the Great Basin. © 2008 Wiley Periodicals, Inc. [source] Distinguishing between naturally and culturally flaked cobbles: A test case from Alberta, CanadaGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 7 2004Jason David Gillespie Distinguishing between naturally and culturally produced, simply flaked cobbles has been a problem for proponents of a pre-Clovis occupation in the Americas. Several sites in Alberta have been assigned a pre-Clovis status based on the presence of simply flaked cobbles found in Late Pleistocene till deposits. Historically, these types of assemblages have been assigned a cultural status based on subjective criteria and appeals to the analyst's expertise. To determine the archaeological status of two such assemblages from Alberta (Varsity Estates and Silver Springs), they were compared to a known natural assemblage and two known cultural assemblages. Chi-square testing was used to evaluate several lithic attributes. Only those attributes that statistically differentiated between natural and cultural assemblages were used for further analyses. All cobbles were then scored using these attributes. A point was awarded when a statistically significant attribute of human-manufacture was present. These points were then totaled, providing an aggregate score for each cobble. These scores were plotted to determine whether the test assemblages had closer affinities with the known natural or known cultural assemblages. The results indicate that the proposed pre-Clovis assemblages have closer affinities to known natural assemblages than to cultural assemblages. Our results suggest that these sites provide no evidence for a pre-Clovis occupation in the Americas. © 2004 Wiley Periodicals, Inc. [source] Tectonics and quaternary evolution of the Northern Apennines watershed area (upper course of Arno and Tiber rivers, Italy)GEOLOGICAL JOURNAL, Issue 1 2009Marco Bonini Abstract This work examines the connection between Quaternary tectonics and erosion/incision processes in the primary Tuscan-Romagna watershed of the Northern Apennines, which essentially coincides with the topographic culmination of the Nero Unit structural ridge. Tectonic and geomorphic information were collected in the area where this ridge is crossed by the upper Tiber River course forming a deep gorge. Structural analysis and field mapping have revealed that the region experienced polyphase tectonics with superposed thrust folding events identifiable both at the map and mesoscopic scales. Hinterland-SSW-verging thrusts and thrust-related folds deformed the whole thrust pile during the latest deformation phase. Backthrusts/backfolds controlled the development of intermountain basins nearby the main watershed during the Early Pleistocene and seemingly deformed, in the Tiber gorge, a low-relief landscape developed in the Early Pleistocene (ca. 1.1,Ma). Successively, the upper Tiber River course area and Apennines axial zone underwent a generalized uplift, which is manifested by the deep incision of palaeo-morphologies. This proposed sequence of events correlates well with the major geodynamic change of the Apennines revealed by an acceleration of uplift rates in the Middle,Late Pleistocene. This latter event may also correlate with increased rates of river incision recorded in Europe as a consequence of uplift and/or climate change. Copyright © 2008 John Wiley & Sons, Ltd. [source] 2001 August earthquake swarm at Shadwan Island, Gulf of Suez, EgyptGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2006Ahmed Badawy SUMMARY The earthquake swarm that struck Shadwan Island at the entrance of the Gulf of Suez in 2001 August included 408 events. Almost all of these events (94 per cent) were microearthquakes and only 6 per cent had small measurable magnitudes (5.0 > ML, 3.0). Most of the earthquakes were weak and followed each other so closely in time that they could not be identified at more distant stations. The fault plane solutions of the strongest events of the swarm show almost identical focal mechanisms, predominately normal faulting with a significant sinistral strike-slip component for nodal planes trending NW,SE. A comparison with the mechanisms of the 1969 and 1972 events which took place 20 km north of the swarm epicentral region shows similarities in faulting type and orientation of nodal planes. The azimuths of T -axes determined from focal mechanisms in this study are oriented in the NNE,SSW direction. This direction is consistent with the present-day stress field derived from borehole breakouts in the southern Gulf of Suez and the last phase of stress field changes in the Late Pleistocene, as well as with recent GPS results. The source parameters of the largest (ML, 3.0) events of the 2001 August Shadwan swarm have been estimated from the P -wave spectra of the Egyptian National Seismograph Network (ENSN). Averaging of the values obtained at different stations shows relatively similar source parameters, including a fault length of 0.65 ,L, 2 km, a seismic moment of 7.1 × 1012,Mo, 3.0 × 1014 N m and a stress drop of 0.4 ,,,, 10 bar. [source] Differential effects of past climate warming on mountain and flatland species distributions: a multispecies North American mammal assessmentGLOBAL ECOLOGY, Issue 1 2007Robert Guralnick ABSTRACT Aim, The magnitude of predicted range shifts during climate change is likely to be different for species living in mountainous environments compared with those living in flatland environments. The southern edges of ranges in mountain species may not shift northwards during warming as populations instead migrate up available elevational gradients; overall latitudinal range appears therefore to expand. In contrast, flatland species should shift range centroids northwards but not expand or contract their latitudinal range extent. These hypotheses were tested utilizing Late Pleistocene and modern occurrence data. Location, North America. Methods, The location and elevation of modern and Late Pleistocene species occurrences were collected from data bases for 26 species living in mountain or flatland environments. Regressions of elevation change over latitude, and southern and northern range edges were calculated for each species for modern and fossil data sets. A combination of regressions and anovas were used to test whether flatland species shift range edges and latitudinal extents more than mountain species do. Results, Flatland species had significantly larger northward shifts at southern range edges than did mountain-dwelling species from the Late Pleistocene to the present. There was also a significant negative correlation between the amount of change in the latitude of the southern edge of the range and the amount of elevational shifting from the Late Pleistocene to the present. Although significant, only c. 25% of the variance could be explained by this relationship. In addition, there was a weak indication that overall range expansion was less in flatland-dwelling than in mountain-dwelling species. Main conclusions, The approach used here was to examine past species' range responses to warming that occurred after the last ice ages as a means to better predict potential future responses to continued warming. The results confirm predictions of differential southern edge and overall range shifts for species occupying mountain and flatland regions in North America. The findings may be broadly applicable in other regions, thus allowing better modelling of future range and distribution related responses. [source] Disentangling the Harrisson archive to interpret the spatial and temporal distribution of vertebrate remains at Niah Caves, SarawakINTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2009P. J. Piper Abstract During the 1950s and 1960s, excavations by the Sarawak Museum at Niah Cave in northwest Borneo produced an enormous archive of records and artefacts, including in excess of 750,000 macro- and micro-vertebrate remains. The excellent state of preservation of the animal bone, dating from the Late Pleistocene (c. 40,kya) to as recently as c. 500 years ago had the potential to provide unparalleled zooarchaeological information about early hunter-gatherer resource procurement, temporal changes in subsistence patterning, and the impact of peoples on the local and regional environment in Island Southeast Asia. However, the coarse-grained methods of excavation employed during the original investigations and the sheer scale of the archaeological record and bone assemblages dissuaded many researchers from attempting to tackle the Niah archives. This paper outlines how important information on the nature of the archaeological record at Niah has now finally been extracted from the archive using a combination of zooarchaeological analysis and reference to the extensive archaeological records from the site. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sediment sequences and paleosols in the Kyichu Valley, southern Tibet (China), indicating Late Quaternary environmental changesISLAND ARC, Issue 3 2009Knut Kaiser Abstract The Tibetan Plateau is highly sensitive to environmental changes and affects the settings of a far larger territory in Central Asia and beyond. Thus, knowledge on past environmental changes in that area is essential. Even though the Kyichu (Lhasa River) Valley and its tributaries is an easily accessible area, the Late Quaternary landscape evolution of southern Tibet is in general scarcely known. Therefore, 12 sedimentary sections in the middle and lower catchment were subjected to multidisciplinary analyses (sedimentology, paleopedology, AMS 14C and luminescence dating, and charcoal determination) aiming at results on regional paleoenvironmental changes. At the altitude studied (3600,4000 m above sealevel), no glacial relics could be detected, indicating that the valley positions have been unglaciated since the Last Interglacial. The lack of fluvial,lacustrine structures above the floodplain is due to the aggradational character of this tectonically (sub-)active valley, which caused an alluvial burying of older valley bottoms. During the Late Pleistocene the mouth area of the Kyichu was occupied by a lake which was part of a larger dam-lake in the superordinate Yarlung Zhangbo Valley. On the valley flanks, loesses were predominantly deposited before the Last Glacial Maximum (LGM), whereas eolian sands were predominantly deposited around and after the LGM. Paleosols of Last Interglacial, Last Glacial and Holocene ages regularly occur at terrestrial sites representing temperate to cool and humid to semiarid conditions during soil formation. Ages of colluvial sediments indicate that the widespread barren valley slopes were primarily formed by Late Pleistocene erosion followed by a secondary Holocene erosion phase. Charcoal spectra indicate a Late Holocene change from a forest environment to a pastoral environment with sparse grasses, herbs and dwarf shrubs. It is assumed that the Late Holocene environmental changes, such as loss of forests/woodlands and erosion, have at least been reinforced by humans, enhancing a regional climatic aridification and cooling trend. [source] The ostrich in Egypt: past and presentJOURNAL OF BIOGEOGRAPHY, Issue 8 2001Nicolas Manlius Aim This article tracks the evolution of the distribution of ostrich populations, Struthio camelus L., 1758, in Egypt from the Late Pleistocene up to present times with a view to establishing a series of distribution maps for the historical period. An attempt is then made to describe and interpret these maps. Location The country considered is Egypt. Methods We compiled all the information about the presence of the ostrich in Egypt collected from the study of fossil remains, archaeological materials and from the narrative of travellers since the fourteenth century. From the accounts of these travellers, three maps showing the location of this birds in this country are established: from the end of the fourteenth century to the end of the seventeenth century; from the beginning of the eighteenth to the end of the nineteenth century; and lastly, for the twentieth century. Results The ostrich was abundant and broadly distributed in Egypt in the past. However, it has been constantly in decline. It disappeared from the north of the country and lived only in the southeast up to the end of the nineteenth century. The birds reappeared in the latter region at the beginning of the 1960s up to 1991 before disappearing from the country. Main conclusions The principal reasons for the decline of the ostrich in Egypt are the aridification caused by climatic changes and intensive hunting by humans. It is possible that this bird was not sighted in the country between the beginning of the twentieth century and the 1960s, not because it had disappeared, but most probably because it was sufficiently discrete to be noticed. But Retracer l'évolution de la distribution des populations d'autruches, Struthio camelus L., 1758, en Egypte depuis le Pléistocène final jusqu'à nos jours en vue d'établir une série de cartes de distribution pour l'époque historique. Décrire et interpréter ensuite ces cartes. Localisation Le pays considéré est l'Egypte. Méthodes Nous avons compilé toutes les informations portant sur la présence de l'autruche en Egypte, recueillies à partir de l'étude de fossiles des matériaux archéologiques, ou encore des écrits des voyageurs depuis le XIVe siècle. A partir des témoignages de ces voyageurs, trois cartes montrant la localisation de cet animal en Egypte seront établies: depuis la fin du XIVe siècle jusqu'à la fin du XVIIe siècle; depuis le début du XVIIIeà la fin du XIXe siècle; et enfin pour le XXe siècle. Résultats Dans le passé, les populations d'autruches étaient abondantes et largement répandues en Egypte. Cependant, elles n'ont pas cessé de régresser. Elles ont d'abord disparues du nord du pays pour ne plus survivre que dans le sud-est, et ce jusqu'à la fin du XIXe siècle. L'animal est reparut dans cette dernière région au début des années 1960 jusqu'en 1991, avant de disparaître du pays. Conclusions principales Les principales raisons pour lesquelles la population d'autruches a régressé en Egypte tiennent d'une aridification due à des changements climatiques ainsi qu'à une chasse outrancière par l'homme. Il est possible que cet oiseau n'aie pour ainsi dire plus été signalé dans le pays entre le début du XXe siècle et les années 1960, non parce qu'il en aurait disparu mais plutôt parce qu'il aurait su se faire suffisamment discret pour ne pas être repéré. [source] Identification of arid phases during the last 50,cal. ka BP from the Fuentillejo maar-lacustrine record (Campo de Calatrava Volcanic Field, Spain),JOURNAL OF QUATERNARY SCIENCE, Issue 7 2010Juana Vegas Abstract Geochemical (element analysis, molecular analysis of organic compounds), physical, palynological, mineralogical and sedimentary facies analysis were performed to characterise the sedimentary record in Fuentillejo maar-lake in the Central Spanish Volcanic Field of Campo de Calatrava, in order to reconstruct the palaeoenvironmental and palaeoclimatic processes which controlled vegetation patterns and deposition of different sedimentary facies. The upper 20,m of core FUENT-1 show variations in clastic input, water chemistry, vegetation and organic fraction sources in the lake throughout the Late Pleistocene and Holocene. The temporal framework provided by 14C accelerator mass spectrometry dating allows assigning the sequence to the last 50,cal. ka BP. Arid phases identified in the FUENT-1 sequence are correlated to Heinrich events (HE) and to stadials of the Dansgaard/Oeschger (D/O) cycles. Siliciclastic facies with high magnetic susceptibility values, high Juniperus pollen content, a low Paq index (aquatic macrophysics proxy index), a decrease in the relative percentage of the n -C27 and an increase in the n -C31 alkanes are indicative of arid and colder climatic events related to HE 2, HE 1 and the Younger Dryas (YD). Similar short cold and arid phases during the Holocene were identified at 9.2,8.6, 7.5,7 and 5.5,5,cal. ka BP. In dolomite,mud facies, the pollen data show an increase in the herbs component, mainly , Chenopodiaceae, Artemisia and Ephedra , steppe taxa; a low Paq index, a decrease in the relative percentage of the n -C27 alkane and an increase in the n -C31 alkane are also observed. This facies was probably the result of lower lake levels and more saline,alkaline conditions, which can be interpreted as linked to arid,warm periods. These warm and arid phases were more frequent during Marine Isotope Stage (MIS) 3 and the interstadials of MIS 2. HE 4, HE 2, HE 1 and the YD in core FUENT-1 were immediately followed by increases of warm steppe pollen assemblages that document rapid warming similar to the D/O cycles but do not imply increasing humidity in the area. Fuentillejo hydrology is controlled by changes in the atmospheric and oceanic systems that operated on the North Atlantic region at millennial scale during the last 50,cal. ka BP. Copyright © 2009 John Wiley & Sons, Ltd. [source] Late Pleistocene and Holocene glaciation of the Fish Lake valley, northeastern Alaska Range, Alaska,JOURNAL OF QUATERNARY SCIENCE, Issue 7 2009Nicolás E. Young Abstract We reconstructed a chronology of glaciation spanning from the Late Pleistocene through the late Holocene for Fish Lake valley in the north-eastern Alaska Range using 10Be surface exposure dating and lichenometry. After it attained its maximum late Wisconsin extent, the Fish Lake valley glacier began to retreat ca. 16.5,ka, and then experienced a readvance or standstill at 11.6,±,0.3,ka. Evidence of the earliest Holocene glacial activity in the valley is a moraine immediately in front of Little Ice Age (LIA) moraines and is dated to 3.3,3.0,ka. A subsequent advance culminated at ca. AD 610,900 and several LIA moraine crests date to AD 1290, 1640, 1860 and 1910. Our results indicate that 10Be dating from high-elevation sites can be used to help constrain late Holocene glacial histories in Alaska, even when other dating techniques are unavailable. Close agreement between 10Be and lichenometric ages reveal that 10Be ages on late Holocene moraines may be as accurate as other dating methods. Copyright © 2009 John Wiley & Sons, Ltd. [source] Ages and inferred causes of Late Pleistocene glaciations on Mauna Kea, Hawai'i,JOURNAL OF QUATERNARY SCIENCE, Issue 6-7 2008Jeffrey S. Pigati Abstract Glacial landforms on Mauna Kea, Hawai'i, show that the summit area of the volcano was covered intermittently by ice caps during the Late Pleistocene. Cosmogenic 36Cl dating of terminal moraines and other glacial landforms indicates that the last two ice caps, called Older Makanaka and Younger Makanaka, retreated from their maximum positions approximately 23,ka and 13,ka, respectively. The margins and equilibrium line altitudes of these ice caps on the remote, tropical Pacific island were nearly identical, which would seem to imply the same mechanism for ice growth. But modelling of glacier mass balance, combined with palaeotemperature proxy data from the subtropical North Pacific, suggests that the causes of the two glacial expansions may have been different. Older Makanaka air atop Mauna Kea was likely wetter than today and cold, whereas Younger Makanaka times were slightly warmer but significantly wetter than the previous glaciation. The modelled increase in precipitation rates atop Mauna Kea during the Late Pleistocene is consistent with that near sea level inferred from pollen data, which suggests that the additional precipitation was due to more frequent and/or intense tropical storms associated with eastward-moving cold fronts. These conditions were similar to modern La Niña (weak ENSO) conditions, but persisted for millennia rather than years. Increased precipitation rates and the resulting steeper temperature lapse rates created glacial conditions atop Mauna Kea in the absence of sufficient cooling at sea level, suggesting that if similar correlations existed elsewhere in the tropics, the precipitation-dependent lapse rates could reconcile the apparent difference between glacial-time cooling of the tropics at low and high altitudes. Copyright © 2008 John Wiley & Sons, Ltd. [source] Glacial modification of granite tors in the Cairngorms, Scotland,JOURNAL OF QUATERNARY SCIENCE, Issue 8 2006A. M. Hall Abstract A range of evidence indicates that many granite tors in the Cairngorms have been modified by the flow of glacier ice during the Pleistocene. Comparisons with SW England and the use of a space,time transformation across 38 tor groups in the Cairngorms allow a model to be developed for progressive glacial modification. Tors with deeply etched surfaces and no, or limited, block removal imply an absence of significant glacial modification. The removal of superstructure and blocks, locally forming boulder trains, and the progressive reduction of tors to stumps and basal slabs represent the more advanced stages of modification. Recognition of some slabs as tor stumps from which glacial erosion has removed all superstructure allows the original distribution of tors to be reconstructed for large areas of the Cairngorms. Unmodified tors require covers of non-erosive, cold-based ice during all of the cold stages of the Middle and Late Pleistocene. Deformation beneath cold-based glacier ice is capable of the removal of blocks but advanced glacial modification requires former wet-based glacier ice. The depth of glacial erosion at former tor sites remains limited largely to the partial or total elimination of the upstanding tor form. Cosmogenic nuclide exposure ages (Phillips et al., 2006) together with data from weathering pit depths (Hall and Phillips, 2006), from the surfaces of tors and large erratic blocks require that the glacial entrainment of blocks from tors occurred in Marine Isotope Stages (MIS) 4,2, 6 and, probably, at least one earlier phase. The occurrence of glacially modified tors on or close to, the main summits of the Cairngorms requires full ice cover over the mountains during these Stages. Evidence from the Cairngorms indicates that tor morphology can be regarded as an important indicator of former ice cover in many formerly glaciated areas, particularly where other evidence of ice cover is sparse. Recognition of the glacial modification of tors is important for debates about the former existence of nunataks and refugia. Copyright © 2006 John Wiley & Sons, Ltd. [source] A record of Late Pleistocene and Holocene carbon accumulation and climate change from an equatorial peat bog (Kalimantan, Indonesia): implications for past, present and future carbon dynamicsJOURNAL OF QUATERNARY SCIENCE, Issue 7 2004S. E. Page Abstract A 9.5,m core from an inland peatland in Kalimantan, Indonesia, reveals organic matter accumulation started around 26,000,cal.,yr,BP, providing the oldest reported initiation date for lowland ombrotrophic peat formation in SE Asia. The core shows clear evidence for differential rates of peat formation and carbon storage. A short period of initial accumulation is followed by a slow rate during the LGM, with fastest accumulation during the Holocene. Between ,13,000 and 8000,cal.,yr,BP, >,450,cm of peat were deposited, with highest rates of peat (>,2,mm,yr,1) and carbon (>,90,g,C,m,2,yr,1) accumulation between 9530 and 8590,cal.,yr,BP. These data suggest that Kalimantan peatlands acted as a large sink of atmospheric CO2 at this time. Slower rates of peat (0.15,0.38,mm,yr,1) and carbon (7.4,24.0,g,C,m,2,yr,1) accumulation between ,8000 and 500,cal.,yr,BP coincide with rapid peat formation in coastal locations elsewhere in SE Asia. The average LORCA (long-term apparent carbon accumulation rate) for the 9.5,m core is 56,g,C,m,2,yr,1. These data suggest that studies of global carbon sources, sinks and their dynamics need to include information on the past and present sizeable peat deposits of the tropics. Copyright © 2004 John Wiley & Sons, Ltd. [source] Late Quaternary vegetation changes around Lake Rutundu, Mount Kenya, East Africa: evidence from grass cuticles, pollen and stable carbon isotopesJOURNAL OF QUATERNARY SCIENCE, Issue 1 2003Dr M. J. Wooller Abstract Woody, subalpine shrubs and grasses currently surround Lake Rutundu, Mount Kenya. Multiple proxies, including carbon isotopes, pollen and grass cuticles, from a 755-cm-long core were used to reconstruct the vegetation over the past 38 300 calendar years. Stable carbon-isotope ratios of total organic carbon and terrestrial biomarkers from the lake sediments imply that the proportion of terrestrial plants using the C4 photosynthetic pathway was greater during the Late Pleistocene than in the Holocene. Pollen data show that grasses were a major constituent of the vegetation throughout the Late Pleistocene and Holocene. The proportion of grass pollen relative to the pollen from other plants was greatest at the last glacial maximum (LGM). Grass cuticles confirm evidence that C4 grass taxa were present at the LGM and that the majority followed the cold-tolerant NADP-MEC4 subpathway. Copyright © 2003 John Wiley & Sons, Ltd. [source] Late Pleistocene and Holocene whale remains (Cetacea) from Denmark and adjacent countries: Species, distribution, chronology, and trace element concentrationsMARINE MAMMAL SCIENCE, Issue 2 2010Kim Aaris-Sørensen Abstract We describe and review the subfossil whale bones (mammalian order Cetacea) material from the southern Scandinavian area, that is, Skagerrak, Kattegat, the inner Danish waters and the southwestern Baltic Sea. Fifteen species were identified from the subfossil records of which all, except for the bowhead whale (Balaena mysticetus), have also been encountered in the modern times. Fifty-one specimens were radiocarbon dated covering 12 of the subfossil species. The dates fell in three distinct clusters with a few specimens before the last glacial maximum (LGM), a large group between LGM and the Pleistocene/Holocene boundary (ca. 17.0,11.7 cal. kyr BP), and another large group from ca. 8.0 cal. kyr BP onward. Seventeen of the radiocarbon dated specimens have been subjected to trace element analysis by Instrumental Neutron Activation Analysis. Cross plots of the concentrations of Fe and Zn, and Fe and Co show that it is possible to distinguish crayfish eaters from fish/squid eaters. This can be used as a novel and independent method for the determination to species of whale remains of otherwise uncertain speciation. [source] Evidence for late-Pleistocene permafrost in the New Jersey Pine Barrens (latitude 39°N), eastern USAPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2003Hugh M. French Abstract Relict sand wedges, up to 2.5,m deep and 0.4,m wide, are present in the Pine Barrens of southern New Jersey. They indicate the previous existence of permafrost. The wedges are composed predominantly of sand that shows evidence of wind transport and abrasion. Optically-stimulated-luminescence dating of infill material indicates that thermal-contraction-cracking and emplacement of the sand infill must have occurred during two separate periods during the Late Pleistocene. The most recent was in Late Wisconsinan times,,15,18,ka. An earlier period of permafrost conditions is indicated by dates >55,65,ka. On both occasions, the Late-Pleistocene ice sheets would have advanced as far south as northern New Jersey and strong winds would have occurred in the lower mid-latitudes. The sandy soils of the Pine Barrens would have allowed the ice-marginal periglacial zone to extend southwards into southern New Jersey. The sparse tundra vegetation on the sandy substrate, with its relatively high thermal conductivity, would have permitted deep frost penetration because the ,thermal offset' would have been minimized. A mean annual air temperature of between ,3.0°C and ,4.0°C is inferred. Permafrost was probably discontinuous and less than 10,15,m in thickness. Episodes of permafrost thaw are indicated by the widespread occurrence of deformed sediments (,thermokarst involutions') and by various small-scale non-diastrophic structures associated with bog ironstone beds. The presence of soil (ground) wedges in southern New Jersey and adjacent Delaware also suggest conditions of deep seasonal frost, probably when the most recent permafrost degraded. Copyright © 2003 John Wiley & Sons, Ltd. [source] Near Eastern Neolithic genetic input in a small oasis of the Egyptian Western DesertAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Martina Kujanová Abstract The Egyptian Western Desert lies on an important geographic intersection between Africa and Asia. Genetic diversity of this region has been shaped, in part, by climatic changes in the Late Pleistocene and Holocene epochs marked by oscillating humid and arid periods. We present here a whole genome analysis of mitochondrial DNA (mtDNA) and high-resolution molecular analysis of nonrecombining Y-chromosomal (NRY) gene pools of a demographically small but autochthonous population from the Egyptian Western Desert oasis el-Hayez. Notwithstanding signs of expected genetic drift, we still found clear genetic evidence of a strong Near Eastern input that can be dated into the Neolithic. This is revealed by high frequencies and high internal variability of several mtDNA lineages from haplogroup T. The whole genome sequencing strategy and molecular dating allowed us to detect the accumulation of local mtDNA diversity to 5,138 ± 3,633 YBP. Similarly, theY-chromosome gene pool reveals high frequencies of the Near Eastern J1 and the North African E1b1b1b lineages, both generally known to have expanded within North Africa during the Neolithic. These results provide another piece of evidence of the relatively young population history of North Africa. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Modern human cranial diversity in the Late Pleistocene of Africa and Eurasia: Evidence from Nazlet Khater, Pe,tera cu Oase, and HofmeyrAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Isabelle Crevecoeur Abstract The origin and evolutionary history of modern humans is of considerable interest to paleoanthropologists and geneticists alike. Paleontological evidence suggests that recent humans originated and expanded from an African lineage that may have undergone demographic crises in the Late Pleistocene according to archaeological and genetic data. This would suggest that extant human populations derive from, and perhaps sample a restricted part of the genetic and morphological variation that was present in the Late Pleistocene. Crania that date to Marine Isotope Stage 3 should yield information pertaining to the level of Late Pleistocene human phenotypic diversity and its evolution in modern humans. The Nazlet Khater (NK) and Hofmeyr (HOF) crania from Egypt and South Africa, together with penecontemporaneous specimens from the Pe,tera cu Oase in Romania, permit preliminary assessment of variation among modern humans from geographically disparate regions at this time. Morphometric and morphological comparisons with other Late Pleistocene modern human specimens, and with 23 recent human population samples, reveal that elevated levels of variation are present throughout the Late Pleistocene. Comparison of Holocene and Late Pleistocene craniometric variation through resampling analyses supports hypotheses derived from genetic data suggesting that present phenotypic variation may represent only a restricted part of Late Pleistocene human diversity. The Nazlet Khater, Hofmeyr, and Oase specimens provide a unique glimpse of that diversity. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Is Central Asia the eastern outpost of the Neandertal range?AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009A reassessment of the Teshik-Tash child Abstract Since its discovery in southeastern Uzbekistan in 1938, the Teshik-Tash child has been considered a Neandertal. Its affinity is important to studies of Late Pleistocene hominin growth and development as well as interpretations of the Central Asian Middle Paleolithic and the geographic distribution of Neandertals. A close examination of the original Russian monograph reveals the incompleteness of key morphologies associated with the cranial base and face and problems with the reconstruction of the Teshik-Tash cranium, making its Neandertal attribution less certain than previously assumed. This study reassesses the Neandertal status of Teshik-Tash 1 by comparing it to a sample of Neandertal, Middle and Upper Paleolithic modern humans, and recent human sub-adults. Separate examinations of the cranium and mandible are conducted using multinomial logistic regression and discriminant function analysis to assess group membership. Results of the cranial analysis group Teshik-Tash with Upper Paleolithic modern humans when variables are not size-standardized, while results of the mandibular analysis place the specimen with recent modern humans for both raw and size-standardized data. Although these results are influenced by limitations related to the incomplete nature of the comparative sample, they suggest that the morphology of Teshik-Tash 1 as expressed in craniometrics is equivocal. Although, further quantitative studies as well as additional sub-adult fossil finds from this region are needed to ascertain the morphological pattern of this specimen specifically, and Central Asian Middle Paleolithic hominins in general, these results challenge current characterizations of this territory as the eastern boundary of the Neandertal range during the Late Pleistocene. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Development of the Bronze Age landscape in the southeastern Arabian Gulf: new evidence from a buried shell midden in the eastern extremity of the Rub' al-Khali desert, Emirate of Ras al-Khaimah, U.A.E.ARABIAN ARCHAEOLOGY AND EPIGRAPHY, Issue 2 2007A. G. Parker Recent sand quarrying operations for building and construction work in the eastern extremity of the Rub' al-Khali sand sea has revealed sediment exposures through a number of coastal and inland dunes. In the al-Daith district of Ras al-Khaimah (U.A.E.) a Holocene shell midden was exposed 2.8 m below the present dune surface interstratified between phases of Late Pleistocene and late Holocene dune sands. C14 and OSL ages constrain the site giving an insight into phases of landscape instability, dune formation, rates of sediment accretion, and a period of stability and human occupation. To date, Hafit period sites (5200,4500 cal BP) have been recorded in large numbers in the mountains and gravel plains of the Oman mountains. Coastal shell middens have not, as yet, been ascribed to the Hafit period from this part of the region and the study presents the first radiocarbon age from such a site. This study indicates the potential that many other sites exist elsewhere buried under late Holocene dune sediments and these provide an important insight into the development of the coastal landscape of this region. [source] Distinguishing tectonic from climatic controls on range-front sedimentationBASIN RESEARCH, Issue 4 2007M. C. Quigley ABSTRACT Geologic and chronometric studies of alluvial fan sequences in south-central Australia provide insights into the roles of tectonics and climate in continental landscape evolution. The most voluminous alluvial fans in the Flinders Ranges region have developed adjacent to catchments uplifted by Plio-Quaternary reverse faults, implying that young tectonic activity has exerted a first-order control on long-term sediment accumulation rates along the range front. However, optically stimulated luminescence (OSL) dating of alluvial fan sequences indicates that late Quaternary facies changes and intervals of sediment aggradation and dissection are not directly correlated with individual faulting events. Fan sequences record a transition from debris flow deposition and soil formation to clast-supported conglomeritic sedimentation by ,30 ka. This transition is interpreted to reflect a landscape response to increasing climatic aridity, coupled with large flood events that episodically stripped previously weathered regolith from the landscape. Late Pleistocene to Holocene cycles of fan incision and aggradation post-date the youngest-dated surface ruptures and are interpreted to reflect changes in the frequency and magnitude of large floods. These datasets indicate that tectonic activity controlled long-term sediment supply but climate governed the spatial and temporal patterns of range-front sedimentation. Mild intraplate tectonism appears to have influenced Plio-Quaternary sedimentation patterns across much of the southern Australian continent, including the geometry and extent of alluvial fans and sea-level incursions. [source] Phylogeography of the Japanese giant flying squirrel, Petaurista leucogenys (Rodentia: Sciuridae): implication of glacial refugia in an arboreal small mammal in the Japanese IslandsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009TATSUO OSHIDA To test the association between temperate forest dynamics and glacial refugia for arboreal small mammals, we studied the phylogeography of the Japanese giant flying squirrel (Petaurista leucogenys) using complete mitochondrial cytochrome b gene sequences (1140 bp). This squirrel is endemic to three of Japan's main islands: Honshu, Shikoku, and Kyushu. We examined 58 specimens of P. leucogenys collected from 40 localities in Japan. Additionally, two individuals with unknown sampling localities were included in phylogenetic analyses. There were 54 haplotypes of P. leucogenys. We found five major phylogroups (Northern, Central, South-eastern, South-western, and Southern). These phylogroups may have originated from glacial refugia during the Late Pleistocene. After the last glaciation, the Northern phylogroup, widely distributed in eastern Japan, could have extensively expanded northward from its refugia. By contrast, in western Japan, population expansion was restricted to western Japan. All members of four phylogroups existed in western Japan during glaciations. The complicated phylogeographical pattern of P. leucogenys populations originating from western Japan may have resulted from the long history. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 47,60. [source] A warm thermal enclave in the Late Pleistocene of the South-eastern United StatesBIOLOGICAL REVIEWS, Issue 2 2009Dale A. Russell ABSTRACT Physical and biological evidence supports the probable existence of an enclave of relatively warm climate located between the Southern Appalachian Mountains and the Atlantic Ocean in the United States during the Last Glacial Maximum. The region supported a mosaic of forest and prairie habitats inhabited by a "Floridian" ice-age biota. Plant and vertebrate remains suggest an ecological gradient towards Cape Hatteras (35°N) wherein forests tended to replace prairies, and browsing proboscideans tended to replace grazing proboscideans. Beyond 35°N, warm waters of the Gulf Stream were deflected towards the central Atlantic, and a cold-facies biota replaced "Floridian" biota on the Atlantic coastal plain. Because of niche diversity and relatively benign climate, biodiversity may have been greater in the south-eastern thermal enclave than in other unglaciated areas of North America. However, the impact of terminal Pleistocene megafaunal extinctions may also have been shorter and more severe in the enclave than further north. A comparison with biotic changes that occurred in North America approximately 55 million years (ma) ago at the Paleocene-Eocene Thermal Maximum suggests that similar processes of change took place under both ice-house and greenhouse climates. [source] Luminescence dating of Würmian (Weichselian) proglacial sediments from Switzerland: methodological aspects and stratigraphical conclusionsBOREAS, Issue 2 2007FRANK PREUSSER Proglacial deposits from three independently dated sites in the Swiss lowlands were investigated by optically stimulated luminescence (OSL) to test the reliability of the applied dating approach. Using the single-aliquot regenerative-dose technique applied to small aliquots of quartz revealed that in all samples the OSL signal was differentially bleached prior to deposition. A statistical approach is introduced to extract the fraction of aliquots in which the OSL was apparently set to zero at deposition. The statistical treatment provided OSL ages in good consistency with independent age control. However, some uncertainties remain with this approach, since it is difficult to assess the natural scatter caused by dose-rate inhomogeneity exactly. The available data set implies that glaciers reached the Swiss lowlands prior to about 25 000 yr ago. Previously published data from other sites demonstrate that glaciers were present in lowland Switzerland up to about 20000 yr ago. Furthermore, one OSL date of about 70 000 yr for proglacial outwash sediments points to the presence of the Rhône Glacier in the Lake Neuchâtel area during the middle part of the Late Pleistocene. [source] Towards a chronology of the Late Pleistocene in the northern Alpine ForelandBOREAS, Issue 3 2004FRANK PREUSSER Dating results from terrestrial records in the northern foreland of the Alps have been compiled in order to establish an independent chronostratigraphy for the climate history of this region. U/Th dates of peat deposited during the final phase of the Last Interglacial indicate that it lasted until at least c. 115 000 yr ago. The Early Würmian started with a period of severe cold climate causing a substitution of forest by tundra-like vegetation. It is assumed that during this period glaciers advanced to the margin of the foreland of at least the Western Alps. Sediments attributed to this glaciation are dated to about 103 000 yr. Three subsequent interstadials, all characterized by coniferous forest, were interrupted by cold stadials with steppe to tundra-like vegetation. The first interstadial is dated to about 95 000 yr. There is evidence for an interstadial with open coniferous woodland and three phases of steppe vegetation during the Middle Würmian, between c. 50000 and 30 000 yr ago. The last glaciation of the Alpine Foreland reached its maximum extension between 24 000 and 21 500 yr and glaciers rapidly collapsed before ,17 500 yr ago. A series of minor re-advances during the Lateglacial is reported from within the Alps, but the glaciers barely reached the main Alpine valleys during this time. The last of these advances formed the Egesen moraine and occurred at about 11 800 yr ago during the Younger Dryas. [source] Origin and palaeo-environments of calcareous sediments in the Moshaweng dry valley, southeast BotswanaEARTH SURFACE PROCESSES AND LANDFORMS, Issue 6 2002S. Ringrose Abstract Quaternary sedimentation in the Moshaweng dry valley of southeastern Botswana is evaluated on the basis of geomorphological evolution and sedimentological analyses. Stratigraphic evidence reveals an upper surface (1095 m) containing abundant sil-calcrete, an intermediate surface (1085 m) in which sil-calcrete underlies nodular calcrete and lower (1075 m) surface in which sil-calcrete and nodular calcrete are interbedded. This subdivision is reflected in the geochemical composition of the sediments which show an overall trend of decreasing SiO2 content (and increasing CaCO3 content) with depth from the highest to the lowest surface levels. The calcretes and sil-calcretes represent modifications of pre-existing detrital Kalahari Group sand and basal Kalahari pebbles which thinned over a Karoo bedrock high. Modification took place during wet periods when abundant Ca++ -rich groundwater flowed along the structurally aligned valley system. With the onset of drier conditions, water table fluctuations led to the precipitation of nodular calcretes in the phreatic layer to a depth of about 20 m. A major geochemical change resulted in the preferential silicification of the nodular calcrete deposits. Conditions for silica mobilization may be related to drying-induced salinity and in situ geochemical differentiation brought about by pebble dissociation towards the top of the sediment pile. As calcretization and valley formation progressed to lower levels, silica release took place on a diminishing scale. Thermoluminescence dating infers a mid-Pleistocene age for sil-calcrete formation suggesting that valley evolution and original calcrete precipitation are much older. Late stage dissolution of CaCO3 from pre-existing surface calcretes or sil-calcretes led to the formation of pedogenic case-hardened deposits during a time of reduced flow through the Moshaweng system possibly during the upper or late Pleistocene. Copyright © 2002 John Wiley & Sons, Ltd. [source] TIME TO THE MOST RECENT COMMON ANCESTOR AND DIVERGENCE TIMES OF POPULATIONS OF COMMON CHAFFINCHES (FRINGILLA COELEBS) IN EUROPE AND NORTH AFRICA: INSIGHTS INTO PLEISTOCENE REFUGIA AND CURRENT LEVELS OF MIGRATIONEVOLUTION, Issue 1 2002Cortland K. Griswold Abstract We analyzed sequences from a 275-bp hypervariable region in the 5, end of the mitochondrial DNA control region in 190 common chaffinches (Fringilla coelebs) from 19 populations in Europe and North Africa, including new samples from Greece and Morocco. Coalescent techniques were applied to estimate the time to the most recent common ancestor (TMRCA) and divergence times of these populations. The first objective of this study was to infer the locations of refugia where chaffinches survived the last glacial episode, and this was achieved by estimating the TMRCA of populations in regions surrounding the Mediterranean that were unglaciated in the late Pleistocene. Although extant populations in Iberia, Corsica, Greece, and North Africa harbor haplotypes that are basal in a phylogenetic tree, this information alone cannot be used to infer that these localities served as refugia, because it is impossible to infer the ages of populations and their divergence times without also considering the population genetic processes of mutation, migration, and drift. Provided we assume the TMRCAs of populations are a reasonable estimate of a population's age, coalescent-based methods place resident populations in Iberia, Corsica, Greece, and North Africa during the time of the last glacial maximum, suggesting these regions served as refugia for the common chaffinch. The second objective was to determine when populations began diverging from each other and to use this as a baseline to estimate current levels of gene flow. Divergence time estimates suggest that European populations began diverging about 60,000 years before present. The relatively recent divergence of populations in North Africa, Italy, and Iberia may explain why classic migration estimates based on equilibrium assumptions are high for these populations. We compare these estimates with nonequilibrium-based estimates and show that the nonequilibrium estimates are consistently lower than the equilibrium estimates. [source] | ||||||||||||||||