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Sample records for ancient glacial periods

  1. Insights into chemical weathering of the upper continental crust from the geochemistry of ancient glacial diamictites

    Science.gov (United States)

    Li, Su; Gaschnig, Richard M.; Rudnick, Roberta L.

    2016-03-01

    Glacial diamictites, with ages ranging from ∼2900 to 0.01 Ma, record the changing composition of the upper continental crust through time (Gaschnig et al., 2014). Li concentrations and isotopic compositions, combined with Pb isotopic compositions, chemical index of alteration (CIA) values and relative Sr concentrations are used here to assess the degree of chemical weathering recorded in these deposits and the origin of this signature. The δ7Li values of most of the diamictites (ranging from -3.9 to +3.5) are lower than those of mantle-derived basalts (+3.7 ± 2, 2σ), and the low δ7Li values are generally accompanied by high CIA and low Sr/Sr∗ values (or Sr depletion factor, Sr/Sr∗ = Sr/(Ce∗Nd)0.5), reflecting a weathering signature that may have derived from pre-depositional, syn-depositional, and/or post-depositional weathering processes. Profiles through three glacial diamictites with relatively high CIA (a fresh road cut of the Neoproterozoic Nantuo Formation (CIA = 62-69), and drill cores through the Paleoproterozoic Timeball Hill (CIA = 66-75) and Duitschland Formations (CIA = 84-91)) do not show evidence of significant post-depositional weathering. High Th/U, reflecting loss of uranium during oxidative weathering, is seen in all Paleozoic and Neoproterozoic diamictites and a few Paleoproterozoic deposits. Pb isotopic systematics suggest that this signature was largely inherited from preexisting crust, although a subset of samples (the Neoproterozoic Konnarock, Paleozoic Dwyka, and several of the Paleoproterozoic Duitschland samples) appears to have experienced post-depositional U loss. Modern glaciomarine sediments record little weathering (CIA = 47, Sr/Sr∗ = 0.7, δ7Li = +1.8), consistent with the cold temperatures accompanying glacial periods, and suggesting that limited syn-depositional weathering has occurred. Thus, the chemical weathering signature observed in ancient glacial diamictites appears to be largely inherited from the upper

  2. Inherent characteristics of sawtooth cycles can explain different glacial periodicities

    Science.gov (United States)

    Omta, Anne Willem; Kooi, Bob W.; van Voorn, George A. K.; Rickaby, Rosalind E. M.; Follows, Michael J.

    2016-01-01

    At the Mid-Pleistocene Transition about 1 Ma, the dominant periodicity of the glacial-interglacial cycles shifted from 40 to 100 kyr. Here, we use a previously developed mathematical model to investigate the possible dynamical origin of these different periodicities. The model has two variables, one of which exhibits sawtooth oscillations, resembling the glacial-interglacial cycles, whereas the other variable exhibits spikes at the rapid transitions. When applying a sinusoidal forcing with a fixed period, there emerges a rich variety of cycles with different periodicities, each being a multiple of the forcing period. Furthermore, the dominant periodicity of the system can change, while the forcing periodicity remains fixed, due to either random variations or different frequency components of the orbital forcing. Two key relationships stand out as predictions to be tested against observations: (1) the amplitude and the periodicity of the cycles are approximately linearly proportional to each other, a relationship that is also found in the δ ^{18}O temperature proxy. (2) The magnitude of the spikes increases with increasing periodicity and amplitude of the sawtooth. This prediction could be used to identify one or more currently hidden spiking variables driving the glacial-interglacial transitions. Essentially, the quest would be for any proxy record, concurrent with a dynamical model prediction, that exhibits deglacial spikes which increase at times when the amplitude/periodicity of the glacial cycles increases. In the specific context of our calcifier-alkalinity mechanism, the records of interest would be calcifier productivity and calcite accumulation. We believe that such a falsifiable hypothesis should provide a strong motivation for the collection of further records.

  3. Continuity of brown bear maternal lineages in northern England through the Last-glacial period

    Science.gov (United States)

    Edwards, Ceiridwen J.; Ho, Simon Y. W.; Barnett, Ross; Coxon, Peter; Bradley, Daniel G.; Lord, Tom C.; O'Connor, Terry

    2014-07-01

    Brown bears recolonised Europe rapidly after the Last Glacial Maximum (LGM), but there has been debate about whether bear populations were confined to separate glacial refugia in southern Europe, or if there was continuous gene flow among groups. To look in more detail at recolonisation routes into the British Isles after the LGM, 16 brown bear (Ursus arctos) samples from Lateglacial Yorkshire were analysed for mitochondrial DNA survival. The resulting data were compared with earlier work on Late Pleistocene and Holocene bears from Ireland (Edwards et al., 2011), as well as with both modern and ancient bears from across continental Europe. The results highlight the temporal and spatial continuity of brown bear maternal lineages through the Lateglacial period in northern England. While this region was not a refugial area in the LGM for the Irish Clade 2 brown bears, our data suggest that populations of brown bear in England did act as refugial sources for the later colonisation of Ireland, by Clade 1-i bears, during the Holocene. Our results contribute to a wider understanding of the phylogenetic relationships of brown bears through the Late Quaternary, and lend a valuable perspective on bear migration into peripheral Europe.

  4. Moessbauer studies on ancient Chinese pottery of Yangshao Culture Period

    International Nuclear Information System (INIS)

    Eleven pieces of ancient Chinese pottery (4770 B.C. - 2960 B.C.) of Yangshao Culture Period collected from the Xi'an area have been studied by means of Moessbauer spectroscopy. The samples were refired up to 11000C in steps of 1000C for 2 h in air. The highest temperature up to which the Moessbauer pattern remains basically unchanged can be identified with the original firing temperature. The result indicates that the firing temperatures for most of the sherds were between 900-10000C. The function of the grit contained in the pottery has been discussed. The crimson and reddish painted materials on the surface of sherds have been studied, respectively. The first appearance of pottery can probably be traced back to an even earlier period. (orig.)

  5. Groundwater flow modelling of periods with periglacial and glacial climate conditions - Laxemar

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik (TerraSolve AB, Floda (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden)); Zugec, Nada (Bergab, Goeteborg (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report is concerned with the modelling of a repository at the Laxemar-Simpevarp site during periglacial and glacial climate conditions as a comparison to corresponding modelling carried out for Forsmark /Vidstrand et al. 2010/. The groundwater flow modelling study reported here comprises a coupled thermal-hydraulic-chemical (T-H-C) analysis of periods with periglacial and glacial climate conditions. The objective of the report is to provide bounding hydrogeological estimates at different stages during glaciation and deglaciation of a glacial cycle at Laxemar. Three cases with different climate conditions are analysed here: (i) Temperate case, (ii) Glacial case without permafrost, and (iii) Glacial case with permafrost. The glacial periods are transient and encompass approximately 13,000 years. The simulation results comprise pressures, Darcy fluxes, and water salinities, as well as advective transport performance measures obtained by particle tracking such as flow path lengths, travel times and flow-related transport resistances. The modelling is accompanied by a sensitivity study that addresses the impact of the following matters: the direction of the ice sheet advance and the bedrock hydraulic and transport properties

  6. Groundwater flow modelling of periods with periglacial and glacial climate conditions - Laxemar

    International Nuclear Information System (INIS)

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report is concerned with the modelling of a repository at the Laxemar-Simpevarp site during periglacial and glacial climate conditions as a comparison to corresponding modelling carried out for Forsmark /Vidstrand et al. 2010/. The groundwater flow modelling study reported here comprises a coupled thermal-hydraulic-chemical (T-H-C) analysis of periods with periglacial and glacial climate conditions. The objective of the report is to provide bounding hydrogeological estimates at different stages during glaciation and deglaciation of a glacial cycle at Laxemar. Three cases with different climate conditions are analysed here: (i) Temperate case, (ii) Glacial case without permafrost, and (iii) Glacial case with permafrost. The glacial periods are transient and encompass approximately 13,000 years. The simulation results comprise pressures, Darcy fluxes, and water salinities, as well as advective transport performance measures obtained by particle tracking such as flow path lengths, travel times and flow-related transport resistances. The modelling is accompanied by a sensitivity study that addresses the impact of the following matters: the direction of the ice sheet advance and the bedrock hydraulic and transport properties

  7. The last interglacial-glacial period on spitsbergen, Svalbard

    Science.gov (United States)

    Mangerud, Jan; Svendsen, John Inge

    The glaciation history of Svalbard (78°N) and the NW Barents Sea is reconstructed for the last 130 ka, based on studies of sediments exposed in coastal cliffs at the head of Isfjorden. Four different till beds separated by marine sediments are recognized. The lowest marine formation, containing Mytilus edulis, reflects warmer conditions than at present, and is correlated with the last interglacial, the Eemian of Europe and Oxygen Isotope Substage 5e in the deep sea. The post-Eemian tills are inferred to represent major glaciations around 110 ka BP, 75-50 ka BP, and 25-10 ka BP. During the intervening intervals the glaciers on Svalbard were not significantly larger than at present and the NW Barents Sea was probably ice-free. The ice-free periods, named Phantomodden and Kapp Ekholm interstadials, lasted from about 110 to 75 and from 50 to 25 ka BP respectively. The marine fauna from both these interstadials indicate seasonally ice free conditions. The ages of the recorded glaciations coincide with, or are slightly younger than, periods with insolation minima, which at this latitude is determined by a low tilt of the Earth's axis. Thus we postulate that the Quaternary glaciations of Svalbard were driven by orbital variations with the 41 ka tilt period, in contrast to the lower-latitude glaciations of Scandinavia that were partly driven by the precession cycle with a periodicity of around 23 ka.

  8. The Carbon Cycle as the Main Determinant of Glacial-Interglacial Periods

    CERN Document Server

    de la Cuesta, Diego Jiménez; Núñez, Darío; Rumbos, Beatriz; Vergara-Cervantes, Carlos

    2013-01-01

    An intriguing problem in climate science is the existence of Earth's glacial cycle. We show that it is possible to generate these periodic changes in climate by means of the Earth's carbon cycle as the main source factor. The carbon exchange between the Ocean, the Continent and the Atmosphere is modeled by means of a Lotka-Volterra three species system and the resulting atmospheric carbon cycle is used as the unique radiative forcing mechanism. It is shown that the carbon dioxide and temperature paths that are thus obtained have the same qualitative structure as the 100 kyr glacial-interglacial cycles depicted by the Vostok ice core data, reproducing the asymmetries of rapid heating--slow cooling, and short interglacial--long glacial ages.

  9. Neotropical forest expansion during the last glacial period challenges refuge hypothesis.

    Science.gov (United States)

    Leite, Yuri L R; Costa, Leonora P; Loss, Ana Carolina; Rocha, Rita G; Batalha-Filho, Henrique; Bastos, Alex C; Quaresma, Valéria S; Fagundes, Valéria; Paresque, Roberta; Passamani, Marcelo; Pardini, Renata

    2016-01-26

    The forest refuge hypothesis (FRH) has long been a paradigm for explaining the extreme biological diversity of tropical forests. According to this hypothesis, forest retraction and fragmentation during glacial periods would have promoted reproductive isolation and consequently speciation in forest patches (ecological refuges) surrounded by open habitats. The recent use of paleoclimatic models of species and habitat distributions revitalized the FRH, not by considering refuges as the main drivers of allopatric speciation, but instead by suggesting that high contemporary diversity is associated with historically stable forest areas. However, the role of the emerged continental shelf on the Atlantic Forest biodiversity hotspot of eastern South America during glacial periods has been ignored in the literature. Here, we combined results of species distribution models with coalescent simulations based on DNA sequences to explore the congruence between scenarios of forest dynamics through time and the genetic structure of mammal species cooccurring in the central region of the Atlantic Forest. Contrary to the FRH predictions, we found more fragmentation of suitable habitats during the last interglacial (LIG) and the present than in the last glacial maximum (LGM), probably due to topography. We also detected expansion of suitable climatic conditions onto the emerged continental shelf during the LGM, which would have allowed forests and forest-adapted species to expand. The interplay of sea level and land distribution must have been crucial in the biogeographic history of the Atlantic Forest, and forest refuges played only a minor role, if any, in this biodiversity hotspot during glacial periods. PMID:26755597

  10. Groundwater flow modelling of periods with periglacial and glacial climate conditions - Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Vidstrand, Patrik (TerraSolve AB, Floda (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden)); Zugec, Nada (Bergab, Stockholm (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The groundwater flow modelling study reported here comprises a coupled thermal-hydraulic-chemical (T-H-C) analysis of periods with periglacial and glacial climate conditions. Hydraulic-mechanical (H-M) issues are also handled but no coupled flow modelling is done. The objective of the report is to provide bounding hydrogeological estimates at different stages during glaciation and deglaciation of a glacial cycle for subsequent use in safety assessment applications within SKB's project SR-Site. Three cases with different climate conditions are analysed here: (i) Temperate case, (ii) Glacial case without permafrost, and (iii) Glacial case with permafrost. The glacial periods are transient and encompass approximately 19,000 years. The simulation results comprise residual fluid pressures, Darcy fluxes, and water salinities, as well as advective transport performance measures obtained by particle tracking such as flow path lengths, travel times and flow-related transport resistances. The modelling is accompanied by a sensitivity study that addresses the impact of the following matters: the direction of the ice sheet advance, the speed of the ice sheet margin, the bedrock hydraulic and transport properties, the temperature at the ice-subsurface interface close to the ice sheet margin, and the initial hydrochemical conditions.

  11. Periodic orbits for a discontinuous vector field arising from a conceptual model of glacial cycles

    Science.gov (United States)

    Walsh, James; Widiasih, Esther; Hahn, Jonathan; McGehee, Richard

    2016-06-01

    Conceptual climate models provide an approach to understanding climate processes through a mathematical analysis of an approximation to reality. Recently, these models have also provided interesting examples of nonsmooth dynamical systems. Here we develop a new conceptual model of glacial cycles consisting of a system of three ordinary differential equations defining a discontinuous vector field. Our model provides a dynamical systems framework for a mechanism previously shown to play a crucial role in glacial cycle patterns, namely, an increased ice sheet ablation rate during deglaciations. We use ad hoc singular perturbation techniques to prove the existence of a large periodic orbit crossing the discontinuity boundary, provided the ice sheet edge moves sufficiently slowly relative to changes in the snow line and temperature. Numerical explorations reveal the periodic orbit exists when the time constant for the ice sheet edge has more moderate values.

  12. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania

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    J. Holtvoeth

    2010-06-01

    Full Text Available Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: Site Lz1120 near the southern shore, with flat lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event. Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol from sulphur-oxidising phototrophic bacteria and for the influence of an early human community from the occurrence of coprostanol, a biomarker for human and cattle faeces, in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

  13. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

    Science.gov (United States)

    Holtvoeth, J.; Vogel, H.; Wagner, B.; Wolff, G. A.

    2010-11-01

    Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event). Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats), in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

  14. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania

    Directory of Open Access Journals (Sweden)

    J. Holtvoeth

    2010-11-01

    Full Text Available Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands nearby and probably influenced by river discharge, and site Co1202 which is close to the steep eastern slopes. Variable proportions of terrestrial n-alkanoic acids and n-alkanols as well as compositional changes of ω-hydroxy acids document differences in soil organic matter supply between the sites and during different climate stages (glacial, Holocene, 8.2 ka cooling event. Changes in the vegetation cover are suggested by changes in the dominant chain length of terrestrial n-alkanols. Effective microbial degradation of labile organic matter and in situ contribution of organic matter derived from the microbes themselves are both evident in the sediments. We found evidence for anoxic conditions within the photic zone by detecting epicholestanol and tetrahymanol from sulphur-oxidising phototrophic bacteria and bacterivorous ciliates and for the influence of a settled human community from the occurrence of coprostanol, a biomarker for human and animal faeces (pigs, sheep, goats, in an early Holocene sample. This study illustrates the potential of lipid biomarkers for future environmental reconstructions using one of Europe's oldest continental climate archives, Lake Ohrid.

  15. Halogen species record Antarctic sea ice extent over glacial-interglacial periods

    Directory of Open Access Journals (Sweden)

    A. Spolaor

    2013-02-01

    Full Text Available Sea ice is an integral part of the Earth's climate system because it affects planetary albedo, sea surface salinity, and the atmosphere-ocean exchange of reactive gases and aerosols. Bromine and iodine chemistry is active at polar sea ice margins with the occurrence of bromine explosions and the biological production of organo-iodine from sea ice algae. Satellite measurements demonstrate that concentrations of bromine oxide (BrO and iodine oxide (IO decrease over sea ice toward the Antarctic interior. Here we present speciation measurements of bromine and iodine in the TALDICE (TALos Dome Ice CorE ice core (159°11' E, 72°49' S, 2315 m a.s.l. spanning the last 215 ky. The Talos Dome ice core is located 250 km inland and is sensitive to marine air masses intruding onto the Antarctic Plateau. Talos Dome bromide (Br is positively correlated with temperature and negatively correlated with sodium (Na. Based on the Br/Na seawater ratio, bromide is depleted in the ice during glacial periods and enriched during interglacial periods. Total iodine, consisting of iodide (I and iodate (IO3, peaks during glacials with lower values during interglacial periods. Although IO3 is considered the most stable iodine species in the atmosphere it was only observed in the TALDICE record during glacial maxima. Sea ice dynamics are arguably the primary driver of halogen fluxes over glacial-interglacial timescales, by altering the distance between the sea ice edge and the Antarctic plateau and by altering the surface area of sea ice available to algal colonization. Based on our results we propose the use of both halogens for examining Antarctic variability of past sea ice extent.

  16. Hydrology of surface waters and thermohaline circulation during the last glacial period

    International Nuclear Information System (INIS)

    Sedimentological studies on oceanic cores from the north Atlantic have revealed, over the last glacial period, abrupt climatic changes with a periodicity of several thousand years which contrasts strongly with the glacial-interglacial periodicity (several tens of thousand years). These periods of abrupt climate changes correspond to massive icebergs discharges into the north Atlantic. The aim of this work was to study the evolution of the thermohaline circulation in relation to these episodic iceberg discharges which punctuated the last 60 ka. To reconstruct the oceanic circulation in the past, we have analysed oxygen and carbon stable isotopes on benthic foraminifera from north Atlantic deep-sea cores. First of all, the higher temporal resolution of sedimentary records has enabled us to establish a precise chrono-stratigraphy for the different cores. Then, we have shown the close linkage between surface water hydrology and deep circulation, giving evidence of the sensibility of thermohaline circulation to melt water input in the north Atlantic ocean. Indeed, changes in deep circulation are synchronous from those identified in surface waters and are recorded on a period which lasted ∼ 1500 years. Deep circulation reconstructions, before and during a typical iceberg discharge reveal several modes of circulation linked to different convection sites at the high latitudes of the Atlantic basin. Moreover, the study of the last glacial period gives the opportunity to differentiate circulation changes due to the external forcing (variations of the orbital parameters) and those linked to a more local forcing (icebergs discharges). 105 refs., 50 figs., 14 tabs., 4 appends

  17. Molecular genetic analysis of Dongzhou-period ancient human of Helingeer in Inner Mongolia, China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The mtDNA hypervariable region I (HVR-I) of 10 ancient individuals from Dongzhou-period ancient human populations in Helingeer county of Inner Mongolia were amplified and sequenced to investigate the genetic structure. The relationships between the ancient population and related extant populations, as well as its possible origin at the molecular level, were also studied. Moreover, phylogenetic analysis and multi-dimensional scaling analysis were also performed based on the mtDNA data of the ancient population in Helingeer and the related Eurasian population. The results showed that the ancient population in Helingeer were closer to the northern Asian populations than to the other compared populations in matrilineal lineage. Combining the research results of archaeology and anthropology as well as molecular biology, we inferred that they were nomads who migrated from Mongolia plateau and cis-Baikal region to Helingeer in Inner Mongolia, China.

  18. Links between tropical rainfall and North Atlantic climate during the last glacial period

    Science.gov (United States)

    Deplazes, Gaudenz; Lückge, Andreas; Peterson, Larry C.; Timmermann, Axel; Hamann, Yvonne; Hughen, Konrad A.; Röhl, Ursula; Laj, Carlo; Cane, Mark A.; Sigman, Daniel M.; Haug, Gerald H.

    2013-03-01

    During the last glacial period, the North Atlantic regionexperienced pronounced, millennial-scale alternations between cold, stadial conditions and milder interstadial conditions--commonly referred to as Dansgaard-Oeschger oscillations--as well as periods of massive iceberg discharge known as Heinrich events. Changes in Northern Hemisphere temperature, as recorded in Greenland, are thought to have affected the location of the Atlantic intertropical convergence zone and the strength of the Indian summer monsoon. Here we use high-resolution records of sediment colour--a measure of terrigenous versus biogenic content--from the Cariaco Basin off the coast of Venezuela and the Arabian Sea to assess teleconnections with the North Atlantic climate system during the last glacial period. The Cariaco record indicates that the intertropical convergence zone migrated seasonally over the site during mild stadial conditions, but was permanently displaced south of the basin during peak stadials and Heinrich events. In the Arabian Sea, we find evidence of a weak Indian summer monsoon during the stadial events. The tropical records show a more variable response to North Atlantic cooling than the Greenland temperature records. We therefore suggest that Greenland climate is especially sensitive to variations in the North Atlantic system--in particular sea-ice extent--whereas the intertropical convergence zone and Indian monsoon system respond primarily to variations in mean Northern Hemisphere temperature.

  19. Intensive winds during glacial periods increased sand-dune activity and loess deposition

    Science.gov (United States)

    Crouvi, O.; Enzel, Y.; Amit, R.; Gillespie, A.

    2010-12-01

    The formation of loess in deserts worldwide is mostly attributed to glacial periods, whereas during interglaciations (e.g. the Holocene) loess deposition rates are reported as minimal. Several explanations for this glacial-interglacial change in loess formation were proposed in the past, but no consensus exists. We examined the data available for several well-known loess accretion zones near subtropical deserts (including Sahara, Sinai-Negev, and Arabia) and show that all these loess zones are located downwind of adjacent sand dunes/seas that were active in the late Pleistocene as indicated by dune orientations. Moreover, mineralogical similarity is common to the loess and the upwind sand dunes, intensified erg activity and loess formation are temporally associated and grain-size mode of loess decreases systematically with distance from ergs. These observations suggest that sand dunes were an important primary source for desert loess, probably through aeolian abrasion of sand grains. Only intense, windy episodes in low and mid-latitudes worldwide could have (a) advanced and/or mobilized these dune fields and (b) forcefully abraded sand into silts. The common denominator underlying both dune activity and loess deposition must be winds with sufficient strength to mobilize dunes; either increased aridity at the source or increased precipitation at the sink or both together cannot dominate the coupled silty dust supply and loess deposition, as previously suggested. Both conditions are ubiquitous today in desert margins: most of the studied desert loess regions are located in semi-arid climate, where there is enough rainfall (>150-200 mm/yr) to deposit loess, whereas the loess regions suggested sources (i.e. the adjacent, upwind sand seas) are located in extremely dry (<50 mm/yr) climate. However, loess accretion downwind of ergs today is insignificant; the main change has been wind strength: modern wind durations and strengths are probably insufficient for significant

  20. Vegetation history in central Kentucky and Tennessee (USA) during the last glacial and deglacial periods

    Science.gov (United States)

    Liu, Yao; Andersen, Jennifer J.; Williams, John W.; Jackson, Stephen T.

    2013-03-01

    Knowledge about vegetation dynamics during the last glacial and deglacial periods in southeastern North America is under-constrained owing to low site density and problematic chronologies. New pollen records from two classic sites, Anderson Pond, TN, and Jackson Pond, KY, supported by AMS 14C age models, span 25.2-13.7 ka and 31.0-15.4 ka, respectively. A transition from Pinus dominance to Picea dominance is recorded at Jackson Pond ca. 26.2 ka, ~ coincident with Heinrich Event H2. Anderson and Jackson Ponds record a transition from conifer to deciduous-tree dominance ~ 15.9 and 15.4 ka, respectively, marking the development of no-analog vegetation characterized by moderate to high abundances of Picea, Quercus, Carya, Ulmus, Fraxinus, Ostrya/Carpinus, Cyperaceae, and Poaceae, and preceding by ~ 2000 yr the advent of similar no-analog vegetation in glaciated terrain to the north. No-analog vegetation developed as a time-transgressive, south-to-north pattern, mediated by climatic warming. Sporormiella abundances are consistently low throughout the Jackson and Anderson Pond records, suggesting that megafaunal abundances and effects on vegetation varied regionally or possibly that the Sporormiella signal was not well-expressed at these sites. Additional records with well-constrained chronologies are necessary to assess patterns and mechanisms of vegetation dynamics during the last glacial and deglacial periods.

  1. Intense winter cooling of the surface water in the northern Okinawa Trough during the last glacial period

    OpenAIRE

    Yamamoto, Masanobu; Kishizaki, Midori; Oba, Tadamichi; Kawahata, Hodaka

    2013-01-01

    We generated a 42,000-year record of TEX86 (TEX86L and TEX86H) from core MD98-2195 to better understand changes in the hydrology of the East China Sea (ECS) in the last glacial period. The TEX86-derived temperature showed an intense cooling in the last glacial period, whereas U-37(K)-derived spring sea surface temperature (SST) and foraminiferal Mg/Ca-derived summer SST showed a much smaller-scale cooling. The difference between the TEX86- and Mg/Ca-derived temperatures was around 14 degrees ...

  2. Periodic Glacial Lake Outburst Floods threatening the oldest Buddhist monastery in north-west Nepal

    OpenAIRE

    J. Kropáček; N. Neckel; Tyrna, B.; Holzer, N.; A. Hovden; Gourmelen, N.; Schneider, C.; M. Buchroithner; V. Hochschild

    2014-01-01

    Since 2004 Halji Village, home of the oldest Buddhist Monastery in north-west Nepal has suffered from recurrent Glacial Lake Outburst Floods (GLOFs). Studies of recent satellite images identified a supra-glacial lake, located at a distance of 6.5 km from the village, as a possible source of the flood. During a field survey in 2013, the finding was confirmed and several entrances to en-glacial conduits which are draining the lake were found. The topography of...

  3. The Olympic Games as reflection conditions of development Ancient Greek civilization in Hellenism period

    Directory of Open Access Journals (Sweden)

    Kasianenko Ol'ga Gennadievna

    2009-02-01

    Full Text Available The author has realized the historical analysis of the Olympic Games at consideration the conditions of Ancient Greek civilization development in Hellenism period. Had presented the division into the periodization of Greek civilization development in which had learned a major changes in the world-view of Hellenes under the A. Macedonian influence, notably: professionalization of sport and gradual fading of ideals, making basis of olympism, and also Christianity following late which results in the decline of the Olympic Games.

  4. Periodic Glacial Lake Outburst Floods threatening the oldest Buddhist monastery in north-west Nepal

    OpenAIRE

    J. Kropáček; N. Neckel; Tyrna, B.; Holzer, N.; A. Hovden; Gourmelen, N.; Schneider, C.; M. Buchroithner; V. Hochschild

    2014-01-01

    Since 2004 Halji Village, home of the oldest Buddhist Monastery in north-west Nepal has suffered from recurrent Glacial Lake Outburst Floods (GLOFs). Studies of recent satellite images identified a supra-glacial lake, located at a distance of 6.5 km from the village, as a possible source of the flood. During a field survey in 2013, the finding was confirmed and several entrances to en-glacial conduits which are draining the lake were found. The topography of the lake basin was then mapped by ...

  5. Analysis of the ancient river system in Loulan period in Lop Nur region

    Science.gov (United States)

    Zhu, Jianfeng; Jia, Peng; Nie, Yueping

    2010-09-01

    The Lop Nur region is located in the east of the Tarim Basin. It has served as the strategic passage and communication hub of the Silk Road since Han Dynasty. During Wei-Jin period, the river system there was well developed and the ancient city of Loulan was bred there. In this study, GIS is used to accomplish automatic extraction of the river course in the Lop Nur region at first using ArcGIS. Then the RCI index is constituted to extract ancient river course from Landsat ETM image with band 3 and band 4. It is concluded that the north river course of Peacock River conformed before the end of the 4th century AD according to the distribution of the entire river course of the Lop Nur region. Later, the Peacock River changed its way to south to Tarim River, and flowed into Lop Nur along the direction paralleling Altun Mountain from west to east. It was the change of the river system that mainly caused the decrease in water supply around ancient city of Loulan before the end of 4th century. The ancient city of Loulan has been gradually ruined in the sand because of the absence of water supply since then.

  6. Release of Methane from Bering Sea Sediments During the Last Glacial Period

    Energy Technology Data Exchange (ETDEWEB)

    Mea Cook; Lloyd Keigwin

    2007-11-30

    Several lines of evidence suggest that during times of elevated methane flux the sulfate-methane transition zone (SMTZ) was positioned near the sediment-water interface. We studied two cores (from 700 m and 1457 m water depth) from the Umnak Plateau region. Anomalously low d13C and high d18O in benthic and planktonic foraminifera in these cores are the consequence of diagenetic overgrowths of authigenic carbonates. There are multiple layers of authigenic-carbonate-rich sediment in these cores, and the stable isotope compositions of the carbonates are consistent with those formed during anaerobic oxidation of methane (AOM). The carbonate-rich layers are associated with biomarkers produced by methane-oxidizing archaea, archaeol and glyceryl dibiphytanyl glyceryl tetraether (GDGT). The d13C of the archaeol and certain GDGTs are isotopically depleted. These carbonate- and AOM-biomarker-rich layers were emplaced in the SMTZ during episodes when there was a high flux of methane or methane-rich fluids upward in the sediment column. The sediment methane in the Umnak Plateau region appears to have been very dynamic during the glacial period, and interacted with the ocean-atmosphere system at millennial time scales. The upper-most carbonate-rich layers are in radiocarbon-dated sediment deposited during interstitials 2 and 3, 28-20 ka, and may be associated with the climate warming during this time.

  7. Vegetation cover in West Carpathians during the Last Glacial Period - analogy of present day siberian forest - tundra and taiga

    Czech Academy of Sciences Publication Activity Database

    Jankovská, Vlasta

    Saint-Petersburg : VNIGRI, 2008 - (Priščepa, O.; Subetto, D.; Dzujba, O.), s. 282-289 ISBN 978-5-88953-122-7. [XII. All-Russian Palynological conference. Saint-Petersburg (RU), 29.09.2008-04.10.2008] R&D Projects: GA ČR(CZ) GA205/06/0587 Institutional research plan: CEZ:AV0Z60050516 Keywords : Last Glacial Period * palaeoreconstruction * West Carpathians Subject RIV: EF - Botanics

  8. Synthesis Of Arts In Architecture Of Uzbekistan Of The Ancient Period

    Directory of Open Access Journals (Sweden)

    Nurmukhamedova Shoira Zahidovna

    2015-08-01

    Full Text Available As in ancient architecture of Greece and Rome there was an interconnection between picturesque and monumental forms of arts in antique period in the architecture of Uzbekistan there was a tight connection between architecture and such forms of picturesque arts as monumental painting sculpture. Determinant factor of their application was the scale of the monument itself the height of the walls the conditions of viewing. These forms of arts represented an organic unity in regard to architecture improved it by color and plastic solutions underlying and emphasizing the architectonics of the interior by art means.

  9. The processes and mechanisms of severe sandstorm development in the eastern Hexi Corridor China, during the Last Glacial period

    Science.gov (United States)

    Guan, Qingyu; Pan, Baotian; Yang, Jing; Wang, Lijuan; Zhao, Shilei; Gui, Hongjie

    2013-01-01

    Dust transported by sandstorms has been an important feedback in climate change in the past, and its environmental effects are predicted to have a great impact on future global climatic change. Investigating the grain-size classes and the standard deviations of the modern sandstorm samples, and the samples in the Shagou section (situated in the eastern Hexi Corridor), lead us to suggest that the sand fraction within the range of 275.4-550 μm in this section can be used as a sensitive indicator of severe sandstorms. We selected the size range in the L1 stratum of the Shagou loess section as indicative of temporal changes in sandstorm intensity in the eastern Hexi Corridor and found that during the Last Glacial period, severe sandstorms in the eastern Hexi Corridor occurred with high frequency during these periods: I (70-54 ka B.P.), II (51-48 ka B.P.), III (45-42 ka B.P.), IV (38-33 ka B.P.), V (31-28 ka B.P.) and VI (26-12 ka B.P.) In general, the frequency and intensity of dust storms in the early (MIS 4) and late (MIS 2) periods were both high but they were reduced in the middle period (MIS 3). The primary factors controlling severe sandstorms are hydrology and wind power, followed by the expansion of the source extent. Reduced precipitation caused the source region of sandstorms to expand; in addition, wind speeds also increased at this time. These factors may have directly contributed to the abundance of severe sandstorms. Based on the grain size from a loess section (the Shagou section) in the eastern Hexi Corridor, we propose an evolutionary sequence of the severe sandstorms during the Last Glacial period. This sequence is consistent with the dust records in the Arctic, the Antarctic and low-latitude (the central equatorial Pacific) areas. Thus globally synchronous periods of high dust activity occurred in the Last Glacial period. The strong winds proposed here provide a potential explanation for the global consistency of dust flux changes during the Last

  10. Hydrology of surface waters and thermohaline circulation during the last glacial period; Hydrologie des eaux de surface et circulation thermohaline au cours de la derniere periode glaciaire

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, L.

    1996-03-27

    Sedimentological studies on oceanic cores from the north Atlantic have revealed, over the last glacial period, abrupt climatic changes with a periodicity of several thousand years which contrasts strongly with the glacial-interglacial periodicity (several tens of thousand years). These periods of abrupt climate changes correspond to massive icebergs discharges into the north Atlantic. The aim of this work was to study the evolution of the thermohaline circulation in relation to these episodic iceberg discharges which punctuated the last 60 ka. To reconstruct the oceanic circulation in the past, we have analysed oxygen and carbon stable isotopes on benthic foraminifera from north Atlantic deep-sea cores. First of all, the higher temporal resolution of sedimentary records has enabled us to establish a precise chrono-stratigraphy for the different cores. Then, we have shown the close linkage between surface water hydrology and deep circulation, giving evidence of the sensibility of thermohaline circulation to melt water input in the north Atlantic ocean. Indeed, changes in deep circulation are synchronous from those identified in surface waters and are recorded on a period which lasted {approx} 1500 years. Deep circulation reconstructions, before and during a typical iceberg discharge reveal several modes of circulation linked to different convection sites at the high latitudes of the Atlantic basin. Moreover, the study of the last glacial period gives the opportunity to differentiate circulation changes due to the external forcing (variations of the orbital parameters) and those linked to a more local forcing (icebergs discharges). 105 refs., 50 figs., 14 tabs., 4 appends.

  11. Periodic Glacial Lake Outburst Floods threatening the oldest Buddhist monastery in north-west Nepal

    Directory of Open Access Journals (Sweden)

    J. Kropáček

    2014-11-01

    Full Text Available Since 2004 Halji Village, home of the oldest Buddhist Monastery in north-west Nepal has suffered from recurrent Glacial Lake Outburst Floods (GLOFs. Studies of recent satellite images identified a supra-glacial lake, located at a distance of 6.5 km from the village, as a possible source of the flood. During a field survey in 2013, the finding was confirmed and several entrances to en-glacial conduits which are draining the lake were found. The topography of the lake basin was then mapped by combining Differential Global Positioning System (DGPS measurements with a Structure From Motion (SFM approach from terrestrial photographs. From this model the maximum filling capacity of the lake has been estimated as 1.06 × 106 m3 with a maximum discharge of 77.8 m3 s−1 calculated using an empirical relation. The flooded area in the valley has been estimated by employing a raster-based hydraulic model considering six scenarios of discharge volume and surface roughness. To understand the changes in glacier geometry in the last decade the thinning and retreat of Halji Glacier have been analysed by geodetic mass balance measurements and a time series of satellite images respectively. The GLOF occurrences have further been correlated with cumulative temperature and cumulative liquid precipitation calculated from the High Asia Reanalysis (HAR dataset. Finally, effective mitigation measures and adaption strategies for Halji village have been discussed.

  12. Periodic Glacial Lake Outburst Floods threatening the oldest Buddhist monastery in north-west Nepal

    Science.gov (United States)

    Kropáček, J.; Neckel, N.; Tyrna, B.; Holzer, N.; Hovden, A.; Gourmelen, N.; Schneider, C.; Buchroithner, M.; Hochschild, V.

    2014-11-01

    Since 2004 Halji Village, home of the oldest Buddhist Monastery in north-west Nepal has suffered from recurrent Glacial Lake Outburst Floods (GLOFs). Studies of recent satellite images identified a supra-glacial lake, located at a distance of 6.5 km from the village, as a possible source of the flood. During a field survey in 2013, the finding was confirmed and several entrances to en-glacial conduits which are draining the lake were found. The topography of the lake basin was then mapped by combining Differential Global Positioning System (DGPS) measurements with a Structure From Motion (SFM) approach from terrestrial photographs. From this model the maximum filling capacity of the lake has been estimated as 1.06 × 106 m3 with a maximum discharge of 77.8 m3 s-1 calculated using an empirical relation. The flooded area in the valley has been estimated by employing a raster-based hydraulic model considering six scenarios of discharge volume and surface roughness. To understand the changes in glacier geometry in the last decade the thinning and retreat of Halji Glacier have been analysed by geodetic mass balance measurements and a time series of satellite images respectively. The GLOF occurrences have further been correlated with cumulative temperature and cumulative liquid precipitation calculated from the High Asia Reanalysis (HAR) dataset. Finally, effective mitigation measures and adaption strategies for Halji village have been discussed.

  13. CT of a Ptolemaic period mummy from the ancient Egyptian City of Akhmim.

    Science.gov (United States)

    Chan, Steve S; Elias, Jonathan P; Hysell, Mark E; Hallowell, Michael J

    2008-01-01

    Mummies associated with the ancient city of Akhmim in Egypt provide an important portal for radiologic research concerning the ancient Egyptian population. As part of an ongoing investigation, a mummy of Akhmimic derivation owned by the Academy of Natural Sciences in Philadelphia, Pennsylvania, was scanned with a 16-detector row computed tomographic scanner. The resultant images helped confirm that the mummy was that of a female in her late teens. Although the deliberate omission of hieroglyphic texts on the painted coffin rendered the deceased individual anonymous, it is noteworthy that great care had been taken in preparing the corpse for burial. The mummy represents conscientious work by the embalmers, work that is broadly consistent with methods used during the early Ptolemaic period for well-to-do persons. Features of bodily decomposition, including the rotary dissociation of the C1 and C2 vertebral bodies and a missing right patella, point to neglect of the body prior to its recovery and mummification. The fact that the body was well prepared but thinly wrapped and interred in an uninscribed coffin further suggests that the deceased was not of the community that eventually performed the mummification. This evidence is not inconsistent with a scenario involving the body's postmortem immersion in water. Although it cannot be determined with certainty whether the deceased was a drowning victim, it appears that the treatment of the body followed protocols developed in connection with an ancient Egyptian tradition that persons dying in, or retrieved from, the Nile River were embalmed with special care. PMID:19001656

  14. Glacial-Interglacial period in Lago Sarmiento (Chilean Patagonia) using high resolution seismic

    Science.gov (United States)

    Vizcaino Marti, A.; Dunbar, R. B.; Mucciarone, D. A.; LeRoy, S.; Stadnyk, A. D.

    2011-12-01

    Southern South America is the only large continental landmass situated in the core of the southern westerly wind field. Precipitation in the region is generally produced by frontal systems associated with surface depressions. Stronger westerlies at interannual and longer time scales promote extratropical storms, leading to an increase in precipitation. Orographic effects amplify this process, and the resulting precipitation is an important source of moisture along the Pacific margin of the Andes. Eastward to the Patagonian Andes there is a drying effect, and stronger westerlies produce a decrease in precipitation. Lago Sarmiento is a deep 25 km long and 6 km wide, E-W oriented closed-basin lake located at 51°S 72.5°W and about 70 meters above sea level. The lake is supplied by small ephemeral streams and does not directly receive glacial meltwater. Water level and composition depends on the evaporation-rainfall ratio. The abundant carbonate in the lake sediments precipitate in equilibrium with lake waters. High resolution seismic stratigraphic analyses, obtained using a Chirp 3.5 kHz in Lago Sarmiento, are the basis for an interpretation of the sedimentological changes in the lake. Different acoustic facies show an evolution from glacial sediment facies when ice occupied the drainage basin during the Last Glacial Maximum (LGM). From the Glacial/Glacio-lacustrine acoustic facies we observe an upward trend to a high laminated facies indicating an ice retreat and a domination of lacustrine processes. All shallow water areas of the lake support modern Rivularia (cyanobacteria) bioherms. Individual structures are as much as 5 m in height and 6 m in diameter. Emergent "fossil" bioherms occur along all shorelines and define previous lake highstands. With the exception of autochthonous carbonate deposits along the shoreline of Sarmiento, there are no significant carbonate lithologies present within the drainage basin. In addition to the acoustic facies, a number of

  15. Millennial and sub-millennial scale climatic variations recorded in polar ice cores over the last glacial period

    DEFF Research Database (Denmark)

    Capron, E.; Landais, A.; Chappellaz, J.;

    2010-01-01

    Since its discovery in Greenland ice cores, the millennial scale climatic variability of the last glacial period has been increasingly documented at all latitudes with studies focusing mainly on Marine Isotopic Stage 3 (MIS 3; 28–60 thousand of years before present, hereafter ka) and characterized...... succession of abrupt events associated with long Greenland InterStadial phases (GIS) enabling us to highlight a sub-millennial scale climatic variability depicted by (i) short-lived and abrupt warming events preceding some GIS (precursor-type events) and (ii) abrupt warming events at the end of some GIS...

  16. Shifting Milestones of Natural Sciences: The Ancient Egyptian Discovery of Algol's Period Confirmed

    CERN Document Server

    Jetsu, Lauri

    2016-01-01

    The Ancient Egyptians wrote Calendars of Lucky and Unlucky Days that assigned astronomically influenced prognoses for each day of the year. The best preserved of these calendars is the Cairo Calendar (hereafter CC) dated to 1244--1163 B.C. We have presented evidence that the 2.85 days period in the lucky prognoses of CC is equal to that of the eclipsing binary Algol during this historical era. We wanted to find out the vocabulary that represents Algol in the mythological texts of CC. Here we show that Algol was represented as Horus and thus signified both divinity and kingship. The texts describing the actions of Horus are consistent with the course of events witnessed by any naked eye observer of Algol. These descriptions support our claim that CC is the oldest preserved historical document of the discovery of a variable star. The period of the Moon, 29.6 days, has also been discovered in CC. We show that the actions of Seth were connected to this period, which also strongly regulated the times described as ...

  17. Global climate change linkage with episodic methane release even in the western north Pacific in the last glacial period

    International Nuclear Information System (INIS)

    The remarkable similarity of late Quaternary atmospheric methane and temperature variations recorded in ice cores suggests that methane has played a significant role in millennial-scale climatic oscillations, especially Dansgaard-Oeschger (D-O) interstadial. Variations in the size and distribution of marine-sedimentary reservoirs of methane on the continental margins throughout the world's oceans are thought to be one of the important factors controlling the global methane cycle. Marine sediments can act as hosts to gas hydrates under appropriate conditions of high pressure and/or low temperature, and sufficient organic carbon; on the other hand, they show a significant sensitivity to small perturbations in the physical and chemical conditions within the reservoir. During the Last Glacial, direct and indirect evidence accumulated from geochemical data suggests that methane episodically released from hydrate trapped in the seafloor sediments. Recently, Kennett and coworkers interpreted δ13C variations of planktonic and benthic foraminifera found in Last Glacial sediments in the Santa Barbara Basin (SBB) as evidence for periodic releases of methane, arising from the dissociation of methane hydrate, and its subsequent oxidation in bottom- and/or surface-water environments. This result provided the basis for the 'Clathrate Gun Hypothesis', which highlights the potential role of methane hydrate in Quaternary variations in atmospheric methane concentrations. According to recent observations of anomalous bottom-simulating reflections(BSR), the northwest Pacific marginal sediments around Japan main islands bear large abundances of methane hydrate. In this study, the piston cores from the continental slope sediments in the Oyashio current region, which recently is found to bear immense amounts of methane hydrate, have been investigated about planktonic and benthic foraminiferal carbon isotope records during the past 34 cal. kyr BP. Moreover, in order to investigate

  18. Periodic isolation of the southern coastal plain of South Africa and the evolution of modern humans over late Quaternary glacial to interglacial cycles

    Science.gov (United States)

    Compton, J. S.

    2012-04-01

    Humans evolved in Africa, but where in Africa and by what mechanisms remain unclear. The evolution of modern humans over the last million years is associated with the onset of major global climate fluctuations, glacial to interglacial cycles, related to the build up and melting of large ice sheets in the Northern Hemisphere. During interglacial periods, such as today, warm and wet climates favored human expansion but during cold and dry glacial periods conditions were harsh and habitats fragmented. These large climate fluctuations periodically expanded and contracted African ecosystems and led to human migrations to more hospitable glacial refugia. Periodic isolation of relatively small numbers of humans may have allowed for their rapid evolutionary divergence from the rest of Africa. During climate transitions these divergent groups may have then dispersed and interbred with other groups (hybridization). Two areas at the opposite ends of Africa stand out as regions that were periodically isolated from the rest of Africa: North Africa (the Maghreb) and the southern coastal plain (SCP) of South Africa. The Maghreb is isolated by the Sahara Desert which periodically greens and is reconnected to the rest of Africa during the transition from glacial to interglacial periods. The SCP of South Africa is isolated from the rest of Africa by the rugged mountains of the Cape Fold Belt associated with inedible vegetation and dry climates to the north. The SCP is periodically opened when sea level falls by up to 130 m during glacial maxima to expose the present day submerged inner continental shelf. A five-fold expansion of the SCP receiving more rainfall in glacial periods may have served as a refuge to humans and large migratory herds. The expansive glacial SCP habitat abruptly contracts, by as much as one-third in 300 yr, during the rapid rise in sea level associated with glacial terminations. Rapid flooding may have increased population density and competition on the SCP to

  19. Vast laminated diatom mat deposits from the west low-latitude Pacific Ocean in the last glacial period

    Institute of Scientific and Technical Information of China (English)

    ZHAI Bin; LI Tie Gang; CHANG Feng Ming; CAO Qi Yuan

    2009-01-01

    Diatoms are one of the predominant contributors to global carbon fixation by accounting for over 40% of total oceanic primary production and dominate export production. They play a significant role in marine biogeochemistry cycle. The diatom mat deposits are results of vast diatoms bloom. By analysis of diatom mats in 136°00'-140°00'E, 15°00'-21°00'N, Eastern Philippines Sea, we identified the spe-cies of the diatoms as giant Ethmodiscus rex (Wallich) Hendey. AMS ~(14)C dating shows that the sedi-ments rich in diatom mats occurred during 16000-28600 a B.P., which means the bloom mainly occurred during the last glacial period, while there are no diatom mat deposits in other layers. Preliminary analysis indicates that Antarctic Intermediate Water (AAIW) expanded northward and brought silicate-rich water into the area, namely, silicon leakage processes caused the bloom of diatoms. In addition, the increase of iron input is one of the main reasons for the diatom bloom.

  20. Planktonic Foraminiferal Shell Weight Variability From The Cariaco Basin: Insights Into Carbon Dioxide Concentrations During The Last Glacial Period

    Science.gov (United States)

    McConnell, M. C.; Thunell, R.; Peterson, L. C.; Astor, Y.

    2010-12-01

    Here we present decadal scale records of sediment color reflectance, planktonic foraminiferal shell weight variability, and planktonic foraminiferal carbon isotope composition (δ13C) from the Cariaco Basin, Venezuela for the last glacial period (Marine Isotope Stage 3; ~32-55kyrBP) and demonstrate that the temporal variability in the records is associated with established stadial/interstadial climate oscillations. Sediment trap results from the Cariaco Basin suggest that the shell weight variability is driven, in part, by changes in the surface water carbonate ion concentration [CO3=]. Using the modern relationship between shell weight and [CO3=] for this location, we estimate down-core [CO3=] variability during MIS 3 in order to assess past changes in the surface seawater partial pressure of carbon dioxide (pCO2). This record also provides insight into past changes in pH. We find that the Cariaco Basin was a source for atmospheric carbon dioxide during this time interval and that pCO2 underwent large stadial/interstadial oscillations with higher values during interstadials than during stadials.

  1. Characteristics of ancient Egyptian glazed ceramic objects from Fatimid and Mamluk periods as revealed by ion beam analysis

    Science.gov (United States)

    Sadek, Hamada; M, Abd El Hady M.

    2012-07-01

    Ion beam analysis (PIXE, μPIXE) has been successfully applied in analysis of archaeological materials, it has many advantages. In this work Ion Beam Analysis (IBA) used in analysis of ancient Egyptian glazed ceramic from 10th to the 16th centuries (Fatimid and Mamluk periods). Glazed ceramic samples from Al-Fustat Excavation store have been chosen to represent different colours (green, blue, brown, black ...etc), the colours of glaze depend on many factors such as oxides present in the glaze layer, fluxes and the conditions in which objects had been manufactured in the past. Ion Beam allows the identification of elemental composition of the glaze layer i.e., the information about colorants used in glaze, which is of great importance for compositional data play a key role in solving questions concerning dating, provenance, technology, use and the relationship between ancient cultures with the environment.

  2. Characteristics of ancient Egyptian glazed ceramic objects from Fatimid and Mamluk periods as revealed by ion beam analysis

    International Nuclear Information System (INIS)

    Ion beam analysis (PIXE, μPIXE) has been successfully applied in analysis of archaeological materials, it has many advantages. In this work Ion Beam Analysis (IBA) used in analysis of ancient Egyptian glazed ceramic from 10th to the 16th centuries (Fatimid and Mamluk periods). Glazed ceramic samples from Al-Fustat Excavation store have been chosen to represent different colours (green, blue, brown, black ...etc), the colours of glaze depend on many factors such as oxides present in the glaze layer, fluxes and the conditions in which objects had been manufactured in the past. Ion Beam allows the identification of elemental composition of the glaze layer i.e., the information about colorants used in glaze, which is of great importance for compositional data play a key role in solving questions concerning dating, provenance, technology, use and the relationship between ancient cultures with the environment.

  3. Characterization of ancient Japanese glass excavated from archaeological sites of the Epi-Jomon period in Hokkaido by XRF analysis

    International Nuclear Information System (INIS)

    Ancient glass beads from the Epi-Jomon period, excavated from 7 archaeological sites in Hokkaido, were non-destructively analyzed by using a portable XRF spectrometer. The origin and distribution of the glass beads were analyzed based on their quantitative chemical compositions. The chemical compositions of glass beads from Hokkaido can be classified into two glass types based on their major components: i.e., potash silica glass type (K2O–SiO2) and soda lime silica glass (Na2O–CaO–SiO2). The heavy trace element compositions of glass beads excavated from Hokkaido were basically similar to those excavated from the Kyushu region, Kanto region and Southeast Asia, as reported in our previous studies. From these results it has been found for the first time that glass beads exist with the same origin as those from Honshu distributed in Hokkaido in Epi-Jomon period. (author)

  4. On landscape planning for Ancient City of Spring and Autumn Period%春秋古城景观规划

    Institute of Scientific and Technical Information of China (English)

    罗晓祥

    2012-01-01

    According to the design idea of making up the urban texture and reshaping the historical space, the paper reflects the local features and the culture of the Spring and Autumn Period, illustrates the planning ideas for the tourist resorts by combining the historical culture of the ancient city with the modern one perfectly and redisplaying the vicissitude, the classical elegance and the magnificence of the former city, and highlights the design ideas for the ancient building space with the sense of recognition and the art of the North folk buildings, so as to provide some reference for the design of landscape planning for relative tourist real estate%按照“织补城市肌理,再现历史空间”的设计理念,在体现肥城本地地方特色和春秋文化底蕴的同时,注入旅游景区的规划理念,使古城历史文化与现代都市完美结合,再现昔日古城的沧桑、古朴与庄重,突出了具有认同感和北方民居神韵的古建筑空间设计理念,旨在为相关旅游地产景观规划设计提供参考借鉴。

  5. Native of the marble in ancient city, Nysa on the Meander of Hellenistic and Roman Period, Aydin- Western Anatolia - Turkey

    Science.gov (United States)

    Kadioğlu, M.; Kadioğlu, Y. K.

    2008-07-01

    Nysa, one of the most important cities of Caria in Hellenistic and Roman period, is located on the highway connecting Aydin (ancient name Tralleis) and Denizli, at about three kilometres northwest of Sultanhisar in western Anatolia of Turkey. The archaeological remains of Nysa are located on the slopes on the side of the stream called Tekkecik. The buildings, streets and public squares of the ancient city were supported by vaulted substructures adapted to the topographic conditions. As to the foundation of the city, Strabo relates that three brothers named Athymbros, Athymbrados, and Hydrelos came from Lakedaimon to Caria, and founded there three cities named after themselves. The small rock samples from the building of theatre, stadium, basement of agora and tomb were collected and determined under polarized microscope and confocal Raman spectroscopy to find out the native of these rock sources. The results of these studies reveal that the main rocks of these structures are composed from white colour marble. These marbles have granoblastic texture and are composed of mainly pressure twinned calcite as coarse grain size. The confocal Raman specroscopical studies of reveal that the marble building stone of Nysa city are mainly obtained from Jurassic Cretaceous of Western Anatolia marble.

  6. Native of the marble in ancient city, Nysa on the Meander of Hellenistic and Roman Period, Aydin- Western Anatolia - Turkey

    International Nuclear Information System (INIS)

    Nysa, one of the most important cities of Caria in Hellenistic and Roman period, is located on the highway connecting Aydin (ancient name Tralleis) and Denizli, at about three kilometres northwest of Sultanhisar in western Anatolia of Turkey. The archaeological remains of Nysa are located on the slopes on the side of the stream called Tekkecik. The buildings, streets and public squares of the ancient city were supported by vaulted substructures adapted to the topographic conditions. As to the foundation of the city, Strabo relates that three brothers named Athymbros, Athymbrados, and Hydrelos came from Lakedaimon to Caria, and founded there three cities named after themselves. The small rock samples from the building of theatre, stadium, basement of agora and tomb were collected and determined under polarized microscope and confocal Raman spectroscopy to find out the native of these rock sources. The results of these studies reveal that the main rocks of these structures are composed from white colour marble. These marbles have granoblastic texture and are composed of mainly pressure twinned calcite as coarse grain size. The confocal Raman specroscopical studies of reveal that the marble building stone of Nysa city are mainly obtained from Jurassic Cretaceous of Western Anatolia marble

  7. Dust flux estimates for the Last Glacial Period in East Central Europe based on terrestrial records of loess deposits: a review

    Science.gov (United States)

    Újvári, Gábor; Kovács, János; Varga, György; Raucsik, Béla; Marković, Slobodan B.

    2010-11-01

    Loess-paleosol sequences are significant records of the mineral dust cycle of glacial-interglacial periods. As dust particles give rise to direct and indirect radiative forcing, obtaining a reliable picture of the global and regional patterns of mineral dust fluxes during glacial periods can lead to a better understanding of the contribution of mineral dust to past climate changes. Recent progress in absolute dating of loess deposits in the Carpathian Basin in East Central Europe made it possible to provide correct aeolian flux estimates for the Last Glacial period, marine isotope stage (MIS) 2. Mass accumulation rates (MARs) from chronological data of 33 loess sites exhibited a wide range of values, from 150 to 1422 g m -2 a -1, centered around median and mean values of 338 and 417 g m -2 a -1. MAR and MAR estimates have been also calculated using grain size measurements of many loess samples and loess MARs in order to facilitate comparison with models, and since particles larger than 10 μm have a negligible radiative effect. Here we show that some previous model simulations of the dust cycle at the Last Glacial Maximum (LGM) significantly underestimated the real aeolian flux (ranges of our estimates: MAR=34-324 and MAR=9.3-88.2 g m a) in East Central Europe. For this reason, some simulations of dust-induced direct radiative forcing of the LGM climate failed to yield reliable results for this mid-latitude region as they have been based on three-dimensional dust field models that are not capable of estimating the real aeolian fluxes in Central Europe. A recent global model of top of the atmosphere (TOA) radiative forcing by mineral aerosols at the LGM that has been based on more realistic parameterization of dust sources, transport, and deposition revealed zonally averaged surface cooling of -2 °C for the latitudes of our study area. This surface cooling and TOA radiative forcing (-2 to -3 W m -2) are greater than recognized in other models and draws our

  8. Refining the Icelandic tephrachronology of the last glacial period - The deep-sea core PS2644 record from the southern Greenland Sea

    Science.gov (United States)

    Voelker, Antje H. L.; Haflidason, Haflidi

    2015-08-01

    The PS2644 deep-sea core sequence, retrieved from the northwestern margin of Iceland and covering the last 86 ka, exhibits high sedimentation rates during the last glacial cycle that allow the clear distinction of Greenland stadial (GS)/interstadial (GI) cycles in the various proxy records. Abundance records of rhyolitic, basaltic and tachylytic tephra grains reveal several maxima. Tephra grains of all types were geochemically analyzed in 44 levels. A total of 92 tephras with a distinctive character have been defined within the glacial sequence of gravity core PS2644-5, whereas the Holocene record is dominated by reworked Vedde Ash grains and not suitable for tephra stratigraphic work. Of the 92 tephras only 19 geochemical populations have been linked with confidence to previously defined tephras such as from the Vedde Ash, Faeroe Marine Ash Zones (FMAZ) II and III and North Atlantic Ash Zone (NAAZ) II. For the glacial period informal names were given to 78 new tephras, most of which are basaltic tephras. Several of these layers have a unique geochemical character and might become new chronostratigraphic markers in the North Atlantic region. Linking the tephra populations to the volcanic system producing them, respectively, revealed that Icelandic eruptions dominate with 83 tephra geochemical populations and Jan Mayen with 9. Around 48% of the informal tephra layers linked to the Icelandic volcanic province are produced from either the Grimsvötn or the Veidivötn-Bardarbunga volcanic systems. The intervals spanning from Greenland Stadial (GS) 3 to Greenland Interstadial (GI) 4 (24.5-29 ka BP), from GI 8 to GS 10 (36.9-40.5 ka BP) and from GI 14 to GI 15.2 (50-56 ka BP) are the periods with the highest number of eruptions, all of which are associated with known tephra zones.

  9. High-resolution climate records from two stalagmites in Qixin Cave, southern Guizhou, and Heinrich events during the last glacial period

    Institute of Scientific and Technical Information of China (English)

    ZhangMeiliang; ChengHai; YuanDaoxian; LinYushi; QinJiaming; WangHuat; FengYumei; TuLingling; ZhangHuiling

    2004-01-01

    The time sequence of high-resolution paleoclimatic changes since the last glacial period--60,500 yr B.P.--has been reconstructed with high-precision TIMS-U series dates and analyses of the oxygen isotopes from Q4 and Q6 stalagmites of the Qixin Cave in southern Guizhou. Comparative analyses of δ18O curves from the GISP2' ice core and the two stalagmites shows that the depositional records of the Dansgaard-Oeschger cycle events 1-18 and Heinrich's events H1-H5 from the records of the two stalagmites reflect rapid climate changes over a short time scale since the last glacial stage, and indicates the precise boundary lines at which the cold events occurred. The study results have shown that the records of the cold and warm events from the two stalagmites since 60,500 yr B.P. are the reflection of the paleo-monsoon circulation. Changes are clearly affected by the climate oscillation of the North Atlantic Ocean, and indicate that they have a strong teleconnection with the paleoclimate changes that occurred in the North Polar region. The records of δ18O from the Q4 and Q6 stalagmites indicate that the δ18O values from 60,590 yr B.P. to 11,290 yr B.P. changed from a more negative (or lighter)drift to a heavier or positive drift trend in the last glacial period. The data reflect the weakening of the Asian summer monsoon and the climate which generally became drier and cooler.

  10. INAA OF SOME ANCIENT COINS FROM POST GUPTA PERIOD AND MUGHAL SALTANAT

    Institute of Scientific and Technical Information of China (English)

    NilimaSRajurkar; AKJha; 等

    1994-01-01

    Non-destructive analysis of some electrum coins from post Gupta period and of coins from different mints of Mughal emperors,Shahjahan and Aurangzed.have been done by instrumental neutron activation analysis(INAA) using 252Cf neutron source.The elemental content of these coins are determined by comparator method by mneasuring the activities of the radioisotopes formed after(n,γ) reactions,at their corresponding photopeaks.It is found that identified electrum coins contain copper as a major component and hence can be termed as cupro-electrum coins.As regards the analysis of coins from different mints there is no much variation in silver content while copper content varies from mint to mint.Coins from both the emperore are found to contain considerable amount of gold.

  11. Glacial cycles

    DEFF Research Database (Denmark)

    Kaufmann, R. K.; Juselius, Katarina

    We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr-present). To do so, we estimate models of varying complexity...... and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed...... to simulate glacial cycles accurately. Also, results suggest that non-linear 10 dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles....

  12. Sediment from the Last Two Glacial Periods Amalgamated and Re-Entrained in the Alluvial Piedmont of the North Tian Shan

    Science.gov (United States)

    Malatesta, L. C.; Avouac, J. P.; Brown, N.; Rhodes, E. J.; Prancevic, J.; Pan, J.; Chevalier, M. L.; Saint-Carlier, D.; Zhang, W.

    2015-12-01

    The history of the planet is recorded in its sedimentary basins where the product of mountain erosion is stored, reflecting climatic and tectonic forcing. Were the sediments and the signal they carry to be immediately deposited in a basin, paleo-reconstructions would be straightforward as the age and nature of a deposit would be a testimony of the source and transfer conditions. The sometime intricate path of clastic material along the sediment routing system complicates greatly the situation. We set here to investigate quantitatively the effect of an alluvial piedmont on the sediment flux that crosses it en route to a basin. We focus on the northern piedmont of the Tian Shan (Xinjiang, China). The piedmont is actively deformed by a fold-and-thrust system and experienced several cycles of incision and aggradation in the Pleistocene. We present new OSL dating of terrace and fan material. These data suggest that the most prominent terraces match three glacial maxima 100 kyr apart; thereby the landscape would primarily react to eccentricity cycles. As a consequence, a significant fraction of sediments produced in that period is temporarily deposited in the piedmont before a later incision phase can deliver it to the basin. The OSL ages of alluvial fan strata exposed and recently eroded by the incising river hint at two aggradation phases during the last two glacial periods. Furthermore lose sediment dated at 300 ka is found to be available along the transport route of the sediments and likely entrained during incision phases. We expect the modern sediment flux entering the basin to contain a significant amount of recycled material as old as 180 ka and a non-negligible amount of recycled material as old as 300 ka that can significantly skew geochemical or provenance studies if ignored.

  13. Medicines in ancient period

    Digital Repository Service at National Institute of Oceanography (India)

    Netravalkar, M.G.S.

    stream_size 7 stream_content_type text/plain stream_name New_Trend_Indian_Art_Archaeol_1992_387.pdf.txt stream_source_info New_Trend_Indian_Art_Archaeol_1992_387.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset...

  14. Maternal and paternal genetic diversity of ancient sheep in Estonia from the Late Bronze Age to the post-medieval period and comparison with other regions in Eurasia.

    Science.gov (United States)

    Rannamäe, E; Lõugas, L; Niemi, M; Kantanen, J; Maldre, L; Kadõrova, N; Saarma, U

    2016-04-01

    Sheep were among the first domesticated animals to appear in Estonia in the late Neolithic and became one of the most widespread livestock species in the region from the Late Bronze Age onwards. However, the origin and historical expansion of local sheep populations in Estonia remain poorly understood. Here, we analysed fragments of the hypervariable D-loop of mitochondrial DNA (mtDNA; 213 bp) and the Y-chromosome SRY gene (130 bp) extracted from 31 archaeological sheep bones dated from approximately 800 BC to 1700 AD. The ancient DNA data of sheep from Estonia were compared with ancient sheep from Finland as well as a set of contemporary sheep breeds from across Eurasia in order to place them in a wider phylogeographical context. The analysis shows that: (i) 24 successfully amplified and analysed mtDNA sequences of ancient sheep cluster into two haplogroups, A and B, of which B is predominant; (ii) four of the ancient mtDNA haplotypes are novel; (iii) higher mtDNA haplotype diversity occurred during the Middle Ages as compared to other periods, a fact concordant with the historical context of expanding international trade during the Middle Ages; (iv) the proportion of rarer haplotypes declined during the expansion of sheep from the Near Eastern domestication centre to the northern European region; (v) three male samples showed the presence of the characteristic northern European haplotype, SNP G-oY1 of the Y-chromosome, and represent the earliest occurrence of this haplotype. Our results provide the first insight into the genetic diversity and phylogeographical background of ancient sheep in Estonia and provide basis for further studies on the temporal fluctuations of ancient sheep populations. PMID:26805771

  15. A regional overview of the last glacial period in the temperate NE Atlantic: varying paleoproductivity centers over the last 50 ka BP

    Science.gov (United States)

    Penaud, Aurélie; Eynaud, Frédérique; Ganne, Axelle

    2015-04-01

    Recent palynological investigations carried out in the eastern Gulf of Cadiz (MD99-2339 core) over MIS 3 enable to consider dinoflagellate cyst assemblage patterns over the last 50 ka BP through a compilation of 6 cores from the NE subtropical Atlantic to the Northern Bay of Biscay (also including cores MD95-2042, MD95-2043, MD04-2805CQ, VK03-58bis). Dinocyst signals depict hydrological front latitudinal shifts over the last glacial and associated sea-surface consequences regarding past regimes of primary productivity. We show here new data clearly evidencing subtropical latitudes of Cadiz as being as productive areas over the last glacial as recorded today in the septentrional part of the Bay of Biscay, especially between GI 8 and GI 12. We especially focus on dinocyst-species Lingulodinium machaerophorum relative abundances and absolute concentrations that we first evidence as a powerful tool to reconstruct and discuss productivity shifts through time in the temperate North Atlantic. This spatio-temporal synthesis bring important evidences of fast migrating paleoproductiviy centers from the last glacial period to present, implying also large consequences on the biological pump through time. Regarding this specific session, 5 of the 6 cores discussed here were retrieved by the R/V Marion Dufresne through 3 different cruises: Core MD99-2339 (35.89°N, 7.53°W, 1170m water depth, 18.54m long) was retrieved in a contouritic field in the oriental part of the Gulf of Cadiz by the oceanographic R/V Marion Dufresne during the 1999 International Marine Global Change Studies V (IMAGES V) cruise (Labeyrie, Jansen and Cortijo, 2003). Cores MD95-2042 (37°48'N, 10°10'W, 3146m water depth, 39.56m long) and MD95-2043 (36°8.6'N, 2°37.3'W, 1841m water depth, 36m long) were retrieved from the SW Iberian margin and the central Alboran Sea, respectively, by the oceanographic R/V Marion Dufresne during the 1995 IMAGES I cruise (Bassinot and Labeyrie, 1996). Core MD04-2805 CQ (34

  16. Sediment-palaeosol successions in Calabria and Sardinia suggest spatially differentiated palaeo-vegetation patterns in southern Italy during the Last Glacial period

    Science.gov (United States)

    Sauer, Daniela; Zucca, Claudio; Al-Sharif, Riyad; Zwanzig, Lisa; Madrau, Salvatore; Andreucci, Stefano; Pascucci, Vincenzo; Kadereit, Annette; Scarciglia, Fabio; Brückner, Helmut

    2016-04-01

    Several lakes on the southern Italian peninsula provide valuable palaeoenvironmental archives of the Last Glacial period. These archives include, e.g., the long high-resolution record from varved lake sediments of Lago Grande di Monticchio, the bigger one of two maar lakes situated on top of Mt. Vulture. Its pollen record indicates (1) temperate deciduous forest during MIS5.2-MIS5.1 (St. Germain 2); (2) frequent vegetation fluctuations, then Artemisia steppe during MIS5.1-MIS4; (3) alternations between open steppe (stadials) and wooded steppe (interstadials) during MIS3; and (4) open steppe during MIS2 (Last Glacial Maximum). However, only few palaeosol records of this period have been reported from southern Italy in the literature so far. Such records would allow for gaining insight also into spatial patterns of the vegetation cover during this period that should have formed, e.g., according to relief, elevation, and continentality gradient (related to the much lower coastline during the last glacial period). So far, we have studied three sediment-palaeosol successions in southern Italy, two in the Calabria region, and one in north-western Sardinia. All of them have developed in alluvial fan deposits resting on littoral sediments of the Last Interglacial period (MIS 5). The southernmost succession studied is located near Lazzaro (south of Reggio di Calabria). It is exposed in an alluvial fan overlying the MIS5.5 terrace. Due to strong tectonic uplift (1.3 m ka-1) the alluvial fan has been dissected by the same creek which previously had built it up. Therefore, its internal structure is exposed, exhibiting a detailed sediment-palaeosol sequence. The palaeosols are mainly characterized by accumulation of soil organic matter (SOM), bioturbation and secondary carbonates. They represent Chernozem- and Phaeozem-like soils that most likely formed under steppe to forest steppe. SOM of the two uppermost Lazzaro palaeosols was 14C-dated to 26.8-28.8 ka cal BP and 28

  17. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    Directory of Open Access Journals (Sweden)

    C. Albrecht

    2010-05-01

    Full Text Available Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date.

    For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200 from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5–263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70% and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period.

    We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also

  18. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    Science.gov (United States)

    Albrecht, C.; Vogel, H.; Hauffe, T.; Wilke, T.

    2010-05-01

    Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR) dating of mollusc shells from the same stratigraphic level yielded an age of 130±28 ka. Lithofacies III sediments, i.e. a subdivision of the stratigraphic unit comprising the basal succession of core Co1200 between 181.5-263 cm appeared solid, grayish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO3>70%) and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species) could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated. The agreement between sediment and palaeontological proxies was tested. The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial period. We tested for major faunal changes since the Last Interglacial period and searched for signs of extinction events. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5-25 m) mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid sediment cores also has great significance for future deep drilling

  19. Steppe to forest steppe ecosystems during the last glacial period in S Italy - evidence from sediment-paleosol sequences, compared to lacustrine archives and marine data

    Science.gov (United States)

    Sauer, Daniela; Zwanzig, Lisa; Scarciglia, Fabio; Kadereit, Annette; Brauer, Achim; Al-Sharif, Riyad; Brückner, Helmut

    2013-04-01

    During fieldwork on marine terraces near Lazzaro (Calabria, Southern Italy) in 2010 we discovered an alluvial fan overlying the MIS 5.5 terrace. Due to strong tectonic uplift (1.3 m ka-1) the alluvial fan was dissected by the same creek which previously had built it up. Thus, the internal structure of the fan was exposed, exhibiting a detailed sediment-paleosol sequence. The paleosols are mainly characterized by accumulation of soil organic matter (SOM), bioturbation and secondary carbonates. They represent Chernozem- and Phaeozem-like soils that very likely formed in steppe to forest steppe ecosystems. Strong carbonate accumulations occur in the lowermost part of the profile, between 513 and 693 cm depth. Their thickness and in parts massive character suggest that slope water contributed to the carbonate accumulations. Similar environmental conditions as reflected in the Lazzaro paleosols were reconstructed from the pollen record of Lago Grande di Monticchio, which indicates from 87.98 to 82.73 ka (MIS5b-a) a temperate deciduous forest (St. Germain 2); from 82.73 to 59.00 ka (MIS5a-4) first frequent vegetation fluctuations then Artemisia steppe, from 59.00 to 25.90 ka (MIS3) alternation between open steppe (stadials) and wooded steppe (interstadials); and from 25.90 to 14.30 ka (MIS2) again open steppe (Last Glacial Maximum). SOM of the two uppermost Lazzaro paleosols was 14C-dated to 26.8-28.8 cal ka BP and 28.9-30.3 cal ka BP, respectively. Thus, the formation of these soils falls into the period for which the lacustrine record indicates an alternation between open and wooded steppe. It is still an open question whether the sedimentation that interrupted the ecologically stable times of soil formation was triggered by fluctuations in climate and vegetation cover or by tectonics. The observation that the ages of the paleosols match a period of frequent environmental oscillations suggests that the phases of sedimentation are to a certain degree driven by

  20. Oxygen-isotope variations in post-glacial Lake Ontario

    Science.gov (United States)

    Hladyniuk, Ryan; Longstaffe, Fred J.

    2016-02-01

    The role of glacial meltwater input to the Atlantic Ocean in triggering the Younger Dryas (YD) cooling event has been the subject of controversy in recent literature. Lake Ontario is ideally situated to test for possible meltwater passage from upstream glacial lakes and the Laurentide Ice Sheet (LIS) to the Atlantic Ocean via the lower Great Lakes. Here, we use the oxygen-isotope compositions of ostracode valves and clam shells from three Lake Ontario sediment cores to identify glacial meltwater contributions to ancient Lake Ontario since the retreat of the LIS (∼16,500 cal [13,300 14C] BP). Differences in mineralogy and sediment grain size are also used to identify changes in the hydrologic regime. The average lakewater δ18O of -17.5‰ (determined from ostracode compositions) indicates a significant contribution from glacial meltwater. Upon LIS retreat from the St. Lawrence lowlands, ancient Lake Ontario (glacial Lake Iroquois) lakewater δ18O increased to -12‰ largely because of the loss of low-18O glacial meltwater input. A subsequent decrease in lakewater δ18O (from -12 to -14‰), accompanied by a median sediment grain size increase to 9 μm, indicates that post-glacial Lake Ontario received a final pulse of meltwater (∼13,000-12,500 cal [11,100-10,500 14C] BP) before the onset of hydrologic closure. This meltwater pulse, which is also recorded in a previously reported brief freshening of the neighbouring Champlain Valley (Cronin et al., 2012), may have contributed to a weakening of thermohaline circulation in the Atlantic Ocean. After 12,900 cal [11,020 14C] BP, the meltwater presence in the Ontario basin continued to inhibit entry of Champlain seawater into early Lake Ontario. Opening of the North Bay outlet diverted upper Great Lakes water from the lower Great Lakes causing a period (12,300-8300 cal [10,400-7500 14C] BP) of hydrologic closure in Lake Ontario (Anderson and Lewis, 2012). This change is demarcated by a shift to higher δ18Olakewater

  1. Glacial hydrology

    International Nuclear Information System (INIS)

    Glacial hydrology studies in the Hintereisferner and Kesselwandferner glaciers (Rosenache, Oetztal Alps, Austria) are reported. This comprises intraglacial drainage rates and paths and times of residue of the molten water inside and near the glacier as determined by tracer studies (T, D, 0-18, fluorescence tracers). With 1 separate map

  2. Ancient DNA

    DEFF Research Database (Denmark)

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair......ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair...

  3. Neotropical vegetation response to rapid climate changes during the last glacial period: Palynological evidence from the Cariaco Basin

    Science.gov (United States)

    González, Catalina; Dupont, Lydie M.; Behling, Hermann; Wefer, Gerold

    2008-03-01

    We present new palynological information from the anoxic Cariaco Basin, off Venezuela, that provides insight into the response of northernmost South American vegetation to rapid climate changes between 68 and 28 ka, specifically during North Atlantic Heinrich events (HEs) and Dansgaard/Oeschger cycles. We defined three different vegetation modes: (1) an interstadial mode characterized by the highest pollen concentration and the maximum extension of semi-deciduous and evergreen forests; (2) a stadial mode characterized by increases of salt marshes, herbs, and montane forests; and (3) a Heinrich event mode characterized by the lowest pollen concentrations, abrupt increases of salt marshes, and decreased forest abundance. Similarly, indices of C4/C3 plants show increases during stadials with clear peaks during the onset of HEs, though grasslands did not become dominant during these periods. We alternatively propose that these expansions of C4 plants are associated with the expansion of coastal salt marshes. Our vegetation record suggests the prevalence of humid conditions during interstadials, dry and cold conditions during stadials, and dry and cold conditions together with changes in sea level during HEs. This new palynological evidence supports previous interpretations that main environmental changes in northernmost South America were driven by latitudinal displacements of the Intertropical Convergence Zone and sea-level changes.

  4. Millennial-scale records of North American Monsoon in time and space during the last glacial period: reconstructions from arid northern Mexico

    Science.gov (United States)

    Roy, P.; Quiroz-Jiménez, D.; Charles-Polo, M.; Lozano-Santacruz, R.

    2013-05-01

    The arid northern Mexico is part of the Sonora and Chihuahua Deserts and both the deserts belong to the North American Desert system. The North American Monsoon (NAM) or Mexican Monsoon refers to the system that brings summer precipitation to arid northern Mexico and southwestern USA. It contributes ca. 70-80% of total annual precipitation along the western slopes of the Sierra Madre Occidental (northern Mexico) and ca. 40-50% of total precipitation in Arizona and New Mexico (southwest USA). High-resolution geochemical data from lacustrine deposits located between 23°N and 31°N (paleolakes La Salada, Babicora and San Felipe) provide spatio-temporal and millennial-scale paleohydrological records related to the dynamics of summer precipitation as well as westerly winter storms over the last glacial period. The inverse relationship between proxy records of runoff into lacustrine basins of northern Mexico and winter precipitation over the southwestern USA indicate that the westerly winter storms had minimal influence south of 30°N and the paleohydrological changes are mainly summer precipitation controlled. The variation in summer season precipitation between 20 and 60 cal. kyr BP was driven by long term changes in summer insolation. During an interval of lower summer insolation (i.e. >60 cal. kyr BP), the higher summer precipitation could be related to the NAM expansion as a result of reduced north hemisphere ice sheets. On a millennial-scale, the region received more than average precipitation during the warm interstadials and vice versa.

  5. The Impacts of Glacial Recession on Riverine Nutrient Fluxes and the Age and Bioavailability of Riverine DOM in Gulf of Alaska Watersheds

    Science.gov (United States)

    Hood, E.; Fellman, J.; Spencer, R.; Scott, D.

    2009-05-01

    Watersheds draining into the Gulf of Alaska (GOA) contain 75,300 km2 of glacier ice and are experiencing some of the highest rates of glacial erosion on earth, with thinning rates exceeding 5 meters of water equivalent at low elevations. This ongoing loss of glacial ice is rapidly altering landcover in GOA watersheds and has important implications for the physical and biogeochemical properties of rivers as well as the delivery of freshwater and nutrients to near-shore marine ecosystems along the GOA. We are studying the effects of changing glacial coverage on watershed biogeochemistry in eleven coastal watersheds along the GOA that vary markedly in watershed glacial coverage (range = 0-64%, mean = 36%). Our results indicate that decreased glacial coverage is strongly correlated with the temperature (r2=0.92, pGOA after the hypsothermal warm period ( ˜3,000-5,000 yrs bp). Interestingly, the lability of DOM was significantly positively correlated with 14C age such that the ancient DOM in glacial rivers was highly bioavailable to marine microorganisms. Using a distributed GIS model to estimate dissolved organic carbon fluxes from GOA glaciers, we conservatively estimate that glacial runoff contributes 0.14±0.01 Tg C yr- 1 to freshwater and near-shore marine ecosystems along the GOA. These findings suggest that glacial runoff from GOA watersheds, which is rapidly being altered by climate warming, may be an important source of labile DOM and nutrients to aquatic ecosystems.

  6. Evidence of reworking and resuspension of carbonates during last glacial maximum and early deglacial period along the southwest coast of India

    Indian Academy of Sciences (India)

    Kamlesh Verma; M Sudhakar

    2006-12-01

    A gravity core collected from the upper slope of southwest of Quilon at a water depth of 776m (Lat: 8° 12′ 263′′N, Long: 76° 28′ 281′′E) was analysed for texture (carbonate free), calcium carbonate and organic carbon. Variation in silicic fraction seems to be controlled by silt, i.e., enrichment from 15 ka BP to 10 ka BP and then constant in Holocene. Below 15 ka BP, the silicic fraction gets depleted compared to the Holocene section with a minimum around 21 ka BP. Clay content remains nearly constant except in the Holocene where it shows an enrichment. Carbonate content of less than 63 micron when computed by subtracting coarse fraction content from the total carbonate suggests that the total carbonates are mainly concentrated in the finer fraction. All these carbonate phases show an inverse relationship with silicic fraction except in Holocene. Below 15 ka BP, CaCO3 dominates in sediments comprising more than 65%, such an increase is also seen in the coarse fraction. Coarse fraction from these sections contains abundant nodular type aggregates encrusting small forams. This period is marked by a high sedimentation rate comparable to Holocene. These parameters suggest that the productivity and precipitation have increased in the Holocene due to the intensification of the southwest monsoon. During the last glacial maximum and early deglacial period the high sedimentation rate indicates redeposition of the carbonates from the existing carbonate lithofacies situated between Quilon and Cape Comorin probably due to the slope instability.

  7. Studying Ancient History.

    Science.gov (United States)

    Barrow, Robin

    1982-01-01

    Defends the value and relevance of the study of ancient history and classics in history curricula. The unique homogeneity of the classical period contributes to its instructional manageability. A year-long, secondary-level course on fifth-century Greece and Rome is described to illustrate effective approaches to teaching ancient history. (AM)

  8. Ancient Egypt

    Science.gov (United States)

    Swamy, Ashwin Balegar

    This thesis involves development of an interactive GIS (Geographic Information System) based application, which gives information about the ancient history of Egypt. The astonishing architecture, the strange burial rituals and their civilization were some of the intriguing questions that motivated me towards developing this application. The application is a historical timeline starting from 3100 BC, leading up to 664 BC, focusing on the evolution of the Egyptian dynasties. The tool holds information regarding some of the famous monuments which were constructed during that era and also about the civilizations that co-existed. It also provides details about the religions followed by their kings. It also includes the languages spoken during those periods. The tool is developed using JAVA, a programing language and MOJO (Map Objects Java Objects) a product of ESRI (Environmental Science Research Institute) to create map objects, to provide geographic information. JAVA Swing is used for designing the user interface. HTML (Hyper Text Markup Language) pages are created to provide the user with more information related to the historic period. CSS (Cascade Style Sheets) and JAVA Scripts are used with HTML5 to achieve creative display of content. The tool is kept simple and easy for the user to interact with. The tool also includes pictures and videos for the user to get a feel of the historic period. The application is built to motivate people to know more about one of the prominent and ancient civilization of the Mediterranean world.

  9. Sediment core fossils in ancient Lake Ohrid: testing for faunal change in molluscs since the Last Interglacial period

    OpenAIRE

    Albrecht, C.; H. Vogel; Hauffe, T.; Wilke, T.

    2010-01-01

    Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harboring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date.

    For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200) from the nor...

  10. Southern Hemisphere imprint for Indo-Asian summer monsoons during the last glacial period as revealed by Arabian Sea productivity records

    Science.gov (United States)

    Caley, T.; Zaragosi, S.; Bourget, J.; Martinez, P.; Malaizé, B.; Eynaud, F.; Rossignol, L.; Garlan, T.; Ellouz-Zimmermann, N.

    2013-11-01

    The monsoon is one of the most important climatic phenomena: it promotes inter-hemispheric exchange of energy and affects the economical prosperity of several countries exposed to its seasonal seesaw. Previous studies in both the Indian and Asian monsoon systems have generally suggested a dominant northern hemispheric (NH) control on summer monsoon dynamics at the scale of suborbital-millennial climatic changes, while the forcing/response of Indian and Asian monsoons at the orbital scale remains a matter of debate. Here, six marine sediment cores distributed across the whole Arabian Sea are used to build a regional surface marine productivity signal. The productivity signal is driven by the intensity of Indian summer monsoon winds. Our results demonstrate the existence of an imprint of suborbital southern hemispheric (SH) temperature changes (i.e. Antarctica) on the Indian summer monsoon during the last glacial period that is generally not recognized. During the last deglaciation, the NH played a more significant role. This suggests that fluctuations in the Indian monsoon are better explained in a bipolar context. The δ18O signal recorded in the Asian monsoon speleothem records could be exported by winds from the Indian summer monsoon region, as recently proposed in modelling exercise, explaining the SH signature observed in Asian cave speleothems. Contrary to the view of a passive response of Indian and Asian monsoons to NH anomalies, the present results appear to suggest that the Indo-Asian summer monsoon plays an active role in amplifying millennial inter-hemispheric asymmetric patterns. Additionally, this study confirms previously observed differences between Indian and Asian speleothem monsoonal records at the orbital-precession scale.

  11. Influences of glacial melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin

    Science.gov (United States)

    Aiken, George R.; Robert Spencer; Striegl, Rob; Schuster, Paul F.; Peter Raymond

    2016-01-01

    Responses of near-surface permafrost and glacial ice to climate change are of particular significance for understanding long-term effects on global carbon cycling and carbon export by high-latitude northern rivers. Here we report Δ14C-dissolved organic carbon (DOC) values and dissolved organic matter optical data for the Yukon River, 15 tributaries of the Yukon River, glacial meltwater, and groundwater and soil water end-member sources draining to the Yukon River, with the goal of assessing mobilization of aged DOC within the watershed. Ancient DOC was associated with glacial meltwater and groundwater sources. In contrast, DOC from watersheds dominated by peat soils and underlain by permafrost was typically enriched in Δ14C indicating that degradation of ancient carbon stores is currently not occurring at large enough scales to quantitatively influence bulk DOC exports from those landscapes. On an annual basis, DOC exported was predominantly modern during the spring period throughout the Yukon River basin and became older through summer-fall and winter periods, suggesting that contributions of older DOC from soils, glacial meltwaters, and groundwater are significant during these months. Our data indicate that rapidly receding glaciers and increasing groundwater inputs will likely result in greater contributions of older DOC in the Yukon River and its tributaries in coming decades.  

  12. Recenzja książki: Eleanor Dickey, Ancient Greek scholarship: a guide to finding, reading and understanding scholia, commentaries. lexica and grammatical treatises, from their beginnings to the Byzantine period, Oxford University Press, New York 2007, s. 362.

    OpenAIRE

    Chiżyńska, Katarzyna

    2012-01-01

    In this volume are included two flattering reviews, first of Eleanor Dickey, Ancient Greek scholarship: a guide to finding, reading and understanding scholia, commentaries, lexica and grammatical treatises, from their beginnings to the Byzantine period (New York 2007) and the second of René Nünlist, The ancient critic at work. Terms and concepts of literary criticism in Greek scholia (New York 2009). Both reviewed works focuses on Greek scholarship and are very helpful for modern scholars wit...

  13. A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy

    NARCIS (Netherlands)

    Rasmussen, Sune O.; Bigler, Matthias; Blockley, Simon P.; Blunier, Thomas; Buchardt, Susanne L.; Clausen, Henrik B.; Cvijanovic, Ivana; Dahl-Jensen, Dorthe; Johnsen, Sigfus J.; Fischer, Hubertus; Gkinis, Vasileios; Guillevic, Myriam; Hoek, Wim Z.; Lowe, J. John; Pedro, Joel B.; Popp, Trevor; Seierstad, Inger K.; Steffensen, Jørgen Peder; Svensson, Anders M.; Vallelonga, Paul; Vinther, Bo M.; Walker, Mike J.C.; Wheatley, Joe J.; Winstrup, Mai

    2014-01-01

    Due to their outstanding resolution and well-constrained chronologies, Greenland ice-core records provide a master record of past climatic changes throughout the Last Interglacial–Glacial cycle in the North Atlantic region. As part of the INTIMATE (INTegration of Ice-core, MArine and TErrestrial r

  14. [The campaign of returning to the ancient in sphygmology in the Republican Period as viewed from Mai xue cong shu (Series of Pulse Taking)].

    Science.gov (United States)

    Han, Sujie; Hu, Xiaofeng

    2015-01-01

    From the Southern and Northern Dynasties to the beginning of the Northern Song Dynasty, the models of "master and apprentice" and "physician of long family tradition for generations" were the main ways for teaching medical knowledge. With the rapid amassment of medical books in the Due to the rapid transmission of western science and technology into China in the Republican period, the art of pulse taking had been treated as unscientific. Yao Xinyuan advocated the recovery of ancient pulse taking of the three-portion approach, i.e., taking the pulses at the neck, hands, and feet for comparison. To spread this idea, Yao and Zhang Ziying compiled the Mai xue cong shu (Series of Pulse Taking) in 1937-1947. Altogether 4 issues were published carrying 29 articles concerning the theoretical exploration, experimental research, and clinical practice. Their thinking and approaches were influential to the study and development of modern sphygmology. PMID:26268252

  15. Biogeochemical evidence for freshwater periods during the Last Glacial Maximum recorded in lake sediments from Nam Co, south-central Tibetan Plateau

    OpenAIRE

    Roman Witt; Franziska Günther; Stefan Lauterbach; Thomas Kasper; Roland Mäusbacher; Tandong Yao; Gerd Gleixner

    2016-01-01

    Improved knowledge of deglaciation processes during the termination of the Last Glacial Maximum on the Tibetan Plateau can provide important information for understanding deglaciations in climate-sensitive high-altitude ecosystems. Little, however, is known about this time interval because most lacustrine sediment records from the Tibetan Plateau are younger than 19,000 years. This study focused on a lake sediment record from Nam Co, south-central Tibetan Plateau, covering the interval from ~...

  16. Ancient Egypt.

    Science.gov (United States)

    Evers, Virginia

    This four-week fourth grade social studies unit dealing with religious dimensions in ancient Egyptian culture was developed by the Public Education Religion Studies Center at Wright State University. It seeks to help students understand ancient Egypt by looking at the people, the culture, and the people's world view. The unit begins with outlines…

  17. The ancient tropical rainforest tree Symphonia globulifera L. f. (Clusiaceae) was not restricted to postulated Pleistocene refugia in Atlantic Equatorial Africa

    OpenAIRE

    Budde, K B; González-Martínez, S. C.; Hardy, O J; Heuertz, M

    2013-01-01

    Understanding the history of forests and their species' demographic responses to past disturbances is important for predicting impacts of future environmental changes. Tropical rainforests of the Guineo-Congolian region in Central Africa are believed to have survived the Pleistocene glacial periods in a few major refugia, essentially centred on mountainous regions close to the Atlantic Ocean. We tested this hypothesis by investigating the phylogeographic structure of a widespread, ancient rai...

  18. Ancient DNA

    OpenAIRE

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    In the past two decades, ancient DNA research has progressed from the retrieval of small fragments of mitochondrial DNA from a few late Holocene specimens, to large-scale studies of ancient populations, phenotypically important nuclear loci, and even whole mitochondrial genome sequences of extinct species. However, the field is still regularly marred by erroneous reports, which underestimate the extent of contamination within laboratories and samples themselves. An improved understanding of t...

  19. The amount of glacial erosion of the bedrock

    International Nuclear Information System (INIS)

    The purpose of this study is to estimate an upper bound for the average erosion of fresh bedrock that can reasonably be expected during a glacial period or a single glaciation. The study is based on the assumption that classic sediments, formed by Scandinavian ice erosion during the Quaternary period, still exist within the formerly glaciated area or its periphery. The volume of these sediments thus constitutes the maximum average glacial erosion of bedrock within this area. This volume is calculated by estimating the thickness of the minerogenic Quaternary from well data in Sweden and Denmark and from seismic measurements in adjacent sea areas. The average thickness of the Quaternary deposits and other reogolith in the investigated area was estimated to 16 m. Assuming that the whole volume is the result of glacial erosion of fresh bedrock this corresponds to 12 m depth. However, a great part of the sediments may consist of glacially redistributed Tertiary regolith. As the amount of Tertiary regolith is uncertain the estimated maximum average glacial erosion rate in fresh bedrock is uncertain, and assuming that the total sediment volume is the result of glacial erosion leads to an overestimation of the glacial erosion depth. Considering this, the average glacial erosion during a full glacial period has been estimated to between 0.2 m and 4 m. If the extremes in the made assumptions are excluded the glacial erosion during a glacial cycle can be estimated to about 1 m

  20. Adoption in ancient times

    OpenAIRE

    Bisha Eugena

    2015-01-01

    Since in ancient times, in all human cultures, children transfered from biological parents to parents that want them to create family, for political alliances, for inheritance, for a future marriage, or to care for elderly parents. The practice of adoption was fairly common in different places and periods. Adoption is mention on Bible and Quran. Greeks, Romans, Egyptians and Babylonians had adoption systems.

  1. Ancient genomics

    DEFF Research Database (Denmark)

    Der Sarkissian, Clio; Allentoft, Morten Erik; Avila Arcos, Maria del Carmen;

    2015-01-01

    The past decade has witnessed a revolution in ancient DNA (aDNA) research. Although the field's focus was previously limited to mitochondrial DNA and a few nuclear markers, whole genome sequences from the deep past can now be retrieved. This breakthrough is tightly connected to the massive sequence...... increasing the number of sequence reads to billions effectively means that contamination issues that have haunted aDNA research for decades, particularly in human studies, can now be efficiently and confidently quantified. At present, whole genomes have been sequenced from ancient anatomically modern humans......, archaic hominins, ancient pathogens and megafaunal species. Those have revealed important functional and phenotypic information, as well as unexpected adaptation, migration and admixture patterns. As such, the field of aDNA has entered the new era of genomics and has provided valuable information when...

  2. Volcanic and glacial evolution of Chachani-Nocarane complex (Southern Peru) deduced from the geomorphologic map.

    Science.gov (United States)

    Alcalá, J.; Zamorano, J. J.; Palacios, D.

    2012-04-01

    The Chachani-Nocarane (16°11'S; 71°31'W; 6.057 m asl) is a large volcanic complex located in the western Central-Andean Cordillera, South of Peru. The date of the last eruption is not known and there are no registers of recent volcanic activity. The complex is shaped by glacial forms belonging to different phases, and periglacial forms (several generations of rock glaciers) which alternate with volcanic forms. The aim of this research is to establish the glacio-volcanic evolution of the volcanic complex Chachani-Nocarane. In order to do so, a detailed 1:20.000 scale geomorphological map was elaborated by integrating the following techniques: interpretation of the 1:35.000 scale aerial photographs (Instituto Geográfico Nacional de Perú, 1956) and the analysis of satellite images (Mrsid; NASA, 2000). Finally, the cartography was corrected though field work campaigns. Through the geomorphologic analysis of the landforms and their relative position, we have identified twelve phases, seven volcanic and five glacial phases. The most ancient volcanic phase is locate to the north area of the study area and correspond with Nocarane and Chingana volcanoes, alignment NW-SE. Above those ensemble the rest of the large delimited geomorphological units overlap. The most recent is located to the SW and consists of a complex series of domes, lava cones and voluminous lavas. Within the glacial phases, the most ancient one is related to the Last Glacial Maximum during the Pleistocene. Over this period, glaciers formed moraines from 3150 to 3600 m asl. The most recent glacier pulsation corresponds to the Little Ice Age (LIA). The moraines related to that event are the closest to the summits, located between 5.100 and 5.300 m asl, and they represent the last trace of glacial activity on the volcanic complex. Currently, this tropical mountain does not have glaciers. The only solid-state water reserves are found in the form of permafrost, as shown by various generations of rock

  3. Coupling of millennial-scale changes in sea surface temperature and precipitation off northeastern Brazil with high-latitude climate shifts during the last glacial period

    Science.gov (United States)

    Jaeschke, Andrea; Rühlemann, Carsten; Arz, Helge; Heil, Gerrit; Lohmann, Gerrit

    2007-12-01

    High-resolution records of alkenone-derived sea surface temperatures and elemental Ti/Ca ratios from a sediment core retrieved off northeastern Brazil (4°S) reveal short-term climate variability throughout the past 63,000 a. Large pulses of terrigenous sediment discharge, caused by increased precipitation in the Brazilian hinterland, coincide with Heinrich events and the Younger Dryas period. Terrigenous input maxima related to Heinrich events H6-H2 are characterized by rapid cooling of surface water ranging between 0.5° and 2°C. This signature is consistent with a climate model experiment where a reduction of the Atlantic meridional overturning circulation (AMOC) and related North Atlantic cooling causes intensification of NE trade winds and a southward movement of the Intertropical Convergence Zone, resulting in enhanced precipitation off northeastern Brazil. During deglaciation the surface temperature evolution at the core site predominantly followed the Antarctic warming trend, including a cooling, prior to the Younger Dryas period. An abrupt temperature rise preceding the onset of the Bølling/Allerød transition agrees with model experiments suggesting a Southern Hemisphere origin for the abrupt resumption of the AMOC during deglaciation caused by Southern Ocean warming and associated with northward flow anomalies of the South Atlantic western boundary current.

  4. Periodization

    OpenAIRE

    Lorenz, Daniel S.; Reiman, Michael P.; Walker, John C.

    2010-01-01

    Background: Clinicians are constantly faced with the challenge of designing training programs for injured and noninjured athletes that maximize healing and optimize performance. Periodization is a concept of systematic progression—that is, resistance training programs that follow predictable patterns of change in training variables. The strength training literature is abundant with studies comparing periodization schemes on uninjured, trained, and untrained athletes. The rehabilitation litera...

  5. The Ancient Greece's roots of Olimpism

    Directory of Open Access Journals (Sweden)

    Bubka Sergej Nazarovich

    2011-10-01

    Full Text Available The paper focused on the phenomena of sport in Ancient Greece along with history, traditions, religion, education, culture and art. Economic and political conditions are analysed which promote or hamper development of Olympic Games in Ancient Greece. Exceptional stability of Ancient Olympic games during more than eleven centuries are noted as well as their influence on the life of Greek polices of those days. Hellenistic period needs of individual consideration.

  6. Contrasting scaling properties of interglacial and glacial climates

    Science.gov (United States)

    Shao, Zhi-Gang; Ditlevsen, Peter D.

    2016-03-01

    Understanding natural climate variability is essential for assessments of climate change. This is reflected in the scaling properties of climate records. The scaling exponents of the interglacial and the glacial climates are fundamentally different. The Holocene record is monofractal, with a scaling exponent H~0.7. On the contrary, the glacial record is multifractal, with a significantly higher scaling exponent H~1.2, indicating a longer persistence time and stronger nonlinearities in the glacial climate. The glacial climate is dominated by the strong multi-millennial Dansgaard-Oeschger (DO) events influencing the long-time correlation. However, by separately analysing the last glacial maximum lacking DO events, here we find the same scaling for that period as for the full glacial period. The unbroken scaling thus indicates that the DO events are part of the natural variability and not externally triggered. At glacial time scales, there is a scale break to a trivial scaling, contrasting the DO events from the similarly saw-tooth-shaped glacial cycles.

  7. Alaska Harbor Seal Glacial Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Floating glacial ice serves as a haul-out substrate for a significant number (10-15%) of Alaskan harbor seals, and thus surveying tidewater glacial fjords is an...

  8. The History and Practice of Ancient Astronomy

    CERN Document Server

    Evans, James

    1998-01-01

    The History and Practice of Ancient Astronomy combines new scholarship with hands-on science to bring readers into direct contact with the work of ancient astronomers. While tracing ideas from ancient Babylon to sixteenth-century Europe, the book places its greatest emphasis on the Greek period, when astronomers developed the geometric and philosophical ideas that have determined the subsequent character of Western astronomy. The author approaches this history through the concrete details of ancient astronomical practice. Carefully organized and generously illustrated, the book can teach reade

  9. Did the ancient Egyptians migrate to ancient Nigeria?

    Directory of Open Access Journals (Sweden)

    Jock M. Agai

    2014-01-01

    Full Text Available Literatures concerning the history of West African peoples published from 1900 to 1970 debate�the possible migrations of the Egyptians into West Africa. Writers like Samuel Johnson and�Lucas Olumide believe that the ancient Egyptians penetrated through ancient Nigeria but Leo�Frobenius and Geoffrey Parrinder frowned at this opinion. Using the works of these early�20th century writers of West African history together with a Yoruba legend which teaches�about the origin of their earliest ancestor(s, this researcher investigates the theories that the�ancient Egyptians had contact with the ancient Nigerians and particularly with the Yorubas.Intradisciplinary and/or interdisciplinary implications: There is an existing ideology�amongst the Yorubas and other writers of Yoruba history that the original ancestors of�the Yorubas originated in ancient Egypt hence there was migration between Egypt and�Yorubaland. This researcher contends that even if there was migration between Egypt and�Nigeria, such migration did not take place during the predynastic and dynastic period as�speculated by some scholars. The subject is open for further research.

  10. Quaternary glacial evolution in the Central Cantabrian Mountains (Northern Spain)

    Science.gov (United States)

    Serrano, E.; González-Trueba, J. J.; Pellitero, R.; González-García, M.; Gómez-Lende, M.

    2013-08-01

    The glacial evolution of the Cantabrian Mountains is not well known. Previous studies have focused on the extent of the glacial maximum and the presence of younger features in several massifs. Recently, efforts have been made to date glacial periods, particularly the glacial maximum. This work presents a reconstruction of the glacial evolution in the Cantabrian Mountains, providing data on the environmental characteristics and timing of the different stages from the Quaternary glacial maximum to the Little Ice Age. The study area covers 3000 km2 between the 4°58'W and 3°34'W and includes eleven massifs of the central area of the Cantabrian Mountains. The selected sectors have an Atlantic and Atlantic-Mediterranean transitional climate and include the highest massifs (above 2600 m) and low-altitude glacierised massifs (lower than 2000 m). Glacial extent and evolution have been reconstructed on the basis of detailed geomorphological and morphostratigraphic mapping. The equilibrium line altitude (palaeo-ELA) has been estimated for the different stages of each tongue. The ELA has been assessed by the AAR and modified Kurowski methods and altitude methods have been considered. A numerical chronological framework is proposed using 17 AMS radiocarbon and one OSL data obtained in lake and bog deposits from three massifs. Four main glacial stages have been differentiated, between 38,000 BP and the Little Ice Age. They correspond to different cold environments, and the number of glacial stages varies from one to four among the different massifs. Conclusions are analysed in the context of the Quaternary glacial evolution of other Iberian mountains.

  11. Changes in Glaciers and Glacial Lakes and the Identification of Dangerous Glacial Lakes in the Pumqu River Basin, Xizang (Tibet

    Directory of Open Access Journals (Sweden)

    Tao Che

    2014-01-01

    Full Text Available Latest satellite images have been utilized to update the inventories of glaciers and glacial lakes in the Pumqu river basin, Xizang (Tibet, in the study. Compared to the inventories in 1970s, the areas of glaciers are reduced by 19.05% while the areas of glacial lakes are increased by 26.76%. The magnitudes of glacier retreat rate and glacial lake increase rate during the period of 2001–2013 are more significant than those for the period of the 1970s–2001. The accelerated changes in areas of the glaciers and glacial lakes, as well as the increasing temperature and rising variability of precipitation, have resulted in an increased risk of glacial lake outburst floods (GLOFs in the Pumqu river basin. Integrated criteria were established to identify potentially dangerous glacial lakes based on a bibliometric analysis method. It is found, in total, 19 glacial lakes were identified as dangerous. Such finding suggests that there is an immediate need to conduct field surveys not only to validate the findings, but also to acquire information for further use in order to assure the welfare of the humans.

  12. Human Migration and Diffusion in Northeastern Margin of the Qinghai-Tibet Plateau since the Late Glacial Period%晚冰期以来青藏高原东北缘人类的迁移与扩散

    Institute of Scientific and Technical Information of China (English)

    侯光良; 张雪莲; 肖景义; 鄂崇毅

    2013-01-01

    利用考古遗迹、年代和区域DEM数据,采用GIS方法,综合分析了晚冰期以来,人类在青藏高原东北缘的迁移与扩散.结果表明:16~6 kaBP人类活动的足迹已遍布青藏高原东北缘,早期人类活动没有固定的聚落,表现为高度流动、长距离、大范围的迁移特征;晚期则实现了半定居.末次冰消期生活在黄土高原西端较低海拔的人群沿着黄河谷地进入高原,到达海拔2600m的共和盆地,并以该盆地为枢纽,向北于14 kaBP进入海拔3000m以上的青海湖盆地,向南于11 kaBP登上了4000m的青藏高原主体,向西在全新世早期进入柴达木盆地,并通过格尔木河河谷翻越昆仑山进入可可西里和羌塘高原.6 ~2 kaBP本区跨进新石器—青铜时代,有固定的聚落,发生了2次显著的文化扩散,5~4 kaBP马家窑文化在本区黄河—湟水谷地扩散;3 kaBP畜牧业的确立,人类再次向高原腹地扩散,并实现了对海拔4000m以上高原的长期占领.%In this paper, the data of archaeological sites, age and regional DEM were used to comprehensively analyze the human migration and diffusion in northeastern margin of the Qinghai - Tibet Plateau since the Late Glacial Period based on GIS. The results showed that the remains of human activities spread all over the northeastern margin of the plateau in the late Paleolithic period of 16 -6 kaBP, when there were no the fixed human settlements , and human activities were highly migratory with long distance. In the late deglaciation, human who lived in the west Loess Plateau with low elevation migrated to the Qinghai - Tibet Plateau along the Yellow River valley, arrived in the Gonghe Basin with an elevation of 2 600 m a. S. 1. , came into the Qinghai Lake basin with an elevation over 3 000 m a. S. 1. Northward at 14 kaBP, then migrated to the main part of the Qinghai - Tibet Plateau with an elevation about 4 000 m a. S. L. At 11 kaBP southward, came into the Qaidam Basin

  13. Seasonality and increasing frequency of Greenland glacial earthquakes.

    Science.gov (United States)

    Ekström, Göran; Nettles, Meredith; Tsai, Victor C

    2006-03-24

    Some glaciers and ice streams periodically lurch forward with sufficient force to generate emissions of elastic waves that are recorded on seismometers worldwide. Such glacial earthquakes on Greenland show a strong seasonality as well as a doubling of their rate of occurrence over the past 5 years. These temporal patterns suggest a link to the hydrological cycle and are indicative of a dynamic glacial response to changing climate conditions. PMID:16556839

  14. Apps for Ancient Civilizations

    Science.gov (United States)

    Thompson, Stephanie

    2011-01-01

    This project incorporates technology and a historical emphasis on science drawn from ancient civilizations to promote a greater understanding of conceptual science. In the Apps for Ancient Civilizations project, students investigate an ancient culture to discover how people might have used science and math smartphone apps to make their lives…

  15. Mechanisms in ancient Chinese books with illustrations

    CERN Document Server

    Hsiao, Kuo-Hung

    2014-01-01

    This book presents a unique approach for studying mechanisms and machines with drawings that were depicted unclearly in ancient Chinese books. The historical, cultural and technical backgrounds of the mechanisms are explained, and various mechanisms described and illustrated in ancient books are introduced. By utilizing the idea for the conceptual design of modern mechanisms, all feasible designs of ancient mechanisms with uncertain members and joints that meet the technical standards of the subjects’ time periods are synthesized systematically. Ancient Chinese crossbows (the original crossbow and repeating crossbows), textile mechanisms (silk-reeling mechanism, spinning mechanisms, and looms), and many other artisan's tool mechanisms are used as illustrated examples.  Such an approach provides a logical method for the reconstruction designs of ancient mechanisms with uncertain structures. It also provides an innovative direction for researchers to further identify the original structures of mechanisms...

  16. Sub-pluvial Saqqara and its possible impact on ancient Egyptian civilization in the Old Kingdom Period (4600 - 4100 yrs BP)

    Science.gov (United States)

    Welc, Fabian; Marks, Leszek

    2014-05-01

    Geological and geoarchaeological investigations were carried out at several archaeological sites in northern Egypt within the Memphis Necropolis (Saqqara, Abusir, and Giza). Sedimentological analysis of exposures in western Saqqara, excavated by the Polish-Egyptian archaeological team led by Professor Karol Myśliwiec (Institute of Mediterranean and Oriental Cultures, Polish Academy of Sciences), supplied with significant paleoclimatic data and enabled reconstruction of regional climate change during the Old Kingdom Period (4600 - 4100 yrs BP). Potential influence of this climate change on development of the early Egyptian civilization in this area was determined. Examined exposures indicated that during the Old Kingdom Period the area of Saqqara (at present located in a desert) has been many a time flooded with sheet floods, water of which was heavily charged with debris moving down-slope. Performed geochemical and sedimentological analyses proved that climate in the Old Kingdom time was warm and relatively wet. In 4200 - 4100 yrs BP a quick climate change from wet to extremely dry occurred, with occasional stormy winds. These unfavorable climatic conditions were accompanied by catastrophically low seasonal floods of the Nile, resulting in famine and drought recorded in archaeological data and consequently, leading to a disintegration of the Egyptian state. The authors' investigations indicated that a climate change in Egypt in the second half of the 3rd millennium BC is however not as univocal as considered previously. Well-known gradual aridification of the north-eastern Africa, initiated about 5000 yrs BP, has not been unidirectional and was varied regionally. The collected data indicate univocally that there were quasi-cyclic climatic fluctuations. In spite of a distinct trend, the dry period has been interrupted by numerous short wet episodes, occurring during the interval 4600 - 4200 yrs BP and especially at the end of the Old Kingdom Period (ca. 4200 yrs BP

  17. Ancient seismic record of the Tarascan (Purhepecha) Empire. Preclasic Period (3000 Yr B.P.). Jaracuaro Island, Patzcuaro Lake. Michoacan, Mexico

    Science.gov (United States)

    Rodriguez Pascua, Miguel Angel; Garduño-Monroy, Victor Hugo; Perez-Lopez, Raul; Israde-Alcantara, Isabel

    2010-05-01

    The Pátzcuaro lake is located in the Mexican State of Michoacán in the Transmexican Volcanic Belt. The Jarácuaro island is formed by Holocene lake sediments highly deformed by active faults (Morelia-Acambay Fault System, MAFS, more than 200 km long). MAFS is an E-W strike-slip fault with a transtensive component in the Pázcuaro Lake zone. Several paleoseismic studies were carried out in the island. Four trenches were made in the active faults that cross the island and it is possible observe that there are two andesitic blocks (>4 m3) over two different faults with surface rupture. The archaeological evidences (pottery, idols, etc), founded in the soils affected by the fault, implies that the age of the events concern to the Pre - Classic period (3.000 years B.P.).The Tarascan (or Purhépecha) Empire supported this earthquakes and put the blocks close both faults on the hanging wall block. The andesitic blocks are carved and polished and the quarry where this blocks were extracted is 1.5 km long out the lake. This cultural behaviour was profusely used by the Tarascan related to natural disasters but not documented before related to earthquakes. Maybe this is ones of the oldest human seismic manifestation, and is the first time that is connected a fault with a seismic movement.

  18. Did the ancient egyptians discover Algol?

    Science.gov (United States)

    Jetsu, L.; Porceddu, S.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Markkanen, T.; Toivari-Viitala, J.

    2013-02-01

    Fabritius discovered the first variable star, Mira, in 1596. Holwarda determined the 11 months period of Mira in 1638. Montanari discovered the next variable star, Algol, in 1669. Its period, 2.867 days, was determined by Goodricke (178). Algol was associated with demon-like creatures, "Gorgon" in ancient Greek and "ghoul" in ancient Arab mythology. This indicates that its variability was discovered much before 1669 (Wilk 1996), but this mythological evidence is ambiguous (Davis 1975). For thousands of years, the Ancient Egyptian Scribes (AES) observed stars for timekeeping in a region, where there are nearly 300 clear nights a year. We discovered a significant periodicity of 2.850 days in their calendar for lucky and unlucky days dated to 1224 BC, "the Cairo Calendar". Several astrophysical and astronomical tests supported our conclusion that this was the period of Algol three millennia ago. The "ghoulish habits" of Algol could explain this 0.017 days period increase (Battersby 2012).

  19. The Language of Ancient Greek Philological Texts

    OpenAIRE

    Brigita Kukjalko

    2011-01-01

    Annotation to the Doctoral Thesis by Brigita Aleksejeva: The Language of Ancient Greek Philological Texts An Ancient Greek philological text often combined the research of various language-related issues, which are nowadays studied by separate branches of linguistics – such as orthography, phonology, morphology, lexicology, syntax, and stylistics. The language of these texts differs from that of the fictional and non-theoretical texts of the period: since they represent the origins of the ...

  20. Satire: From Ancient To Modern Period

    OpenAIRE

    Jensen, Mathias; Heilmann, Tobias; Munk, Jacob; Rainer, camilla; Møller, Tina

    2015-01-01

    This paper will investigate and try to comprehend a part of our daily life, something that we use and see every day around us, which is satire. In order to understand the definition of satire, how satire is constructed and the cultural and historical connection from the satirical text to its point of origin, the theories from Robert C. Elliot, George A. Test, Ruben Quintero, Paul Simpson and Mary Fulbrook will offer a framework for this paper. The theories from Simpson and Fulbrook will provi...

  1. Ancient DNA from marine mammals

    DEFF Research Database (Denmark)

    Foote, Andrew David; Hofreiter, Michael; Morin, Philip A

    2012-01-01

    such as bone, tooth, baleen, skin, fur, whiskers and scrimshaw using ancient DNA (aDNA) approaches provide an oppor- tunity for investigating such changes over evolutionary and ecological timescales. Here, we review the application of aDNA techniques to the study of marine mammals. Most of the studies have...... focused on detecting changes in genetic diversity following periods of exploitation and environmental change. To date, these studies have shown that even small sample sizes can provide useful information on historical genetic diversity. Ancient DNA has also been used in investigations of changes...... in distribution and range of marine mammal species; we review these studies and discuss the limitations of such ‘presence only’ studies. Combining aDNA data with stable isotopes can provide further insights into changes in ecology and we review past studies and suggest future potential applications. We also...

  2. Radiocarbon dating of ancient Japanese documents

    International Nuclear Information System (INIS)

    History is a reconstruction of past human activity, evidence of which is remained in the form of documents or relics. For the reconstruction of historic period, the radiocarbon dating of ancient documents provides important information. Although radiocarbon age is converted into calendar age with the calibration curve, the calibrated radiocarbon age is still different from the historical age when the document was written. The difference is known as 'old wood effect' for wooden cultural property. The discrepancy becomes more serious problem for recent sample which requires more accurate age determination. Using Tandetron accelerator mass spectrometer at Nagoya University, we have measured radiocarbon ages of Japanese ancient documents, sutras and printed books written dates of which are clarified from the paleographic standpoint. The purpose is to clarify the relation between calibrated radiocarbon age and historical age of ancient Japanese document by AMS radiocarbon dating. This paper reports 23 radiocarbon ages of ancient Japanese documents, sutras and printed books. The calibrated radiocarbon ages are in good agreement with the corresponding historical ages. It was shown by radiocarbon dating of the ancient documents that Japanese paper has little gap by 'old wood effect'; accordingly, ancient Japanese paper is a suitable sample for radiocarbon dating of recent historic period. (author)

  3. Esotericism Ancient and Modern

    OpenAIRE

    Frazer, Michael

    2006-01-01

    Leo Strauss presents at least two distinct accounts of the idea that the authors in the political-philosophical canon have often masked their true teachings. A weaker account of esotericism, dependent on the contingent fact of persecution, is attributed to the moderns, while a stronger account, stemming from a necessary conflict between philosophy and society, is attributed to the ancients. Although most interpreters agree that Strauss here sides with the ancients, this view fails to consider...

  4. The Persistence of Glacial Valleys in the New Zealand Southern Alps

    Science.gov (United States)

    Prasicek, G.; Larsen, I. J.; Montgomery, D. R.

    2014-12-01

    One of the most fundamental insights for understanding how landscapes evolve is based on determining whether topography was modified by glaciers or rivers. Alpine landscapes featuring horns, knife-edged ridges, and U-shaped valleys are commonly associated with glacial sculpting, whereas fluvial erosion is known to produce V-shaped valleys via links between river incision and landsliding. Rivers, landslides, and glaciers are all capable of rapid erosion comparable to the highest rates of rock uplift, and there has been progress in modeling fluvial erosion and hillslope response, as well as understanding how landscapes react to the onset of glaciation. However, the timescale involved in the transition from a glacial to a fluvial landscape is poorly constrained and it is unclear how long glacial morphology can survive following deglaciation. We tested whether the fluvial and hillslope erosional response to tectonic forcing controls the timescale over which glacial topography persists into interglacial periods. We used digital terrain data to quantify the degree of glacial imprint on topography by geomorphometric analysis of cross-sectional valley shape across a spatial gradient in rock uplift and erosion rates in the New Zealand Southern Alps. Our results show that tectonic forcing is a first-order control on landscape evolution and on the persistence of glacial morphology. In Earth's most rapidly uplifting mountain ranges the lifespan of glacial topography is on the order of one interglacial period, preventing the development of a cumulative glacial signal from the added erosional impact of subsequent glacial stages. Thus we suggest that the present-day physiographic signature of glaciated landscapes is best expressed in, and limited by the extent of low uplift terrain. In addition, emphasizing that the presence of glacially preconditioned topography greatly influences glacial extent and erosion, our results imply that tectonic forcing governs the impact of climate

  5. Sub-glacial volcanic eruptions

    Science.gov (United States)

    White, Donald Edward

    1956-01-01

    The literature on sub-glacial volcanic eruptions and the related flood phenomena has been reviewed as a minor part of the larger problem of convective and conductive heat transfer from intrusive magma. (See Lovering, 1955, for a review of the extensive literature on this subject.) This summary of data on sub-glacial eruptions is part of a program that the U.S. Geological Survey is conducting in connection with its Investigations of Geologic Processes project on behalf of the Division of Research, U.S. Atomic Energy Commission.

  6. Damping of glacial-interglacial cycles from anthropogenic forcing

    CERN Document Server

    Haqq-Misra, Jacob

    2014-01-01

    Climate variability over the past million years shows a strong glacial-interglacial cycle of ~100,000 years as a combined result of Milankovitch orbital forcing and climatic resonance. It has been suggested that anthropogenic contributions to radiative forcing may extend the length of the present interglacial, but the effects of anthropogenic forcing on the periodicity of glacial-interglacial cycles has received little attention. Here I demonstrate that moderate anthropogenic forcing can act to damp this 100,000 year cycle and reduce climate variability from orbital forcing. Future changes in solar insolation alone will continue to drive a 100,000 year climate cycle over the next million years, but the presence of anthropogenic warming can force the climate into an ice-free state that only weakly responds to orbital forcing. Sufficiently strong anthropogenic forcing that eliminates the glacial-interglacial cycle may serve as an indication of an epoch transition from the Pleistocene to the Anthropocene.

  7. Moessbauer effect study of ancient Egyptian pottery

    International Nuclear Information System (INIS)

    Moessbauer spectroscopy was used in examining ancient Egyptian pottery. From the values of Moessbauer parameters and the differences for the individual samples, conclusions could be drawn as to the temperature of baking and the kind of clay used in various archaeological periods. (A.K.)

  8. [Psychiatry in ancient Mexico].

    Science.gov (United States)

    Calderón Narváez, G

    1992-12-01

    Using studies on prehispanic and early post-conquest documents of Ancient Mexico--such as the Badianus Manuscript, also known as Libellus de Medicinalibus Indorum Herbis, and Brother Bernardino de Sahagún's famous work History of the Things of the New Spain, a description of some existing medical and psychiatric problems, and treatments Ancient Aztecs resorted to, is presented. The structure of the Aztec family, their problems with the excessive ingestion of alcoholic beverages, and the punishments native authorities had implemented in order to check alcoholism up are also described. PMID:1341125

  9. Mid-late Pleistocene glacial evolution in the Grove Mountains, East Antarctica, constraints from cosmogenic 10Be surface exposure dating of glacial erratic cobbles

    Science.gov (United States)

    Dong, Guocheng; Huang, Feixin; Yi, Chaolu; Liu, Xiaohan; Zhou, Weijian; Caffee, Marc W.

    2016-08-01

    Glacial histories from the East Antarctic Ice Sheet (EAIS) provide keys to understanding correlations between the EAIS and global climate. They are especially helpful in the assessment of global sea level change, and as a means of quantifying the magnitude of past glacial activity and the rate at which ice responded to climate change. Given the significance of EAIS glacial histories, it is imperative that more glacial chronologic data for this region be obtained, especially for the mid-to-late Pleistocene. We report cosmogenic 10Be surface exposure dating results from glacially transported cobbles embedded in blue-ice moraine material at Mount Harding, the Grove Mountains, EAIS. Forty exotic cobbles sampled along two profiles (A and B) on this blue-ice moraine present apparent exposure-ages ranging from 7.2 to 542.2 ka. We explore this scattered dataset by using Principal Component Analysis (PCA) to identify statistically significant trends in the data. We identify a correlation between exposure-age and distance of the cobbles from Mount Harding. In profile A, cobbles further from Mount Harding yield older exposure-ages than those that are relatively close. In profile B, cobbles closer to Mount Harding are found to have relatively older exposure-ages. In term of glacial history we suggest that the direction of ice flow changed during the period from ∼60 to 200 ka, and that multiple glacial fluctuations occurred in the mid-late Pleistocene.

  10. Glacial Cycles and Milankovitch Forcing

    CERN Document Server

    Raghuraman, Shiv Priyam

    2015-01-01

    Using a recent conceptual model of the glacial-interglacial cycles we present more evidence of Milankovitch cycles being the trigger for retreat and forming of ice sheets in the cycles. This model is based on a finite approximation of an infinite dimensional model which has three components: Budyko's energy balance model describing the annual mean temperatures at latitudes, Widiasih's ODE which describes the behavior of the edge of the ice sheet, and Walsh et al. who introduced a snow line to account for glacial accumulation and ablation zones. Certain variables in the model are made to depend on the Milankovitch cycles, in particular, the obliquity of the Earth's axis and the eccentricity of the Earth's orbit. We see as a result that deglaciation and glaciation do occur mostly due to obliquity and to some extent eccentricity.

  11. Uncertainty in Greenland glacial isostatic adjustment

    DEFF Research Database (Denmark)

    Milne, G. A.; Lecavalier, B.; Kjeldsen, K. K.; Kjaer, K. H.; Wolstencroft, M.; Wake, L. M.; Ross Simpson, M. J.; Long, A. J.; Woodroffe, S.; Korsgaard, N. J.; Bjork, A. A.; Khan, Shfaqat Abbas

    It is well known that the interpretation of geodetic data in Greenland to constrain recent ice mass changes requires knowledge of isostatic land motion associated with past changes in the ice sheet. In this talk we will consider a variety of factors that limit how well the signal due to past mass...... changes (commonly referred to as glacial isostatic adjustment (GIA)) can be defined. Predictions based on a new model of Greenland GIA will be shown. Using these predictions as a reference, we will consider the influence of plausible variations in some key aspects of both the Earth and ice load components...... periods of the ice history with a focus on the past few thousand years. In particular, we will show predictions of contemporary land motion and gravity changes due to loading changes following the Little Ice Age computed using a new reconstruction of ice thickness changes based largely on empirical data...

  12. Ancient deforestation revisited.

    Science.gov (United States)

    Hughes, J Donald

    2011-01-01

    The image of the classical Mediterranean environment of the Greeks and Romans had a formative influence on the art, literature, and historical perception of modern Europe and America. How closely does is this image congruent with the ancient environment as it in reality existed? In particular, how forested was the ancient Mediterranean world, was there deforestation, and if so, what were its effects? The consensus of historians, geographers, and other scholars from the mid-nineteenth century through the first three quarters of the twentieth century was that human activities had depleted the forests to a major extent and caused severe erosion. My research confirmed this general picture. Since then, revisionist historians have questioned these conclusions, maintaining instead that little environmental damage was done to forests and soils in ancient Greco-Roman times. In a reconsideration of the question, this paper looks at recent scientific work providing proxy evidence for the condition of forests at various times in ancient history. I look at three scientific methodologies, namely anthracology, palynology, and computer modeling. Each of these avenues of research offers support for the concept of forest change, both in abundance and species composition, and episodes of deforestation and erosion, and confirms my earlier work. PMID:20669043

  13. A Vibrant Ancient City

    Institute of Scientific and Technical Information of China (English)

    WANGTONG

    2004-01-01

    LIJIANG is a small city onthe Yunnan-Guizhou Plateau in southern Chinawith an 800-year history.Word of its ancient language and music, and unique natural scenery has spread over the decades, and Lijiang is now known throughout the world. It was added

  14. Ancient Egypt: History 380.

    Science.gov (United States)

    Turk, Laraine D.

    "Ancient Egypt," an upper-division, non-required history course covering Egypt from pre-dynastic time through the Roman domination is described. General descriptive information is presented first, including the method of grading, expectation of student success rate, long-range course objectives, procedures for revising the course, major course…

  15. Ancient Egypt: Personal Perspectives.

    Science.gov (United States)

    Wolinski, Arelene

    This teacher resource book provides information on ancient Egypt via short essays, photographs, maps, charts, and drawings. Egyptian social and religious life, including writing, art, architecture, and even the practice of mummification, is conveniently summarized for the teacher or other practitioner in a series of one to three page articles with…

  16. Creative Ventures: Ancient Civilizations.

    Science.gov (United States)

    Stark, Rebecca

    The open-ended activities in this book are designed to extend the imagination and creativity of students and encourage students to examine their feelings and values about historic eras. Civilizations addressed include ancient Egypt, Greece, Rome, Mayan, Stonehenge, and Mesopotamia. The activities focus upon the cognitive and affective pupil…

  17. Ancient ports of Kalinga

    Digital Repository Service at National Institute of Oceanography (India)

    Tripati, S.

    which plied between Kalinga and south east Asian countries. Nanda Raja, is said to have attacked Kalinga with the intention of getting access to the sea for the landlocked Kingdom of Magadha (Bihar). The ancient texa Artha Sastra (3rd-4th century B...

  18. 低纬西太平洋末次冰期以来海洋孢粉记录对海平面变化的不同响应%THE DIFFERENT RESPONSE OF MARINE POLLEN RECORDS TO THE SEA LEVEL CHANGE IN THE LOW LATITUDE WEST PACIFIC SINCE THE LAST GLACIAL PERIOD

    Institute of Scientific and Technical Information of China (English)

    边叶萍; 李家彪; 翦知湣; 初凤友; 翁成郁; Kuhnt Wolfgang

    2012-01-01

    between the sea-level change and the marine pollen record, mainly the mangrove pollen and fern spore record. In this study, the palynological analysis of two marine core, MD06 -3075 (06. 4762°N,125. 8322°E;1878m water depth,30. 76m in length) in the southern Philippines and MD98-2178 (03. 6200°N,118. 7000°E; 1984m water depth, 35.6m in length) in the north East Borneo, the detailed oxygen isotope records, and other marine pollen records in the West Pacific, provide the regional vegetation and climate history since the Last Glacial. Based on AMS C dating and plankton foraminifera oxygen isotope record, the core MD06-3075 covers last 52ka,and the core MD98-2178 covers last 92ka( pollen analysis includes records of the last 77 ka) . The palynological record shows low representation of mangrove pollen and fern spore during the glacial period,indicating lower sea level and drier climate condition during the glacial period than the deglacial period, especially the Last Glacial Maximum. However,through the comparison of marine pollen records in the West Pacific area,there are some different pollen records in the southern South China Sea. It shows significantly high value of mangrove pollen from a marine core in the slope area and fern spore from marine core in the Sunda Shelf. These differences may be caused by the drop of sea level change,which lead to the explosion of the Sunda Shelf and the changes of vegetation distribution and distance between vegetation source and deposition point. Therefore, the interpretation of marine pollen data should be combing with the multiple sedimentary index and the geophysical survey record, which would raise the recognition of the influence of sea level change and the corresponding sedimentary environment evolution on marine pollen transportation and deposition, enhancing the extraction of the paleoclimate and paleoenviroment information from the marine palynology.

  19. Glacial onset predated Late Ordovician climate cooling

    Science.gov (United States)

    Pohl, Alexandre; Donnadieu, Yannick; Le Hir, Guillaume; Ladant, Jean-Baptiste; Dumas, Christophe; Alvarez-Solas, Jorge; Vandenbroucke, Thijs R. A.

    2016-06-01

    The Ordovician glaciation represents the acme of one of only three major icehouse periods in Earth's Phanerozoic history and is notorious for setting the scene for one of the "big five" mass extinction events. Nevertheless, the mechanisms that drove ice sheet growth remain poorly understood and the final extent of the ice sheet crudely constrained. Here using an Earth system model with an innovative coupling method between ocean, atmosphere, and land ice accounting for climate and ice sheet feedback processes, we report simulations portraying for the first time the detailed evolution of the Ordovician ice sheet. We show that the emergence of the ice sheet happened in two discrete phases. In a counterintuitive sequence of events, the continental ice sheet appeared suddenly in a warm climate. Only during the second act, and set against a background of decreasing atmospheric CO2, followed steeply dropping temperatures and extending sea ice. The comparison with abundant sedimentological, geochemical, and micropaleontological data suggests that glacial onset may have occurred as early as the Middle Ordovician Darriwilian, in agreement with recent studies reporting third-order glacioeustatic cycles during the same period. The second step in ice sheet growth, typified by a sudden drop in tropical sea surface temperatures by ˜8°C and the further extension of a single, continental-scale ice sheet over Gondwana, marked the onset of the Hirnantian glacial maximum. By suggesting the presence of an ice sheet over Gondwana throughout most of the Middle and Late Ordovician, our models embrace the emerging paradigm of an "early Paleozoic Ice Age."

  20. A 33,000-year-old incipient dog from the Altai Mountains of Siberia: evidence of the earliest domestication disrupted by the Last Glacial Maximum.

    Directory of Open Access Journals (Sweden)

    Nikolai D Ovodov

    Full Text Available BACKGROUND: Virtually all well-documented remains of early domestic dog (Canis familiaris come from the late Glacial and early Holocene periods (ca. 14,000-9000 calendar years ago, cal BP, with few putative dogs found prior to the Last Glacial Maximum (LGM, ca. 26,500-19,000 cal BP. The dearth of pre-LGM dog-like canids and incomplete state of their preservation has until now prevented an understanding of the morphological features of transitional forms between wild wolves and domesticated dogs in temporal perspective. METHODOLOGY/PRINCIPAL FINDING: We describe the well-preserved remains of a dog-like canid from the Razboinichya Cave (Altai Mountains of southern Siberia. Because of the extraordinary preservation of the material, including skull, mandibles (both sides and teeth, it was possible to conduct a complete morphological description and comparison with representative examples of pre-LGM wild wolves, modern wolves, prehistoric domesticated dogs, and early dog-like canids, using morphological criteria to distinguish between wolves and dogs. It was found that the Razboinichya Cave individual is most similar to fully domesticated dogs from Greenland (about 1000 years old, and unlike ancient and modern wolves, and putative dogs from Eliseevichi I site in central Russia. Direct AMS radiocarbon dating of the skull and mandible of the Razboinichya canid conducted in three independent laboratories resulted in highly compatible ages, with average value of ca. 33,000 cal BP. CONCLUSIONS/SIGNIFICANCE: The Razboinichya Cave specimen appears to be an incipient dog that did not give rise to late Glacial-early Holocene lineages and probably represents wolf domestication disrupted by the climatic and cultural changes associated with the LGM. The two earliest incipient dogs from Western Europe (Goyet, Belguim and Siberia (Razboinichya, separated by thousands of kilometers, show that dog domestication was multiregional, and thus had no single place of

  1. Inverse correlation between ancient winter and summer monsoons in East Asia?

    Institute of Scientific and Technical Information of China (English)

    ZHOU BoTao; ZHAO Ping

    2009-01-01

    There is a scientific debate on the relationship between ancient winter and summer monsoons in East Asia. Some scholars think that East Asian winter and summer monsoons are anti-correlated, and oth-ers think not. For this reason, this study is motivated to assess their linkage from the paleoclimate simulation perspective, through analyzing the Last Glacial Maximum (LGM) and mid-Holocene (MH) climate simulated by CCSM3 model. Compared to the present climate, the Aleutian low is found to be deepened and the East Asian winter monsoon (EAWM) is stronger during the LGM winter. The Pacific high in summer is noticed to be weakened and the East Asian summer monsoon (EASM) is weaker at the LGM. During the MH, the Aleutian low and the Asian high in winter are intensified, and the Asian low and the Pacific high in summer are enhanced, indicating that the EAWM and EASM are both stronger than today. Therefore, the EAWM is not always negatively correlated to the EASM. Their relationship may be different at different geological stages. It can be obtained at least from the numerical simulation results that the EAWM and the EASM is negatively correlated during the cooling period, while positively correlated during the warming period.

  2. Ancient climate change, antifreeze, and the evolutionary diversification of Antarctic fishes.

    Science.gov (United States)

    Near, Thomas J; Dornburg, Alex; Kuhn, Kristen L; Eastman, Joseph T; Pennington, Jillian N; Patarnello, Tomaso; Zane, Lorenzo; Fernández, Daniel A; Jones, Christopher D

    2012-02-28

    The Southern Ocean around Antarctica is among the most rapidly warming regions on Earth, but has experienced episodic climate change during the past 40 million years. It remains unclear how ancient periods of climate change have shaped Antarctic biodiversity. The origin of antifreeze glycoproteins (AFGPs) in Antarctic notothenioid fishes has become a classic example of how the evolution of a key innovation in response to climate change can drive adaptive radiation. By using a time-calibrated molecular phylogeny of notothenioids and reconstructed paleoclimate, we demonstrate that the origin of AFGP occurred between 42 and 22 Ma, which includes a period of global cooling approximately 35 Ma. However, the most species-rich lineages diversified and evolved significant ecological differences at least 10 million years after the origin of AFGPs, during a second cooling event in the Late Miocene (11.6-5.3 Ma). This pattern indicates that AFGP was not the sole trigger of the notothenioid adaptive radiation. Instead, the bulk of the species richness and ecological diversity originated during the Late Miocene and into the Early Pliocene, a time coincident with the origin of polar conditions and increased ice activity in the Southern Ocean. Our results challenge the current understanding of the evolution of Antarctic notothenioids suggesting that the ecological opportunity that underlies this adaptive radiation is not linked to a single trait, but rather to a combination of freeze avoidance offered by AFGPs and subsequent exploitation of new habitats and open niches created by increased glacial and ice sheet activity. PMID:22331888

  3. Glacial rebound and crustal stress in Finland

    International Nuclear Information System (INIS)

    The last ice age of Fennoscandinavia continues to have geological repercussions across Finland despite the last ice having retreated almost 10,000 years ago: land uplift, shoreline retreat, and the stress state of the crust continues to evolve. This report focusses on the glacial rebound signals for Finland and the Gulf of Bothnia and explores the consequences of the ongoing deformation. The rebound signals include the geological evidence as well as instrumental observations: the tide gauge and lake-level measurements of the past century, the changes in geodetic levels recorded in the repeat levelling surveys of the region and the direct measurement of crustal deformation (radial and horizontal) using high-precision space-geodesy measurements. These signals provide constraints on the Earth's rheology, its elasticity and viscosity, and the glacial history of the region. Once observationally constrained, the rebound models are used to predict both the ongoing evolution of shorelines and the changing state of stress within the crust. This report covers: (i) A review of glacial rebound modelling for Scandinavia (Sections 2 and 3). (ii) Review of observational evidence relating to sea-level change and crustal rebound (Section 4). (iii) New earth and ice-sheet model results from the inversion of the geological evidence for sea-level change, including models of shoreline evolution (Sections 5 and 6). (iv) Earth-model results from the inversion of the geodetic evidence for sea-level change (Section 7). (v) Development of crustal stress models for past and present stress states (Section 8). (vi) Conclusions and recommendations (Section 9). Specific conclusions reached pertain to: (i) Thickness of ice cover over Scandinavia since the Last Glacial Maximum, particularly for the Lateglacial period. (ii) Sea-level change and shoreline evolution for the Baltic area since the time the region became ice-free for the last time. (iii) The predicted rates of present-day crustal

  4. Ancient Paleo-DNA of Pre-Copper Age North-Eastern Europe: Establishing the Migration Traces of R1a1 Y-DNA Haplogroup

    Directory of Open Access Journals (Sweden)

    Alexander S. Semenov

    2016-03-01

    Full Text Available The work considers the problems of paleogenetics and anthropology connected with problem of pre-Copper Age after-Glacial repopulation process of the North-Eastern Europe. The unified data, obtained in various laboratories in 2010-2016, collects a certain amount of the ancient mt-DNA and Y-DNA haplogroup samples of the considered period, what allows establishing the connection between some of them, comparing them with the data of neighboring regions, and attributing them to certain migration flows traceable in archeology. The paper makes an attempt to build a picture of the population of North-Eastern Europe in pre-Copper Age time and to systemize the paleo DNA genotyping results into clusters corresponding to different migration waves. The paper can be of use for biomedical purposes also, as some correlations between diseases and haplogroups were noticed in various medical works.

  5. Ancient and modern colonization of North America by hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), an invasive insect from East Asia.

    Science.gov (United States)

    Havill, Nathan P; Shiyake, Shigehiko; Lamb Galloway, Ashley; Foottit, Robert G; Yu, Guoyue; Paradis, Annie; Elkinton, Joseph; Montgomery, Michael E; Sano, Masakazu; Caccone, Adalgisa

    2016-05-01

    Hemlock woolly adelgid, Adelges tsugae, is an invasive pest of hemlock trees (Tsuga) in eastern North America. We used 14 microsatellites and mitochondrial COI sequences to assess its worldwide genetic structure and reconstruct its colonization history. The resulting information about its life cycle, biogeography and host specialization could help predict invasion by insect herbivores. We identified eight endemic lineages of hemlock adelgids in central China, western China, Ulleung Island (South Korea), western North America, and two each in Taiwan and Japan, with the Japanese lineages specializing on different Tsuga species. Adelgid life cycles varied at local and continental scales with different sexual, obligately asexual and facultatively asexual lineages. Adelgids in western North America exhibited very high microsatellite heterozygosity, which suggests ancient asexuality. The earliest lineages diverged in Asia during Pleistocene glacial periods, as estimated using approximate Bayesian computation. Colonization of western North America was estimated to have occurred prior to the last glacial period by adelgids directly ancestral to those in southern Japan, perhaps carried by birds. The modern invasion from southern Japan to eastern North America caused an extreme genetic bottleneck with just two closely related clones detected throughout the introduced range. Both colonization events to North America involved host shifts to unrelated hemlock species. These results suggest that genetic diversity, host specialization and host phylogeny are not predictive of adelgid invasion. Monitoring non-native sentinel host trees and focusing on invasion pathways might be more effective methods of preventing invasion than making predictions using species traits or evolutionary history. PMID:26880353

  6. Alaskan mountain glacial melting observed by satellite gravimetry

    Science.gov (United States)

    Chen, J. L.; Tapley, B. D.; Wilson, C. R.

    2006-08-01

    We use satellite gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) as an indication of mass change to study potential long-term mountain glacial melting in southern Alaska and West Canada. The first 3.5 yr of GRACE monthly gravity data, spanning April 2002-November 2005, show a prominent glacial melting trend in the mountain regions around the Gulf of Alaska (GOA). GRACE-observed surface mass changes correlate remarkably well with available mass balance data at Gulkana and Wolverine, two benchmark glaciers of the U.S. Geological Survey (USGS), although the GRACE signals are smaller in magnitude. In addition, terrestrial water storage (TWS) changes estimated from an advanced land surface model show significant mass loss in this region during the same period. After correcting for the leakage errors and removing TWS contributions using model estimates, we conclude that GRACE-observed glacial melting in the GOA mountain region is equivalent to ˜ - 101 ± 22 km 3/yr, which agrees quite well with the assessment of ˜ - 96 ± 35 km 3/yr based on airborne laser altimetry data, and is consistent with an earlier estimate based on the first 2 yr of GRACE data. This study demonstrates the significant potentials of satellite gravity measurements for monitoring mountain glacial melting and regional climate change.

  7. Late Quaternary glacially influenced sedimentation on the north-west Irish margin: facies, sediment delivery and link to glacial history

    Science.gov (United States)

    Benetti, Sara; Sacchetti, Fabio; Georgiopoulou, Aggeliki; Cofaigh, Colm Ó.; Edwards, Robin; Toms, Lee; McCarron, Steve

    2013-04-01

    This presentation will discuss the sedimentary processes that took place since the last glaciation on the north-eastern margin of the Rockall Trough, offshore Ireland. With the use of seventeen sediment cores collected along the axes of two major canyons and across the northern Rockall Trough, changes in sedimentary processes from shelf edge to basin floor are revealed and examined. The aim is to better understand the sedimentary processes that occurred along the canyons and in the trough during the last glaciation, through the deglaciation and into the Holocene. On the basis of sedimentary structures, texture, grain size, X-radiograph character and physical properties thirteen depositional facies are recognised. These facies are interpreted in terms of depositional processes as: (1) Massive diamicton deposited as subglacial till on the continental shelf during the last glacial advance; (2) Fining upward gravels and sands, related to rise in sea level and changing of hydrographic conditions on the shelf over time; (3) Plumites deposited during deglaciation on the upper slope; (4) Widespread hemipelagites of Holocene and glacial age; (5) Heavily bioturbated, foraminiferal rich contourites of Holocene and glacial age; (6) coarse- and fine-grained turbidites deposited mainly on the lower slope and trough during the last glacial period; (7) diamicton and chaotic mud beds deposited in the trough by glaciogenic debris flows. Margin physiography, distance from the ice sheet grounding zone, style of glaciation on the shelf and strength of deep sea circulation are the main controlling factors for these depositional processes.

  8. Glacial lakes Buni and Jezerce: Albania

    OpenAIRE

    Milivojević Milovan; Kovačević-Majkić Jelena

    2005-01-01

    The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstru...

  9. Phosphorus burial in the ocean over glacial-interglacial time scales

    OpenAIRE

    Tamburini, F.; K. B. Föllmi

    2009-01-01

    The role of nutrients, such as phosphorus (P), and their impact on primary productivity and the fluctuations in atmospheric CO2 over glacial-interglacial periods are intensely debated. Suggestions as to the importance of P evolved from an earlier proposal that P actively participated in changing productivity rates and therefore climate change, to most recent ones that changes in the glacial ocean inventory of phosphorus were important but not influential if compared to ...

  10. Ancient human microbiomes

    Science.gov (United States)

    Warinner, Christina; Speller, Camilla; Collins, Matthew J.; Lewis, Cecil M.

    2015-01-01

    Very recently, we discovered a vast new microbial self: the human microbiome. Our native microbiota interface with our biology and culture to influence our health, behavior, and quality of life, and yet we know very little about their origin, evolution, or ecology. With the advent of industrialization, globalization, and modern sanitation, it is intuitive that we have changed our relationship with microbes, but we have little information about the ancestral state of our microbiome, and therefore, we lack a foundation for characterizing this change. High-throughput sequencing has opened up new opportunities in the field of paleomicrobiology, allowing us to investigate the evolution of the complex microbial ecologies that inhabit our bodies. By focusing on recent coprolite and dental calculus research, we explore how emerging research on ancient human microbiomes is changing the way we think about ancient disease and how archaeological studies can contribute to a medical understanding of health and nutrition today. PMID:25559298

  11. Comets in ancient India

    CERN Document Server

    Gupta, Patrick Das

    2014-01-01

    The Indo-aryans of ancient India observed stars and constellations for ascertaining auspicious times for sacrificial rites ordained by vedas. It is but natural that they would have recounted in the vedic texts about comets. In Rigveda ($\\sim $ 1700 - 1500 BC) and Atharvaveda ($\\sim $ 1150 BC), there are references to dhumaketus and ketus, which stand for comets in Sanskrit. Varahamihira in 550 AD and Ballala Sena ($\\sim $ 1100 - 1200 AD) have described a large number of comets recorded by ancient seers such as Parashara, Vriddha Garga, Narada, Garga, etc. In this article, I conjecture that an episode narrated in Mahabharata of a radiant king, Nahusha, ruling the heavens, and later turning into a serpent after he had kicked the seer Agastya (also the star Canopus), is a mythological retelling of a cometary event.

  12. Defining Astrology in Ancient and Classical History

    Science.gov (United States)

    Campion, Nicholas

    2015-05-01

    Astrology in the ancient and classical worlds can be partly defined by its role, and partly by the way in which scholars spoke about it. The problem is complicated by the fact that the word is Greek - it has no Babylonian or Egyptian cognates - and even in Greece it was interchangeable with its cousin, 'astronomy'. Yet if we are to understand the role of the sky, stars and planets in culture, debates about the nature of ancient astrology, by both classical and modern scholars, must be taken into account. This talk will consider modern scholars' typologies of ancient astrology, together with ancient debates from Cicero in the 1st century BC, to Plotinus (204/5-270 AD) and Isidore of Seville (c. 560 - 4 April 636). It will consider the implications for our understanding of astronomy's role in culture, and conclude that in the classical period astrology may be best understood through its diversity and allegiance to competing philosophies, and that its functions were therefore similarly varied.

  13. Chemistry Progress and Civilization in Ancient China

    Institute of Scientific and Technical Information of China (English)

    JIANG Yu-Qian; RUAN Shu-Xiang; TANG Shan; SHUAI Zhi-Gang

    2011-01-01

    @@ During the 6,000 years of Chinese civilization, chemistry has played an essential role.The bronzed chime bells of the Warring States Period (475-221 BC) unearthed in Hubei Province shows not only the excellence in musical instruments in ancient China, but also the technological advances in metallurgy.Chinese alchemy was not originated from the quest to turn common metals to gold, instead, it was for searching medicines for longevity of human beings, mostly practised by Taoists.

  14. INDIGENOUS MEDICINE AND THE STATE IN ANCIENT INDIA

    OpenAIRE

    Bala, Poonam

    1985-01-01

    Several arguments have been forwarded for the stagnation of Ayurveda, and most of these focus on the discrimination that Ayurveda faces under Mughal and then under British rule. Even for Ancient India, the halcyon portrait of Ayurveda synergetically related with religion and politics during the period, as has been portrayed in many books of history and in countless lores, is false. This paper then deals with the interaction between the State and Ayurvedic medicine in ancient India.

  15. Humanities Scholars and Databases for Ancient Chinese Books

    OpenAIRE

    Shih-Chuan Chen; Wen-Chi Huang; Ming-Der Wu

    2006-01-01

    In every field, scholars find an increasing availability of electronic resources. Studies have shown that humanities scholars use and cite fewer electronic resources than their science and technologycounterparts. Moreover, humanities scholars prefer monographs to periodicals or other resources. They continue to use ancient books and documents. In the digital era, many full-text databases of ancient Chinese books and documents have been created. In this study, ten professors of Chinese literat...

  16. Identifying the Practice of Tattooing in Ancient Egypt and Nubia

    OpenAIRE

    Geoffrey J. Tassie

    2003-01-01

    Tattooing was practised by many ancient societies, including the ancient Egyptians and Nubians. Egypt, for example, boasts iconographic and physical evidence for tattooing for a period spanning at least 4000 years – the longest known history of tattooing in the world. The second oldest physical evidence for tattooing worldwide was recovered from Middle Kingdom contexts in Egypt and C-Group contexts in Nubia (the Hanslabjoch ice man being the oldest). It has been suggested that tattooing was a...

  17. Sustainability of Ancient Water Supply Facilities in Jerusalem

    OpenAIRE

    Barghouth, Jamal M.; Al-Sa`ed, Rashed M. Y.

    2009-01-01

    This paper presents an overview on the sustainability of ancient water supply systems in Jerusalem from the Chalcolithic period (4500–3200 B.C.) until the present time. Archaeological evidences and landscape settings were applied utilizing all available and accessible literature relevant to ancient water resources management in Jerusalem. Irrigated agriculture was practiced for many centuries in this region, hence sustainable water supply facilities were erected, including well developed aq...

  18. Suicide in ancient Greece.

    Science.gov (United States)

    Laios, K; Tsoukalas, G; Kontaxaki, M-I; Karamanou, M; Androutsos, G

    2014-01-01

    The theme of suicide appears several times in ancient Greek literature. However, each such reference acquires special significance depending on the field from which it originates. Most of the information found in mythology, but the suicide in a mythological tale, although in terms of motivation and mental situation of heroes may be in imitation of similar incidents of real life, in fact is linked with the principles of the ancient Greek religion. In ancient drama and mainly in tragedies suicide conduces to the tragic hypostasis of the heroes and to the evolution of the plot and also is a tool in order to be presented the ideas of poets for the relations of the gods, the relation among gods and men and the relation among the men. In ancient Greek philosophy there were the deniers of suicide, who were more concerned about the impact of suicide on society and also these who accepted it, recognizing the right of the individual to put an end to his life, in order to avoid personal misfortunes. Real suicides will be found mostly from historical sources, but most of them concern leading figures of the ancient world. Closer to the problem of suicide in the everyday life of antiquity are ancient Greek medicines, who studied the phenomenon more general without references to specific incidents. Doctors did not approve in principal the suicide and dealt with it as insane behavior in the development of the mental diseases, of melancholia and mania. They considered that the discrepancy of humors in the organ of logic in the human body will cause malfunction, which will lead to the absurdity and consequently to suicide, either due to excessive concentration of black bile in melancholia or due to yellow bile in mania. They believed that greater risk to commit suicide had women, young people and the elderly. As therapy they used the drugs of their time with the intention to induce calm and repression in the ill person, therefore they mainly used mandragora. In general, we would say

  19. Glacial-Interglacial Atmospheric CO2 Change--The Glacial Burial Hypothesis

    Institute of Scientific and Technical Information of China (English)

    Ning ZENG

    2003-01-01

    Organic carbon buried under the great ice sheets of the Northern Hemisphere is suggested to bethe missing link in the atmospheric CO2 change over the glacial-interglacial cycles. At glaciation, theadvancement of continental ice sheets buries vegetation and soil carbon accumulated during warmer pe-riods. At deglaciation, this burial carbon is released back into the atmosphere. In a simulation over twoglacial-interglacial cycles using a synchronously coupled atmosphere-land-ocean carbon model forced byreconstructed climate change, it is found that there is a 547-Gt terrestrial carbon release from glacialmaximum to interglacial, resulting in a 60-Gt (about 30-ppmv) increase in the atmospheric CO2, with theremainder absorbed by the ocean in a scenario in which ocean acts as a passive buffer. This is in contrastto previous estimates of a land uptake at deglaciation. This carbon source originates from glacial burial,continental shelf, and other land areas in response to changes in ice cover, sea level, and climate. The inputof light isotope enriched terrestrial carbon causes atmospheric 513C to drop by about 0.3% at deglaciation,followed by a rapid rise towards a high interglacial value in response to oceanic warming and regrowthon land. Together with other ocean based mechanisms such as change in ocean temperature, the glacialburial hypothesis may offer a full explanation of the observed 80 100-ppmv atmospheric CO2 change.

  20. Dance in Ancient Greek Culture

    OpenAIRE

    Spalva, Rita

    2015-01-01

    The greatness and harmony of ancient Greece has had an impact upon the development of the Western European culture to this day. The ancient Greek culture has influenced contemporary literature genres and systems of philosophy, principles of architecture, sculpture and drama and has formed basis for such sciences as astronomy and mathematics. The art of ancient Greece with its penchant for beauty and clarity has been the example of the humanity’s search for an aesthetic ideal. Despite only bei...

  1. How can a glacial inception be predicted?

    CERN Document Server

    Crucifix, Michel

    2011-01-01

    The Early Anthropogenic Hypothesis considers that greenhouse gas concentrations should have declined during the Holocene in absence of humankind activity, leading to glacial inception around the present. It partly relies on the fact that present levels of northern summer incoming solar radiation are close to those that, in the past, preceded a glacial inception phenomenon, associated to declines in greenhouse gas concentrations. However, experiments with various numerical models of glacial cycles show that next glacial inception may still be delayed by several ten thousands of years, even with the assumption of greenhouse gas concentration declines during the Holocene. Furthermore, as we show here, conceptual models designed to capture the gross dynamics of the climate system as a whole suggest also that small disturbances may sometimes cause substantial delays in glacial events, causing a fair level of unpredictability on ice age dynamics. This suggests the need of a validated mathematical description of the...

  2. Gnomons in Ancient China

    Science.gov (United States)

    Li, Geng

    Gnomon shadow measurement was one of the most fundamental astronomical observations in ancient China. It was crucial for calendar making, which constituted an important aspect of imperial governance. A painted stick discovered from a prehistoric (2300 BC) astronomical site of Taosi (see Chap. 201, "Taosi Observatory", 10.1007/978-1-4614-6141-8_215") is the oldest gnomon known of China. From second century BC onward, gnomon shadow measurements have been essential part of calendrical practice. Various historical measurements are discussed in this chapter.

  3. Climate and Ancient Societies

    DEFF Research Database (Denmark)

    Climate, and human responses to it, have a strongly interconnected relationship. This when climate change occurs, the result of either natural or human causes, societies should react and adapt to these. But do they? If so, what is the nature of that change, and are the responses positive...... or negative for the long-term survival of social groups? In this volume, scholars from diverse disciplines including archaeology, geology and climate sciences explore scientific and material evidence for climate changes in the past, their causes, their effects on ancient societies and how those societies...

  4. Mathematics in ancient Greece

    CERN Document Server

    Dantzig, Tobias

    2006-01-01

    More than a history of mathematics, this lively book traces mathematical ideas and processes to their sources, stressing the methods used by the masters of the ancient world. Author Tobias Dantzig portrays the human story behind mathematics, showing how flashes of insight in the minds of certain gifted individuals helped mathematics take enormous forward strides. Dantzig demonstrates how the Greeks organized their precursors' melange of geometric maxims into an elegantly abstract deductive system. He also explains the ways in which some of the famous mathematical brainteasers of antiquity led

  5. Northern Hemisphere moisture variability during the Last Glacial period

    Science.gov (United States)

    Asmerom, Y.; Polyak, V. J.; Lachniet, M. S.

    2013-12-01

    It was previously shown that large oxygen isotope variability related to changing moisture sources in the southwestern United States (SW) match the Greenland ice core temperature record. The variations were attributed to changes in the ratio of winter to summer precipitation delivered to the SW, with lighter winter δ18O values compared to summer monsoon rainfall, due to meridonial shifts in the position of the polar jet stream, which directs winter storm tracks. Cold stadial δ18O excursions are associated with strongly negative values, while interstadials have higher than average δ18O values. Although these data documented moisture source variability to the SW, the question of effective moisture variability remains unanswered. Here we present new high-resolution δ18O and δ13C isotopic data from a precisely dated speleothem, FS-AH1, from Fort Stanton Cave, New Mexico USA. The sample grew continuously between 47.6 and 11.1 kyr. The new chronology is more precise than previous work due to high sample growth rate, new gains in efficiency provided by our upgraded Neptune MC-ICPMS and new more precise determinations of the half-lives of 230Th and 234U. The FS-AH1 δ18O and the Greenland δ18O data (on the GICC05 time scale) show a remarkable match, both with respect to stadials/interstadial amplitudes and variability, and in the overall long-term trend. Our interpretation of the δ18O data remains the same, an indicator of moisture source variability. The δ18O and δ13C isotopic data show no correlation (R2 soil zone overlying the cave, with low δ13C attributed to high soil productivity, high effective moisture, and wet conditions. The stadial and interstadial events are expressed mutely, if at all, in the δ13C data, while the secular variation follows the change in Northern Hemisphere summer insolation (insolation), similar to other Northern Hemisphere data, such as the strength of the East Asian summer monsoon as recorded in the Hulu speleothem, although the match to the East Asian monsoon is inverse. The much diminished expression of stadials and interstadials and secular variations in the effective moisture proxy data that match insolation seem to be hemispherical in scale. In humid settings, such as east Asia monsoon regions, warm temperatures lead to northward shift of the ITCZ and increase in the strength of the Asian monsoon, while in the desert SW any increase in the strength in the North American monsoon is counterbalanced by decrease in winter moisture due to the northward shift of the polar jet stream and more importantly, the onset of more evaporative conditions. In contrast to the large and rapid shifts seen in the Greenland ice core data and the apparent shift in position in air masses, as indicated by our δ18O data, large-scale changes in moisture regimes in the Northern Hemisphere seem to be driven by changes in insolation. Locations that are sensitive to small changes in atmospheric pressure and/or sea surface temperature gradients may be the exception.

  6. The Change from SOV to SVO in Ancient Greek.

    Science.gov (United States)

    Taylor, Ann

    1994-01-01

    Examines the distribution of clause types in ancient Greek during the Homeric (pre-800 B.C.) and Hellenistic (ca. 100 A.D.) periods, as well as an intermediate period (ca. 450 B.C.), delineating the evolution from a subject-object-verb (SOV) to a subject-verb-object (SVO) structure. (49 references) (MDM)

  7. Exploring Ancient Skies A Survey of Ancient and Cultural Astronomy

    CERN Document Server

    Kelley, David H

    2011-01-01

    Exploring Ancient Skies brings together the methods of archaeology and the insights of modern astronomy to explore the science of astronomy as it was practiced in various cultures prior to the invention of the telescope. The book reviews an enormous and growing body of literature on the cultures of the ancient Mediterranean, the Far East, and the New World (particularly Mesoamerica), putting the ancient astronomical materials into their archaeological and cultural contexts. The authors begin with an overview of the field and proceed to essential aspects of naked-eye astronomy, followed by an examination of specific cultures. The book concludes by taking into account the purposes of ancient astronomy: astrology, navigation, calendar regulation, and (not least) the understanding of our place and role in the universe. Skies are recreated to display critical events as they would have appeared to ancient observers—events such as the supernova of 1054 A.D., the "lion horoscope," and the Star of Bethlehem. Explori...

  8. Ancient celtic horns

    Science.gov (United States)

    Campbell, Murray

    2002-11-01

    There is considerable evidence from iconographic and documentary sources that musical lip-reed instruments were important in the early celtic communities of Scotland and Ireland. In recent years several studies have been undertaken with the aim of gaining a better understanding of the musical nature of these ancient horns, and of their place in the life and culture of the time. A valuable source of tangible evidence is to be found in the archaeological remains deposited across Scotland and the whole of Ireland. A project is now under way, under the auspices of the Kilmartin House Trust and the general direction of John Purser, which has brought together an international team of musicians, craftsmen, archaeologists, musicologists and physicists with the aim of analyzing ancient musical artifacts, reconstructing some of the original instruments, and analyzing the sounds they produce. This paper describes acoustical studies carried out on a number of recent reconstructions of wooden and bronze instruments, and discusses the role of acoustics in this type of investigation. [Work supported by Sciart and EPSRC.

  9. Damage and repair of ancient DNA

    DEFF Research Database (Denmark)

    Mitchell, David; Willerslev, Eske; Hansen, Anders

    2005-01-01

    Under certain conditions small amounts of DNA can survive for long periods of time and can be used as polymerase chain reaction (PCR) substrates for the study of phylogenetic relationships and population genetics of extinct plants and animals, including hominids. Because of extensive DNA...... degradation, these studies are limited to species that lived within the past 10(4)-10(5) years (Late Pleistocene), although DNA sequences from 10(6) years have been reported. Ancient DNA (aDNA) has been used to study phylogenetic relationships of protists, fungi, algae, plants, and higher eukaryotes such as...... early native Americans. Hence, ancient DNA contains information pertinent to numerous fields of study including evolution, population genetics, ecology, climatology, medicine, archeology, and behavior. The major obstacles to the study of aDNA are its extremely low yield, contamination with modern DNA...

  10. Ancestry of modern Europeans: contributions of ancient DNA.

    Science.gov (United States)

    Lacan, Marie; Keyser, Christine; Crubézy, Eric; Ludes, Bertrand

    2013-07-01

    Understanding the peopling history of Europe is crucial to comprehend the origins of modern populations. Of course, the analysis of current genetic data offers several explanations about human migration patterns which occurred on this continent, but it fails to explain precisely the impact of each demographic event. In this context, direct access to the DNA of ancient specimens allows the overcoming of recent demographic phenomena, which probably highly modified the constitution of the current European gene pool. In recent years, several DNA studies have been successfully conducted from ancient human remains thanks to the improvement of molecular techniques. They have brought new fundamental information on the peopling of Europe and allowed us to refine our understanding of European prehistory. In this review, we will detail all the ancient DNA studies performed to date on ancient European DNA from the Middle Paleolithic to the beginning of the protohistoric period. PMID:23052219

  11. Ancient Land Routes On The Paximadhi Peninsula, Karystos, Euboea

    Science.gov (United States)

    Keller, D.; Hom, E.

    Recent regional surface surveys have placed more focus on rural investigations, but the means of transport and communication within those rural surroundings has not always received adequate attention. The Southern Euboea Exploration Project has undertaken a new phase of research in the Karystos area with the goal of developing a methodology that allows for a more detailed record of the pre-modern land routes. On the Paximadhi peninsula it was possible to identify numerous fragments of suspected ancient routes dating to the Classical and Hellenistic periods. In the majority of cases these fragments were closely associated with adjacent datable ancient sites. By taking into consideration the evidence recorded during the survey it was sometimes possible to propose the extension of these ancient segments and to theorize the directions, lengths, and purposes of ancient networks.

  12. Authenticity in ancient DNA studies

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Willerslev, Eske

    2006-01-01

    Ancient DNA studies represent a powerful tool that can be used to obtain genetic insights into the past. However, despite the publication of large numbers of apparently successful ancient DNA studies, a number of problems exist with the field that are often ignored. Therefore, questions exist as ...

  13. Tamil merchant in ancient Mesopotamia.

    Directory of Open Access Journals (Sweden)

    Malliya Gounder Palanichamy

    Full Text Available Recent analyses of ancient Mesopotamian mitochondrial genomes have suggested a genetic link between the Indian subcontinent and Mesopotamian civilization. There is no consensus on the origin of the ancient Mesopotamians. They may be descendants of migrants, who founded regional Mesopotamian groups like that of Terqa or they may be merchants who were involved in trans Mesopotamia trade. To identify the Indian source population showing linkage to the ancient Mesopotamians, we screened a total of 15,751 mitochondrial DNAs (11,432 from the literature and 4,319 from this study representing all major populations of India. Our results although suggest that south India (Tamil Nadu and northeast India served as the source of the ancient Mesopotamian mtDNA gene pool, mtDNA of these ancient Mesopotamians probably contributed by Tamil merchants who were involved in the Indo-Roman trade.

  14. Tamil merchant in ancient Mesopotamia.

    Science.gov (United States)

    Palanichamy, Malliya Gounder; Mitra, Bikash; Debnath, Monojit; Agrawal, Suraksha; Chaudhuri, Tapas Kumar; Zhang, Ya-Ping

    2014-01-01

    Recent analyses of ancient Mesopotamian mitochondrial genomes have suggested a genetic link between the Indian subcontinent and Mesopotamian civilization. There is no consensus on the origin of the ancient Mesopotamians. They may be descendants of migrants, who founded regional Mesopotamian groups like that of Terqa or they may be merchants who were involved in trans Mesopotamia trade. To identify the Indian source population showing linkage to the ancient Mesopotamians, we screened a total of 15,751 mitochondrial DNAs (11,432 from the literature and 4,319 from this study) representing all major populations of India. Our results although suggest that south India (Tamil Nadu) and northeast India served as the source of the ancient Mesopotamian mtDNA gene pool, mtDNA of these ancient Mesopotamians probably contributed by Tamil merchants who were involved in the Indo-Roman trade. PMID:25299580

  15. Holocene glacial discharge fluctuations and recent instability in East Antarctica

    Science.gov (United States)

    Crespin, Julien; Yam, Ruth; Crosta, Xavier; Massé, Guillaume; Schmidt, Sabine; Campagne, Philippine; Shemesh, Aldo

    2014-05-01

    Antarctica holds the largest ice sheet in the world, the East Antarctic Ice Sheet (EAIS), and plays a significant role in both local and global climate through the interactions between ice sheets, ocean, sea ice, and atmosphere. Our understanding of East Antarctica Holocene climate variability relies mainly on ice cores that however do not document glacial discharge history. Here, we present the first high resolution δ18Odiatom record derived from two marine sediment cores retrieved on the East Antarctic continental shelf to reconstruct glacial discharge off Adélie Land and George V Land (AL-GVL) over the last 11,000 years from decadal to centennial resolution. Our results suggest multi-centennial glacier advances and retreats until 2000 cal yr BP, followed by a period of relative instability marked by two major glacial retreats centered at ˜1700 cal yr BP and ˜1980 CE. We suggest that the multi-centennial oscillations during the Early/Mid-Holocene reflect glacier fluctuations in response to long-term local seasonal insolation and short-term solar variability. We also propose that δ18Odiatom variability over the last 2000 years was the result of a recent change in the AL-GVL region to increasing atmospheric influence, linked to ENSO intensification and teleconnections strengthening between low and high latitudes.

  16. Ancient Chinese Sundials

    Science.gov (United States)

    Deng, Kehui

    Timekeeping was essential in the agricultural society of ancient China. The use of sundials for timekeeping was associated with the use of the gnomon, which had its origin in remote antiquity. This chapter studies three sundials (guiyi 晷仪) from the Qin and Han dynasties, the shorter shadow plane sundial (duanying ping yi 短影平仪) invented by Yuan Chong in the Sui Dynasty, and the sundial chart (guiyingtu 晷影图) invented by Zeng Minxing in the Southern Song dynasty. This chapter also introduces Guo Shoujing's hemispherical sundial (yang yi 仰仪). A circular stone sundial discovered at the Small Wild Goose Pagoda in Xi'an is also mentioned. It is dated from the Sui and Tang dynasties. A brief survey of sundials from the Qing dynasty shows various types of sundials.

  17. Characterization of Ancient Tripitaka

    Science.gov (United States)

    Gong, Y. X.; Geng, L.; Gong, D. C.

    2015-08-01

    Tripitaka is the world's most comprehensive version of Buddhist sutra. There are limited numbers of Tripitaka currently preserved, most of them present various patterns of degradation. As little is known about the materials and crafts used in Tripitaka, it appeared necessary to identify them, and to further define adapted conservation treatment. In this work, a study concerning the paper source and dyestuff of the Tripitaka from approximate 16th century was carried out using fiber analysis and thin-layer chromatography (TLC). The results proved that the papers were mainly made from hemp or bark of mulberry tree, and indigo was used for colorizing the paper. At the end, we provide with suggestions for protecting and restoring the ancient Tripitaka.

  18. Late Glacial to Holocene relative sea-level change in Assynt, northwest Scotland, UK

    Science.gov (United States)

    Hamilton, Christine A.; Lloyd, Jeremy M.; Barlow, Natasha L. M.; Innes, James B.; Flecker, Rachel; Thomas, Caleb P.

    2015-09-01

    Relative sea-level change (RSL), from the Late Glacial through to the late Holocene, is reconstructed for the Assynt region, northwest Scotland, based on bio- and lithostratigraphical analysis. Four new radiocarbon-dated sea-level index points help constrain RSL change for the Late Glacial to the late Holocene. These new data, in addition to published material, capture the RSL fall during the Late Glacial and the rise and fall associated with the mid-Holocene highstand. Two of these index points constrain the Late Glacial RSL history in Assynt for the first time, reconstructing RSL falling from 2.47 ± 0.59 m OD to 0.15 ± 0.59 m OD at c. 14,000-15,000 cal yr BP. These new data test model predictions of glacial isostatic adjustment (GIA), particularly during the early deglacial period which is currently poorly constrained throughout the British Isles. Whilst the empirical data from the mid- to late-Holocene to present matches quite well with the recent GIA model output, there is a relatively poor fit between the timing of the Late Glacial RSL fall and early Holocene RSL rise. This mismatch, also evident elsewhere in northwest Scotland, may result from uncertainties associated with both the global and local ice components of GIA models.

  19. A permafrost glacial hypothesis to explain atmospheric CO2 and the ice ages during the Pleistocene

    Directory of Open Access Journals (Sweden)

    R. Tarozo

    2010-10-01

    Full Text Available Over the past several 100 ka glacial-interglacial cycles, the concentration of atmospheric CO2 was closely coupled to global temperature, which indicates the importance of CO2 as a greenhouse gas. The reasons for changes in atmospheric CO2 have mainly been sought in the ocean, yet proxy evidence does not support the notion of increased oceanic carbon storage during glacials. Here we present results from the first permafrost loess sequence in Siberia spanning two glacial cycles (~240 ka, which reveal that permafrost soils repeatedly sequestered huge amounts of terrestrial carbon during glacial periods. This can be explained with permafrost favouring more intensive waterlogging conditions and better preservation of soil organic matter. Terrestrial carbon stored in permafrost soils was released upon warming and provided a powerful feedback mechanism for the glacial terminations. We outline a "permafrost glacial hypothesis" building on integrated annual insolation forcing, which readily explains the observed succession of the ice ages during the Pleistocene, including the mid-Pleistocene transition.

  20. Late-glacial atmospheric CO{sub 2} reconstructions from western Norway using fossil leaves

    Energy Technology Data Exchange (ETDEWEB)

    Birks, H.H.; Birks, H.J.B. [Sheffield Univ. (United Kingdom). Dept. of Animal and Plant Sciences; Beerling, D.J.; Woodward, F.I. [Bergen Univ. (Norway). Botanical Inst.

    1995-12-31

    Analyses of air bubbles trapped in Antarctic ice-cores have shown that atmospheric CO{sub 2} concentrations are 180-200 ppmv during glacial periods, and ca. 280 ppmv during interglacials, including the Holocene. The change from glacial to Holocene concentrations occurred steadily over ca. 5000 years, slightly lagging the temperature increase inferred from {delta}{sup 18}. Antarctic ice cores lack fine time resolution over the late-glacial/early Holocene period 12-9000 {sup 14}C yr BP, that includes the Younger Dryas cold oscillation. The stomatal density on leaves is inversely proportional to the concentration of atmospheric CO{sub 2}. A late glacial sequence at Kraakenes, western Norway, contains well-preserved Salix herbacea (dwarf willow) leaves, dated from 11700-9600 {sup 14}C yr BP. If the stomatal density is measured on the fossil leaves, a calibration derived from the relationship of stomatal density of modern material of the same species to known CO{sub 2} concentrations can be used to reconstruct CO{sub 2} concentrations of the past. Because of the decadal time-resolution available at Kraakenes through the late-glacial and early Holocene, a detailed record of CO{sub 2} concentrations can be reconstructed over this period, that will complement the ice core record. (author)

  1. Lake bed environments, modern sedimentation and the glacial and post-glacial history of Windermere, UK

    OpenAIRE

    Miller, Helen

    2014-01-01

    Windermere, the largest natural lake in England, is a glacial ribbon lake located in the southeast of the Lake District. High resolution geophysical datasets, combined with sediment analysis, geomorphological mapping and historical research have been used to investigate the lake bed environments, recent sediment record of pollution and glacial and post-glacial history of the lake and surrounding catchment. The data are used to generate a present-day landscape map of Windermere, revealing...

  2. Forceful DuetA Comparison Between "Sublimity"in Ancient Rome and "Vigor of Style" in Jianan Period%雄浑二重奏——古罗马“崇高”与建安“风骨”的比较

    Institute of Scientific and Technical Information of China (English)

    简梦莹

    2012-01-01

    中国汉末魏.初时期文学所特有的“风骨”风格与古罗马时期所崇尚的“崇高”都体现了中西方人民对雄浑的阳剐之美的崇尚。他们时代接近,风格相仿.可谓是世界文学史上早期的“雄浑”二重奏。但是在追求雄浑的道路上。中国古代文论家远没有古代西方学者们的论述严谨缜密。由于地域、文化、社会背景的不同,他们在描写内容、表现形式上都有差异,但是对文质合一的文学之美的追求却高度一致。我们发现阳刚这种雄浑之美除了是古代先民在生活中所共同向往、追求的可与自然环境相抗衡的力量外,我们还找到了在公元前后通过丝绸之路进行文化交流的实证。这无疑又为我们打开了新的思路,在探索中西文论的比较中加入二者文化互相交融、互相影响的重要因素。%The unique "Vigor of Style" in Chinese literature during the period between the late Eastern Han Dynasty and the early Wei-jin Period and "Sublimity" advocated in ancient Roman period Mike embody both Chinese people and Western people' s advocacy of forceful masculine beauty. They are close in style and age and can be described as the early "forceful" duet in the history of the world literature. But in the pursuit of forcefulness, ancient western scholars expounded their ideas more rigorously and meticulously than the ancientChinese literary critics. Due to different geographical, cultural, and social backgrounds, their descriptions differed in contents and forms, but their pursuit of the unity of literary quality and beauty was highly consistent. We have found that vigorous masculine beauty was the power which all our ancient ancestors yearned for and pursued in their lives and could compete with the natural environment. We have also got the evidence for cultural exchange that was carried out through the Silk Road around the Christian Era. It undoubtedly broadens our

  3. Astronomy in the Ancient Caucasus

    Science.gov (United States)

    Simonia, Irakli; Jijelava, Badri

    This chapter discusses the role of recurrent heavenly phenomena in the formation of ancient cultural traditions. Artifacts bearing witness to astronomical and calendrical practices in the ancient Caucasus are described and we analyze the significance of the "boats of the sun" petroglyphs at Gobustan in Azerbaijan, the solar station at Abuli in Georgia, and the "sky dial" at Carahunge in Armenia. Similarities and differences between the ancient cultures of the region are discussed. Finally, we present the results of the latest field research and new facts and hypotheses.

  4. The Ancient Egyptian Demonology Project

    OpenAIRE

    Weber, Felicitas

    2016-01-01

    “The Ancient Egyptian Demonology Project: Second Millennium BCE” was intended and funded as a three-year project (2013-2016) to explore the world of Ancient Egyptian demons in the 2nd millennium BC. It intends to create a classification and ontology of benevolent and malevolent demons. Whereas ancient Egyptians did not use a specific term denoting “demons”, liminal beings known from various other cultures such as δαίμονες, ghosts, angels, Mischwesen, genies, etc., were nevertheless described ...

  5. Did the ancient Egyptians migrate to ancient Nigeria?

    OpenAIRE

    Jock M. Agai

    2014-01-01

    Literatures concerning the history of West African peoples published from 1900 to 1970 debate�the possible migrations of the Egyptians into West Africa. Writers like Samuel Johnson and�Lucas Olumide believe that the ancient Egyptians penetrated through ancient Nigeria but Leo�Frobenius and Geoffrey Parrinder frowned at this opinion. Using the works of these early�20th century writers of West African history together with a Yoruba legend which teaches�about the origin of their earliest ancesto...

  6. Last glacial aeolian dynamics at the Titel loess plateau (Vojvodina, Serbia)

    Science.gov (United States)

    Marković, S. B.; Bokhorst, M. P.; Machalett, B.; Štrbac, D.; Hambach, U.; Basarin, B.; Svirčev, Z.; Stevens, T.; Frechen, M.; Vandenberghe, J.

    2009-04-01

    and magnetic susceptibility values in a weakly developed pedocomplex, V-L1S1. Loess sub-layers intercalated into V-L1S1 preserve evidence of episodes of abrupt cooling and aridification. In contrast with other European loess sites, the middle glacial pedocomplex is weakly developed at exposures on the Titel loess plateau. The uppermost late glacial loess stratum V-L1L1 shows low values of magnetic susceptibility and clay content, plus high values of carbonate content and the presence of a few frigophilous and cold resistant snails, preserved in sediments laid down during the coldest palaeoclimatic interval of the last glacial period. Composite mollusc associations in loess unit V-L1L1 suggest a higher diversity of environments in comparison to those preserved in the V-L1L2 and V-L1S1 units. In addition to climatic changes over interglacial-glacial and interstadial-stadial timescales, climate proxies (especially grain size) in the last glacial loess exhibit many abrupt fluctuations. Evidence of similar abrupt high frequency fluctuations during the last glacial period appear in loess through out much of Eurasia. Without a detailed and precise chronological framework, provided by independent dating, as yet it is not possible to determine whether the variations recorded in the Titel plateau loess are related to widely documented events in the North Atlantic or independent regional or local depositional/environmental variations. The intensity of deposition of coarser material during the relatively cold early last glacial exceeds that during the coldest last glacial maximum. This may be explainable via changes in general atmospheric circulation, as well as changes in the transportation and depositio regime of the Danube fluvial system. During the last glacial maximum, extension of the ice sheets in northern Europe was greatest and may have redirected the penetration of Atlantic air masses to the east (e.g. Dodonov and Baiguzina, 1995). Model results presented in van

  7. Temporal Record of Glacial Dynamics in Southern Alaska During the Neogene-A Marine Perspective

    Science.gov (United States)

    Jaeger, J. M.; Cowan, E.; Finney, B.; Stoner, J.

    2004-05-01

    The Gulf of Alaska (GoA) margin features high mountains next to the ocean trapping abundant precipitation that fuels erosive glacial activity and exceptionally high sediment yields. As climate determines the timing and patterns of precipitation, it controls glacial dynamics, erosion, and sediment/meltwater fluxes to the ocean. Minimal terrestrial sediment storage allows proxy signals of terrestrial climate change such as precipitation, temperature, and glacial mass balance to be rapidly transferred to oceanic sediment records via glaciers and rivers. A reevaluation of DSDP Site 178 stratigraphy coupled with Holocene seismic reflection data and ultra-high resolution sediment cores covering the Little Ice Age reveal that GoA margin strata preserve a strong temporal record of terrestrial paleoclimatic signals on timescales ranging from the seasonal to Quaternary. Over this diverse range of time scales, the nature of sediment input from glaciers to the marine environment follows a cycle of storage and release, with the magnitude of release controlled by climatic forcing. As has been noted for ODP Site 887 in the southern GoA, the extent of sediment delivery to the northern GoA during the Quaternary is forced by the magnitude of glacial advances as reflected in Pacific Ocean benthic del O-18 variations. Over the Holocene, seismic reflection profiles reveal that sediment fluxes appear to have been minimal during the warm early Holocene Hypsithermal Period when glacial coverage is believed to have been minimal. These fluxes likely doubled during the renewal of glacial activity during the late Holocene Neoglacial period. During Little Ice Age glacial advances (~1200-1900 A.D.), sediment release peaked for several decades immediately following terrestrial moraine production and declined by 80-90 percent during the following half century. Likewise, on seasonal time scales, the magnitude of sediment flux from the tidewater Hubbard glacier appears to be positively forced by

  8. [Ancient Egyptian Odontology].

    Science.gov (United States)

    Berghult, B

    1999-01-01

    In ancient Egypt during the reign of Pharaoh Djoser, circa 2650 BC, the Step Pyramid was constructed by Imhotep. He was later worshiped as the God of Medicine. One of his contemporaries was the powerful writer Hesy who is reproduced on a panel showing a rebus of a swallow, a tusk and an arrow. He is therefore looked upon as being the first depicted odontologist. The art of writing begun in Egypt in about 3100 BC and the medical texts we know from different papyri were copied with hieratic signs around 1900-1100 BC. One of the most famous is the Papyrus Ebers. It was purchased by professor Ebers on a research travel to Luxor in 1873. Two years later a beautiful facsimile in color was published and the best translation came in 1958 in German. The text includes 870 remedies and some of them are related to teeth and oral troubles like pain in the mouth, gingivitis, periodontitis and cavities in the teeth. The most common oral pain was probably pulpitis caused by extreme attrition due to the high consumption of bread contaminated with soil and/or quern minerals. Another text is the Papyrus Edwin Smith with four surgical cases of dental interest. The "toothworms" that were presumed to bring about decayed teeth have not been identified in the medical texts. It was not until 1889 W.D. Miller presented a scientific explanation that cavities were caused by bacteria. In spite of extensive research only a few evidence of prosthetic and invasive treatments have been found and these dental artifacts have probably been made post mortem. Some of the 150 identified doctors were associated with treatments of disorders of the mouth. The stele of Seneb from Sa'is during the 26th dynasty of Psamtik, 664-525 BC, shows a young man who probably was a dental healer well known to Pharaoh and his court. Clement of Alexandria mentions circa 200 AD that the written knowledge of the old Egyptians was gathered in 42 collections of papyri. Number 37-42 contained the medical writings. The

  9. Eternal Egypt: Masterworks of Ancient Art from the British Museum. Learning from Exhibitions.

    Science.gov (United States)

    Johnson, Mark M.

    2001-01-01

    Introduces the exhibition "Eternal Egypt: Masterworks of Ancient Art from the British Museum" that explores the four major periods of Egyptian history. Provides background information on ancient Egypt and describes the art that was present in each of the four kingdoms. (CMK)

  10. The Charm of An Ancient Southern City

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    AN artistic narrow bridge winds into a place of pavilions, terraces and open halls, all under the pleasant shade of green trees. This is Mist-Water Pavilion Park in Gantang Lake in the city of Jiujiang, Jiangxi Province. When you stand here in the quiet and elegant historic garden and look out over the water on all four sides, you can’t help but think of the ancient war that took place on this very spot 1,700 years ago. During the Three Kingdoms Period (220-280), this was

  11. Ancient Egypt, Sacred Science, and Transatlantic Romanticism

    OpenAIRE

    Redd, Marques Jerard

    2011-01-01

    Ancient Egyptian culture has been a powerful influence on a major tradition of English literature that runs from Edmund Spenser's The Faerie Queene (1596), one of whose major iconographic centers is the temple of Isis, to John Crowley's four-volume novel Ægypt (2007). My dissertation focuses on the Romantic period - the midpoint of this trajectory - because it is an extremely intense moment of this influence. In addition to the visions of Egypt presented in the Bible, Greco-Roman writers, a...

  12. Ancient and Current Chaos Theories

    Directory of Open Access Journals (Sweden)

    Güngör Gündüz

    2006-07-01

    Full Text Available Chaos theories developed in the last three decades have made very important contributions to our understanding of dynamical systems and natural phenomena. The meaning of chaos in the current theories and in the past is somewhat different from each other. In this work, the properties of dynamical systems and the evolution of chaotic systems were discussed in terms of the views of ancient philosophers. The meaning of chaos in Anaximenes’ philosophy and its role in the Ancient natural philosophy has been discussed in relation to other natural philosophers such as of Anaximander, Parmenides, Heraclitus, Empedocles, Leucippus (i.e. atomists and Aristotle. In addition, the fundamental concepts of statistical mechanics and the current chaos theories were discussed in relation to the views in Ancient natural philosophy. The roots of the scientific concepts such as randomness, autocatalysis, nonlinear growth, information, pattern, etc. in the Ancient natural philosophy were investigated.

  13. Ancient Astronomical Monuments of Athens

    Science.gov (United States)

    Theodossiou, E.; Manimanis, V. N.

    2010-07-01

    In this work, four ancient monuments of astronomical significance found in Athens and still kept in the same city in good condition are presented. The first one is the conical sundial on the southern slope of the Acropolis. The second one is the Tower of the Winds and its vertical sundials in the Roman Forum of Athens, a small octagonal marble tower with sundials on all 8 of its sides, plus a water-clock inside the tower. The third monument-instrument is the ancient clepsydra of Athens, one of the findings from the Ancient Agora of Athens, a unique water-clock dated from 400 B.C. Finally, the fourth one is the carved ancient Athenian calendar over the main entrance of the small Byzantine temple of the 8th Century, St. Eleftherios, located to the south of the temple of the Annunciation of Virgin Mary, the modern Cathedral of the city of Athens.

  14. Reconstructing ancient genomes and epigenomes

    DEFF Research Database (Denmark)

    Orlando, Ludovic Antoine Alexandre; Gilbert, M. Thomas P.; Willerslev, Eske

    2015-01-01

    DNA studies have now progressed to whole-genome sequencing for an increasing number of ancient individuals and extinct species, as well as to epigenomic characterization. Such advances have enabled the sequencing of specimens of up to 1 million years old, which, owing to their extensive DNA damage and...... contamination, were previously not amenable to genetic analyses. In this Review, we discuss these varied technical challenges and solutions for sequencing ancient genomes and epigenomes....

  15. Orthopedic surgery in ancient Egypt

    OpenAIRE

    Blomstedt, Patric

    2014-01-01

    Background — Ancient Egypt might be considered the cradle of medicine. The modern literature is, however, sometimes rather too enthusiastic regarding the procedures that are attributed an Egyptian origin. I briefly present and analyze the claims regarding orthopedic surgery in Egypt, what was actually done by the Egyptians, and what may have been incorrectly ascribed to them. Methods — I reviewed the original sources and also the modern literature regarding surgery in ancient Egypt, concentra...

  16. The Holocene British and Irish ancient forest fossil beetle fauna: implications for forest history, biodiversity and faunal colonisation

    Science.gov (United States)

    Whitehouse, Nicki J.

    2006-08-01

    This paper presents a new review of our knowledge of the ancient forest beetle fauna from Holocene archaeological and palaeoecological sites in Great Britain and Ireland. It examines the colonisation, dispersal and decline of beetle species, highlighting the scale and nature of human activities in the shaping of the landscape of the British Isles. In particular, the paper discusses effects upon the insect fauna, and examines in detail the fossil record from the Humberhead Levels, eastern England. It discusses the local extirpation of up to 40 species in Britain and 15 species in Ireland. An evaluation of the timing of extirpations is made, suggesting that many species in Britain disappear from the fossil record between ca 3000 and 1000 cal BC (ca 5000-3000 cal BP), although some taxa may well have survived until considerably later. In Ireland, there are two distinct trends, with a group of species which seem to be absent after ca 2000 cal BC (ca 4000 cal BP) and a further group which survives until at least as late as the medieval period. The final clearance of the Irish landscape over the last few hundred years was so dramatic, however, that some species which are not especially unusual in a British context were decimated. Reasons behind the extirpation of taxa are examined in detail, and include a combination of forest clearance and human activities, isolation of populations, lack of temporal continuity of habitats, edaphic and competition factors affecting distribution of host trees (particularly pine), lack of forest fires and a decline in open forest systems. The role of climate change in extirpations is also evaluated. Consideration is given to the significance of these specialised ancient forest inhabitants in Ireland in the absence of an early Holocene land-bridge which suggests that colonisation was aided by other mechanisms, such as human activities and wood rafting. Finally, the paper discusses the Continental origins of the British and Irish fauna and

  17. Pleistocene glacial terminations triggered by synchronous changes in Southern and Northern Hemisphere insolation: The insolation canon hypothesis

    OpenAIRE

    Schulz, Kai; Zeebe, Richard E.

    2007-01-01

    Throughout the last similar to 900 kyr, the Late Pleistocene, Earth has experienced periods of cold glacial climate, punctuated by seven abrupt transitions to warm interglacials, the so-called terminations. Although most of glacial ice is located in the Northern Hemisphere (NH), the Southern Hemisphere (SH) seems to play a crucial role in deglaciation. Variation in the seasonal distribution of solar insolation is one candidate for the cause of these climatic shifts. But so far, no simple mech...

  18. 春秋战国与古希腊廉政思想之比较及其当代价值%Comparison of the Thought Against Corruption in Periods of Spring and Autumn and Warring States and Ancient Greek and Its Contemporary Value

    Institute of Scientific and Technical Information of China (English)

    高建林

    2013-01-01

    中国春秋战国时期和古希腊时代是人类史上的轴心时代,作为东西方文化的胚胎期,各有其独立的文化体系,其廉政思想亦具许多相似和相异之处。比较其异同,对于构建当今廉政文化体系,推进廉政文化建设,定会得到不少启示和借鉴。%Periods of Spring and Autumn and the Warring States and ancient Greek are both regarded as the axial era in hu-man history. As the embryonic phase of the eastern and western civilization, they possess respective and independent cultural systems. The thoughts against corruption in the two periods share many similarities and display many differences. When com-paring their similar and different points, we can surely obtain much enlightenment and reference so as to construct the contem-porary anti-corruption cultural system and promote the anti-corruption construction.

  19. A first look at the ACER-SST dataset: Mapping the spatio-temporal variability of sea-surface temperatures in the last Glacial and the Holocene

    Science.gov (United States)

    Rehfeld, Kira; Laepple, Thomas; Bassinot, Franck; Daniau, Anne-Laure; Desprat, Stéphanie; Kim, Jung-Hyun; Fernanda Sánchez-Goñi, Maria; Harrison, Sandy

    2016-04-01

    Climate in the last Glacial was characterized by abrupt and large-scale changes around cold Heinrich-Events and warm Dansgaard-Oeschger excursions in the Northern high latitudes. The global repercussions of these periods of rapid dynamics are, to date, unconstrained. Here, we present a first statistical analysis of the global multi-proxy ACER (Abrupt Climate Changes and Environmental Responses) sea surface temperature dataset, spanning the last 80 thousand years, to investigate the spatial footprints of glacial climate dynamics. In a first step we evaluate the spatial and temporal variability throughout the Glacial period, and contrast them with that during the Holocene. In a second step we investigate to which extent a temporal synchroneity of extreme events during the Glacial is detectable in the proxy records, and analyze the reversibility of Glacial dynamics.

  20. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

    OpenAIRE

    J. Holtvoeth; H. Vogel; Wagner, B.; Wolff, G.A.

    2010-01-01

    Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shore, with low-lying lands ne...

  1. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

    OpenAIRE

    J. Holtvoeth; H. Vogel; Wagner, B.; Wolff, G.A.

    2010-01-01

    Abstract. Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin’s hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: site Lz1120 near the southern shor...

  2. Lipid biomarkers in Holocene and glacial sediments from ancient Lake Ohrid (Macedonia, Albania)

    OpenAIRE

    J. Holtvoeth; H. Vogel; Wagner, B.; Wolff, G.A.

    2010-01-01

    Organic matter preserved in Lake Ohrid sediments originates from aquatic and terrestrial sources. Its variable composition reflects climate-controlled changes in the lake basin's hydrology and related organic matter export, i.e. changes in primary productivity, terrestrial plant matter input and soil erosion. Here, we present first results from lipid biomarker investigations of Lake Ohrid sediments from two near-shore settings: Site Lz1120 near the southern shore, with flat lands nearby and p...

  3. Glacial lakes Buni and Jezerce: Albania

    Directory of Open Access Journals (Sweden)

    Milivojević Milovan

    2005-01-01

    Full Text Available The paper presents glacial lakes and glacial relief forms at the foothill of the peak Maja Jezerce in Mt. Prokletije in Albania, near the border with Montenegro. The group of lakes Buni and Jezerce, which consists of six lakes and which genetically belongs to glacial-erosional lakes, is analyzed. Lakes are situated at the cirque bottom, between the moraines and limestone ridges. Except presented morphometric characteristics of lake basins, data about cirque are given, as well as the reconstruction of the glacier which was formed here. Recent erosion processes are intensive in this area and have considerably changed post-Pleistocene morphology of the lake, as well as the cirque bottom.

  4. Hedera helix L. and damages in Tlos Ancient City

    OpenAIRE

    Elinç, Z.K.; Korkut, T.; Kaya, L.G.

    2013-01-01

    There are various plant types in Tlos Ancient City of Fethiye district in the Province of Mugla, a city where different residential ruins of Lycia Civilization starting from Classical Age until Byzantine Period. Tlos is an important city in West-Lycia and is situated right on the control point of Lycia Way. Hedera helix L. is one of the plants living in this area, which attracts the attention as it mostly harms the ancient ruins. One of the most important reasons why Hedera helix L. is gr...

  5. [Ancient mental healing and cognitive behavior therapy in comparison].

    Science.gov (United States)

    Hoellen, B; Laux, J

    1988-01-01

    Although cognitive-behavior therapy (CBT) is a relatively new psychotherapeutic approach, the theoretical antecedents actually date back two thousand years, to the period of the hellenistic philosophers. The Stoic Epictetus is often acknowledged as the main philosophical father of CBT and especially of rational-emotive therapy (RET). Beck and Ellis frequently noted that they have drawn upon the writings of the ancient philosophers in developing their psychotherapeutic techniques. This paper reviews some implications of hellenistic philosophy for CBT. We like to show that the teachings of the ancient 'healer of souls' are remarkably consistent with the current theoretical framework and techniques of CBT. PMID:3073604

  6. Glacial retreat between the Late-Glacial and Early Holocene sequences in the Southern French Alps : definition of an accurate pattern by new Cosmic Ray Exposure ages.

    Science.gov (United States)

    Cossart, Etienne; Fort, Monique; Bourlès, Didier; Braucher, Régis; Carcaillet, Julien; Perrier, Romain; Siame, Lionel; Gribenski, Natacha

    2010-05-01

    The Southern French Alps, characterized by many climatic influences (oceanic, continental and mediterranean), remain a scientific problem for palaeo-environmental studies. Indeed, the lack of chronological benchmarks hitherto hampered the definition of sequences of glacier variations since the Last Glacial Maximum (LGM), even if a scenario was based upon an extensive fieldwork realized in the Ubaye valley. This scenario was then considered as a regional model by many geomorphologists, but this valley is not necessarily representative of the entire region. Firstly, this valley is the driest area within the Southern French Alps due the sheltering effect of relief against humid fluxes. Secondly, topography (altitudes, slopes and shapes) of the upper part of watersheds are not particularly prone to snow accumulation into the cirques. The established scenario is as follows. Glaciers shrank and decayed between the LGM and the Late-Glacial periods and glaciers were restricted in cirques areas during the Late-Glacial and Holocene glaciations. We try to discuss this model thanks to geomorphic investigations and new chronological benchmarks acquired in Briançonnais area, in the upper part of Durance watershed. The upper part of the Durance watershed was chosen because it corresponds to the accumulation zone of the main glacier of the Southern French Alps during the LGM. Thanks to extensive fieldwork and geomorphic mapping of remnants of past glaciations, and thanks to new chronological data (about 35 cosmic ray exposure -CRE- ages, acquired in 2004 and 2009) we propose here the first absolute scenario established in the very upper part of the catchment. To assess CRE ages, we sampled glacially-polished surfaces, along both longitudinal and transverse valley cross-sections, in order to assess both the retreat of the front and the thinning rate of the glacial tongue. We also paid attention to knobs located at the outlet of glacial cirques, and some morainic ridges. The

  7. In-stream net ecosystem metabolism differences across a glacial coverage gradient in southeast Alaska

    Science.gov (United States)

    Nassry, M. Q.; Hood, E. W.; Scott, D.; Vermilyea, A.

    2010-12-01

    As glacier ice gives way to successional vegetation, streams located in glacier-containing watersheds receive decreased contributions from glacial meltwater and increased contributions from terrestrial landscapes. Aquatic communities in streams receiving varying amounts of glacial meltwater were compared during this research to determine the effect of changing inputs of glacial meltwater on net ecosystem metabolism (NEM). In particular, we tested the hypothesis that decreased inputs of glacier meltwater will result in increased NEM in coastal streams in southeast Alaska. Dissolved oxygen and temperature measurements were collected at 5-minute increments using multi-sensor probes for 48 hours at four study streams. Additionally, discharge and velocity measurements were collected along with surface water samples during each of three replicate study periods at all four streams. Single station diel curves of in-stream oxygen concentration and water temperature changes were generated to establish community respiration (CR24) and gross primary production (GPP) values. The study watersheds, all of which are adjacent to the Juneau Icefield, range in area from 23-158 km2 and in watershed glacial coverage from 0-40%. This research will provide new insights into how changes in runoff from rapidly thinning and receding glaciers in southeast Alaska will affect aquatic community metabolism in downstream ecosystems. Ultimately, this will provide a better understanding of the changing in-stream processing capabilities in watersheds affected by land cover changes resulting from glacial recession.

  8. Differentiating Hydrothermal, Pedogenic, and Glacial Weathering in a Cold Volcanic Mars-Analog Environment

    Science.gov (United States)

    Scudder, N. A.; Horgan, B.; Havig, J.; Rutledge, A.; Rampe, E. B.; Hamilton, T.

    2016-01-01

    Although the current cold, dry environment of Mars extends back through much of its history, its earliest periods experienced significant water- related surface activity. Both geomorphic features (e.g., paleolakes, deltas, and river valleys) and hydrous mineral detections (e.g., clays and salts) have historically been interpreted to imply a "warm and wet" early Mars climate. More recently, atmospheric modeling studies have struggled to produce early climate conditions with temperatures above 0degC, leading some studies to propose a "cold and icy" early Mars dominated by widespread glaciation with transient melting. However, the alteration mineralogy produced in subglacial environments is not well understood, so the extent to which cold climate glacial weathering can produce the diverse alteration mineralogy observed on Mars is unknown. This summer, we will be conducting a field campaign in a glacial weathering environment in the Cascade Range, OR in order to determine the types of minerals that these environments produce. However, we must first disentangle the effects of glacial weathering from other significant alteration processes. Here we attempt a first understanding of glacial weathering by differentiating rocks and sediments weathered by hydrothermal, pedogenic, and glacial weathering processes in the Cascades volcanic range.

  9. Bifurcations and strange nonchaotic attractors in a phase oscillator model of glacial-interglacial cycles

    CERN Document Server

    Mitsui, Takahito; Aihara, Kazuyuki

    2015-01-01

    Glacial-interglacial cycles are large variations in continental ice mass and greenhouse gases, which have dominated climate variability over the Quaternary. The dominant periodicity of the cycles is $\\sim $40 kyr before the so-called middle Pleistocene transition between $\\sim$1.2 and $\\sim$0.7 Myr ago, and it is $\\sim $100 kyr after the transition. In this paper, the dynamics of glacial-interglacial cycles are investigated using a phase oscillator model forced by the time-varying incoming solar radiation (insolation). We analyze the bifurcations of the system and show that strange nonchaotic attractors appear through nonsmooth saddle-node bifurcations of tori. The bifurcation analysis indicates that mode-locking is likely to occur for the 41 kyr glacial cycles but not likely for the 100 kyr glacial cycles. The sequence of mode-locked 41 kyr cycles is robust to small parameter changes. However, the sequence of 100 kyr glacial cycles can be sensitive to parameter changes when the system has a strange nonchaoti...

  10. Head of all years astronomy and calendars at Qumran in their ancient context

    CERN Document Server

    Ben-Dov, Jonathan

    2008-01-01

    Covering a wide array of sources from ancient Mesopotamia to the Dead Sea Scrolls, this volume offers a different perspective on Jewish apocalyptic time-reckoning during the Second Temple period, based on a calendar year of 364 days.

  11. Glacial-interglacial organic carbon record from the Makassar Strait, Indonesia: Implications for regional changes in continental vegetation

    Science.gov (United States)

    Visser, K.; Thunell, R.; Goni, M.A.

    2004-01-01

    Recent studies convincingly show that climate in the Western Pacific Warm Pool and other equatorial/tropical regions was significantly colder (by ???3-4??C) during glacial periods, prompting a reexamination of the late Pleistocene paleoenvironments of these regions. This study examines changes in continental vegetation during the last two deglaciations (Terminations I and II) using a sediment core (MD9821-62) recovered from the Makassar Strait, Indonesia. Evidence based on the lignin phenol ratios suggests that vegetation on Borneo and other surrounding islands did not significantly change from tropical rainforest during the last two glacial periods relative to subsequent interglacial periods. This supports the hypothesis that the winter monsoon increased in strength during glacial periods, allowing Indonesia to maintain high rainfall despite the cooler conditions. ?? 2003 Elsevier Ltd. All rights reserved.

  12. Ancient DNA in Greece. Problems and prospects

    International Nuclear Information System (INIS)

    The promise associated with early 'ancient DNA' results has not been translated into routine techniques of value to archaeologists. The reasons for this are partly technical - ancient DNA analysis is an extremely difficult technique - and partly practical - ancient DNA analysis is often an 'after thought' to an archaeological project. In this paper ancient human DNA analysis is briefly reviewed paying particular attention to specimens originating from Greek archaeological contexts. Problems commonly encountered during ancient DNA research are summarised and recommendations for future strategies in the application of ancient DNA in archaeology are proposed. (author)

  13. Climatic implications of correlated upper Pleistocene glacial and fluvial deposits on the Cinca and Gallego rivers, NE Spain

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Claudia J [Los Alamos National Laboratory; Mcdonald, Eric [NON LANL; Sancho, Carlos [NON LANL; Pena, Jose- Luis [NON LANL

    2008-01-01

    We correlate Upper Pleistocene glacial and fluvial deposits of the Cinca and Gallego River valleys (south central Pyrenees and Ebro basin, Spain) using geomorphic position, luminescence dates, and time-related trends in soil development. The ages obtained from glacial deposits indicate glacial periods at 85 {+-} 5 ka, 64 {+-} 11 ka, and 36 {+-} 3 ka (from glacial till) and 20 {+-} 3 ka (from loess). The fluvial drainage system, fed by glaciers in the headwaters, developed extensive terrace systems in the Cinca River valley at 178 {+-} 21 ka, 97 {+-} 16 ka, 61 {+-} 4 ka, 47 {+-} 4 ka, and 11 {+-} 1 ka, and in the Gallego River valley at 151 {+-} 11 ka, 68 {+-} 7 ka, and 45 {+-} 3 ka. The times of maximum geomorphic activity related to cold phases coincide with Late Pleistocene marine isotope stages and heinrich events. The maximum extent of glaciers during the last glacial occurred at 64 {+-} 11 ka, and the terraces correlated with this glacial phase are the most extensive in both the Cinca (61 {+-} 4 ka) and Gallego (68 {+-} 7 ka) valleys, indicating a strong increase in fluvial discharge and availability of sediments related to the transition to deglaciation. The global Last Glacial Maximum is scarcely represented in the south central Pyrenees owing to dominantly dry conditions at that time. Precipitation must be controlled by the position of the Iberian Peninsula with respect to the North Atlantic atmospheric circulation system. The glacial systems and the associated fluvial dynamic seem sensitive to (1) global climate changes controlled by insolation, (2) North Atlantic thermohaline circulation influenced by freshwater pulses into the North Atlantic, and (3) anomalies in atmospheric circulation in the North Atlantic controlling precipitation on the Iberian peninsula. The model of glacial and fluvial evolution during the Late Pleistocene in northern Spain could be extrapolated to other glaciated mountainous areas in southern Europe.

  14. The history of parkinsonism: descriptions in ancient Indian medical literature.

    Science.gov (United States)

    Ovallath, Sujith; Deepa, P

    2013-05-01

    The clinical syndrome of parkinsonism was identified in ancient India even before the period of Christ and was treated methodically. The earliest reference to bradykinesia dates to 600 bc. Evidences prove that as early as 300 bc, Charaka proposed a coherent picture of parkinsonism by describing tremor, rigidity, bradykinesia, and gait disturbances as its components. The scenario was further developed by Madhava, Vagbhata, and Dalhana all through history. The 15th-century classic "Bhasava rajyam" introduced the term kampavata, which may be regarded as an ayurvedic analogue of parkinsonism. The pathogenesis of kampavata centered on the concept of imbalance in the vata factor, which controls psychomotor activities. The essential element in therapy was the administration of powdered seed of Mucuna pruriens, or atmagupta, which as per reports, contains 4%-6% of levodopa. In addition to proving the existence and identification of parkinsonism in ancient India, the study points to the significance of ancient Indian Sanskrit works in medical history. PMID:23483637

  15. Trace elements in ancient ceramics: Pt.4

    International Nuclear Information System (INIS)

    In the last period of Tong Dynasty, Jingdezhen began its production of ceramics. During the Song Dynasty, the ceramic industry greatly developed and produced fine white ware at Hutian. In the Yuan Dynastry, Hutian became the centre of production making the world famous blue and white wares. Here are reported results of analyses of ancient porcelians of Hutian in Jiangdezhen by reactor neutron activation analysis. The results show that the patterns of eight rare earth elements are apparently different for products in different periods, indicating that methods for producing ceramics or kinds of clay used were different. The contents of some other trace elements such as hafnium, tantalum, thorium and uranium show the same regularity in difference of composition also

  16. Unknown ancient Greek ophthalmological instruments and equipment.

    Science.gov (United States)

    Lascaratos, J; Marketos, S

    1997-01-01

    Discoveries of some ancient medical instruments and equipment found in the Hellenic world have been published in magazines of general interest and in a rare Greek medical journal, yet none caught the attention of ophthalmologists. Among these instruments are two forms of the famous 'Kenteterion', dating from the Hellenistic period, used for the couching of cataract. These were found on the island of Milos in the last century. Two magnifying lenses of the Archaic period from the recent Cretan excavations gave us the opportunity to discuss the problem of their medical use. The two drop-bottles from the excavations on Cyprus and at Tanagra, which are also described, seem to be of medical, and possible ophthalmological, use. PMID:9657298

  17. Sustainability of Ancient Water Supply Facilities in Jerusalem

    Directory of Open Access Journals (Sweden)

    Jamal M. Barghouth

    2009-11-01

    Full Text Available This paper presents an overview on the sustainability of ancient water supply systems in Jerusalem from the Chalcolithic period (4500–3200 B.C. until the present time. Archaeological evidences and landscape settings were applied utilizing all available and accessible literature relevant to ancient water resources management in Jerusalem. Irrigated agriculture was practiced for many centuries in this region, hence sustainable water supply facilities were erected, including well developed aqueducts, water harvesting pools and irrigation channels for water storage and landscaping purposes. To cope with seismic events, soil subsidence and water leakage, ancient water engineers and architects applied innovative construction methods for the erection of water pools, channels and aqueduct systems. Ancient water supply systems in Jerusalem are valuable treasures of past civilizations and crucial urban environmental facilities and their protection is consistent with sustainable development principles. Effective environmental assessment as a decision-making process for sustainable development can be applied to preserve threatened ancient water facilities from major development proposals and urban infrastructure projects in Jerusalem.

  18. Critical insolation-CO2 relation for diagnosing past and future glacial inception

    Science.gov (United States)

    Ganopolski, A.; Winkelmann, R.; Schellnhuber, H. J.

    2016-01-01

    The past rapid growth of Northern Hemisphere continental ice sheets, which terminated warm and stable climate periods, is generally attributed to reduced summer insolation in boreal latitudes. Yet such summer insolation is near to its minimum at present, and there are no signs of a new ice age. This challenges our understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception. Here we propose a critical functional relationship between boreal summer insolation and global carbon dioxide (CO2) concentration, which explains the beginning of the past eight glacial cycles and might anticipate future periods of glacial inception. Using an ensemble of simulations generated by an Earth system model of intermediate complexity constrained by palaeoclimatic data, we suggest that glacial inception was narrowly missed before the beginning of the Industrial Revolution. The missed inception can be accounted for by the combined effect of relatively high late-Holocene CO2 concentrations and the low orbital eccentricity of the Earth. Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.

  19. Critical insolation-CO2 relation for diagnosing past and future glacial inception

    Science.gov (United States)

    Ganopolski, Andrey; Winkelmann, Ricarda; Schellnhuber, Hans Joachim

    2016-04-01

    Past rapid growth of Northern Hemisphere continental ice sheets, which terminated rather stable and warm climate periods, is generally attributed to reduced summer insolation in boreal latitudes (Milanković , 1941; Hays et al., 1976, Paillard, 1998). Yet pertinent summer insolation is near to its minimum at present (Berger and Loutre, 2002), and there are no signs of a new ice age (Kemp et al., 2011). This challenges our scientific understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception (Masson-Delmotte et al., 2013). Here we propose a fundamental functional relationship between boreal summer insolation and global CO2 concentration, which explains the beginning of the past eight glacial cycles and can anticipate future periods when glacial inception may occur again. Using a simulations ensemble generated by an Earth system model of intermediate complexity constrained by paleoclimatic data, we show that glacial inception was narrowly missed before the beginning of the Industrial Revolution. This can be explained by the combined effect of relatively high late-Holocene CO2 concentration and low orbital eccentricity of the Earth (Loutre and Berger, 2003). Additionally, our analysis shows that even in the absence of human perturbations no significant buildup of ice sheets would occur within the next several thousand years and that the current interglacial would likely last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1000 to 1500 GtC may already postpone the next glacial inception by at least 100,000 years (Archer and Ganopolski, 2005; Paillard, 2006). Our simulations demonstrate that under natural conditions alone the Earth system would be expected to stay in the delicate interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time.

  20. Critical insolation-CO2 relation for diagnosing past and future glacial inception.

    Science.gov (United States)

    Ganopolski, A; Winkelmann, R; Schellnhuber, H J

    2016-01-14

    The past rapid growth of Northern Hemisphere continental ice sheets, which terminated warm and stable climate periods, is generally attributed to reduced summer insolation in boreal latitudes. Yet such summer insolation is near to its minimum at present, and there are no signs of a new ice age. This challenges our understanding of the mechanisms driving glacial cycles and our ability to predict the next glacial inception. Here we propose a critical functional relationship between boreal summer insolation and global carbon dioxide (CO2) concentration, which explains the beginning of the past eight glacial cycles and might anticipate future periods of glacial inception. Using an ensemble of simulations generated by an Earth system model of intermediate complexity constrained by palaeoclimatic data, we suggest that glacial inception was narrowly missed before the beginning of the Industrial Revolution. The missed inception can be accounted for by the combined effect of relatively high late-Holocene CO2 concentrations and the low orbital eccentricity of the Earth. Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time. PMID:26762457

  1. Ancient Chinese Medicine Men

    Institute of Scientific and Technical Information of China (English)

    LIWUZHOU; TANZHEN

    2004-01-01

    SOME 2,500 years ago Duke Huan, ruler of the State of Qi in the Spring and Autumn Period (770-476 B.C.), gave an audience to famous doctor Bian Que who, upon observing the monarch's complexion, told him that he had a potentially fatal illness.

  2. Susruta of ancient India

    Directory of Open Access Journals (Sweden)

    Raju V

    2003-01-01

    Full Text Available "It is interesting that while in Hindu medicine, cataract was defined by Susruta as opacity due to derangement of the intraocular fluid, subsequent history is full of fantasies and prejudices concerning its nature." Duke Elder[1] "All in all Susruta must be considered the greatest surgeon of the pre medieval period." A.O. Whipple[2

  3. Night blindness and ancient remedy

    Directory of Open Access Journals (Sweden)

    H.A. Hajar Al Binali

    2014-01-01

    Full Text Available The aim of this article is to briefly review the history of night blindness and its treatment from ancient times until the present. The old Egyptians, the Babylonians, the Greeks and the Arabs used animal liver for treatment and successfully cured the disease. The author had the opportunity to observe the application of the old remedy to a patient. Now we know what the ancients did not know, that night blindness is caused by Vitamin A deficiency and the animal liver is the store house for Vitamin A.

  4. Tuberculosis in ancient times

    Directory of Open Access Journals (Sweden)

    Louise Cilliers

    2008-09-01

    Full Text Available In spite of an array of effective antibiotics, tuberculosis is still very common in developing countries where overcrowding, malnutrition and poor hygienic conditions prevail. Over the past 30 years associated HIV infection has worsened the situation by increasing the infection rate and mortality of tuberculosis. Of those diseases caused by a single organism only HIV causes more deaths internationally than tuberculosis. The tubercle bacillus probably first infected man in Neolithic times, and then via infected cattle, but the causative Mycobacteriacea have been in existence for 300 million years. Droplet infection is the most common way of acquiring tuberculosis, although ingestion (e.g. of infected cows’ milk may occur. Tuberculosis probably originated in Africa. The earliest path gnomonic evidence of human tuberculosis in man was found in osteo-archaeological findings of bone tuberculosis (Pott’s disease of the spine in the skeleton of anEgyptian priest from the 21st Dynasty (approximately 1 000 BC. Suggestive but not conclusiveevidence of tuberculotic lesions had been found in even earlier skeletons from Egypt and Europe. Medical hieroglyphics from ancient Egypt are silent on the disease, which could be tuberculosis,as do early Indian and Chinese writings. The Old Testament refers to the disease schachapeth, translated as phthisis in the Greek Septuagint. Although the Bible is not specific about this condition, tuberculosis is still called schachapeth in modern Hebrew. In pre-Hippocratic Greece Homer did not mention phthisis, a word meaning non-specific wasting of the body. However. Alexander of Tralles (6th century BC seemed to narrow the concept down to a specific disease, and in the Hippocratic Corpus (5th-4th centuries BC phthisis can be recognised as tuberculosis. It was predominantly a respiratory disease commonly seen and considered to be caused by an imbalance of bodily humours. It was commonest in autumn, winter and spring

  5. Geochemical Weathering in Glacial and Proglacial Environments

    Science.gov (United States)

    Tranter, M.

    2003-12-01

    It seems counterintuitive that chemical erosion in glaciated regions proceeds at rates comparable to those of temperate catchments with comparable specific runoff (Anderson et al., 1997). All the usual factors that are associated with elevated rates of chemical weathering ( Drever, 1988, 1994), such as water, soil, and vegetation, are either entirely absent or absent for much of the year. For example, glaciated regions are largely frozen for significant periods each year, the residence time of liquid water in the catchment is low ( Knight, 1999), there are thin, skeletal soils at best, and vegetation is either absent or limited ( French, 1997). Other chapters in this volume have highlighted how these factors are important in other, more temperate and tropical environments. Even so, chemical erosion rates in glaciated terrain are usually near to or greater than the continental average ( Sharp et al., 1995; Wadham et al., 1997; Hodson et al., 2000). This is because glaciated catchments usually have high specific runoff, there are high concentrations of freshly comminuted rock flour, which is typically silt sized and coated with microparticles, and adsorbed organic matter or surface precipitates that may hinder water-rock interactions are largely absent ( Tranter, 1982). In short, the rapid flow of water over fine-grained, recently crushed, reactive mineral surfaces maximizes both the potential rates of chemical weathering and chemical erosion.A range of both lab- and field-based studies of glacial chemical weathering have been undertaken, mainly on the smaller glaciers of Continental Europe (e.g., Brown et al., 1993a, b), Svalbard (e.g., Hodson et al., 2002), and North America (e.g., Anderson et al., 2000). The field-based studies typically generate hydrographs of glacier runoff, which show a characteristic diurnal cycle during summer in low latitudes ( Figure 1), and more subdued diurnal cycles at high latitudes (Figure 2 and Figure 3). The concentration of ions in

  6. The Influence of Glacial-Interglacial Cycles on the Erosion of Orogens

    Science.gov (United States)

    Yanites, Brian; Ehlers, Todd

    2010-05-01

    The evolution of mountain topography and sediment flux to adjacent basins is dictated by variations in the rates of rock-uplift, climate, lithology, and vegetation. Currently, many mountainous settings are in a state of a ‘glacial hangover' whereby Quaternary glaciation has dramatically altered catchment morphology and produced non-equilibrium conditions with respect to the environmental conditions preceding this major climatic transition. In this study, we investigate transients in mountain erosion and morphology due to glacial-interglacial cycles imposed on landscapes previously dominated by fluvial and hillslope processes. In our approach, we use a surface process model to produce an equilibrium fluvial landscape for rock uplift rates between 0.25-1.0 mm/yr. The landscapes are then subjected to repeated glacial cycles of different periodicity and intensity. Variations in predicted glacial basal sliding velocity, erosion, topography and sediment flux are tracked. Results indicate that glacial processes increase rates of valley bottom erosion by one to two orders of magnitude higher than fluvial processes, a result consistent with low-temperature thermochronological data from a number of glaciated catchments worldwide. Increased rates of hillslope and ridgetop erosion occur in response to increased glacial erosion and lag behind the onset of glaciation, thereby producing a complicated history of local relief. The timescale of this lag can vary by orders of magnitude and depends on model parametrization. We also find that two broad effects compete to control the evolution of sediment leaving such an orogen: 1) the topographic disequilibrium with glacial processes acts to initially increase sediment production, but as the topography readjusts, the disequilibrium wanes; 2) the initial geometry of the drainage basin is inefficient at providing ice to the sliding portions of the glaciers, thus impeding erosion early on, but as the topography becomes more ‘glacial

  7. Long-term evolution of hillslopes and drainage networks under repeated impact of glacial erosion

    Science.gov (United States)

    Salcher, Bernhard; Baumann, Sebastian; Kober, Florian; Robl, Jörg

    2015-04-01

    The morphology of hillslopes is an important indicator of landscape change and erosion. In nonglacial catchments, its characteristics depend to a large extent on channel processes and are a function of climate, tectonic and underlying bedrock. These factors may however become secondary when affected by glacial erosion as it is the case in many mid- to high-latitude mountain belts. The perturbation of the initial steady state hillslope morphology (where uplift is balanced by surface lowering rates) will tend to become successively larger if the repeated action of glacial processes exceeds the potential of fluvial readjustment during deglaciated periods. In the limiting case that fluvial or colluvial readjustments to the topography are smaller than modifications by glacial action, the history of glacial erosion rate may be faithfully archived in the form of hillslopes and the channel network (Salcher et al., 2014). This relation is furthermore important as significant mass is generally mobilized and eroded in the hillslope domain delivering material to the channel system. Here we analyzed the glacially modified topography of the European Central Alps, a region which has been multiply glaciated during the Quaternary and were tectonic processes have largely ceased. The higher elevated catchments suffered a more intense impact of glacial erosion than lower elevated catchments whereas fluvial (steady state) processes dominate the alpine foothills or regions outside the former ice sheets. To investigate variations to the hillslope domain we utilized digital elevation models to define hillslope parameters (area, length relief) as function of channel head locations. Channel heads are then calculated as a function of minimum channel plan curvature. Our results show that hillslope area, relief and length increases with the cumulative impact of glacial action. This relation is however only valid were individual tributary glaciers and associated headward erosion could evolve

  8. On the glacial erosion of the south-western Barents Sea shelf

    Science.gov (United States)

    Sverre Laberg, Jan; Andreassen, Karin; Vorren, Tore O.

    2010-05-01

    The Barents Sea has experienced profound glacial erosion during the late Pliocene and Pleistocene which resulted in the development of a characteristic glacial morphology of the continental shelf and deposition of a several km thick sediment wedge/fan along the western margin prograding into the deep sea. During the middle and late Pleistocene, glacial erosion was most severe beneath the paleo-ice streams of the Barents Sea Ice Sheet and affected mainly the trough areas (~200.000 km2). The total erosion is estimated to 435 - 530 m, the average erosion 0.6 - 0.8 mm/yr and the average sedimentation rates on the continental slope were 18 - 22 cm/kyr. The first-order control on the amount of erosion was probably the glaciations duration and velocity of the ice streams. Erosion by paleo-ice streams affected a larger area (~575.000 km2) during the early and middle Pleistocene because they were less topographically stable due to a less pronounced paleo-relief. Also, glaciotectonism was more extensive during this period. The total erosion was estimated to 330 - 420 m and the average erosion 0.4 - 0.5 mm/yr. The average sedimentation rates were 50 - 64 cm/kyr, 2 - 3 times higher than during the succeeding period. In the late Pliocene - early Pleistocene period, proglacial processes including glacifluvial erosion dominated. The total erosion was found to be 170 - 230 m, the average erosion 0.15 - 0.2 mm/yr and the average sedimentation rates were 16 - 22 cm/kyr. In total, the glacial erosion of the troughs has been relatively high throughout the late Pliocene - Pleistocene period, about 1000 - 1100 m. For the banks the erosion is inferred to have increased from late Pliocene to peak in early - middle Pleistocene, later there has been little erosion in these areas which implies a total of 500 - 650 m of erosion. The average glacial erosion during the whole late Pliocene and Pleistocene period is 38 cm/kyr, one order of magnitude higher than the average glacial erosion of the

  9. Late glacial aridity in southern Rocky Mountains

    Energy Technology Data Exchange (ETDEWEB)

    Davis, O.K.; Pitblado, B.L. [Univ. of Arizona, Tucson, AZ (United States)

    1995-09-01

    While the slopes of the present-day Colorado Rocky Mountains are characterized by large stands of subalpine and montane conifers, the Rockies of the late glacial looked dramatically different. Specifically, pollen records suggest that during the late glacial, Artemisia and Gramineae predominated throughout the mountains of Colorado. At some point between 11,000 and 10,000 B.P., however, both Artemisia and grasses underwent a dramatic decline, which can be identified in virtually every pollen diagram produced for Colorado mountain sites, including Como Lake (Sangre de Cristo Mountains), Copley Lake and Splains; Gulch (near Crested Butte), Molas Lake (San Juan Mountains), and Redrock Lake (Boulder County). Moreover, the same pattern seems to hold for pollen spectra derived for areas adjacent to Colorado, including at sites in the Chuska Mountains of New Mexico and in eastern Wyoming. The implications of this consistent finding are compelling. The closest modem analogues to the Artemisia- and Gramineae-dominated late-glacial Colorado Rockies are found in the relatively arid northern Great Basin, which suggests that annual precipitation was much lower in the late-glacial southern Rocky Mountains than it was throughout the Holocene.

  10. Palaeoceanographic changes in Hornsund Fjord (Spitsbergen, Svalbard) over the last millennium: new insights from ancient DNA

    Science.gov (United States)

    Pawłowska, Joanna; Zajączkowski, Marek; Łącka, Magdalena; Lejzerowicz, Franck; Esling, Philippe; Pawlowski, Jan

    2016-07-01

    This paper presents a reconstruction of climate-driven environmental changes over the last millennium in Hornsund Fjord (Svalbard), based on sedimentological and micropalaeontological records. Our palaeo-investigation was supported by an analysis of foraminiferal ancient DNA (aDNA), focusing on the non-fossilized monothalamous species. The main climatic fluctuations during the last millennium were the Medieval Warm Period (MWP, AD 1000-1600), the Little Ice Age (LIA, AD 1600-1900) and the modern warming (MW, AD 1900 to present). Our study indicates that the environmental conditions in Hornsund during the MWP and the early LIA (before ˜ AD 1800) were relatively stable. The beginning of the LIA (˜ AD 1600) was poorly evidenced by the micropalaeontological record but was well marked in the aDNA data by an increased proportion of monothalamous foraminifera, especially Bathysiphon sp. The early LIA (˜ 1600 to ˜ AD 1800) was marked by an increase in the abundance of sequences of Hippocrepinella hirudinea and Cedhagenia saltatus. In the late LIA (after ˜ AD 1800), the conditions in the fjord became glacier-proximal and were characterized by increased meltwater outflows, high sedimentation and a high calving rate. This coincided with an increase in the percentages of sequences of Micrometula sp. and Vellaria pellucidus. During the MW, the major glacier fronts retreated rapidly to the inner bays, which limited the iceberg discharge to the fjord's centre and caused a shift in the foraminiferal community that was reflected in both the fossil and aDNA records. The palaeoceanographic changes in the Hornsund fjord over the last millennium were driven mainly by the inflow of shelf-originated water masses and glacial activity. However, the environmental changes were poorly evidenced in the micropalaeontological record, but they were well documented in our aDNA data. We considerably increased the number of potential proxy species by including monothalamous foraminifera in the

  11. Glacial marine sediments from the Antarctic Peninsula: A record of climate change and glacial fluctuations during the late holocene

    International Nuclear Information System (INIS)

    Physical oceanographic measurements (211 CTDT casts) and bottom sediment samples (>104) provide the data base for the following conclusions. Subpolar glacial regimes in the South Shetland Islands are dominated by extensive surface melting, elevated equilibrium lines (ELA) and efficient conduction of surface meltwater to the terminus of tidewater and terrestrial glaciers. These conditions control sedimentary processes in the marine realm by the efficient and widespread dispersal of suspended sediment by overflow plumes. Terrigenous facies, therefore, dominate throughout the fjord system. The transition to polar conditions within glaciers along the Danco Coast and Palmer Archipelago is characterized by lower ELA (near sea level), limited surface melting and dynamic sea ice conditions. Basal melt processes appear to dominate, especially where subglacial marine cavities exist beneath glacial termini. Most terrigenous sediment is transported by ice-rafting or by cold, mid-water plumes, which spread horizontally until restricted by bathymetric features. Biogenic (diatom) muds and ice-rafted debris dominate sedimentation in outer bay settings; the former is enhanced by warmer temperatures, increased sunlight, and minimal disturbance of surface layers within the fjords. These facies transitions are well constrained statistically by regression analyses of textural and compositional variations with respect to distance from sediment sources (glacial termini). Correlation trends within individual ice drainage systems can be applied to marine sediment cores which contain a record spanning approximately the last 3,000 years (based upon accelerator 14C and 210Pb chronologies). A period of enhanced terrigenous (surface meltwater) input following more extensive glacier ice is documented in Hughes Bay on the northern Danco Coast

  12. Understanding Malaria: Fighting an Ancient Scourge

    Science.gov (United States)

    Understanding Malaria Fighting an Ancient Scourge U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Institute of Allergy and Infectious Diseases Understanding Malaria Fighting an Ancient Scourge U.S. DEPARTMENT OF HEALTH ...

  13. Acupuncture: From Ancient Practice to Modern Science

    Science.gov (United States)

    ... Section CAM Acupuncture From Ancient Practice to Modern Science Past Issues / Winter 2009 Table of Contents For ... of Progress / Acupuncture From Ancient Practice to Modern Science / Low Back Pain and CAM / Time to Talk / ...

  14. The eye and its diseases in Ancient Egypt

    DEFF Research Database (Denmark)

    Andersen, S. Ry

    1997-01-01

    Ophthalmology, History of ophthalmology, eyes in the Ancient Egypt, eye disease in Ancient Egypt, porotic hyperostosis, mummification......Ophthalmology, History of ophthalmology, eyes in the Ancient Egypt, eye disease in Ancient Egypt, porotic hyperostosis, mummification...

  15. Potential flood volume of Himalayan glacial lakes

    Directory of Open Access Journals (Sweden)

    K. Fujita

    2013-07-01

    Full Text Available Glacial lakes are potentially dangerous sources of glacial lake outburst floods (GLOFs, and represent a serious natural hazard in Himalayan countries. Despite the development of various indices aimed at determining the outburst probability, an objective evaluation of the thousands of Himalayan glacial lakes has yet to be completed. In this study we propose a single index, based on the depression angle from the lakeshore, which allows the lakes to be assessed using remotely sensed digital elevation models (DEMs. We test our approach on five lakes in Nepal, Bhutan, and Tibet using images taken by the declassified Hexagon KH-9 satellite before these lakes experienced an outburst flood. All five lakes had a steep lakefront area (SLA, on which a depression angle was steeper than our proposed threshold of 10° before the GLOF event, but the SLA was no longer evident after the events. We further calculated the potential flood volume (PFV; i.e., the maximum volume of floodwater that could be released if the lake surface was lowered sufficiently to eradicate the SLA. This approach guarantees repeatability to assess the possibility of GLOF hazards because it requires no particular expertise to carry out, though the PFV does not quantify the GLOF risk. We calculated PFVs for more than 2000 Himalayan glacial lakes using visible band images and DEMs of ASTER data. The PFV distribution follows a power-law function. We found that 794 lakes did not have an SLA, and consequently had a PFV of zero, while we also identified 49 lakes with PFVs of over 10 million m3, which is a comparable volume to that of recorded major GLOFs. This PFV approach allows us to preliminarily identify and prioritize those Himalayan glacial lakes that require further detailed investigation on GLOF hazards and risk.

  16. Interrelated Glacial, Volcanic and Hydrologic Processes on the Tharsis Montes, Olympus Mons and Hecates Tholus, Mars

    Science.gov (United States)

    Head, J. W.; Marchant, D. R.; Shean, D. E.; Fassett, C. I.; Wilson, L.

    2005-12-01

    Volcanic, hydrological and glacial processes are prominent in the geological history of Mars and assessment of areas where their relationships can be established provides important information on their nature and intensity. An effort to examine these interrelationships is motivated by the uncertainties that exist in atmospheric general circulation models concerning the homogeneous or heterogeneous distribution of water ice during periods of high obliquity and resulting transport of polar volatiles equatorward. Geological evidence for distinctive and very large tropical mountain glacial deposits on the NW flanks of the Tharsis Montes shows that the emplacement of ice in the equatorial regions is heterogeneous and is intimately linked to the presence of large volcanic edifices on the broad Tharsis rise. Accumulation of ice and formation of glaciers is likely caused by adiabatic cooling of water-laden polar air masses and precipitation and accumulation on the NW volcano flanks (F. Forget, personal communication). The resulting glacial deposits show interesting relationships to volcanic deposits formed prior to, during and subsequent to glaciation. Evidence that the glacial deposits formed from cold-based glaciation comes from the lack of modification of delicate structures associated with underlying lava flows (seen in detrended altimetry data). Evidence that volcanism occurred during glaciation is five-fold: 1) narrow linear ridges in the glacial deposits radial to the volcano are interpreted as dikes that were intruded into the glacier, rapidly melting the adjacent ice and collapsing, as has been proposed for englacial dike intrusions in Iceland; 2) broad, steep-sided, thick lobate flow-like features are interpreted to represent sill-like subglacial lava flows at the volcano-glacial interface; 3) circular donut-like annuli surround vent-like craters suggesting localized subglacial explosive eruptions; 4) steep asymmetric lava flows at glacial deposit margins are

  17. Historical distribution of Sundaland's Dipterocarp rainforests at Quaternary glacial maxima.

    Science.gov (United States)

    Raes, Niels; Cannon, Charles H; Hijmans, Robert J; Piessens, Thomas; Saw, Leng Guan; van Welzen, Peter C; Slik, J W Ferry

    2014-11-25

    The extent of Dipterocarp rainforests on the emergent Sundaland landmass in Southeast Asia during Quaternary glaciations remains a key question. A better understanding of the biogeographic history of Sundaland could help explain current patterns of biodiversity and support the development of effective forest conservation strategies. Dipterocarpaceae trees dominate the rainforests of Sundaland, and their distributions serve as a proxy for rainforest extent. We used species distribution models (SDMs) of 317 Dipterocarp species to estimate the geographic extent of appropriate climatic conditions for rainforest on Sundaland at the last glacial maximum (LGM). The SDMs suggest that the climate of central Sundaland at the LGM was suitable to sustain Dipterocarp rainforest, and that the presence of a previously suggested transequatorial savannah corridor at that time is unlikely. Our findings are supported by palynologic evidence, dynamic vegetation models, extant mammal and termite communities, vascular plant fatty acid stable isotopic compositions, and stable carbon isotopic compositions of cave guano profiles. Although Dipterocarp species richness was generally lower at the LGM, areas of high species richness were mostly found off the current islands and on the emergent Sunda Shelf, indicating substantial species migration and mixing during the transitions between the Quaternary glacial maxima and warm periods such as the present. PMID:25385612

  18. Ancient medicine--a review.

    Science.gov (United States)

    Zuskin, Eugenija; Lipozencić, Jasna; Pucarin-Cvetković, Jasna; Mustajbegović, Jadranka; Schachter, Neil; Mucić-Pucić, Branka; Neralić-Meniga, Inja

    2008-01-01

    Different aspects of medicine and/or healing in several societies are presented. In the ancient times as well as today medicine has been closely related to magic, science and religion. Various ancient societies and cultures had developed different views of medicine. It was believed that a human being has two bodies: a visible body that belongs to the earth and an invisible body of heaven. In the earliest prehistoric days, a different kind of medicine was practiced in countries such as Egypt, Greece, Rome, Mesopotamia, India, Tibet, China, and others. In those countries, "medicine people" practiced medicine from the magic to modern physical practices. Medicine was magical and mythological, and diseases were attributed mostly to the supernatural forces. The foundation of modern medicine can be traced back to ancient Greeks. Tibetan culture, for instance, even today, combines spiritual and practical medicine. Chinese medicine developed as a concept of yin and yang, acupuncture and acupressure, and it has even been used in the modern medicine. During medieval Europe, major universities and medical schools were established. In the ancient time, before hospitals had developed, patients were treated mostly in temples. PMID:18812066

  19. Wisdom of an Ancient City

    Institute of Scientific and Technical Information of China (English)

    GE JIANXIONG

    2010-01-01

    @@ The famous painting,Along the River During Qingming Festival,impresses visitors at the China Pavilion not iust because of the animated figures in the electronic version of the painting but because it shows a prosperous view of Kaifeng,capital of the Northern Song Dynasty (960-1127).It also showcases the wisdom of city planning in ancient China.

  20. The ancient art of memory.

    Science.gov (United States)

    Hobson, Allan

    2013-12-01

    Revision of Freud's theory requires a new way of seeking dream meaning. With the idea of elaborative encoding, Sue Llewellyn has provided a method of dream interpretation that takes into account both modern sleep science and the ancient art of memory. Her synthesis is elegant and compelling. But is her hypothesis testable? PMID:24304762

  1. Discovering the Ancient Temperate Rainforest.

    Science.gov (United States)

    Lindsay, Anne

    1997-01-01

    Two activities for grades 3 through 8 explore species adaptation and forestry issues in the North American rainforests. In one activity, students create imaginary species of plants or animals that are adapted for life in an ancient temperate rainforest. In the second activity, students role play groups affected by plans to log an area of the…

  2. The Ancient Martian Climate System

    Science.gov (United States)

    Haberle, Robert M.

    2014-01-01

    Today Mars is a cold, dry, desert planet. The atmosphere is thin and liquid water is not stable. But there is evidence that very early in its history it was warmer and wetter. Since Mariner 9 first detected fluvial features on its ancient terrains researchers have been trying to understand what climatic conditions could have permitted liquid water to flow on the surface. Though the evidence is compelling, the problem is not yet solved. The main issue is coping with the faint young sun. During the period when warmer conditions prevailed 3.5-3.8 Gy the sun's luminosity was approximately 25% less than it is today. How can we explain the presence of liquid water on the surface of Mars under such conditions? A similar problem exists for Earth, which would have frozen over under a faint sun even though the evidence suggests otherwise. Attempts to solve the "Faint Young Sun Paradox" rely on greenhouse warming from an atmosphere with a different mass and composition than we see today. This is true for both Mars and Earth. However, it is not a straightforward solution. Any greenhouse theory must (a) produce the warming and rainfall needed, (b) have a plausible source for the gases required, (c) be sustainable, and (d) explain how the atmosphere evolved to its present state. These are challenging requirements and judging from the literature they have yet to be met. In this talk I will review the large and growing body of work on the early Mars climate system. I will take a holistic approach that involves many disciplines since our goal is to present an integrated view that touches on each of the requirements listed in the preceding paragraph. I will begin with the observational evidence, which comes from the geology, mineralogy, and isotopic data. Each of the data sets presents a consistent picture of a warmer and wetter past with a thicker atmosphere. How much warmer and wetter and how much thicker is a matter of debate, but conditions then were certainly different than

  3. Dating ancient Chinese celadon porcelain by neutron activation analysis and bayesian classification

    International Nuclear Information System (INIS)

    Dating ancient Chinese porcelain is one of the most important and difficult problems in porcelain archaeological field. Eighteen elements in bodies of ancient celadon porcelains fired in Southern Song to Yuan period (AD 1127-1368) and Ming dynasty (AD 1368-1644), including La, Sm, U, Ce, etc., were determined by neutron activation analysis (NAA). After the outliers of experimental data were excluded and multivariate normal distribution was tested, and Bayesian classification was used for dating of 165 ancient celadon porcelain samples. The results show that 98.2% of total ancient celadon porcelain samples are classified correctly. It means that NAA and Bayesian classification are very useful for dating ancient porcelain. (authors)

  4. High-precision dating and correlation of ice, marine and terrestrial sequences spanning Heinrich Event 3: Testing mechanisms of interhemispheric change using New Zealand ancient kauri (Agathis australis)

    Science.gov (United States)

    Turney, Chris S. M.; Palmer, Jonathan; Bronk Ramsey, Christopher; Adolphi, Florian; Muscheler, Raimund; Hughen, Konrad A.; Staff, Richard A.; Jones, Richard T.; Thomas, Zoë A.; Fogwill, Christopher J.; Hogg, Alan

    2016-04-01

    Robustly testing hypotheses of geographic synchroneity of abrupt and extreme change during the late Pleistocene (60,000 to 11,650 years ago) requires a level of chronological precision often lacking in ice, marine and terrestrial sequences. Here we report a bidecadally-resolved New Zealand kauri (Agathis australis) tree-ring sequence spanning two millennia that preserves a record of atmospheric radiocarbon (14C) during ice-rafted debris event Heinrich Event 3 (HE3) in the North Atlantic and Antarctic Isotope Maximum 4 (AIM4) in the Southern Hemisphere. Using 14C in the marine Cariaco Basin and 10Be preserved in Greenland ice, the kauri 14C sequence allows us to precisely align sequences across this period. We observe no significant difference between atmospheric and marine 14C records during HE3, suggesting no stratification of surface waters and collapse in Atlantic Meridional Overturning Circulation (AMOC). Instead our results support recent evidence for a weakened AMOC across at least two millennia of the glacial period. Our work adds to a growing body of literature confirming that Heinrich events are not the cause of stadial cooling and suggests changes in the AMOC were not the primary driver of antiphase temperature trends between the hemispheres. Decadally-resolved 14C in ancient kauri offers a powerful new (and complementary) approach to polar ice core CH4 alignment for testing hypotheses of abrupt and extreme climate change.

  5. Changing glacial coverage influences stream dissolved organic matter signatures in coastal watersheds of southeast Alaska

    Science.gov (United States)

    Fellman, J. B.; Hood, E. W.; Stubbins, A.; Spencer, R. G.; Raymond, P.

    2012-12-01

    Glacier runoff is a major source of freshwater to Arctic and sub-Arctic streams and coastal marine zones. However, relatively little is known about how glacier runoff influences stream biogeochemical signatures, especially with regard to dissolved organic matter (DOM). We collected streamwater weekly to fortnightly during the glacial runoff season of 2012 from four coastal watersheds in southeast Alaska that ranged in glacier coverage from 0 to 63% and a glacier outflow stream. This allowed us to determine how changing glacier coverage influences the chemical signature of DOM. We also used δ18O of streamwater, snow/glacial icemelt, and rainfall to elucidate how the origin of streamwater influences stream DOM signatures. All streams showed a decrease in δ18O in early May coincident with snowmelt. By the end of May, δ18O in the non-glacial stream increased reflecting the increasing contribution of rainfall and groundwater to streamflow. However, δ18O in the glacial-fed streams remained depleted well into the summer months of July and August. This seasonal shift in δ18O was reflected in the DOM signatures for all streams. Glacier-fed streams showed an overall decrease in dissolved organic carbon (DOC) concentration from May through July, but concentrations increased in the non-glacial stream during the same period. Similarly, stream specific ultraviolet absorbance (SUVA254) and fluorescence index (FI) values decreased during the glacial meltwater season reflecting the decreasing contribution of plant derived, aromatic carbon to the bulk DOM pool. Overall, δ18O was significantly related to DOC concentration, SUVA254, and FI (all precession and subsequent changes in freshwater input to streamflow could substantially influence the biogeochemistry of freshwater and coastal marine ecosystems by altering the timing, magnitude and chemical signature of DOM delivered to streams.

  6. The Glacial-Interglacial Monsoon Recorded by Speleothems from Sulawesi, Indonesia

    Science.gov (United States)

    Kimbrough, A. K.; Gagan, M. K.; Dunbar, G. B.; Krause, C.; Hantoro, W. S.; Cheng, H.; Edwards, R. L.; Shen, C. C.; Sun, H.; Cai, B.; Hellstrom, J. C.; Rifai, H.

    2015-12-01

    The Indo-Pacific Warm Pool is a primary source of heat and moisture to the global atmosphere and a key player in tropical and global climate variability. There is mounting evidence that atmospheric convection and oceanic processes in the tropics can modulate global climate on orbital and sub-orbital timescales. Glacial-interglacial cycles represent the largest natural climate changes over the last 800 kyr with each cycle terminated by rapid global warming and sea level rise. Our understanding of the role and response of tropical atmospheric convection during these periods of dramatic warming is limited. We present the first speleothem paleomonsoon record for southwest Sulawesi (5ºS, 119ºE), spanning two glacial-interglacial cycles, including glacial termination IV (~340 kyr BP) and both phases of termination III (~248 and ~220 kyr BP). This unique record is constructed from multiple stalagmites from two separate caves and is based on a multi-proxy approach (δ18O, δ13C, Mg/Ca, Sr/Ca) that provides insight into the mechanisms controlling Australian-Indonesian summer monsoon variability. Speleothem δ18O and trace element data indicate a rapid increase in rainfall at glacial terminations and wet interglacials. Terminations IV, III, and I are each characterized by an abrupt 3‰ decrease in δ18O. Variability in δ18O leading-in to glacial terminations is also similar, and corresponds to October insolation. Prior to deglaciation, there is a distinct shift to higher δ18O that is synchronized with weak monsoon intervals in Chinese speleothem records. The remarkably consistent pattern among terminations implies that the response of tropical convection to changing background climates is well regulated. Furthermore, we find that speleothem δ13C leads δ18O by ~5 kyr during glacial terminations. The early decrease in speleothem δ13C may reflect the response of tropical vegetation to rising atmospheric CO2 and temperature, rather than regional changes in rainfall.

  7. Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume.

    Science.gov (United States)

    Abe-Ouchi, Ayako; Saito, Fuyuki; Kawamura, Kenji; Raymo, Maureen E; Okuno, Jun'ichi; Takahashi, Kunio; Blatter, Heinz

    2013-08-01

    The growth and reduction of Northern Hemisphere ice sheets over the past million years is dominated by an approximately 100,000-year periodicity and a sawtooth pattern (gradual growth and fast termination). Milankovitch theory proposes that summer insolation at high northern latitudes drives the glacial cycles, and statistical tests have demonstrated that the glacial cycles are indeed linked to eccentricity, obliquity and precession cycles. Yet insolation alone cannot explain the strong 100,000-year cycle, suggesting that internal climatic feedbacks may also be at work. Earlier conceptual models, for example, showed that glacial terminations are associated with the build-up of Northern Hemisphere 'excess ice', but the physical mechanisms underpinning the 100,000-year cycle remain unclear. Here we show, using comprehensive climate and ice-sheet models, that insolation and internal feedbacks between the climate, the ice sheets and the lithosphere-asthenosphere system explain the 100,000-year periodicity. The responses of equilibrium states of ice sheets to summer insolation show hysteresis, with the shape and position of the hysteresis loop playing a key part in determining the periodicities of glacial cycles. The hysteresis loop of the North American ice sheet is such that after inception of the ice sheet, its mass balance remains mostly positive through several precession cycles, whose amplitudes decrease towards an eccentricity minimum. The larger the ice sheet grows and extends towards lower latitudes, the smaller is the insolation required to make the mass balance negative. Therefore, once a large ice sheet is established, a moderate increase in insolation is sufficient to trigger a negative mass balance, leading to an almost complete retreat of the ice sheet within several thousand years. This fast retreat is governed mainly by rapid ablation due to the lowered surface elevation resulting from delayed isostatic rebound, which is the lithosphere

  8. North Atlantic Deep Water Production during the Last Glacial Maximum

    Science.gov (United States)

    Howe, Jacob N. W.; Piotrowski, Alexander M.; Noble, Taryn L.; Mulitza, Stefan; Chiessi, Cristiano M.; Bayon, Germain

    2016-06-01

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.

  9. Hedera helix L. and damages in Tlos Ancient City

    Directory of Open Access Journals (Sweden)

    Elinç, Z.K.

    2013-03-01

    Full Text Available There are various plant types in Tlos Ancient City of Fethiye district in the Province of Mugla, a city where different residential ruins of Lycia Civilization starting from Classical Age until Byzantine Period. Tlos is an important city in West-Lycia and is situated right on the control point of Lycia Way. Hedera helix L. is one of the plants living in this area, which attracts the attention as it mostly harms the ancient ruins. One of the most important reasons why Hedera helix L. is growing commonly in this region is the perfect ecological circumstances for the growth of this plant of the location where this ancient city is situated in. Additionally the fact that the ruins of the city are left on their fate, is another perfect circumstance for the Hedera helix L. to grow. Climbing or creeping stems of Hedera helix L. stick easily to the objects it touches and encircle them. Due to this characteristic, the walls of the ancient city are covered by this plant. Nevertheless, Hedera helix L. does not only harm the ancient constructions and natural rocks but also woody plants. The harm caused by dried out or cut Hedera helix L. are more than the harm caused by them when they were untouched. The subject of this study is to prove the shape and level of the harm caused by Hedera helix L. on ancient ruins of Tlos. At the same time, this study will underline the fighting methods against Hedera helix L. by comparing similar studies in other countries. Knowledge collected after this study will offer an insight into the excavation and restoration studies undertaken in all Mediterranean countries.

  10. The ancient tropical rainforest tree Symphonia globulifera L. f. (Clusiaceae) was not restricted to postulated Pleistocene refugia in Atlantic Equatorial Africa.

    Science.gov (United States)

    Budde, K B; González-Martínez, S C; Hardy, O J; Heuertz, M

    2013-07-01

    Understanding the history of forests and their species' demographic responses to past disturbances is important for predicting impacts of future environmental changes. Tropical rainforests of the Guineo-Congolian region in Central Africa are believed to have survived the Pleistocene glacial periods in a few major refugia, essentially centred on mountainous regions close to the Atlantic Ocean. We tested this hypothesis by investigating the phylogeographic structure of a widespread, ancient rainforest tree species, Symphonia globulifera L. f. (Clusiaceae), using plastid DNA sequences (chloroplast DNA [cpDNA], psbA-trnH intergenic spacer) and nuclear microsatellites (simple sequence repeats, SSRs). SSRs identified four gene pools located in Benin, West Cameroon, South Cameroon and Gabon, and São Tomé. This structure was also apparent at cpDNA. Approximate Bayesian Computation detected recent bottlenecks approximately dated to the last glacial maximum in Benin, West Cameroon and São Tomé, and an older bottleneck in South Cameroon and Gabon, suggesting a genetic effect of Pleistocene cycles of forest contraction. CpDNA haplotype distribution indicated wide-ranging long-term persistence of S. globulifera both inside and outside of postulated forest refugia. Pollen flow was four times greater than that of seed in South Cameroon and Gabon, which probably enabled rapid population recovery after bottlenecks. Furthermore, our study suggested ecotypic differentiation-coastal or swamp vs terra firme-in S. globulifera. Comparison with other tree phylogeographic studies in Central Africa highlighted the relevance of species-specific responses to environmental change in forest trees. PMID:23572126

  11. Gas records from the West Greenland ice margin covering the Last Glacial termination: a horizontal ice core

    DEFF Research Database (Denmark)

    Petrenko, V.; Severinghaus, J.P.; Brook, E.J.;

    2006-01-01

    (atm) and delta N-15 of N-2 are apparent, and alterations in methane are found in only a few ice sections. Using measurements of these gases, we have unambiguously identified a stratigraphic section containing ice from the end of last glacial period as well as Bolling-Allerod, Younger Dryas and...... Preboreal intervals. Extensive sections of ice from the Holocene and most ages within the last glacial period are probably also present. Very accurate dating has been possible in the ice section containing the Younger Dryas-Preboreal abrupt climate transition signal. The ice at Pakitsoq is folded and non...

  12. Evidence for the assimilation of ancient glacier organic carbon in a proglacial stream food web

    Science.gov (United States)

    Fellman, Jason; Hood, Eran; Raymond, Peter A.; Hudson, J.H.; Bozeman, Maura; Arimitsu, Mayumi L.

    2015-01-01

    We used natural abundance δ13C, δ15N, and Δ14C to compare trophic linkages between potential carbon sources (leaf litter, epilithic biofilm, and particulate organic matter) and consumers (aquatic macroinvertebrates and fish) in a nonglacial stream and two reaches of the heavily glaciated Herbert River. We tested the hypothesis that proglacial stream food webs are sustained by organic carbon released from glacial ecosystems. Carbon sources and consumers in the nonglacial stream had carbon isotope values that ranged from -30‰ to -25‰ for δ13C and from -14‰ to 53‰ for Δ14C reflecting a food web sustained mainly on contemporary primary production. In contrast, biofilm in the two glacial stream sites was highly Δ14C-depleted (-215‰ to 175‰) relative to the nonglacial stream consistent with the assimilation of ancient glacier organic carbon. IsoSource modeling showed that in upper Herbert River, macroinvertebrates (Δ14C = -171‰ to 22‰) and juvenile salmonids (Δ14C = −102‰ to 17‰) reflected a feeding history of both biofilm (~ 56%) and leaf litter (~ 40%). We estimate that in upper Herbert River on average 36% of the carbon incorporated into consumer biomass is derived from the glacier ecosystem. Thus, 14C-depleted glacial organic carbon was likely transferred to higher trophic levels through a feeding history of bacterial uptake of dissolved organic carbon and subsequent consumption of 14C-depleted biofilm by invertebrates and ultimately fish. Our findings show that the metazoan food web is sustained in part by glacial organic carbon such that future changes in glacial runoff could influence the stability and trophic structure of proglacial aquatic ecosystems.

  13. Glacial cycles drive variations in the production of oceanic crust

    CERN Document Server

    Crowley, John W; Huybers, Peter; Langmuir, Charles H; Park, Sung-Hyun

    2014-01-01

    Glacial cycles redistribute water between the oceans and continents causing pressure changes in the upper mantle, with potential consequences for melting of Earth's interior. A numerical model of mid-ocean ridge dynamics that explicitly includes melt transport is used to calculate the melting effects that would be caused by Plio-Pleistocene sea-level variations. Model results interpreted in the context of an analytical approximation predict sea-level induced variations in crustal thickness on the order of hundreds of meters. The specifics of the response depend on rates of sea-level change, mid-ocean ridge spreading rates, and mantle permeability. Spectral analysis of the bathymetry of the Australian-Antarctic ridge shows significant spectral energy near 23, 41, and 100 ky periods, consistent with model results and with the spectral content of Pleistocene sea-level variability. These results support the hypothesis that sea-floor topography records the magmatic response to changes in sea level, reinforcing the...

  14. Glacial curvilineations: gradual or catastrophic origin?

    Science.gov (United States)

    Clark, Chris; Livingstone, Stephen

    2016-04-01

    Glacial curvilineations (GCLs) are enigmatic landforms that have recently been discovered in Poland (Lesemann et al., 2010, 2014). They comprise parallel sets of sinuous ridges separated by troughs that are found in tunnel valleys and replicate the morphology and pattern of the valley sides. The sedimentology for some has been reported to indicate that the sediment composition relates to a pre-GCL phase. So far just one theory for their formation exists - erosion by longitudinal-vortices within high-energy subglacial meltwater flows (Lesemann et al., 2010). Here, we provide an alternative hypothesis for their formation developed from observations of GCLs found along the southern sector of the Laurentide Ice Sheet. In all cases GCLs were found associated with tunnel valley widenings or hollows and occur as distinct parallel sets that mimic each other in terms of nicks and cusps. Using analogies from tree-rings and coral growth we take such mimicry as indicating either incremental growth or development from a template over time. Although without a strong physical explanation we find it much less likely that a series of parallel water channels would maintain such strong mimicry. We instead suggest that subglacial thawing of frozen ground in association with discrete water bodies (tunnel valleys or subglacial lakes) resulted in retrogressive bank failure, possibly along a glide plane provided by a frozen surface. References: Lesemann, J.-E., Piotrowski, J. a, Wysota, W., 2010. "Glacial curvilineations": New glacial landforms produced by longitudinal vortices in subglacial meltwater flows. Geomorphology 120, 153-161. Lesemann, J.-E., Piotrowski, J. a, Wysota, W., 2014. Genesis of the "glacial curvilineation" landscape by meltwater processes under the former Scandinavian Ice Sheet, Poland. Sediment. Geol. 312, 1-18.

  15. Towards an improved inventory of Glacial Lake Outburst Floods in the Himalayas

    Science.gov (United States)

    Veh, Georg; Walz, Ariane; Korup, Oliver; Roessner, Sigrid

    2016-04-01

    The retreat of glaciers in the Himalayas and the associated release of meltwater have prompted the formation and growth of thousands of glacial lakes in the last decades. More than 2,200 of these lakes have developed in unconsolidated moraine material. These lakes can drain in a single event, producing potentially destructive glacial lake outburst floods (GLOFs). Only 44 GLOFs in the Himalayas have been documented in more detail since the 1930s, and evidence for a change, let alone an increase, in the frequency of these flood events remains elusive. The rare occurrence of GLOFs is counterintuitive to our hypothesis that an increasing amount of glacial lakes has to be consistent with a rising amount of outburst floods. Censoring bias affects the GLOF record, such that mostly larger floods with commensurate impact have been registered. Existing glacial lake inventories are also of limited help for the identification of GLOFs, as they were created in irregular time steps using different methodological approach and covering different regional extents. We discuss the key requirements for generating a more continuous, close to yearly time series of glacial lake evolution for the Himalayan mountain range using remote sensing data. To this end, we use sudden changes in glacial lake areas as the key diagnostic of dam breaks and outburst floods, employing the full archive of cloud-free Landsat data (L5, L7 and L8) from 1988 to 2015. SRTM and ALOS World 3D topographic data further improve the automatic detection of glacial lakes in an alpine landscape that is often difficult to access otherwise. Our workflow comprises expert-based classification of water bodies using thresholds and masks from different spectral indices and band ratios. A first evaluation of our mapping approach suggests that GLOFs reported during the study period could be tracked independently by a significant reduction of lake size between two subsequent Landsat scenes. This finding supports the feasibility

  16. Impact of brine-induced stratification on the glacial carbon cycle

    Directory of Open Access Journals (Sweden)

    N. Bouttes

    2010-04-01

    Full Text Available During the cold period of the Last Glacial Maximum (LGM, about 21 000 years ago atmospheric CO2 was around 190 ppm (Monnin et al., 2001, much lower than the pre-industrial concentration of 280 ppm. The causes of this substantial drop remain partially unresolved, despite intense research. Understanding the origin of reduced atmospheric CO2 during glacial times is crucial to comprehend the evolution of the different carbon reservoirs within the Earth system (atmosphere, terrestrial biosphere and ocean. In this context, the ocean is believed to play a major role as it can store large amounts of carbon (Sigman and Boyle, 2000, especially in the abyss, which is a carbon reservoir that is thought to have expanded during glacial times. To create this larger reservoir, one possible mechanism is to produce very dense glacial waters, thereby stratifying the deep ocean and reducing the carbon exchange between the deep and surface ocean (Paillard and Parrenin, 2004. The existence of such very dense waters has been inferred in the LGM deep Atlantic from sediment pore water salinity (Adkins et al., 2002. Based on these observations, we study the impact of a brine mechanism on the glacial carbon cycle. This mechanism relies on the formation and rapid sinking of brines, very salty water released during sea ice formation, which brings salty dense water down to the bottom of the ocean. It provides two major features: a direct link from the surface to the deep ocean along with an efficient way of setting a strong stratification. We show with the CLIMBER-2 coupled carbon-climate model (Petoukhov et al., 2000 that such a brine mechanism can account for a significant decrease in atmospheric CO2 and contribute to the glacial-interglacial change. This mechanism can be amplified by low vertical diffusion resulting from the brine-induced stratification. The results obtained substantially improve the modeled glacial distribution of oceanic

  17. Impact of brine-induced stratification on the glacial carbon cycle

    Directory of Open Access Journals (Sweden)

    N. Bouttes

    2010-09-01

    Full Text Available During the cold period of the Last Glacial Maximum (LGM, about 21 000 years ago atmospheric CO2 was around 190 ppm, much lower than the pre-industrial concentration of 280 ppm. The causes of this substantial drop remain partially unresolved, despite intense research. Understanding the origin of reduced atmospheric CO2 during glacial times is crucial to comprehend the evolution of the different carbon reservoirs within the Earth system (atmosphere, terrestrial biosphere and ocean. In this context, the ocean is believed to play a major role as it can store large amounts of carbon, especially in the abyss, which is a carbon reservoir that is thought to have expanded during glacial times. To create this larger reservoir, one possible mechanism is to produce very dense glacial waters, thereby stratifying the deep ocean and reducing the carbon exchange between the deep and upper ocean. The existence of such very dense waters has been inferred in the LGM deep Atlantic from sediment pore water salinity and δ18O inferred temperature. Based on these observations, we study the impact of a brine mechanism on the glacial carbon cycle. This mechanism relies on the formation and rapid sinking of brines, very salty water released during sea ice formation, which brings salty dense water down to the bottom of the ocean. It provides two major features: a direct link from the surface to the deep ocean along with an efficient way of setting a strong stratification. We show with the CLIMBER-2 carbon-climate model that such a brine mechanism can account for a significant decrease in atmospheric CO2 and contribute to the glacial-interglacial change. This mechanism can be amplified by low vertical diffusion resulting from the brine-induced stratification. The modeled glacial distribution of oceanic δ13C as well as the deep ocean salinity are substantially improved and better agree with reconstructions from

  18. Glacial evolution of the Ampato Volcanic Complex (Peru)

    Science.gov (United States)

    Alcalá, J.; Palacios, D.; Zamorano, J. J.; Vázquez, L.

    2009-04-01

    then digitized in a Geographical Information System (GIS) using the existing 1:100,000 maps (National Geographical Institute of Peru) as a topographical base. Once the geomorphological maps had been analyzed, we decided to focus on the glacial evolution of a representative section of the Ampato Complex, specifically the Huayuray valley, located north of the HualcaHualca volcano. According to the altitudinal position and the degree of conservation of the moraines along the Quebrada, glacial phases of the Last Glacial Maximum (LGM), the Neoglacial and the Little Ice Age (LIA) were identified. The GIS was then used to delimit and calculate the ice surface area of each one. The same was also done for the years 1955 and 2000 AD, based on the interpretation of aerial photographs and satellite images from those years. Next, the ELA was calculated using the Altitude Area (AA) method (Osmaston, 2005) using GIS and the glacier paleotopography was reconstructed using geomorphological evidence (Carr, S & Coleman, C, 2007). To obtain numerical ages of moraine boulders and glacially abraded bedrock we applied cosmogenic36Cl surface exposure dating (Gosse & Phillips, 2001), which is the best method for volcanic rocks with no quartz content. Samples were collected from stable boulders located at the crests of moraine ridges and over 1 m in height. They were analyzed following procedures by Zreda et al. (1999) and Phillips (2003); physical analyses were undertaken at Universidad Complutense in Spain and physic-chemical analyses at the PRIME laboratory (Purdue University). LGM moraine forms always occupy the lowest altitude position, forming well-defined moraine arcs and ridges, with large dimensions and well preserved. During this phase, the climate was colder and damper than is currently the case in the Central Andes. Calculations show mean temperature during this period to have been 4 - 6°C below present values, and with more abundant precipitation (Seltzer et al., 2002). Under

  19. Modelling end-glacial earthquakes at Olkiluoto

    International Nuclear Information System (INIS)

    The objective of this study is to obtain estimates of the possible effects that post-glacial seismic events in three verified deformation zones (BFZ100, BFZ021/099 and BFZ214) at the Olkiluoto site may have on nearby fractures in terms of induced fracture shear displacement. The study is carried out by use of large-scale models analysed dynamically with the three dimensional distinct element code 3DEC. Earthquakes are simulated in a schematic way; large planar discontinuities representing earthquake faults are surrounded by a number of smaller discontinuities which represent rock fractures in which shear displacements potentially could be induced by the effects of the slipping fault. Initial stresses, based on best estimates of the present-day in situ stresses and on state-of-the-art calculations of glacially-induced stresses, are applied. The fault rupture is then initiated at a pre-defined hypocentre and programmed to propagate outward along the fault plane with a specified rupture velocity until it is arrested at the boundary of the prescribed rupture area. Fault geometries, fracture orientations, in situ stress model and material property parameter values are based on data obtained from the Olkiluoto site investigations. Glacially-induced stresses are obtained from state-of-the-art ice-crust/mantle finite element analyses. The response of the surrounding smaller discontinuities, i.e. the induced fracture shear displacement, is the main output from the simulations

  20. Genetic Drift. The ancient Egyptian dwarfs of the Walters Art Museum.

    Science.gov (United States)

    Kozma, Chahira

    2010-10-01

    The ancient Egyptians left an impressive artistic legacy documenting many aspects of their society including the existence of dwarfs as highly valued members. In previous publications in the Journal, I discussed dwarfs and skeletal dysplasia in ancient Egypt. In this study, I examined the ancient Egyptian representations of dwarfs of the Walters Art Museum in Baltimore, Maryland. One of the highlights of the collection is a group of five ivory figurines from Predynastic Times (pre 3500-3100 BCE) depicting a couple, a man with a child, and two females. Representations from other periods include ordinary as well as dwarf deities. The dwarf gods, Bes and Ptah, are frequently depicted holding or biting snakes or standing on crocodiles symbolizing their ability to ward off dangers. A couple of statuettes from the Greco-Roman Period that, in contrast to earlier Egyptian Periods, depict harsh physical anomalies, twisted bodies, and facial pain. The artistic impression can be interpreted as either tragic or humorous. The grotesque depiction of dwarfs during the Greco-Roman Period in ancient Egypt is believed to be due to a greater infusion of Hellenistic influence. This study provides a microcosm of the legacy of dwarfs in ancient Egypt and supports the premise that dwarfs were accepted and integrated in the ancient Egyptian society, and with a few exceptions, their disorder was not depicted as a physical handicap. PMID:20799327

  1. Psychiatric Thoughts in Ancient India

    Directory of Open Access Journals (Sweden)

    Ravi Abhyankar

    2015-01-01

    Full Text Available A review of the literature regarding psychiatric thoughts in ancient India is attempted. Besides interesting reading, many of the concepts are still relevant and can be used in day-to-day practice especially towards healthy and happy living. Certain concepts are surprisingly contemporary and valid today. They can be used in psychotherapy and counselling and for promoting mental health. However, the description and classification of mental illness is not in tune with modern psychiatry.

  2. ANCIENT BREAD STAMPS FROM JORDAN

    OpenAIRE

    Kakish, Randa

    2014-01-01

    Marking bread was an old practice performed in different parts of the old world. It was done for religious, magical, economic and identification purposes. Bread stamps differ from other groups of stamps. Accordingly, the aim of this article is to identify such stamps, displayed or stored, in a number of Jordanian Archaeological Museums. A col-lection of twelve ancient bread stamps were identified and studied. Two of the stamps were of unknown provenance while the others came from al-Shuneh, D...

  3. Ancient Technology in Contemporary Surgery

    OpenAIRE

    Buck, Bruce A.

    1982-01-01

    Archaeologists have shown that ancient man developed the ability to produce cutting blades of an extreme degree of sharpness from volcanic glass. The finest of these prismatic blades were produced in Mesoamerica about 2,500 years ago. The technique of production of these blades was rediscovered 12 years ago by Dr. Don Crabtree, who suggested possible uses for the blades in modern surgery. Blades produced by Dr. Crabtree have been used in experimental microsurgery with excellent results. Anima...

  4. Regional hydrology controls stream microbial biofilms: evidence from a glacial catchment

    Directory of Open Access Journals (Sweden)

    A. Richter

    2004-08-01

    Full Text Available Glaciers are highly responsive to global warming and important agents of landscape heterogeneity. While it is well established that glacial ablation and snowmelt regulate stream discharge, linkage among streams and streamwater hydrogeochemistry, the controls of these factors on stream microbial biofilms remain insufficiently understood. We investigated glacial (metakryal, hypokryal, groundwater-fed (krenal and snow-fed (rhithral streams – all of them representative for alpine stream networks – and present evidence that these hydrologic and hydrogeochemical factors differentially affect sediment microbial biofilms. Average microbial biomass and bacterial carbon production were low in the glacial streams, whereas bacterial cell size, biomass, and carbon production were higher in the tributaries, most notably in the krenal stream. Whole-cell in situ fluorescence hybridization revealed reduced detection rates of the Eubacteria and higher abundance of α-Proteobacteria in the glacial stream, a pattern that most probably reflects the trophic status of this ecosystem. Our data suggest low flow during the onset of snowmelt and autumn as a short period (hot moment of favorable environmental conditions with pulsed inputs of allochthonous nitrate and dissolved organic carbon, and with disproportional high microbial growth. Krenal and rhithral streams with more constant and favorable environments serve as possible sources of microbes and organic matter to the main glacial channel during periods (e.g. snowmelt of elevated hydrologic linkage among streams. Ice and snow dynamics have a crucial impact on microbial biofilms, and we thus need better understanding of the microbial ecology and enhanced consideration of critical hydrological episodes in future models predicting alpine stream communities.

  5. Glacial and periglacial geomorphology and its paleoclimatological significance in three North Ethiopian Mountains, including a detailed geomorphological map

    Science.gov (United States)

    Hendrickx, Hanne; Jacob, Miro; Frankl, Amaury; Nyssen, Jan

    2015-10-01

    Geomorphological investigations and detailed mapping of past and present (peri)glacial landforms are required in order to understand the impact of climatic anomalies. The Ethiopian Highlands show a great variety in past and contemporary climate, and therefore, in the occurrence of glacial and periglacial landforms. However, only a few mountain areas have been studied, and detailed geomorphological understanding is lacking. In order to allow a fine reconstruction of the impact of the past glacial cycle on the geomorphology, vegetation complexes, and temperature anomalies, a detailed geomorphological map of three mountain areas (Mt. Ferrah Amba, 12°51‧N 39°29‧E; Mt. Lib Amba, 12°04‧N 39°22‧; and Mt. Abuna Yosef, 12°08‧N 39°11‧E) was produced. In all three study areas, inactive solifluction lobes, presumably from the Last Glacial Maximum (LGM), were found. In the highest study area of Abuna Yosef, three sites were discovered bearing morainic material from small late Pleistocene glaciers. These marginal glaciers occurred below the modeled snowline and existed because of local topo-climatic conditions. Evidence of such Pleistocene avalanche-fed glaciers in Ethiopia (and Africa) has not been produced earlier. Current frost action is limited to frost cracks and small-scale patterned ground phenomena. The depression of the altitudinal belts of periglacial and glacial processes during the last cold period was assessed through periglacial and glacial landform mapping and comparisons with data from other mountain areas taking latitude into account. The depression of glacial and periglacial belts of approximately 600 m implies a temperature drop around 6 °C in the last cold period. This cooling is in line with temperature depressions elsewhere in East Africa during the LGM. This study serves as a case study for all the intermediate mountains (3500-4200 m) of the North Ethiopian highlands.

  6. Virtual gallery of ancient coins through conoscopic holography

    Science.gov (United States)

    Schirripa Spagnolo, Giuseppe; Majo, Raffaele; Carli, Marco; Ambrosini, Dario; Paoletti, Domenica

    2003-10-01

    Physical access to historic and artistic manufactures can be limited by a lot of factors. In particular, the access to the collection of the ancient coins is difficult, especially for students. Indeed, for coins digital archive of high quality three-dimensional model and remote fruition is of great interest. In this work we propose 3D acquisition and digitizing techniques for the virtualized reality of ancient coins (virtual gallery). The system used for creating 3D shape of coins is based on conoscopic holography. This technique is a non-contact three-dimensional measuring technique that makes possible to produce holograms, even with incoherent light, with fringe periods that can be measured precisely to determine the exact distance to the point measured. It is suitable to obtain 3D profile with high resolution also on surface with unevenness reflectivity (this situation is usual on the surface of the ancient coins). By conoscopic holography, high-resolution 3D model can be obtained. However, accurate representation and high-quality display are fundamental requirements to avoid misinterpretation of the data. Therefore, virtual galleries can be obtained through a procedure involving 3D acquisition, 3D model and visualization. In conclusion, we propose an optoelectronic application, integrated with multimedia techniques, in order to improve the access to collection of ancient coins belonging to museums or privates.

  7. [The history of medicine in the ancient time].

    Science.gov (United States)

    Tesarová, Drahomíra

    2012-01-01

    This article deals with the history of medicine in the ancient Greece; from the cult of the God Asklepios, to the founder of the scientific rational medicine, Hippokrates. The humoral theory of Hippokrates is explained (the human body consists from four liquids) and his ideal of a physician's approach to a patient is emphasized. In the Hellenistic period the medical development continued in the Alexandria Medical School (Herofilos and Erasistratos). At first, not much attention was given to medicine and scientific health prevention in ancient Rome. Only 293 AD have physicians from Greece first been invited to Rome--e.g. Asklepiades. During the reign of C. lulius Caesar, foreigners, who engaged in medical practice, were granted Roman citizenship and thanks to a number of benefits the medical condition in Roman Empire blossomed. Medical clinics (iatreia), infirmaries (valetudinaria) and, under the influence of Christianity, hospitals were established. In the 2nd century AD ancient medicine reached its climax with physician Galenos, who created the entire system of medical science and became the most significant, but also last medical figure of ancient Rome. PMID:22442893

  8. Ideas of Physical Forces and Differential Calculus in Ancient India

    OpenAIRE

    Girish, T. E.; Nair, C. Radhakrishnan

    2010-01-01

    We have studied the context and development of the ideas of physical forces and differential calculus in ancient India by studying relevant literature related to both astrology and astronomy since pre-Greek periods. The concept of Naisargika Bala (natural force) discussed in Hora texts from India is defined to be proportional to planetary size and inversely related to planetary distance. This idea developed several centuries prior to Isaac Newton resembles fundamental physical forces in natur...

  9. Analysis of Ancient DNA in Microbial Ecology.

    Science.gov (United States)

    Gorgé, Olivier; Bennett, E Andrew; Massilani, Diyendo; Daligault, Julien; Pruvost, Melanie; Geigl, Eva-Maria; Grange, Thierry

    2016-01-01

    The development of next-generation sequencing has led to a breakthrough in the analysis of ancient genomes, and the subsequent genomic analyses of the skeletal remains of ancient humans have revolutionized the knowledge of the evolution of our species, including the discovery of a new hominin, and demonstrated admixtures with more distantly related archaic populations such as Neandertals and Denisovans. Moreover, it has also yielded novel insights into the evolution of ancient pathogens. The analysis of ancient microbial genomes allows the study of their recent evolution, presently over the last several millennia. These spectacular results have been attained despite the degradation of DNA after the death of the host, which results in very short DNA molecules that become increasingly damaged, only low quantities of which remain. The low quantity of ancient DNA molecules renders their analysis difficult and prone to contamination with modern DNA molecules, in particular via contamination from the reagents used in DNA purification and downstream analysis steps. Finally, the rare ancient molecules are diluted in environmental DNA originating from the soil microorganisms that colonize bones and teeth. Thus, ancient skeletal remains can share DNA profiles with environmental samples and identifying ancient microbial genomes among the more recent, presently poorly characterized, environmental microbiome is particularly challenging. Here, we describe the methods developed and/or in use in our laboratory to produce reliable and reproducible paleogenomic results from ancient skeletal remains that can be used to identify the presence of ancient microbiota. PMID:26791510

  10. On the glacial and inter-glacial thermohaline circulation and the associated transports of heat and freshwater

    Directory of Open Access Journals (Sweden)

    M. Ballarotta

    2014-03-01

    Full Text Available The change of the thermohaline circulation (THC between the Last Glacial Maximum (LGM, ≈ 21 kyr ago and the present day climate are explored using an Ocean General Circulation Model and stream functions projected in various coordinates. Compared to the present day period, the LGM circulation is reorganised in the Atlantic Ocean, in the Southern Ocean and particularly in the abyssal ocean, mainly due to the different haline stratification. Due to stronger wind stress, the LGM tropical circulation is more vigorous than under modern conditions. Consequently, the maximum tropical transport of heat is slightly larger during the LGM. In the North Atlantic basin, the large sea-ice extent during the LGM constrains the Gulf Stream to propagate in a more zonal direction, reducing the transport of heat towards high latitudes and reorganising the freshwater transport. The LGM circulation is represented as a large intrusion of saline Antarctic Bottom Water into the Northern Hemisphere basins. As a result, the North Atlantic Deep Water is shallower in the LGM simulation. The stream functions in latitude-salinity coordinates and thermohaline coordinates point out the different haline regimes between the glacial and interglacial period, as well as a LGM Conveyor Belt circulation largely driven by enhanced salinity contrast between the Atlantic and the Pacific basin. The thermohaline structure in the LGM simulation is the result of an abyssal circulation that lifts and deviates the Conveyor Belt cell from the area of maximum volumetric distribution, resulting in a ventilated upper layer above a deep stagnant layer, and an Atlantic circulation more isolated from the Pacific. An estimation of the turnover times reveal a deep circulation almost sluggish during the LGM, and a Conveyor Belt cell more vigorous due to the combination of stronger wind stress and shortened circulation route.

  11. Similar millennial climate variability on the Iberian margin during two early Pleistocene glacials and MIS 3

    Science.gov (United States)

    Birner, B.; Hodell, D. A.; Tzedakis, P. C.; Skinner, L. C.

    2016-01-01

    Although millennial-scale climate variability (MIS) 37-41 from approximately 1235 to 1320 ka) during the "41 ka world" at Integrated Ocean Drilling Program Site U1385 (the "Shackleton Site") on the southwest Iberian margin. Millennial-scale climate variability was suppressed during interglacial periods (MIS 37, MIS 39, and MIS 41) and activated during glacial inceptions when benthic δ18O exceeded 3.2‰. Millennial variability during glacials MIS 38 and MIS 40 closely resembled Dansgaard-Oeschger events from the last glacial (MIS 3) in amplitude, shape, and pacing. The phasing of oxygen and carbon isotope variability is consistent with an active oceanic thermal bipolar see-saw between the Northern and Southern Hemispheres during most of the prominent stadials. Surface cooling was associated with systematic decreases in benthic carbon isotopes, indicating concomitant changes in the meridional overturning circulation. A comparison to other North Atlantic records of ice rafting during the early Pleistocene suggests that freshwater forcing, as proposed for the late Pleistocene, was involved in triggering or amplifying perturbations of the North Atlantic circulation that elicited a bipolar see-saw response. Our findings support similarities in the operation of the climate system occurring on millennial time scales before and after the Middle Pleistocene Transition despite the increases in global ice volume and duration of the glacial cycles.

  12. Glacial refugia, recolonization patterns and diversification forces in Alpine-endemic Megabunus harvestmen.

    Science.gov (United States)

    Wachter, Gregor A; Papadopoulou, Anna; Muster, Christoph; Arthofer, Wolfgang; Knowles, L Lacey; Steiner, Florian M; Schlick-Steiner, Birgit C

    2016-06-01

    The Pleistocene climatic fluctuations had a huge impact on all life forms, and various hypotheses regarding the survival of organisms during glacial periods have been postulated. In the European Alps, evidence has been found in support of refugia outside the ice shield (massifs de refuge) acting as sources for postglacial recolonization of inner-Alpine areas. In contrast, evidence for survival on nunataks, ice-free areas above the glacier, remains scarce. Here, we combine multivariate genetic analyses with ecological niche models (ENMs) through multiple timescales to elucidate the history of Alpine Megabunus harvestmen throughout the ice ages, a genus that comprises eight high-altitude endemics. ENMs suggest two types of refugia throughout the last glacial maximum, inner-Alpine survival on nunataks for four species and peripheral refugia for further four species. In some geographic regions, the patterns of genetic variation are consistent with long-distance dispersal out of massifs de refuge, repeatedly coupled with geographic parthenogenesis. In other regions, long-term persistence in nunataks may dominate the patterns of genetic divergence. Overall, our results suggest that glacial cycles contributed to allopatric diversification in Alpine Megabunus, both within and at the margins of the ice shield. These findings exemplify the power of ENM projections coupled with genetic analyses to identify hypotheses about the position and the number of glacial refugia and thus to evaluate the role of Pleistocene glaciations in driving species-specific responses of recolonization or persistence that may have contributed to observed patterns of biodiversity. PMID:27037513

  13. An investigation into the ancient abortion laws: comparing ancient Persia with ancient Greece and Rome.

    Science.gov (United States)

    Yarmohammadi, Hassan; Zargaran, Arman; Vatanpour, Azadeh; Abedini, Ehsan; Adhami, Siamak

    2013-01-01

    Since the dawn of medicine, medical rights and ethics have always been one of mankind's concerns. In any civilisation, attention paid to medical laws and ethics depends on the progress of human values and the advancement of medical science. The history of various civilisations teaches that each had its own views on medical ethics, but most had something in common. Ancient civilisations such as Greece, Rome, or Assyria did not consider the foetus to be alive and therefore to have human rights. In contrast, ancient Persians valued the foetus as a living person equal to others. Accordingly, they brought laws against abortion, even in cases of sexual abuse. Furthermore, abortion was considered to be a murder and punishments were meted out to the mother, father, and the person performing it. PMID:24304111

  14. Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

    Directory of Open Access Journals (Sweden)

    L. M. Dupont

    2011-11-01

    Full Text Available Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome for the last glacial as well as for other glacial periods of the past 300 Ka.

  15. Mean annual temperature in New Zealand during the last glacial maximum derived from dissolved noble gases in groundwater

    Science.gov (United States)

    Seltzer, A. M.; Stute, M.; Morgenstern, U.; Stewart, M. K.; Schaefer, J. M.

    2015-12-01

    This study presents a reconstruction of mean annual surface temperature in New Zealand over the last glacial period using groundwater noble gas paleothermometry. Low resolution 14C-derived mean recharge ages of groundwater from the Deep Moutere, Deep Wairau, and Taranaki aquifers range from roughly 41,500 yr to present, including the last glacial maximum (LGM). Modeled noble gas temperatures of probable glacial-age samples range from roughly 3.7-6.2 °C cooler than present. We present an error-weighted mean cooling of 4.6 ± 0.5°C relative to present during last glacial period. The screened depth intervals of some wells sampled in this study allow for a degree of mixing during extraction between groundwater layers of different recharge age. Mixing with modern groundwater may slightly elevate the noble gas temperatures (NGTs) of glacial-age samples while making them appear substantially younger. Given the uncertainty in dating, we cannot rule out a larger LGM temperature depression of up to ∼6 °C. The ∼4.6 °C cooling estimate agrees with a number of terrestrial paleoclimate reconstructions near the study area as well as the majority of nearby paleoceanographic temperature studies.

  16. Differences between the glacial cycles of Antarctic temperature and greenhouse gases

    Directory of Open Access Journals (Sweden)

    A. W. Omta

    2012-03-01

    Full Text Available Ice-core measurements have indicated that the atmospheric concentrations of the greenhouse gases CO2 and CH4 show glacial-interglacial variations in step with Antarctic temperature. To obtain more insight into the nature of this relationship for cycles of different frequencies, measured time series of temperature, CO2, and CH4 are reanalysed. The results indicate that the temperature signal consists of a linear superposition of a component related to CO2 with a period of ~100 000 yr and a component related to variations in the obliquity of the Earth's orbital plane with a period of ~41 000 yr. This suggests that either there operate very different feedback mechanisms at the different time scales or that CO2 is not merely a~passive follower and amplifier of the glacial-interglacial variations in Antarctic temperature.

  17. Mapping The Ancient Maya Landscape From Space

    Science.gov (United States)

    Sever, Tom; Arnold, James E. (Technical Monitor)

    2002-01-01

    The Peten region of northern Guatemala is one of the last places on earth where major archeological sites remain to be discovered. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper and IKONOS satellite and airborne Star3-I radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as cities, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. The use of bajos for farming has been a source of debate within the professional community for many years. But the recent detection and verification of cultural features within the bajo system by our research team are providing conclusive evidence that the ancient Maya had adapted well to wetland environments from the earliest times and utilized them until the time of the Maya collapse. The use of the bajos for farming is also an important resource for the future of the current inhabitants who are experiencing rapid population growth. Remote sensing imagery is also demonstrating that in the Preclassic period (600 BC- AD 250), the Maya had already achieved a high organizational level as evidenced by the construction of massive temples and an elaborate inter-connecting roadway system. Although they experienced several setbacks such as droughts and hurricanes, the Maya nevertheless managed the delicate forest ecosystem successfully for several centuries. However, around AD 800, something happened to the Maya to cause their rapid decline and eventual disappearance from the region. The evidence indicates that at this time there was increased climatic dryness, extensive deforestation, overpopulation, and widespread warfare. This raises a question that

  18. Paleolithic human exploitation of plant foods during the last glacial maximum in North China

    OpenAIRE

    Liu, Li; Bestel, Sheahan; Shi, Jinming; Song, Yanhua; Chen, Xingcan

    2013-01-01

    Three grinding stones from Shizitan Locality 14 (ca. 23,000–19,500 calendar years before present) in the middle Yellow River region were subjected to usewear and residue analyses to investigate human adaptation during the last glacial maximum (LGM) period, when resources were generally scarce and plant foods may have become increasingly important in the human diet. The results show that these tools were used to process various plants, including Triticeae and Paniceae grasses, Vigna beans, Dio...

  19. Empirical estimation of present-day Antarctic glacial isostatic adjustment and ice mass change

    OpenAIRE

    Gunter, B.C.; Didova, O.; Riva, R. E. M.; Ligtenberg, S. R. M.; J. T. M. Lenaerts; King, M.A.; M. R. van den Broeke; T. Urban

    2014-01-01

    This study explores an approach that simultaneously estimates Antarctic mass balance and glacial isostatic adjustment (GIA) through the combination of satellite gravity and altimetry data sets. The results improve upon previous efforts by incorporating a firn densification model to account for firn compaction and surface processes as well as reprocessed data sets over a slightly longer period of time. A range of different Gravity Recovery and Climate Experiment (GRACE) gravity ...

  20. Origin of the Glacial Cycles: A Collection of Articles

    OpenAIRE

    Muller, R. A.; G.J. MacDonald

    1997-01-01

    This collection of articles describes a new theory of glacial cycles and its application to a number of data sets that represent conditions during glacial times. The widely held conventional theory of glacial cycles, which is due to Milankovitch, attributes cycles in the earth's ice cover to perturbations in the motion of the earth and the resulting changes of insolation (solar heating) in the Northern Hemisphere. The strongest effects are expected to come from changes in the earth's ...

  1. [Medicine in ancient Mesopotamia - part 2].

    Science.gov (United States)

    Martins E Silva, J

    2010-01-01

    The second part embraces exclusively the main characteristics of the medicine in Ancient Mesopotamia, in its main facets: concept of disease, healers and practice. The disease was considered a divine punishment or resultant from a malign influence. Insofar, the medicine began by being preventive, by the use of appropriate amulets or by offerings or sacrifices intending to pacify those malign forces. The treatment of the generality of the diseases privileged the expulsion of those spirits and malign influences from the patient body, purifying it, which was done by the specific intervention of a approximately shipu (clergymanexorcist); not having results, the treatment was continued by the asû (practical healer) that appealed to a group of physical manipulations, limited surgical acts and the administration or application of prescriptions, resultants of the mixture of organic and inorganic substances. In case of failing, the patients (as well as common healthy individuals or rule leaders) could fall back upon a priest diviner (bârû) that, by examination of the organs of an animal especially sacrificed for, would give a final decision about the disease or the future. Besides this more occult facet, nourished in religious faiths and in the magic, the medicine of Ancient Mesopotamia included rational knowledge, certainly as the result of systematic patients observation and semiotic interpretation. From those observations and knowledge referred to the Sumerian period, carefully logged, refined and transmitted to the following generations, it was built a valuable group of texts with the description of symptoms, signs, diagnosis and prognostic of the most common diseases, still identifiable in the present. PMID:20353716

  2. Public Library Systems in Ancient South India

    OpenAIRE

    Raman Nair, R.

    1991-01-01

    The paper puts forward and substantiates the view that the concept of free public library service goes back to ancient times. Governments of those days were aware of their responsibility to provide to all citizens free information service. The study observes with reference to ancient Indian records that educational facilities and libraries were accessible to people of Ancient India without any discrimination based on economic status, caste, religion or geographical boundaries. Scholars handl...

  3. Paleodistribution modeling suggests glacial refugia in Scandinavia and out-of-Tibet range expansion of the Arctic fox.

    Science.gov (United States)

    Fuentes-Hurtado, Marcelo; Hof, Anouschka R; Jansson, Roland

    2016-01-01

    Quaternary glacial cycles have shaped the geographic distributions and evolution of numerous species in the Arctic. Ancient DNA suggests that the Arctic fox went extinct in Europe at the end of the Pleistocene and that Scandinavia was subsequently recolonized from Siberia, indicating inability to track its habitat through space as climate changed. Using ecological niche modeling, we found that climatically suitable conditions for Arctic fox were found in Scandinavia both during the last glacial maximum (LGM) and the mid-Holocene. Our results are supported by fossil occurrences from the last glacial. Furthermore, the model projection for the LGM, validated with fossil records, suggested an approximate distance of 2000 km between suitable Arctic conditions and the Tibetan Plateau well within the dispersal distance of the species, supporting the recently proposed hypothesis of range expansion from an origin on the Tibetan Plateau to the rest of Eurasia. The fact that the Arctic fox disappeared from Scandinavia despite suitable conditions suggests that extant populations may be more sensitive to climate change than previously thought. PMID:26811782

  4. The impact of the North American glacial topography on the evolution of the Eurasian ice sheet over the last glacial cycle

    Science.gov (United States)

    Liakka, Johan; Löfverström, Marcus; Colleoni, Florence

    2016-05-01

    Modeling studies have shown that the continental-scale ice sheets in North America and Eurasia in the last glacial cycle had a large influence on the atmospheric circulation and thus yielded a climate distinctly different from the present. However, to what extent the two ice sheets influenced each others' growth trajectories remains largely unexplored. In this study we investigate how an ice sheet in North America influences the downstream evolution of the Eurasian ice sheet, using a thermomechanical ice-sheet model forced by climate data from atmospheric snapshot experiments of three distinctly different phases of the last glacial cycle: the Marine Isotope Stages 5b, 4, and 2 (Last Glacial Maximum - LGM). Owing to the large uncertainty associated with glacial changes in the Atlantic meridional overturning circulation, each atmospheric snapshot experiment was conducted using two distinctly different ocean heat transport representations. Our results suggest that changes in the North American paleo-topography may have largely controlled the zonal distribution of the Eurasian ice sheet. In the MIS4 and LGM experiments, the Eurasian ice sheet migrates westward towards the Atlantic sector - largely consistent with geological data and contemporary ice-sheet reconstructions - due to a low wave number stationary wave response, which yields a cooling in Europe and a warming in northeastern Siberia. The expansion of the North American ice sheet between MIS4 and the LGM amplifies the Siberian warm anomaly, which limits the glaciation there and may therefore help explain the progressive westward migration of the Eurasian ice sheet in this time period. The ocean heat transport only has a small influence on the stationary wave response to the North American glacial topography; however, because temperature anomalies have a smaller influence on an ice sheet's ablation in a colder climate than in a warmer one, the impact of the North American glacial topography on the Eurasian ice

  5. Glacial isostatic uplift of the European Alps

    Science.gov (United States)

    Mey, Juergen; Scherler, Dirk; Wickert, Andrew D.; Egholm, David L.; Tesauro, Magdala; Schildgen, Taylor F.; Strecker, Manfred R.

    2016-04-01

    Present-day vertical movements of the Earth's surface are mostly due to tectonic deformation, volcanic processes, and crustal loading/unloading. In tectonically stable regions of North America and Scandinavia, vertical movements are almost entirely attributable to glacial isostatic rebound after the melting of the Laurentide and Fennoscandian ice sheets. In contrast, the Pleistocene Alpine icecap grew on a younger mountain belt that formed by collision of the European and African plates, still subject to shortening. Therefore, measured uplift is potentially a composite signal of tectonic shortening and unloading after deglaciation and concomitant erosion. Deciphering the contributions of tectonics and crustal unloading to present-day uplift rates in formerly-glaciated mountain belts is a prerequisite to using uplift data to estimate the viscosity structure of the Earth's mantle, a key variable in geodynamics. We evaluate the post-LGM glacial-isostatic rebound of the Alps following a 4-tiered procedure. First, we estimated the thickness distribution of sedimentary valley fills to create a bedrock map of the entire mountain belt. Second, this map was used as topographic basis for the reconstruction of the Alpine icecap using a numerical ice-flow model. Third, we estimated the equilibrium deflection of the Alpine lithosphere, using the combined loads of ice and sediments with a variable effective elastic thickness. Finally, we used an exponential decay function to infer the residual deflection and the present-day uplift rate for a range of upper mantle viscosities. Our analysis shows that virtually all of the geodetically measured surface uplift in the Swiss and the Austrian Alps can be attributed to glacial unloading and redistribution of sediments, assuming an upper-mantle viscosity lower than that inferred for an old craton (e.g., Fennoscandia), but higher than that for a region with recent crustal thinning (e.g., Basin and Range province).

  6. Aiding the Interpretation of Ancient Documents

    DEFF Research Database (Denmark)

    Roued-Cunliffe, Henriette

    tool it is important first to comprehend the interpretation process involved in reading ancient documents. This is not a linear process but rather a recursive process where the scholar moves between different levels of reading, such as ‘understanding the meaning of a character’ or ‘understanding......How can Decision Support System (DSS) software aid the interpretation process involved in the reading of ancient documents? This paper discusses the development of a DSS prototype for the reading of ancient texts. In this context the term ‘ancient documents’ is used to describe mainly Greek...

  7. Re-inventing ancient human DNA

    OpenAIRE

    Knapp, Michael; Lalueza-Fox, Carles; Hofreiter, M.

    2015-01-01

    For a long time, the analysis of ancient human DNA represented one of the most controversial disciplines in an already controversial field of research. Scepticism in this field was only matched by the long-lasting controversy over the authenticity of ancient pathogen DNA. This ambiguous view on ancient human DNA had a dichotomous root. On the one hand, the interest in ancient human DNA is great because such studies touch on the history and evolution of our own species. On the other hand, beca...

  8. Chinese Ancient Football with Romanticism

    Institute of Scientific and Technical Information of China (English)

    江凌; 李晓勤

    2004-01-01

    Like other traditional Chinese sports, the ancient Chinese football, which used to be called “cuju”, has some differences from several sports in western countries concerning cultural and hamanist purport as well as metal aspiration, although it was similar with modern football to some extent, such as a leather-made ball with a bladder, rectangle sports ground, referee, goal and certain competitiveness. The author tries to talk about such difference in cultural and humanist purport as well as mental aspiration by making a comparison between “cuju” and modern football.

  9. Ancient Indian Leaps into Mathematics

    CERN Document Server

    Yadav, B S

    2011-01-01

    This book presents contributions of mathematicians covering topics from ancient India, placing them in the broader context of the history of mathematics. Although the translations of some Sanskrit mathematical texts are available in the literature, Indian contributions are rarely presented in major Western historical works. Yet some of the well-known and universally-accepted discoveries from India, including the concept of zero and the decimal representation of numbers, have made lasting contributions to the foundation of modern mathematics. Through a systematic approach, this book examines th

  10. Testing the "Mudball Earth" Hypothesis: Are Neoproterozoic Glacial Deposits Capped with Supraglacial Dust?

    Science.gov (United States)

    Goodman, J. C.; Alvim Lage, C.

    2014-12-01

    The Snowball Earth hypothesis has inspired several variants which may help to explain some of the great mysteries of the Neoproterozoic glaciations. One of these, the "Mudball Earth", proposes that as the Earth remained completely frozen for millions of years, a layer of dust accumulated on the ice surface. This dust layer would darken the planet, making it easier for the Earth to escape from the highly stable snowball climate state. This hypothesis is testable: after the ice melted at the end of a glacial era, this dust would sink to the bottom of the ocean, possibly forming a distinct clay, mud, or silt layer on the top of the glacial till deposits: this "clay drape" would then be covered by the cap carbonates that mark a return to warm climate. Sublimation and ice flow during the glacial episode should make this layer thicker at the equator and thinner or absent in the poles. Is this clay layer actually present in the rock record? Is it more prevalent at the paleoequator, as predicted? A clay drape has been noticed anecdotally, but no global survey has been done to date. We conducted a thorough literature review of all sites where Neoproterozoic glacial diamictites have been observed, identifying the type of rock that lies between the diamictite and the postglacial cap carbonate, when present, during both Sturtian and Marinoan glacial periods. Only a few publications identify a distinct clay/silt/mud layer that might represent weathered dust. These sites are not grouped by paleolatitude in any obvious way. With access only to published reports, we cannot determine whether such a layer is absent, went unreported, or was misinterpreted by us. With this work we hope to attract the attention of Neoproterozoic field geologists, inviting them to comment on the presence or absence of strata which could confirm or reject the "Mudball" hypothesis.

  11. Impact of the oceanic geothermal heat flux on a glacial ocean state

    Science.gov (United States)

    Ballarotta, M.; Roquet, F.; Falahat, S.; Zhang, Q.; Madec, G.

    2015-08-01

    The oceanic geothermal heating (OGH) has a significant impact on the present-day ocean state, but its role during glacial periods, when the ocean circulation and stratification were different from those of today, remains poorly known. In the present study, we analyzed the response of the glacial ocean to OGH, by comparing ocean simulations of the Last Glacial Maximum (LGM, ∼ 21 ka ago) including or not geothermal heating. We found that applying the OGH warmed the Antarctic Bottom Waters (AABW) by ∼ 0.4 °C and increased the abyssal circulation by 15 to 30 % north of 30° S in the deep Pacific and Atlantic basins. The geothermally heated deep waters were then advected toward the Southern Ocean where they upwelled to the surface due to the Ekman transport. The extra heat transport towards Antarctica acted to reduce the amount of sea ice contributing to the freshening of the whole AABW overturning cell. The global amount of salt being conserved, this bottom freshening induced a salinification of the North Atlantic and North Pacific surface and intermediate waters, contributing to the deepening of the North Atlantic Deep Water. This indirect mechanism is responsible for the largest observed warming, found in the North Atlantic deep western boundary current between 2000 and 3000 m (up to 2 °C). The characteristic time scale of the ocean response to the OGH corresponds to an advective time scale (associated with the overturning of the AABW cell) rather than a diffusive time scale. The OGH might facilitate the transition from a glacial to an inter-glacial state but its effect on the deep stratification seems insufficient to drive alone an abrupt climate change.

  12. Impact of the oceanic geothermal heat flux on a glacial ocean state

    Directory of Open Access Journals (Sweden)

    M. Ballarotta

    2015-08-01

    Full Text Available The oceanic geothermal heating (OGH has a significant impact on the present-day ocean state, but its role during glacial periods, when the ocean circulation and stratification were different from those of today, remains poorly known. In the present study, we analyzed the response of the glacial ocean to OGH, by comparing ocean simulations of the Last Glacial Maximum (LGM, ∼ 21 ka ago including or not geothermal heating. We found that applying the OGH warmed the Antarctic Bottom Waters (AABW by ∼ 0.4 °C and increased the abyssal circulation by 15 to 30 % north of 30° S in the deep Pacific and Atlantic basins. The geothermally heated deep waters were then advected toward the Southern Ocean where they upwelled to the surface due to the Ekman transport. The extra heat transport towards Antarctica acted to reduce the amount of sea ice contributing to the freshening of the whole AABW overturning cell. The global amount of salt being conserved, this bottom freshening induced a salinification of the North Atlantic and North Pacific surface and intermediate waters, contributing to the deepening of the North Atlantic Deep Water. This indirect mechanism is responsible for the largest observed warming, found in the North Atlantic deep western boundary current between 2000 and 3000 m (up to 2 °C. The characteristic time scale of the ocean response to the OGH corresponds to an advective time scale (associated with the overturning of the AABW cell rather than a diffusive time scale. The OGH might facilitate the transition from a glacial to an inter-glacial state but its effect on the deep stratification seems insufficient to drive alone an abrupt climate change.

  13. Cosmogenic 10Be constraints on Little Ice Age glacial advances in the eastern Tian Shan, China

    Science.gov (United States)

    Li, Yanan; Li, Yingkui; Harbor, Jon; Liu, Gengnian; Yi, Chaolu; Caffee, Marc W.

    2016-04-01

    Presumed Little Ice Age (LIA) glacial advances, represented by a set of fresh, sharp-crested, boulder covered and compact moraines a few hundred meters downstream from modern glaciers, have been widely recognized in the Central Asian highlands. However, few studies have constrained the formation ages of these moraines. We report 31 10Be exposure ages from presumed LIA moraines in six glacial valleys in the Urumqi River headwater area and the Haxilegen Pass area of the eastern Tian Shan, China. Our results reveal that the maximum LIA glacial extent occurred mainly around 430 ± 100 yr, a cold and wet period as indicated by proxy data from ice cores, tree rings, and lake sediments in Central Asia. We also dated a later glacial advance to 270 ± 55 yr. However, 10Be exposure ages on several presumed LIA moraines in front of small, thin glaciers are widely scattered and much older than the globally recognized timing of the LIA. Historical topographic maps indicate that most glaciers were more extensive in the early 1960s, and two of our 10Be sample sites were located close to the ice front at that time. Boulders transported by these small and thin glaciers may be reworked from deposits originally formed prior to the LIA glacial advances, producing apparently old and widely scattered exposure ages due to varied nuclide inheritance. Other published ages indicated an earlier LIA advance around 790 ± 300 yr in the easternmost Tian Shan, but in our study area the more extensive advance around 430 ± 100 yr likely reworked or covered deposits from this earlier event.

  14. Reconstruction of Last Glacial to early Holocene monsoon variability from relict lake sediments of the Higher Central Himalaya, Uttrakhand, India

    DEFF Research Database (Denmark)

    Juyal, N.; Pant, R.K.; Basavaiah, N.;

    2009-01-01

    correspondence at the millennial scale between our data and that of continental and marine records from the Indian sub-continent suggests that Goting basin responded to periods of strengthened monsoon during the Last Glacial to early Holocene. We attribute the millennial scale monsoon variability to climatic...

  15. Abrupt climate variability of eastern Anatolia vegetation during the last glacial

    Directory of Open Access Journals (Sweden)

    N. Pickarski

    2015-07-01

    Full Text Available Detailed analyses of the Lake Van pollen and stable oxygen isotope record allow the identification of millennial-scale vegetation and environmental changes in eastern Anatolia throughout the last glacial. The climate within the last glacial period (∼75–15 ka BP was cold and dry, with low arboreal pollen (AP levels. The driest and coldest period corresponds to Marine Isotope Stage (MIS 2 (∼28–14.5 ka BP dominated by the highest values of xerophytic steppe vegetation. Our high-resolution multi proxy record shows rapid expansions and contractions that mimic the stadial-interstadial pattern of the Dansgaard–Oeschger (DO events as recorded in the Greenland ice cores, and thus, provide a linkage to North Atlantic climate oscillations. Periods of reduced moisture availability characterized at Lake Van by enhanced xerophytic species correlates well with increase in ice-rafted debris (IRD and a decrease of sea surface temperature (SST in the North Atlantic. Furthermore, comparison with the marine realm reveals that the complex atmosphere–ocean interaction can be recognized by the strength and position of the westerlies in eastern Anatolia. Influenced by rough topography at Lake Van, the expansion of temperate species (e.g. deciduous Quercus was stronger during interstadials DO 19, 17–16, 14, 12 and 8. However, Heinrich events (HE, characterized by highest concentrations of ice-rafted debris in marine sediments, are identified in eastern Anatolia by AP values not lower and high steppe components not more abundant than during DO stadials. In addition, this work is a first attempt to establish a continuous microscopic charcoal record over the last glacial in the Near East, which documents an initial immediate response to millennial-scale climate and environmental variability and enables the shed light on the history of fire activity during the last glacial.

  16. [Ancient history of Indian pharmacy].

    Science.gov (United States)

    Okuda, Jun; Natsume, Yohko

    2010-01-01

    The study of the ancient history of Indian medicine has recently been revived due to the publication of polyglot translations. However, little is known of ancient Indian pharmacy. Archaeological evidence suggests the Indus people lived a settled life approximately in 2500 B.C. Their cities were enjoying the cleanest and most hygienic daily life with elaborate civic sanitation systems. The whole conception shows a remarkable concern for health. Then, the early Aryans invaded India about 1500 B.C. and the Vedic age started. The Rgveda texts contain the hymns for Soma and those for herbs. The term Ayurveda (i.e., science of life) is found in some old versions of both Ramāyana and Mahābhārata and in the Atharvaveda. Suśruta had the credit of making a breakthrough in the field of surgery. The Ayurveda, a work on internal medicine, gives the following transmission of sages: Brahmā-->Daksa-->Prajāpati-->Aśivinau-->Indra-->Caraka. On the other hand, the Suśruta-samhitā, which deals mainly with surgical medicine, explains it as follows; Indra-->Dhanvantari-->Suśruta Both Caraka and Suśruta were medical doctors as well as pharmacists, so they studied more than 1000 herbs thoroughly. The Ayurveda had been used by his devotees for medical purposes. It eventually spread over Asia with the advanced evolution of Buddhism. PMID:21032887

  17. Genome-wide patterns of selection in 230 ancient Eurasians

    Science.gov (United States)

    Mathieson, Iain; Lazaridis, Iosif; Rohland, Nadin; Mallick, Swapan; Patterson, Nick; Roodenberg, Songül Alpaslan; Harney, Eadaoin; Stewardson, Kristin; Fernandes, Daniel; Novak, Mario; Sirak, Kendra; Gamba, Cristina; Jones, Eppie R.; Llamas, Bastien; Dryomov, Stanislav; Pickrel, Joseph; Arsuaga, Juan Luís; de Castro, José María Bermúdez; Carbonell, Eudald; Gerritsen, Fokke; Khokhlov, Aleksandr; Kuznetsov, Pavel; Lozano, Marina; Meller, Harald; Mochalov, Oleg; Moiseyev, Vayacheslav; Rojo Guerra, Manuel A.; Roodenberg, Jacob; Vergès, Josep Maria; Krause, Johannes; Cooper, Alan; Alt, Kurt W.; Brown, Dorcas; Anthony, David; Lalueza-Fox, Carles; Haak, Wolfgang; Pinhasi, Ron; Reich, David

    2016-01-01

    Ancient DNA makes it possible to directly witness natural selection by analyzing samples from populations before, during and after adaptation events. Here we report the first scan for selection using ancient DNA, capitalizing on the largest genome-wide dataset yet assembled: 230 West Eurasians dating to between 6500 and 1000 BCE, including 163 with newly reported data. The new samples include the first genome-wide data from the Anatolian Neolithic culture whose genetic material we extracted from the DNA-rich petrous bone and who we show were members of the population that was the source of Europe’s first farmers. We also report a complete transect of the steppe region in Samara between 5500 and 1200 BCE that allows us to recognize admixture from at least two external sources into steppe populations during this period. We detect selection at loci associated with diet, pigmentation and immunity, and two independent episodes of selection on height. PMID:26595274

  18. Ideas of Physical Forces and Differential Calculus in Ancient India

    CERN Document Server

    Girish, T E

    2011-01-01

    We have studied the context and development of the ideas of physical forces and differential calculus in ancient India by studying relevant literature related to both astrology and astronomy since pre-Greek periods. The concept of Naisargika Bala (natural force) discussed in Hora texts from India is defined to be proportional to planetary size and inversely related to planetary distance. This idea developed several centuries prior to Isaac Newton resembles fundamental physical forces in nature especially gravity. We show that the studies on retrograde motion and Chesta Bala of planets like Mars in the context of astrology lead to development of differential calculus and planetary dynamics in ancient India. The idea of instantaneous velocity was first developed during the 1st millennium BC and Indians could solve first order differential equations as early as 6th cent AD. Indian contributions to astrophysics and calculus during European dark ages can be considered as a land mark in the pre-renaissance history ...

  19. Cleaning of Ancient Document Images Using Modified Iterative Global Threshold

    Directory of Open Access Journals (Sweden)

    N.Venkata Rao

    2011-11-01

    Full Text Available Ancient document Image processing is an important area attracting many researchers in the recent period. Binarization is the first step while cleaning the document for further processing. Based on the degradation of the original document, either global or local thresholding methods are preferred. Thresholding phenomenon is a simple and practical approach to identify the cluster of pixels that are most likely associated with background information, while separating the object information. In this paper we propose a modified iterative global thresholding approach to separate the clusters of fore ground and background. The relative closeness towards background intensity is computed in each iteration after image equalization. Camera captured images of ancient printed documents, stone carvings and palm leaves are evaluated in the present paper.

  20. The breast: from Ancient Greek myths to Hippocrates and Galen.

    Science.gov (United States)

    Iavazzo, C R; Trompoukis, C; Siempos, I I; Falagas, M E

    2009-01-01

    This is a historical article about Ancient Greek literature from mythological times until the first centuries AD with regard to the female breast. We endeavoured to collect several elegant narratives on the topic as well as to explore the knowledge of Ancient Greek doctors on the role, physiology and pathology of breast and the treatment of its diseases. We identified such descriptions in myths regarding Amazons, Hercules, Zeus, Hera and Amaltheia. Furthermore, descriptions on the topic were also found in the work of Hippocrates, Aristoteles, Soranos, Alexander of Aphrodisias, Celsus, Archigenis, Leonides, Galen and Oribasius. We may conclude that some of today's medical knowledge or practice regarding the breast was also known in the historical period. PMID:19891848

  1. Characteristics of Soil Fertility of Buried Ancient Paddy at Chuodun Site in Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    LU Jia; HU Zheng-yi; CAO Zhi-hong; YANG Lin-zhang; LIN Xian-gui; DONG Yuan-hua; DING Jin-long; ZHENG Yun-fei

    2006-01-01

    Field investigation and laboratory analysis of 22 ancient paddy soils excavated at Chuodun site, Kunshan City, JiangsuProvince, China were carried out in 2003 to (1) understand the basic characteristics of ancient paddy soils, (2) compare the difference of soil fertility between ancient paddy soils and recent paddy soils, and (3) inquire into mechanisms of the sustainability of paddy soil. The oldest paddy soils at Chuodun site can be dated back to Neolithic age, around 6 000 aBP. These ancient fields were buried in about 1-m deep from the soil surface and their areas ranged from 0.32 to 12.9 m2 with an average of 5.2 m2. The paddy soils with > 5 000 pellets phytolith g-1 soil were termed intensively cultivated paddy soils (ICPS) and those with < 5 000 pellets phytolith g-1 soil were called weakly cultivated soils (WCPS). The contents of organic carbon (OC), and total N in the former were significantly higher than that in the latter. Ancient paddy soils had higher soil pH and C/N, total and available P, and lower contents of OC, DOC, total N, S, Cu, Fe, and available K, S, Fe, Mn, and Cu compared with recent paddy soils, which were attributed to application of chemical and manure fertilizers, pollution and acidification in recent paddy soils. The variation coefficients of OC and other nutrients in ancient paddy soils with higher PI were greater than that in ancient paddy soils with low PI, which indicated that human activities had a great impact on the spatial variability of soil nutrients. The contents of OC, total N, P and S in ancient paddy soils were higher than that in ancient moss of the same age, which indicated that planting rice during Majiabang culture period was beneficial to the accumulation of those life elements.

  2. The upper Pleistocene on the northern face of the Guadarrama Mountains (central Spain): Palaeoclimatic phases and glacial activity

    Science.gov (United States)

    Bullón, Teresa

    2016-09-01

    The present paper provides new information on Pleistocene glacial activity in a mountainous area of the Iberian Central System. A sediment analysis associated with Pleistocene modelling was carried out using: (1) granulometric and morphometric procedures, (2) quartz grain microtexture techniques (SEM) to discriminate between glacial and no glacial origins of sediments, (3) clay X-ray diffraction study to determine intra-Pleistocene climate variability, and (4) optically stimulated luminescence (OSL) absolute dating. The results show that the sediments were formed in two different phases associated with glacial dynamics, one of them was 35-30 ky BP and another was 25-20 ky BP, separated by a short intermediate warm-wet period. Identification of glacial phenomena is new for the northern slopes of the Guadarrama Mountains (facing the north Meseta, Duero basin), although they are not unusual within the general context of the Iberian Central System. From the data provided, we deduce that glaciation in these mountains was much more intense and widespread than had previously been thought because, on the northern slopes, glaciers occupied large areas reaching the base of the mountains. The evidence favours new interpretations of Pleistocene morphology in the centre of the Iberian Peninsula and, by extension, on the southwestern edge of Europe; it also highlights the sensitivity of mountainous areas with regard to Quaternary climate changes.

  3. Effects of glacial meltwater on corrosion of copper canisters

    International Nuclear Information System (INIS)

    The composition of glacial meltwater and its reactions in the bedrock are examined. The evidences that there are or should be from past intrusions of glacial meltwater and oxygen deep in the bedrock are also considered. The study is concluded with an evaluation of the potential effects of oxygenated meltwater on the corrosion of copper canisters. (46 refs., 3 figs., 2 tabs.)

  4. Attitudes Toward Deviant Sex in Ancient Mesopotamia

    Science.gov (United States)

    Bullough, Vern L.

    1971-01-01

    The article concludes that the whole question of sexual life in ancient Mesopotamia is difficult to reconstruct and fraught with many uncertainties. Nevertheless, it seems certain that the ancient Mesopotamians had fewer prohibitions against sex than our own civilization, and regarded as acceptable many practices which later societies condemned.…

  5. The Idea of Ancient Greek Philosophy

    Institute of Scientific and Technical Information of China (English)

    苏雪

    2016-01-01

    As the source of western philosophy, ancient Greek philosophy had a profound influence on western philosophy. Ancient philosophers were hard to reach a consensus on the existence of all the things in the world. They tried to grasp the profound understanding of the world, which is the clue of the history of philosophy.

  6. Women--Sex Objects in Ancient Egypt.

    Science.gov (United States)

    Mutimer, Brian T. P.

    Although it has been said that the women in Ancient Egypt enjoyed a reasonable state of social and professional equality with men, this paper presents an alternate theory--that women were second-class citizens whose physical prowess was secondary to their role as sex objects. It appears that men and women in Ancient Egypt often participated in the…

  7. An ancient rangefinder for teaching surveying methods

    OpenAIRE

    Sparavigna, Amelia Carolina

    2012-01-01

    Rangefinders are instruments used for ballistics and for surveying in general. Here we propose a discussion of some of them, ranging from the ancient Rome to the modern methods. Using an ancient roman artefact as a model, we can pre-pare a rangefinder at no cost for teaching surveying methods to students of engineering and military schools

  8. Outreach Testing of Ancient Astronomy

    Science.gov (United States)

    Sanmartin, J. R. S.; Blanco, M. B. M.

    2015-10-01

    fundamental quantity being given by half the difference between solar distances to vertical at winter and summer solstices, with value about 23.5°. Day and year periods greatly differing by about 2 ½ orders of magnitude, 1 day against 365 days, helps students to correctly visualize and interpret the experimental measurements. Since the gnomon serves to observe at night the moon shadow too, students can also determine the inclination of the lunar orbital plane, as about 5 degrees away from the ecliptic, thus explaining why eclipses are infrequent. Independently, earth taking longer between spring and fall equinoxes than from fall to spring (the solar anomaly), as again verified by the students, was explained in ancient Greek science, which posited orbits universally as circles or their combination, by introducing the eccentric circle, with earth placed some distance away from the orbital centre when considering the relative motion of the sun, which would be closer to the earth in winter. In a sense, this can be seen as hint and approximation of the elliptic orbit proposed by Kepler many centuries later. EPSC Abstracts Vol. 10, EPSC2015-40, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress Secondly, by observing lunar phases and eclipses from the ground, students could also determine, following Aristarchus of Samos in the 3rd century BC, 4 length ratios involving moon and sun distances to earth, and radii of all three, moon, sun, and earth. The angular width of the moon could be first determined with simplest optical devices as about half a degree; this yields the ratio between moon diameter 2RM and distance DM to earth. Next, eclipses of sun prove its angular width, and thus ratio 2RS/DS, similar to the lunar one, though the relatively high lunar orbital eccentricity, 0.055, does result in not quite a full eclipse if at lunar apogee. Further, at a half-moon phase, when the angle sun-moon-earth is a right one, the angle

  9. Outreach Testing of Ancient Astronomy

    Science.gov (United States)

    Sanmartin, J. R. S.; Blanco, M. B. M.

    2015-10-01

    fundamental quantity being given by half the difference between solar distances to vertical at winter and summer solstices, with value about 23.5°. Day and year periods greatly differing by about 2 ½ orders of magnitude, 1 day against 365 days, helps students to correctly visualize and interpret the experimental measurements. Since the gnomon serves to observe at night the moon shadow too, students can also determine the inclination of the lunar orbital plane, as about 5 degrees away from the ecliptic, thus explaining why eclipses are infrequent. Independently, earth taking longer between spring and fall equinoxes than from fall to spring (the solar anomaly), as again verified by the students, was explained in ancient Greek science, which posited orbits universally as circles or their combination, by introducing the eccentric circle, with earth placed some distance away from the orbital centre when considering the relative motion of the sun, which would be closer to the earth in winter. In a sense, this can be seen as hint and approximation of the elliptic orbit proposed by Kepler many centuries later. EPSC Abstracts Vol. 10, EPSC2015-40, 2015 European Planetary Science Congress 2015 c Author(s) 2015 EPSC European Planetary Science Congress Secondly, by observing lunar phases and eclipses from the ground, students could also determine, following Aristarchus of Samos in the 3rd century BC, 4 length ratios involving moon and sun distances to earth, and radii of all three, moon, sun, and earth. The angular width of the moon could be first determined with simplest optical devices as about half a degree; this yields the ratio between moon diameter 2RM and distance DM to earth. Next, eclipses of sun prove its angular width, and thus ratio 2RS/DS, similar to the lunar one, though the relatively high lunar orbital eccentricity, 0.055, does result in not quite a full eclipse if at lunar apogee. Further, at a half-moon phase, when the angle sun-moon-earth is a right one, the angle

  10. Post glacial rebounds measure the viscosity of the lithosphere

    CERN Document Server

    Garai, J

    2003-01-01

    The observed higher uplift rates before the end of deglaciation requires the existence of a low viscosity channel or layer. The uplifts observed after the end of deglaciation does not show any contribution from this low viscosity channel and a homogeneous viscosity model fits very well to the observed uplift. Most of the researchers therefore prefer the homogeneous model and suggest that the higher uplift rate before the end of deglaciation is the result of elastic contamination. It has been shown that the elastic deformation of the lithosphere is far too small to be responsible for the observed extra uplift; therefore, the homogeneous viscosity model should be discredited. The homogeneous viscosity of the postglacial period and the high uplift rate of the late glacial period can be explained with a model which has an upper layer determining the homogeneous viscosity and the layer below it which has a low viscosity. The contribution to the uplift of this low viscosity layer is indistinguishable from an instan...

  11. Variations of organic carbon isotopic composition and its environmental significance during the last glacial on western Chinese Loess Plateau

    Institute of Scientific and Technical Information of China (English)

    CHEN Fahu; RAO Zhiguo; ZHANG Jiawu; JIN Ming; MA Jianying

    2006-01-01

    A high-resolution loess section in the western Chinese Loess Plateau, Yuanbao Section,was sampled for organic carbon isotopic analyses.The soil organic carbon isotope (δ13Corg) varied between -22.6‰ and -27.5‰ during the last glacial at the section. During the last interstadial, the δ13Corg values were more negative than those in both early and late periods of the last glacial by 4‰. The isotopic composition indicates a coupled response of the pure C3 plants to the temperature, precipitation and the concentration of atmospheric CO2. Decrease in temperature and the atmospheric CO2 concentration from the last interstadial to Last Glaicial Maximum (LGM) caused the organic carbon isotopes to become positive by 1.5‰-2.0‰. The amplitude of 4‰in the δ13Corg variation during the last glacial should be mainly caused by the precipitation change.Therefore, the δ13Corg variations of the Yuanbao Section during the last glacial period documented the large-amplitude fluctuation of the monsoon precipitation, which is estimated to be 250-310 mm more during the last interstadial than that in the LGM, and 100 mm more than that during early last glacial. The rapid changes of the monsoon precipitation on millennial scale during the last glacial have also been recorded in the isotopic variations in Yuanbao loess section. As the isotopic composition varies complicatedly as shown in the Ioess-paleosol sequence, it cannot be simply attributed to the abundances of C3and C4 plants or be used as an indicator of the summer monsoon variations.

  12. Structural recognition of ancient Chinese ideographic characters

    Institute of Scientific and Technical Information of China (English)

    Li Ning; Chen Dan

    2014-01-01

    Ancient Chinese characters, typically the ideographic characters on bones and bronze before Shang Dynasty (16th—11th century B.C.), are valuable culture legacy of history. However the recognition of Ancient Chinese characters has been the task of paleography experts for long. With the help of modern computer technique, everyone can expect to be able to recognize the characters and understand the ancient inscriptions. This research is aimed to help people recognize and understand those ancient Chinese characters by combining Chinese paleography theory and computer information processing technology. Based on the analysis of ancient character features, a method for structural character recognition is proposed. The important characteristics of strokes and basic components or radicals used in recognition are introduced in detail. A system was implemented based on above method to show the effectiveness of the method.

  13. Effects of glacial/post-glacial weathering compared with hydrothermal alteration - implications for matrix diffusion. Results from drillcore studies in porphyritic quartz monzodiorite from Aespoe SE Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Landstroem, Ove [Studsvik Eco and Safety AB, Nykoeping (Sweden); Tullborg, Eva-Lena [Terralogica AB, Graabo (Sweden); Eriksson, Gunda; Sandell, Yvonne [Studsvik Nuclear AB, Nykoeping (Sweden)

    2001-08-01

    in slight dissolution of these minerals. Quartz and K-feldspar have remained almost unaltered. Besides the thin weathered surface rim, slight alteration of plagioclase and increase in porosity is indicated in the 2-3 cm zone below the surface. Decrease of U and Cs concentrations in this zone is then interpreted as being due to leaching/diffusion processes, confined to the Weichselian glaciation (< 100 ka). The 234U/238U is close to unity indicating bulk leaching of U under oxic conditions. The deposition of U in Ya 1192 and leaching of U from BAS 1 are coeval to quaternary glacial, interstadial and interglacial periods during which the hydrogeological and geochemical conditions changed significantly. A main question in performance assessment is whether oxygenated glacial meltwater can penetrate to repository depth (500 m) and modify the redox conditions. The bedrock surface at BAS 1 has certainly been in contact with glacial meltwater as well as meteoric water, resulting in oxidation/ alteration of pyrite, oxidation/mobilisation of U, and probably also desorption/ mobilisation of Cs. In contrast, no signs of oxygenated glacial meltwater influence were found in the YA 1192 core (170 m depth). In fact, the absence of Fe oxyhydroxide but presence of fresh pyrite in the fracture filling and the altered zone at YA 1192 as well as deposition of U are contradictory to interactions with oxidising glacial meltwater from the late glaciations.

  14. Effects of glacial/post-glacial weathering compared with hydrothermal alteration - implications for matrix diffusion. Results from drillcore studies in porphyritic quartz monzodiorite from Aespoe SE Sweden

    International Nuclear Information System (INIS)

    slight dissolution of these minerals. Quartz and K-feldspar have remained almost unaltered. Besides the thin weathered surface rim, slight alteration of plagioclase and increase in porosity is indicated in the 2-3 cm zone below the surface. Decrease of U and Cs concentrations in this zone is then interpreted as being due to leaching/diffusion processes, confined to the Weichselian glaciation (< 100 ka). The 234U/238U is close to unity indicating bulk leaching of U under oxic conditions. The deposition of U in Ya 1192 and leaching of U from BAS 1 are coeval to quaternary glacial, interstadial and interglacial periods during which the hydrogeological and geochemical conditions changed significantly. A main question in performance assessment is whether oxygenated glacial meltwater can penetrate to repository depth (500 m) and modify the redox conditions. The bedrock surface at BAS 1 has certainly been in contact with glacial meltwater as well as meteoric water, resulting in oxidation/ alteration of pyrite, oxidation/mobilisation of U, and probably also desorption/ mobilisation of Cs. In contrast, no signs of oxygenated glacial meltwater influence were found in the YA 1192 core (170 m depth). In fact, the absence of Fe oxyhydroxide but presence of fresh pyrite in the fracture filling and the altered zone at YA 1192 as well as deposition of U are contradictory to interactions with oxidising glacial meltwater from the late glaciations

  15. Global Inventory of Terrestrial Glacial Megafloods

    Science.gov (United States)

    Baker, V. R.

    2010-12-01

    After centuries of geological controversy it is now well-established that the last major deglaciation of planet Earth involved huge fluxes of water from the wasting continental ice sheets, and that much of this water was delivered as floods of immense magnitude and relatively short duration. These late Quaternary megafloods had short-term peak flows comparable in discharge to the more prolonged fluxes of ocean currents. (The discharges for both ocean currents and megafloods generally exceed one million cubic meters per second, hence the prefix “mega.”) Some outburst floods likely induced very rapid, short-term effects on Quaternary climates. The late Quaternary megafloods also greatly altered drainage evolution and the planetary patterns of water and sediment movement to the oceans. The classic Channeled Scabland region is now seen a but a small component in a source-to-sink system extending from ice-marginal lacustrine (glacial lakes Columbia and Missoula) and possible subglacial sources beneath the Cordilleran Ice Sheet, through the scabland intermediate zone, and on to sink relationships on the abyssal plain of the Pacific Ocean. Other North American glacial megaflood landscapes are now recognized in the Columbia and Snake River drainages of the northwestern U.S.; in the spillway systems of the upper Mississippi Basin; near the Great Lakes and adjacent St. Lawrence Basin; the Hudson River Basin; the Mackenzie Basin; the Yukon Basin (Porcupine River); the Sustina and Copper River Basins (Alaska); and the Hudson Strait. South American megafloods in the Santa Cruz River system (Argentina) emanated from the Patagonian Ice Sheet, and other Patagonian megaflooding probably occurred on the Chilean side. In Eurasia, the megaflooding from the margins of the Fennoscandian Ice Sheet spilled through the English Channel. In the mountain areas of central northern Asia, there were megaflood outbursts from the Issyk-Kul area, the Altai Mountains (upper Ob drainage), and the

  16. Modelling of mineral dust for interglacial and glacial climate conditions with a focus on Antarctica

    Directory of Open Access Journals (Sweden)

    N. Sudarchikova

    2015-05-01

    Full Text Available The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide unique information about deposition of aeolian dust particles transported over long distances. These cores are a palaeoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol–climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission, atmospheric transport and precipitation, which will help to interpret palaeodata from Antarctic ice cores. The investigated periods include four interglacial time slices: the pre-industrial control (CTRL, mid-Holocene (6000 yr BP; hereafter referred to as "6 kyr", last glacial inception (115 000 yr BP; hereafter "115 kyr" and Eemian (126 000 yr BP; hereafter "126 kyr". One glacial time interval, the Last Glacial Maximum (LGM (21 000 yr BP; hereafter "21 kyr", was simulated as well to be a reference test for the model. Results suggest an increase in mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two-thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one-third of the increase in dust deposition. The moderate change in dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times higher

  17. Dust deposition in Antarctica in glacial and interglacial climate conditions: a modelling study

    Directory of Open Access Journals (Sweden)

    N. Sudarchikova

    2014-09-01

    Full Text Available The mineral dust cycle responds to climate variations and plays an important role in the climate system by affecting the radiative balance of the atmosphere and modifying biogeochemistry. Polar ice cores provide a unique information about deposition of aeolian dust particles transported over long distance. These cores are a paleoclimate proxy archive of climate variability thousands of years ago. The current study is a first attempt to simulate past interglacial dust cycles with a global aerosol-climate model ECHAM5-HAM. The results are used to explain the dust deposition changes in Antarctica in terms of quantitative contribution of different processes, such as emission, atmospheric transport and precipitation, which will help to interpret paleodata from Antarctic ice cores. The investigated periods include four interglacial time-slices such as the pre-industrial control (CTRL, mid-Holocene (6000 yr BP, last glacial inception (115 000 yr BP and Eemian (126 000 yr BP. One glacial time interval, which is Last Glacial Maximum (LGM (21 000 yr BP was simulated as well as to be a reference test for the model. Results suggest an increase of mineral dust deposition globally, and in Antarctica, in the past interglacial periods relative to the pre-industrial CTRL simulation. Approximately two thirds of the increase in the mid-Holocene and Eemian is attributed to enhanced Southern Hemisphere dust emissions. Slightly strengthened transport efficiency causes the remaining one third of the increase in dust deposition. The moderate change of dust deposition in Antarctica in the last glacial inception period is caused by the slightly stronger poleward atmospheric transport efficiency compared to the pre-industrial. Maximum dust deposition in Antarctica was simulated for the glacial period. LGM dust deposition in Antarctica is substantially increased due to 2.6 times higher Southern Hemisphere dust emissions, two times stronger atmospheric transport towards

  18. A simple metabolic model of glacial-interglacial energy supply to the upper ocean

    Directory of Open Access Journals (Sweden)

    J. L. Pelegrí

    2011-03-01

    Full Text Available We use a simple two-state two-box ocean to simulate the CO2 signal during the last four glacial-interglacial transitions in the earth system. The model is inspired by the similarity in spatial organization and temporal transition patterns between the earth and other complex systems, such as mammals. The comparison identifies the earth's metabolic rate with net autotrophic primary production in the upper ocean, sustained through new inorganic carbon and nutrients advected from the deep ocean and organic matter remineralized within the upper ocean. We view the glacial-interglacial transition as a switch of the upper ocean from a basal to an enhanced metabolic state, with energy supply initially relying on the remineralization of the local organic sources and the eventual steady state resulting from the increased advective supply of inorganic deep sources. During the interglacial-glacial transition the opposite occurs, with an initial excess of advective supply and primary production that allows the replenishment of the upper-ocean organic storages. We set the relative change in energy supply from the CO2 signal and use genetic algorithms to explore the sensitivity of the model output to both the basal recirculation rate and the intensity-timing of the maximum recirculation rate. The model is capable of reproducing quite well the long-term oscillations, as shown by correlations with observations typically about 0.8. The dominant time scale for each cycle ranges between about 40 and 45 kyr, close to the 41 kyr average obliquity astronomical period, and the deep-ocean recirculation rate increases between one and two orders of magnitude from glacial to interglacial periods.

  19. Ancient and modern environmental DNA

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Winther; Overballe-Petersen, Søren; Ermini, Luca;

    2015-01-01

    DNA obtained from environmental samples such as sediments, ice or water (environmental DNA, eDNA), represents an important source of information on past and present biodiversity. It has revealed an ancient forest in Greenland, extended by several thousand years the survival dates for mainland...... woolly mammoth in Alaska, and pushed back the dates for spruce survival in Scandinavian ice-free refugia during the last glaciation. More recently, eDNA was used to uncover the past 50 000 years of vegetation history in the Arctic, revealing massive vegetation turnover at the Pleistocene....../Holocene transition, with implications for the extinction of megafauna. Furthermore, eDNA can reflect the biodiversity of extant flora and fauna, both qualitatively and quantitatively, allowing detection of rare species. As such, trace studies of plant and vertebrate DNA in the environment have revolutionized our...

  20. Archimedes: Accelerator Reveals Ancient Text

    International Nuclear Information System (INIS)

    Archimedes (287-212 BC), who is famous for shouting 'Eureka' (I found it) is considered one of the most brilliant thinkers of all times. The 10th-century parchment document known as the 'Archimedes Palimpsest' is the unique source for two of the great Greek's treatises. Some of the writings, hidden under gold forgeries, have recently been revealed at the Stanford Synchrotron Radiation Laboratory at SLAC. An intense x-ray beam produced in a particle accelerator causes the iron in original ink, which has been partly erased and covered, to send out a fluorescence glow. A detector records the signal and a digital image showing the ancient writings is produced. Please join us in this fascinating journey of a 1,000-year-old parchment from its origin in the Mediterranean city of Constantinople to a particle accelerator in Menlo Park.

  1. Ancient Acupuncture Literature on Apoplexy

    Institute of Scientific and Technical Information of China (English)

    XU Yi-zeng; BI Zhen; Xiao Yuan-chun

    2003-01-01

    This paper reviews twenty-eight Chinese medicine books with complete prescriptions prior to the Qing Dynasty, and analyzes the characteristics of acupoint selection and needling manipulations from the perspective of apoplectic symptoms. It is concluded that,in ancient times, apoplexy is often treated on the basis of its symptoms and a great number of acupoints are employed; hemiplegia is mainly treated by the acupoints of the Large Intestine Meridian and Gallbladder Meridian,with two key acupoints; coma is mainly treated by first-aid acupoints and qi-supplementing acupoints, with seven key acupoints; wry mouth and convulsion are mainly treated by the local acupoints; as for needling manipulations, moxibustion with moxa cones is principally used, while needling is less used.

  2. Stress evolution and fault stability during the Weichselian glacial cycle

    International Nuclear Information System (INIS)

    In this report we examine how the waxing and waning of an ice sheet during a glacial cycle affects the state of stress in the Earth, and how those changes in stress influence the stability of faults. We focus on the stresses at repository depth in Forsmark and Oskarshamn, and on the stability field at seismogenic depth at the proposed repository sites and at the Paervie endglacial fault in northern Sweden. This study is a modelling study, where we use three-dimensional ice and earth models to calculate the glacial isostatic adjustment (GIA), i.e. the response of the Earth to an ice load, examining both displacements and stresses. We use a flat-earth finite element approach, based on Wu with some modifications. The result presented here is a continuation of previous studies in two dimensions and complement those studies in assessing how the three-dimensionality of the problem affects the conclusions. We use the Fennoscandian ice model of Naeslund, which is a dynamic ice sheet model based on climate reconstructions with constraints from geological observations. The ice model spans the entire Weichselian glaciation but we only use the last 68 kyr, which includes the two major periods of ice cover as depicted in this ice sheet reconstruction. For the GIA calculation we use a number of different earth models, both with flat horizontal layers and with various 3D structures of lithosphere thickness. We do not include lateral variations in the viscosity of the mantle. Comparing the current day rebound velocities predicted by our models with GPS observations from the BIFROST project, we note that in general, we can obtain a reasonable fit to the observations with our models, and that the results are rather sensitive to the assumed viscosity of the mantle. We also find that the differences between data and model results, for all earth models, have common features which we interpret as due to the ice model. These observations are in agreement with numerous other GIA studies

  3. Stress evolution and fault stability during the Weichselian glacial cycle

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Bjoern; Schmidt, Peter; Hieronymus, Christoph (Dept. of Earth Sciences, Uppsala Univ., Uppsala (Sweden))

    2009-10-15

    In this report we examine how the waxing and waning of an ice sheet during a glacial cycle affects the state of stress in the Earth, and how those changes in stress influence the stability of faults. We focus on the stresses at repository depth in Forsmark and Oskarshamn, and on the stability field at seismogenic depth at the proposed repository sites and at the Paervie endglacial fault in northern Sweden. This study is a modelling study, where we use 3-dimensional ice and earth models to calculate the glacial isostatic adjustment (GIA), i.e. the response of the Earth to an ice load, examining both displacements and stresses. We use a flat-earth finite element approach, based on Wu with some modifications. The result presented here is a continuation of previous studies in 2 dimensions and complement those studies in assessing how the 3-dimensionality of the problem affects the conclusions. We use the Fennoscandian ice model of Naeslund, which is a dynamic ice sheet model based on climate reconstructions with constraints from geological observations. The ice model spans the entire Weichselian glaciation but we only use the last 68 kyr, which includes the 2 major periods of ice cover as depicted in this ice sheet reconstruction. For the GIA calculation we use a number of different earth models, both with flat horizontal layers and with various 3D structures of lithosphere thickness. We don't include lateral variations in the viscosity of the mantle. Comparing the current day rebound velocities predicted by our models with GPS observations from the BIFROST project, we note that in general, we can obtain a reasonable fit to the observations with our models, and that the results are rather sensitive to the assumed viscosity of the mantle. We find that the differences between data and model results, for all earth models, have common features which we interpret as due to the ice model. These observations are in agreement with numerous other GIA studies. Our flat

  4. Numerical simulation of Glacial Isostatic Adjustment

    Science.gov (United States)

    Miglio, E.

    2015-12-01

    In the Earth's crust, stress can be subdivided into tectonic background stress, overburden pressure, and pore-fluid pressure. The superposition of the first two and the variation of the third part are key factors in controlling movement along faults. Furthermore, stresses due to sedimentation and erosion contribute to the total stress field. In deglaciated regions, an additional stress must be considered: the rebound stress, which is related to rebounding of the crust and mantle after deglaciation. During the growth of a continental ice sheet, the lithosphere under the iceload is deformed and the removal of the ice load during deglaciation initiates a rebound process. The uplift is well known in formerly glaciated areas, e.g.North America and Scandinavia, and in currently deglaciating areas, e.g.Alaska, Antarctica, and Greenland. The whole process of subsiding and uplifting during the growth and melting of an iceload and all related phenomena is known as glacial isostatic adjustment. During the process of glaciation, the surface of the lithosphere is depressed underneath the ice load and compressional flexural stresses are induced in the upper lithosphere, whereas the bottom of the lithosphere experiences extensional flexural stresses; an additional vertical stress due to the ice load is present and it decreases to zero during deglaciation. During rebound, flexural stresses relax slowly. These stresses are able to change the original stress directions and regime.In this work we aim to study the effect of the GIA process in the context of petroleum engineering. The main aspect we will focus on is the mathematical and numerical modeling of the GIA including thermal effects. We plan also to include a preliminary study of the effect of the glacial erosion. All these phenomena are of paramount importance in petroleum engineering: for example some reservoir have been depleted due to tilting caused by both GIA, erosion and thermal effects.

  5. Urban wastewater and stormwater technologies in ancient Greece.

    Science.gov (United States)

    Angelakis, A N; Koutsoyiannis, D; Tchobanoglous, G

    2005-01-01

    The status of urban sewerage and stormwater drainage systems in ancient Greece is reviewed, based on the results of archaeological studies of the 20th century. Emphasis is given to the construction, operation, and management of sewerage and stormwater drainage systems during the Minoan period (2nd millennium B.C.). The achievements of this period in dealing with the hygienic and the functional requirements of palaces and cities, were so advanced that they can only be compared to modern urban water systems, developed in Europe and North America in the second half of the 19th century A.D. The advanced Minoan technologies were exported to all parts of Greece in later periods of the Greek civilization, i.e. in Mycenaean, Archaic, Classical, and Hellenistic periods. PMID:15607179

  6. Mummification in the Ancient and New World.

    Science.gov (United States)

    Rosso, Ana Maria

    2014-01-01

    In the Ancient and New World there was a custom to preserve the corpse in a natural and artificial way. Since Paleolithic man believed in an afterlife and even in Mesoamerica and the Andes cultures, care and ceremony were practiced to the burial of the dead in an ancestral cult. Mortuary rituals were developed in Pre-dynastic Egypt (4500-3100 BC) but apparently they had begun before in America, c. 5000 BC. Mummies served for assisting the soul to survive and for preventing the dead from frightening the livings. Incas arrived at a point of perfection in these practices after other Andean cultures but we should not forget their older predecessors, the Chinchorro culture on the arid coast of the Atacama Desert. Different steps in the technique can be distinguished in both worlds: natural desiccation covered by animal skins, methods to protect the body skin and flesh removal, replacement with clay; black, red or mud-coated corpses, evisceration, body cavity treatment, cleansing and anointing the interior, brain removal, mummified bodies, corpses covered with natron, before being washed and bandaged or wrapped. It will be necessary to carefully check dates, techniques and periods in the two zones to establish exactly the evolution of the methods applied. PMID:25811691

  7. Cases of Trephination in Ancient Greek Skulls

    Directory of Open Access Journals (Sweden)

    Vasiliki Ζafiri

    2012-01-01

    Full Text Available Background: Trephination, or trepanning, is considered to be one of the most ancient surgical operations with an especially extensive geographical incidence, both in the New World and in the Old. In Europe, more than 200 finds of trephination have been found, from Scandinavia to the Balkans. The technique of trephination or trepanning covers overall the last 10,000 years and exhibits great versatility and adjustability in the knowledge, technical means, therapeutic needs, prejudices and social standards of each period and of each population group. Hippocrates was the one to classify for the first time the kinds of cranial fractures and define the conditions and circumstances for carrying out a trepanning.Aim: The present research aims to investigate the Greek cranial trephinations on sculls from the collection of the Anthropological Museum of the Medical School of Athens that come from archaeological excavations.Method: Skulls were examined by macroscopic observation with reflective light. Furthermore, radiographic representation of the skulls was used.Results: The anthropological researches and the studies of anthropological skeleton remains that came out during archaeological excavations from different eras and areas have given information about the medical practices in the very important geographic area of Greece and in particular, we referred to cases of Greek trephinations.

  8. [Treatment for dystocia in ancient China].

    Science.gov (United States)

    Zhang, Lu

    2012-05-01

    Treatment for dystocia in ancient China includes delivery taboo, delivery promotion decoction and midwifery methods. Before the Sui and Tang dynasties, delivery was more like a rite. In the Sui and Tang dynasties, doctors began to understand dystocia from the physical condition, delivery environment and psychological factors, and the delivery taboo was rejected. After that period, the delivery taboo became a folk custom and was separated from the field of medicine. The herbs for delivery promotion decoctions usually used the principle of regulating the blood and removing stasis and were of slippery character during and before the Tang dynasty. In the Song dynasty promotion decoction was enlarged. In later ages some doctors put forward that emphasis should be on conformity to nature and nursing, not dependence on promotion drugs. Before and during the Tang dynasty, acupuncture and salt smearing had been key methods for abnormal fetal position and there were also case recordings. In the Northern Song dynasty, these two methods were no longer used and the midwife's skill was emphasized. With more and more focus on the midwife's skill, some male doctors depended on midwives and some criticism of midwives also increased. The book Dashengbian reflected maximum distrust of midwives. PMID:22883377

  9. Performance Analysis of Random Forests with SVM and KNN in Classification of Ancient Kannada Scripts

    Directory of Open Access Journals (Sweden)

    Soumya A

    2014-07-01

    Full Text Available Ancient inscriptions which reveal the details of yester years are difficult to interpret by modern readers and efforts are being made in automating such tasks of deciphering historical records. The Kannada script which is used to write in Kannada language has gradually evolved from the ancient script known as Brahmi. Kannada script has traveled a long way from the earlier Brahmi model and has undergone a number of changes during the regimes of Ashoka, Shatavahana, Kadamba, Ganga, Rashtrakuta, Chalukya, Hoysala , Vijayanagara and  Wodeyar dynasties.  In this paper we discuss on Classification of ancient Kannada Scripts during three different periods Ashoka, Kadamba and Satavahana. A reconstructed grayscale ancient Kannada epigraph image is input, which is binarized using Otsu’s method. Normalized Central and Zernike Moment features are extracted for classification. The RF Classifier designed is tested on handwritten base characters belonging to Ashoka, Satavahana and Kadamba dynasties. For each dynasty, 105 handwritten samples with 35 base characters are considered. The classification rates for the training and testing base characters from Satavahana period, for varying number of trees and thresholds of RF are determined. Finally a Comparative analysis of the Classification rates is made for the designed RF with SVM and k-NN classifiers, for the ancient Kannada base characters from 3 different eras Ashoka, Kadamba and Satavahana period.

  10. Differential resilience of ancient sister lakes Ohrid and Prespa to environmental disturbances during the Late Pleistocene

    Science.gov (United States)

    Jovanovska, Elena; Cvetkoska, Aleksandra; Hauffe, Torsten; Levkov, Zlatko; Wagner, Bernd; Sulpizio, Roberto; Francke, Alexander; Albrecht, Christian; Wilke, Thomas

    2016-02-01

    Ancient lakes, such as lakes Ohrid and Prespa on the Balkan Peninsula, have become model systems for studying the link between geological and biotic evolution. Recently, the scientific deep-drilling project Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) was initiated to better understand the environmental, climatic, and limnological evolution of the lake. It revealed that Lake Ohrid experienced a number of environmental disturbances during its ca. 2.0 million year long history. These are comprised of disturbances that lasted over longer periods of time ("press events") such as glacial-interglacial cycles and Heinrich events, as well as sudden and short disturbances ("pulse events") like the deposition of landslides, earthquakes, and volcanic ash depositions. The latter includes one of the most severe volcanic episodes during the Late Pleistocene: the eruption of the Campanian Ignimbrite (known as Y-5 marine tephra layer) from the Campi Flegrei caldera, dated to 39.6 ± 0.1 thousand years ago. The event is recorded by the deposition of a ca. 15 cm thick tephra layer in sediment cores of lakes Ohrid (DEEP-5045-1) and Prespa (Co1204). Coincidently, this pulse event is superimposed by the Heinrich H4 event, 40.4-38.4 thousand years ago. In the current paper, diatoms were used as proxies to compare the responses of these lakes to the Y-5 (pulse) and the H4 (press) disturbances. Based on stratigraphically constrained incremental sum of squares cluster (CONISS) and unconstrained Partitioning Around Medoids (PAM) analyses, we found little evidence that diatom community compositions in either lake responded to the H4 event. However, the Y-5 influx caused clear and rapid diatom community changes. After the initial response, community compositions in Lake Ohrid and, to a lesser extent, in Lake Prespa slowly returned to their quasi pre-disturbance state. Moreover, there is no evidence for disturbance-related extinction events. The combined

  11. Glacial and periglacial buzzsaws: fitting mechanisms to metaphors

    Science.gov (United States)

    Hall, Adrian M.; Kleman, Johan

    2014-03-01

    The buzzsaw hypothesis refers to the potential for glacial and periglacial processes to rapidly denude mountains at and above glacier Equilibrium Line Altitudes (ELAs), irrespective of uplift rates, rock type or pre-existing topography. Here the appropriateness of the buzzsaw metaphor is examined alongside questions of the links between glacial erosion and ELAs, and whether the glacial system can produce low-relief surfaces or limit summit heights. Plateau fragments in mountains on both active orogens and passive margins that have been cited as products of glacial and periglacial buzzsaw erosion instead generally represent dissected remnants of largely inherited, pre-glacial relief. Summit heights may correlate with ELAs but no causal link need be implied as summit erosion rates are low, cirque headwalls may not directly abut summits and, on passive margins, cirques are cut into pre-existing mountain topography. Any simple links between ELAs and glacial erosion break down on passive margins due to topographic forcing of ice-sheet growth, and to the km-scale vertical swaths through which ELAs have shifted through the Quaternary. Glaciers destroy rather than create low-relief rock surfaces through the innate tendency for ice flow to be faster, thicker and warmer along valleys. The glacial buzzsaw cuts down.

  12. [Medicine in ancient Mesopotamia--part 1].

    Science.gov (United States)

    Martins E Silva, J

    2009-01-01

    , would give a final decision about the disease or the future. Separated this more occult facet, nourished in religious faiths and in the magic, the medicine of Ancient Mesopotamia included rational knowledge, certainly as the result of a systematic patients observation and semiotic interpretation. From those observations and knowledge referred to the Sumerian period, carefully logged, refined and transmitted to the following generations, a valuable collection of texts was built with the description of symptoms, signs, diagnosis and prognostic of the most common diseases, still identifiable in the present. PMID:20350469

  13. Different ocean states and transient characteristics in Last Glacial Maximum simulations and implications for deglaciation

    Directory of Open Access Journals (Sweden)

    X. Zhang

    2013-10-01

    Full Text Available The last deglaciation is one of the best constrained global-scale climate changes documented by climate archives. Nevertheless, understanding of the underlying dynamics is still limited, especially with respect to abrupt climate shifts and associated changes in the Atlantic meridional overturning circulation (AMOC during glacial and deglacial periods. A fundamental issue is how to obtain an appropriate climate state at the Last Glacial Maximum (LGM, 21 000 yr before present, 21 ka BP that can be used as an initial condition for deglaciation. With the aid of a comprehensive climate model, we found that initial ocean states play an important role on the equilibrium timescale of the simulated glacial ocean. Independent of the initialization, the climatological surface characteristics are similar and quasi-stationary, even when trends in the deep ocean are still significant, which provides an explanation for the large spread of simulated LGM ocean states among the Paleoclimate Modeling Intercomparison Project phase 2 (PMIP2 models. Accordingly, we emphasize that caution must be taken when alleged quasi-stationary states, inferred on the basis of surface properties, are used as a reference for both model inter-comparison and data model comparison. The simulated ocean state with the most realistic AMOC is characterized by a pronounced vertical stratification, in line with reconstructions. Hosing experiments further suggest that the response of the glacial ocean is dependent on the ocean background state, i.e. only the state with robust stratification shows an overshoot behavior in the North Atlantic. We propose that the salinity stratification represents a key control on the AMOC pattern and its transient response to perturbations. Furthermore, additional experiments suggest that the stratified deep ocean formed prior to the LGM during a time of minimum obliquity (~ 27 ka BP. This indicates that changes in the glacial deep ocean already occur before

  14. Geologically ancient DNA: fact or artefact?

    DEFF Research Database (Denmark)

    Hebsgaard, Martin Bay; Phillips, Matthew J.; Willerslev, Eske

    2005-01-01

    Studies continue to report ancient DNA sequences and viable microbial cells that are many millions of years old. In this paper we evaluate some of the most extravagant claims of geologically ancient DNA. We conclude that although exciting, the reports suffer from inadequate experimental setup and...... insufficient authentication of results. Consequently, it remains doubtful whether amplifiable DNA sequences and viable bacteria can survive over geological timescales. To enhance the credibility of future studies and assist in discarding false-positive results, we propose a rigorous set of authentication...... criteria for work with geologically ancient DNA....

  15. Inland post-glacial dispersal in East Asia revealed by mitochondrial haplogroup M9a'b

    Directory of Open Access Journals (Sweden)

    Wang Wen-Zhi

    2011-01-01

    Full Text Available Abstract Background Archaeological studies have revealed a series of cultural changes around the Last Glacial Maximum in East Asia; whether these changes left any signatures in the gene pool of East Asians remains poorly indicated. To achieve deeper insights into the demographic history of modern humans in East Asia around the Last Glacial Maximum, we extensively analyzed mitochondrial DNA haplogroup M9a'b, a specific haplogroup that was suggested to have some potential for tracing the migration around the Last Glacial Maximum in East Eurasia. Results A total of 837 M9a'b mitochondrial DNAs (583 from the literature, while the remaining 254 were newly collected in this study pinpointed from over 28,000 subjects residing across East Eurasia were studied here. Fifty-nine representative samples were further selected for total mitochondrial DNA sequencing so we could better understand the phylogeny within M9a'b. Based on the updated phylogeny, an extensive phylogeographic analysis was carried out to reveal the differentiation of haplogroup M9a'b and to reconstruct the dispersal histories. Conclusions Our results indicated that southern China and/or Southeast Asia likely served as the source of some post-Last Glacial Maximum dispersal(s. The detailed dissection of haplogroup M9a'b revealed the existence of an inland dispersal in mainland East Asia during the post-glacial period. It was this dispersal that expanded not only to western China but also to northeast India and the south Himalaya region. A similar phylogeographic distribution pattern was also observed for haplogroup F1c, thus substantiating our proposition. This inland post-glacial dispersal was in agreement with the spread of the Mesolithic culture originating in South China and northern Vietnam.

  16. Multiple Glacial Refugia of the Low-Dispersal Ground Beetle Carabus irregularis: Molecular Data Support Predictions of Species Distribution Models

    Science.gov (United States)

    Homburg, Katharina; Drees, Claudia; Gossner, Martin M.; Rakosy, László; Vrezec, Al; Assmann, Thorsten

    2013-01-01

    Classical glacial refugia such as the southern European peninsulas were important for species survival during glacial periods and acted as sources of post-glacial colonisation processes. Only recently, some studies have provided evidence for glacial refugia north of the southern European peninsulas. In the present study, we combined species distribution models (SDMs) with phylogeographic analyses (using mitochondrial DNA = mtDNA) to investigate if the cold-adapted, stenotopic and flightless ground beetle species, Carabus irregularis, survived the Last Glacial Maximum (LGM) in classical and/or other refugia. SDMs (for both a western European and for a Carpathian subgroup) were calculated with MAXENT on the basis of 645 species records to predict current and past distribution patterns. Two mtDNA loci (CO1 and ND5, concatenated sequence length: 1785 bp) were analyzed from 91 C. irregularis specimens to reconstruct the phylogeography of Central and eastern European populations and to estimate divergence times of the given lineages. Strong intra-specific genetic differentiation (inter-clade ΦST values ranged from 0.92 to 0.99) implied long-term isolation of major clades and subsclades. The high divergence between the nominate subspecies and the Carpathian subspecies C. i. montandoni points to two independent species rather than subspecies (K-2P distance 0.042 ± 0.004; supposed divergence of the maternal lineages dated back 1.6 to 2.5 million years BP) differing not only morphologically but also genetically and ecologically from each other. The SDMs also inferred classical as well as other refugia for C. irregularis, especially north of the Alps, in southeastern Europe and in the Carpathians. The coincidences between the results of both methods confirm the assumption of multiple glacial refugia for the studied species and the usefulness of combining methodological approaches for the understanding of the history of low-dispersal insect species. PMID:23593425

  17. Signatures of Glacial Erosion and Retreat in the Landscape: Cosmogenic and Numerical Modeling Constraints

    Science.gov (United States)

    Ward, D. J.; Anderson, R. S.; Briner, J. P.; Guido, Z. S.

    2007-12-01

    We use cosmogenic radionuclide (CRN) exposure ages to constrain numerical simulations of deglaciation histories in the Middle Boulder Creek drainage, Colorado Front Range, and the Animas River valley, San Juan Mountains, Colorado. We present 18 new 10Be exposure ages from glacially polished bedrock sampled in the Middle Boulder Creek valley. All of these ages are younger than the ~19-22 ka terminal moraine age based on 26Al and 36Cl measurements by Schildgen (2000) and Benson et al. (2005). Exposure ages decrease with distance upvalley from the moraine, and the youngest ages in the uppermost valley are uniformly ~13 ka. We include 4 10Be ages in a cross section across the mid-valley, which show a pattern of Last Glacial Maximum (LGM) ages (12-14 ka) within the glacial footprint, and older exposure ages (~40 ka) near the trim lines. A similar age trend is seen in the Animas River valley in southwestern Colorado, which was occupied by a lobe of the LGM ice sheet that capped the San Juan mountains. Deglaciation began here ca. 19.4 ka, based on a 10Be depth profile in a proglacial terrace. A longitudinal transect of exposure ages from glacially polished samples indicates that terminus retreat proceeded at ~15 m/yr until complete deglaciation ca. 12.3 ka. Neither valley has obvious recessional deposits within the LGM glacial footprint. The first-order trend in each valley is a monotonic glacial retreat, but there are other possible retreat scenarios. For instance, we would like to test whether the same trend in 10Be concentrations could be generated by episodic retreat punctuated by periods of readvance. To investigate these scenarios, we modified the GC2D numerical glacier simulation (see Kessler et al., 2006) to incorporate a CRN accumulation layer. This layer can contain any starting value of CRN concentration. Production over each timestep is scaled to DEM latitude and altitude. Production is taken to be zero in areas covered by more than 10 m of ice. The CRN

  18. Oxygen depletion recorded in upper waters of the glacial Southern Ocean

    Science.gov (United States)

    Lu, Zunli; Hoogakker, Babette A. A.; Hillenbrand, Claus-Dieter; Zhou, Xiaoli; Thomas, Ellen; Gutchess, Kristina M.; Lu, Wanyi; Jones, Luke; Rickaby, Rosalind E. M.

    2016-03-01

    Oxygen depletion in the upper ocean is commonly associated with poor ventilation and storage of respired carbon, potentially linked to atmospheric CO2 levels. Iodine to calcium ratios (I/Ca) in recent planktonic foraminifera suggest that values less than ~2.5 μmol mol-1 indicate the presence of O2-depleted water. Here we apply this proxy to estimate past dissolved oxygen concentrations in the near surface waters of the currently well-oxygenated Southern Ocean, which played a critical role in carbon sequestration during glacial times. A down-core planktonic I/Ca record from south of the Antarctic Polar Front (APF) suggests that minimum O2 concentrations in the upper ocean fell below 70 μmol kg-1 during the last two glacial periods, indicating persistent glacial O2 depletion at the heart of the carbon engine of the Earth's climate system. These new estimates of past ocean oxygenation variability may assist in resolving mechanisms responsible for the much-debated ice-age atmospheric CO2 decline.

  19. Oxygen depletion recorded in upper waters of the glacial Southern Ocean.

    Science.gov (United States)

    Lu, Zunli; Hoogakker, Babette A A; Hillenbrand, Claus-Dieter; Zhou, Xiaoli; Thomas, Ellen; Gutchess, Kristina M; Lu, Wanyi; Jones, Luke; Rickaby, Rosalind E M

    2016-01-01

    Oxygen depletion in the upper ocean is commonly associated with poor ventilation and storage of respired carbon, potentially linked to atmospheric CO2 levels. Iodine to calcium ratios (I/Ca) in recent planktonic foraminifera suggest that values less than ∼2.5 μmol mol(-1) indicate the presence of O2-depleted water. Here we apply this proxy to estimate past dissolved oxygen concentrations in the near surface waters of the currently well-oxygenated Southern Ocean, which played a critical role in carbon sequestration during glacial times. A down-core planktonic I/Ca record from south of the Antarctic Polar Front (APF) suggests that minimum O2 concentrations in the upper ocean fell below 70 μmol kg(-1) during the last two glacial periods, indicating persistent glacial O2 depletion at the heart of the carbon engine of the Earth's climate system. These new estimates of past ocean oxygenation variability may assist in resolving mechanisms responsible for the much-debated ice-age atmospheric CO2 decline. PMID:27029225

  20. Mitochondrial DNA Signals of Late Glacial Recolonization of Europe from Near Eastern Refugia

    Science.gov (United States)

    Pala, Maria; Olivieri, Anna; Achilli, Alessandro; Accetturo, Matteo; Metspalu, Ene; Reidla, Maere; Tamm, Erika; Karmin, Monika; Reisberg, Tuuli; Kashani, Baharak Hooshiar; Perego, Ugo A.; Carossa, Valeria; Gandini, Francesca; Pereira, Joana B.; Soares, Pedro; Angerhofer, Norman; Rychkov, Sergei; Al-Zahery, Nadia; Carelli, Valerio; Sanati, Mohammad Hossein; Houshmand, Massoud; Hatina, Jiři; Macaulay, Vincent; Pereira, Luísa; Woodward, Scott R.; Davies, William; Gamble, Clive; Baird, Douglas; Semino, Ornella; Villems, Richard; Torroni, Antonio; Richards, Martin B.

    2012-01-01

    Human populations, along with those of many other species, are thought to have contracted into a number of refuge areas at the height of the last Ice Age. European populations are believed to be, to a large extent, the descendants of the inhabitants of these refugia, and some extant mtDNA lineages can be traced to refugia in Franco-Cantabria (haplogroups H1, H3, V, and U5b1), the Italian Peninsula (U5b3), and the East European Plain (U4 and U5a). Parts of the Near East, such as the Levant, were also continuously inhabited throughout the Last Glacial Maximum, but unlike western and eastern Europe, no archaeological or genetic evidence for Late Glacial expansions into Europe from the Near East has hitherto been discovered. Here we report, on the basis of an enlarged whole-genome mitochondrial database, that a substantial, perhaps predominant, signal from mitochondrial haplogroups J and T, previously thought to have spread primarily from the Near East into Europe with the Neolithic population, may in fact reflect dispersals during the Late Glacial period, ∼19–12 thousand years (ka) ago. PMID:22560092

  1. Glacial lake deltas in New England record continuous, not delayed, postglacial rebound

    Science.gov (United States)

    Hooke, Roger LeBaron; Ridge, John Charles

    2016-05-01

    Deltas formed in Lake Hitchcock, a glacial lake that developed in the Connecticut River Valley, New England, between ∼18.3 and 12.5 ka. The heights of topset/foreset contacts of these deltas presently increase northward, linearly, at rate of ∼0.9 m/km. Others have interpreted this as indicating that isostatic rebound did not begin until after the lake drained, several kiloyears after glacial retreat began. However, (non-elastic) adjustment of Earth's lithosphere to changing loads is known to occur on time scales of years. Late-glacial shoreline features elsewhere in New England also increase in elevation with distance from the LGM margin at ∼0.9 m/km, suggesting that this is a result of fundamental properties of the crust and mantle, and independent of the history of glacier retreat. On the basis of a numerical model of flexure of the lithosphere beneath a circular load, we suggest that deflection of the lithosphere is remarkably linear in a zone 50-200 km wide between the retreating ice margin and a forebulge, and that initial rebound of this zone is spatially quite uniform for some kiloyears before differential rebound starts. Thus, lake shorelines, formed over a period of some centuries during deglaciation would, today, rise linearly northward.

  2. The role of orbital forcing, carbon dioxide and regolith in 100 kyr glacial cycles

    Directory of Open Access Journals (Sweden)

    A. Ganopolski

    2011-12-01

    Full Text Available The origin of the 100 kyr cyclicity, which dominates ice volume variations and other climate records over the past million years, remains debatable. Here, using a comprehensive Earth system model of intermediate complexity, we demonstrate that both strong 100 kyr periodicity in the ice volume variations and the timing of glacial terminations during past 800 kyr can be successfully simulated as direct, strongly nonlinear responses of the climate-cryosphere system to orbital forcing alone, if the atmospheric CO2 concentration stays below its typical interglacial value. The existence of long glacial cycles is primarily attributed to the North American ice sheet and requires the presence of a large continental area with exposed rocks. We show that the sharp, 100 kyr peak in the power spectrum of ice volume results from the long glacial cycles being synchronized with the Earth's orbital eccentricity. Although 100 kyr cyclicity can be simulated with a constant CO2 concentration, temporal variability in the CO2 concentration plays an important role in the amplification of the 100 kyr cycles.

  3. Numerical modelling of iceberg calving force responsible for glacial earthquakes

    Science.gov (United States)

    Sergeant, Amandine; Yastrebov, Vladislav; Castelnau, Olivier; Mangeney, Anne; Stutzmann, Eleonore; Montagner, Jean-Paul

    2016-04-01

    Glacial earthquakes is a class of seismic events of magnitude up to 5, occurring primarily in Greenland, in the margins of large marine-terminated glaciers with near-grounded termini. They are caused by calving of cubic-kilometer scale unstable icebergs which penetrate the full-glacier thickness and, driven by the buoyancy forces, capsize against the calving front. These phenomena produce seismic energy including surface waves with dominant energy between 10-150 s of period whose seismogenic source is compatible with the contact force exerted on the terminus by the iceberg while it capsizes. A reverse motion and posterior rebound of the terminus have also been measured and associated with the fluctuation of this contact force. Using a finite element model of iceberg and glacier terminus coupled with simplified fluid-structure interaction model, we simulate calving and capsize of icebergs. Contact and frictional forces are measured on the terminus and compared with laboratory experiments. We also study the influence of geometric factors on the force history, amplitude and duration at the laboratory and field scales. We show first insights into the force and the generated seismic waves exploring different scenarios for iceberg capsizing.

  4. The Last Glacial Maximum experiment in PMIP4-CMIP6

    Science.gov (United States)

    Kageyama, Masa; Braconnot, Pascale; Abe-Ouchi, Ayako; Harrison, Sandy; Lambert, Fabrice; Peltier, W. Richard; Tarasov, Lev

    2016-04-01

    The Last Glacial Maximum (LGM), around 21,000 years ago, is a cold climate extreme. As such, it has been the focus of many studies on modelling and climate reconstruction, which have brought knowledge on the mechanisms explaining this climate, in terms of climate on the continents and of the ocean state, and in terms relationships between climate changes over land, ice sheets and oceans. It is still a challenge for climate or Earth System models to represent the amplitude of climate changes for this period, under the following forcings: - Ice sheets, which represent perturbations in land surface type, altitude and land/ocean distribution - Atmospheric composition - Astronomical parameters Feedbacks from the vegetation and dust are also known to have played a role in setting up the LGM climate but have not been accounted for in previous PMIP experiments. In this poster, we will present the experimental set-up of the PMIP4 LGM experiment, which is presently being discussed and will be finalized for March 2016. For more information and discussion of the PMIP4-CMIP6 experimental design, please visit: https://wiki.lsce.ipsl.fr/pmip3/doku.php/pmip3:cmip6:design:index

  5. 'Ancient episteme' and the nature of fossils: a correction of a modern scholarly error.

    Science.gov (United States)

    Jordan, J M

    2016-04-01

    Beginning the nineteenth-century and continuing down to the present, many authors writing on the history of geology and paleontology have attributed the theory that fossils were inorganic formations produced within the earth, rather than by the deposition of living organisms, to the ancient Greeks and Romans. Some have even gone so far as to claim this was the consensus view in the classical period up through the Middle Ages. In fact, such a notion was entirely foreign to ancient and medieval thought and only appeared within the manifold of 'Renaissance episteme,' the characteristics of which have often been projected backwards by some historians onto earlier periods. This paper endeavors to correct this error, explain the development of the Renaissance view, describe certain ancient precedents thereof, and trace the history of the misinterpretation in the literature. PMID:26797724

  6. Glacial-interglacial variation in denudation rates from interior Texas, USA, established with cosmogenic nuclides

    Science.gov (United States)

    Hidy, Alan J.; Gosse, John C.; Blum, Michael D.; Gibling, Martin R.

    2014-03-01

    The Brazos, Colorado, and Trinity rivers of Texas drain a tectonically quiescent, non-glaciated, and low-relief landscape inland from the Gulf of Mexico, where long-term [103-105 a] changes in denudation rates are probably driven largely by climate change. Here, we use cosmogenic 10Be to obtain spatially averaged denudation rates for these river catchments, primarily from terrace deposits associated with glacial or interglacial intervals over the past half million years. The denudation rates are ∼30-35% higher during interglacial periods than during glacial periods, and correlate broadly with temperature. The results are consistent with predictions from the BQART sediment flux model, and support the hypothesis that increased weathering rates associated with warmer climates will accelerate landscape erosion. Furthermore, by analyzing 26Al/10Be in these deposits, we can estimate the bed load sourced from up-catchment surfaces. The stored coastal plain fraction varies from ∼10% to 30%, and is greater during times of relatively lower sea level. The results indicate that although sediment flux is moderated by coastal-plain storage, increased up-catchment flux during warmer interglacial periods outpaces evacuation of stored sediment during glacial periods, resulting in a net increase in sediment flux to the ocean during warm intervals. If this temperature-sediment flux relationship is valid beyond the Plio-Pleistocene transition, then global sediment flux to the ocean from passive, non-glaciated, and low-relief landscapes would have been greater during the Pliocene than in the cooler Quaternary.

  7. Accounting And Forms Of Accountability In Ancient Civilizations: Mesopotamia And Ancient Egypt

    OpenAIRE

    SALVADOR CARMONA

    2005-01-01

    The aim of this paper is to identify the relevance and implications of ancient accounting practices to the contemporary theorizing of accounting. The paper provides a synthesis of the literature on ancient accounting particularly in relation to issues of human accountability, identifies its major achievements and outlines some of the key challenges facing researchers. We argue that far from being an idiosyncratic research field of marginal interest, research in ancient accounting is a rich an...

  8. The colour of Sirius as recorded in ancient Chinese texts

    Science.gov (United States)

    Jiang, Xiao-yuan

    1993-04-01

    At present, Sirius is white, but in the West there has long existed a succession of records purporting that the star is red, which would mean difficulty for the current theory of stellar evolution. In this paper I have systematically examined the more reliable records regarding the colour of Sirius in extant ancient Chinese texts from B. C. times to the + 7th century and found that, during this period, Sirius was unquestionably white, thus relieving the present theory of stellar evolution of any threat from this direction.

  9. The eye and its diseases in Ancient Egypt.

    Science.gov (United States)

    Andersen, S R

    1997-06-01

    Based on a study of mummies, skeletons, burial rites, medical instruments, medicaments, literature and objets d'art from Ancient Egypt before the Hellenistic Period, the understanding of the eye, its diseases and their treatment at that time is described. Magic spells, religious rites and medical treatments, especially with eye ointments, were probably used often complementary to one another. We must be very cautious about our conclusions in regard to the effectiveness of the treatments. Eye diseases have been depicted only exceptionally in Egyptian art, except for blindness and 'symbolic blindness'. PMID:9253993

  10. AN INTERESTING CASE OF ANCIENT SCHWANNOMA

    Directory of Open Access Journals (Sweden)

    Binu

    2015-01-01

    Full Text Available INTRODUCTION : Schwannoma is a common benign tumour of nerve sheath. Degenerating type of schwannoma is called ancient schwannoma. Ancient schwannomas of scalp are rare and are often misdiagnosed as sebaceous cyst or dermoid cyst. CASE REPORT : We present a thirty two year old male presented with scalp swel ling of eight years duration. X - ray showed no intracranial extension. He underwent excision of the tumour and histopathology was reported as ancient schwannoma. DISCUSSION : Histopathologically , ancient schwannomas charecterised by cellular Antoni type A ar eas and less cellular Antoni type - B areas. 9 th , 7 th , 11 th , 5 th and 4 th cranial nerves are often affected and may be associated with multiple neuro fibramatosis (Von - Recklinghausen’s disease. Impact : Case is presented for its rarity and possible pre - operative misdiagnosis

  11. Genetic Diversity among Ancient Nordic Populations

    DEFF Research Database (Denmark)

    Melchior, Linea; Lynnerup, Niels; Siegismund, Hans R;

    2010-01-01

    locations was similar to that among extant Danes, the diversity at four sites was considerably higher. This supports previous observations for ancient Britons. The overall occurrence of haplogroups did not deviate from extant Scandinavians, however, haplogroup I was significantly more frequent among the...... ancient Danes (average 13%) than among extant Danes and Scandinavians ( approximately 2.5%) as well as among other ancient population samples reported. Haplogroup I could therefore have been an ancient Southern Scandinavian type "diluted" by later immigration events. Interestingly, the two Neolithic...... samples (4,200 YBP, Bell Beaker culture) that were typed were haplogroup U4 and U5a, respectively, and the single Bronze Age sample (3,300-3,500 YBP) was haplogroup U4. These two haplogroups have been associated with the Mesolithic populations of Central and Northern Europe. Therefore, at least for...

  12. Faience: the ceramic technology of ancient Egypt

    OpenAIRE

    Sparavigna, Amelia Carolina

    2012-01-01

    Faiences are ancient Egyptian ceramic materials, considered as "high-tech" products. The paper discussed the method by which the faiences were produced and the application of SEM and Raman spectroscopy to their analysis

  13. NIMI TANTRA (Opthalmology of Ancient India)

    OpenAIRE

    Ramachandran, C.K.

    1984-01-01

    The art of opthalmology was well developed in ancient India and was known as Nimi Tantra. In this paper the author presents the main features of Nimi Tantra an authoritative treatises written by Nimi, a prominent opthalmologist of his time.

  14. Ancient Magnetic Reversals: Clues to the Geodynamo.

    Science.gov (United States)

    Hoffman, Kenneth A.

    1988-01-01

    Discusses the question posed by some that the earth's magnetic field may reverse. States that rocks magnetized by ancient fields may offer clues to the underlying reversal mechanism in the earth's core. (TW)

  15. Factors controlling variability in the oxidative capacity of the troposphere since the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    L. T. Murray

    2013-09-01

    Full Text Available The oxidative capacity of past atmospheres is highly uncertain. We present here a new climate-biosphere-chemistry modeling framework to determine oxidant levels in the present and past troposphere. We use the GEOS-Chem chemical transport model driven by meteorological fields from the NASA Goddard Institute of Space Studies (GISS ModelE, with land cover and fire emissions from dynamic global vegetation models. We present time-slice simulations for the present day, late preindustrial (AD 1770, and the Last Glacial Maximum (LGM; 19–23 ka, and we test the sensitivity of model results to uncertainty in lightning and fire emissions. We find that most preindustrial and paleo climate simulations yield reduced oxidant levels relative to the present day. Contrary to prior studies, tropospheric mean OH in our ensemble shows little change at the LGM relative to the preindustrial (0.5 ± 12%, despite large reductions in methane concentrations. We find a simple linear relationship between tropospheric mean ozone photolysis rates, water vapor, and total emissions of NOx and reactive carbon that explains 72% of the variability in global mean OH in 11 different simulations across the last glacial-interglacial time interval and the Industrial Era. Key parameters controlling the tropospheric oxidative capacity over glacial-interglacial periods include overhead stratospheric ozone, tropospheric water vapor, and lightning NOx emissions. Variability in global mean OH since the LGM is insensitive to fire emissions. Our simulations are broadly consistent with ice-core records of Δ17O in sulfate and nitrate at the LGM, and CO, HCHO, and H2O2 in the preindustrial. Our results imply that the glacial-interglacial changes in atmospheric methane observed in ice cores are predominantly driven by changes in its sources as opposed to its sink with OH.

  16. Rethinking the Ancient Sulfur Cycle

    Science.gov (United States)

    Fike, David A.; Bradley, Alexander S.; Rose, Catherine V.

    2015-05-01

    The sulfur biogeochemical cycle integrates the metabolic activity of multiple microbial pathways (e.g., sulfate reduction, disproportionation, and sulfide oxidation) along with abiotic reactions and geological processes that cycle sulfur through various reservoirs. The sulfur cycle impacts the global carbon cycle and climate primarily through the remineralization of organic carbon. Over geological timescales, cycling of sulfur is closely tied to the redox state of Earth's exosphere through the burial of oxidized (sulfate) and reduced (sulfide) sulfur species in marine sediments. Biological sulfur cycling is associated with isotopic fractionations that can be used to trace the fluxes through various metabolic pathways. The resulting isotopic data provide insights into sulfur cycling in both modern and ancient environments via isotopic signatures in sedimentary sulfate and sulfide phases. Here, we review the deep-time δ34S record of marine sulfates and sulfides in light of recent advances in understanding how isotopic signatures are generated by microbial activity, how these signatures are encoded in marine sediments, and how they may be altered following deposition. The resulting picture shows a sulfur cycle intimately coupled to ambient carbon cycling, where sulfur isotopic records preserved in sedimentary rocks are critically dependent on sedimentological and geochemical conditions (e.g., iron availability) during deposition.

  17. Ancient Admixture in Human History

    Science.gov (United States)

    Patterson, Nick; Moorjani, Priya; Luo, Yontao; Mallick, Swapan; Rohland, Nadin; Zhan, Yiping; Genschoreck, Teri; Webster, Teresa; Reich, David

    2012-01-01

    Population mixture is an important process in biology. We present a suite of methods for learning about population mixtures, implemented in a software package called ADMIXTOOLS, that support formal tests for whether mixture occurred and make it possible to infer proportions and dates of mixture. We also describe the development of a new single nucleotide polymorphism (SNP) array consisting of 629,433 sites with clearly documented ascertainment that was specifically designed for population genetic analyses and that we genotyped in 934 individuals from 53 diverse populations. To illustrate the methods, we give a number of examples that provide new insights about the history of human admixture. The most striking finding is a clear signal of admixture into northern Europe, with one ancestral population related to present-day Basques and Sardinians and the other related to present-day populations of northeast Asia and the Americas. This likely reflects a history of admixture between Neolithic migrants and the indigenous Mesolithic population of Europe, consistent with recent analyses of ancient bones from Sweden and the sequencing of the genome of the Tyrolean “Iceman.” PMID:22960212

  18. Ancient history of flatfish research

    Science.gov (United States)

    Berghahn, Rüdiger; Bennema, Floris Pieter

    2013-01-01

    Owing to both their special appearance and behavior flatfish have attracted the special attention of people since ages. The first records of humans having been in touch with flatfish date back to the Stone Age about 15,000 years B.C. Detailed descriptions were already given in the classical antiquity and were taken up 1400 years later in the Renaissance by the first ichthyologists, encyclopédists, and also by practical men. This was more than 200 years before a number of common flatfish species were given their scientific names by Linnaeus in 1758. Besides morphology, remarkable and sometimes amusing naturalistic observations and figures are bequeathed. Ancient history of flatfish research is still a wide and open array. Examples are presented how the yield of information and interpretation from these times increases with interdisciplinary cooperation including archeologists, zoologists, ichthyologists, historians, art historians, fisheries and fishery biologist. The timeline of this contribution ends with the start of modern fishery research at the end of the 19th century in the course of the rapidly increasing exploitation of fish stocks.

  19. Glacial erosion changes internal mountain structure, responses to plate tectonics

    OpenAIRE

    Trulove, Susan

    2008-01-01

    Intense glacial erosion has not only carved the surface of the highest coastal mountain range on earth, the spectacular St. Elias range in Alaska, but has elicited a structural response from deep within the mountain.

  20. Numerical simulation of the evolution of glacial valley cross sections

    CERN Document Server

    Seddik, Hakime; Sugiyama, Shin; Naruse, Renji

    2009-01-01

    A numerical model was developed for simulating the formation of U-shaped glacial valleys by coupling a two-dimensional ice flow model with an erosion model for a transverse cross section. The erosion model assumes that the erosion rate varies quadratically with sliding speed. We compare the two-dimensional model with a simple shallow-ice approximation model and show the differences in the evolution of a pre-glacial V-shaped valley profile using the two models. We determine the specific role of the lateral shear stresses acting on the glacier side walls in the formation of glacial valleys. By comparing the model results with field data, we find that U-shaped valleys can be formed within 50 ka. A shortcoming of the model is that it primarily simulates the formation of glacial valleys by deepening, whereas observed valleys apparently have formed mainly by widening.

  1. Aquifers of Alluvial and Glacial Origin - Direct Download

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set represents the extent of the alluvial and glacial aquifers north of the southern-most line of glaciation. Aquifers are shown in the States of Maine,...

  2. Glacial Ridge National Wildlife Refuge : Annual Narrative Fiscal Year 2005

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Glacial Ridge National Wildlife Refuge summarizes Refuge activities during the 2005 fiscal year. The report begins with an...

  3. Glacial Ridge National Wildlife Refuge : Annual Narrative Fiscal Year 2006

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Glacial Ridge National Wildlife Refuge summarizes Refuge activities during the 2006 fiscal year. The report begins with an...

  4. One million cubic kilometers of fossil ice in Valles Marineris: Relicts of a 3.5 Gy old glacial landsystem along the Martian equator

    Science.gov (United States)

    Gourronc, Marine; Bourgeois, Olivier; Mège, Daniel; Pochat, Stéphane; Bultel, Benjamin; Massé, Marion; Le Deit, Laetitia; Le Mouélic, Stéphane; Mercier, Denis

    2014-01-01

    Self-consistent landform assemblages suggest that Valles Marineris, the giant valley system that stretches along the Martian equator, was entirely glaciated during Late Noachian to Early Hesperian times and still contains huge volumes of fossil ice. Some of these glacial landform assemblages are illustrated here, with representative examples selected in three regions: Ius Chasma, Central Candor Chasma and the junction between Coprates Chasma and Capri Chasma. A morphological boundary separating an upper spur-and-gully morphology from a smooth basal escarpment has been spectacularly preserved along valley walls throughout Valles Marineris. The boundary winds around topographic obstacles and displays long-wavelength variations in elevation. It is associated with lateral benches, hanging valleys and truncated spurs. Comparisons with terrestrial analogs indicate that it is most reasonably interpreted as a glacial trimline. Chasma floors are covered by various kinds of terrains, including hummocky terrains, platy terrains, lateral banks, layered benches and a draping mantle. Landforms in these terrains and their spatial relationship with the interpreted trimline suggest that they correspond to various disintegration stages of an ancient glacial fill, currently protected by a superficial cover of ablation till. Altogether, these landforms and terrains compose a full glacial landsystem with wet-based glaciers that were able to flow and slide over their beds. It was most probably fed by ice accumulating at low elevations directly from the atmosphere onto valley floors and walls, with only minor contributions from tributary glaciers flowing down from higher elevations. Similar fossil glacial landsystems dating back from the early Martian history are to be expected in many other low-latitude troughs such as chasmata, chaos, valleys, impact craters and other basins.

  5. Evolution of supra-glacial lakes across the Greenland Ice Sheet

    Science.gov (United States)

    Sundal, A. V.; Shepherd, A.; Nienow, P.; Hanna, E.; Palmer, S.; Huybrechts, P.

    2009-04-01

    We have used 268 cloud-free Moderate-resolution Imaging Spectroradiometer (MODIS) images spanning the 2003 and 2005-2007 melt seasons to study the seasonal evolution of supra-glacial lakes in three different regions of the Greenland Ice Sheet. Lake area estimates were obtained by developing an automated classification method for their identification based on 250 m resolution MODIS surface reflectance observations. Widespread supra-glacial lake formation and drainage is observed across the ice sheet, with a 2-3 weeks delay in the evolution of total supra-glacial lake area in the northern areas compared to the south-west. The onset of lake growth varies by up to one month inter-annually, and lakes form and drain at progressively higher altitudes during the melt season. A correlation was found between the annual peak in total lake area and modelled annual runoff across all study areas. Our results indicate that, in a future warmer climate (Meehl et al., 2007), Greenland supra-glacial lakes can be expected to form at higher altitudes and over a longer time period than is presently the case, expanding the area and time period over which connections between the ice sheet surface and base may be established (Das et al., 2008) with potential consequences for ice sheet discharge (Zwally et al., 2002). Das, S., Joughin, M., Behn, M., Howat, I., King, M., Lizarralde, D., & Bhatia, M. (2008). Fracture propagation to the base of the Greenland Ice Sheet during supra-glacial lake drainage. Science, 5877, 778-781. Meehl, G.A., Stocker, T.F., Collins W.D., Friedlingstein, P., Gaye, A.T., Gregory, J.M., Kitoh, A., Knutti, R., Murphy, J.M., Noda, A., Raper, S.C.B., Watterson, I.G., Weaver, A.J. & Zhao, Z.C. (2007). Global Climate Projections. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor

  6. Glacial climate driven sedimentation overwhelms tectonics in the battle for control of margin architecture: Southeast Alaska, St. Elias Orogeny

    Science.gov (United States)

    Gulick, S. P.; Jaeger, J. M.; Willems, B.; Powell, R. D.; Lowe, L. A.

    2006-12-01

    The interplay of tectonic and climatic processes is fundamental to the development of mountain belts and the ensuing patterns of deformation and erosion. Of equal significance is the interaction of tectonic and climatic processes in the development of orogenic sedimentary basins, or in the case of a coastal mountain belt, in the growth of a continental margin. The Chugach-St. Elias Orogeny, which is driven by the collision of the Yakutat microplate with North America in southeast Alaska, has generated the highest coastal relief in the world. The combined forces of tectonic uplift and glacial erosion have resulted in the accumulation of over 5 km of sediment to form the continental shelf and the creation of the Surveyor Fan that is over 2 km thick proximally. High-resolution GI-gun seismic data allow for detailed examination of the margin architecture off the Bering Glacier within the leading edge of the Yakutat block. The deformation and growth of the margin appears to have first undergone a tectonically dominated phase followed more recently by a glacially dominated phase. During the tectonically dominated period a broad anticline-syncline system helped create accommodation space and the margin both shallowed and widened to its current 50 km width. Based on ties with industry well cuttings, the dominance switched sometime between 0.75 and 1.25 Ma to being completely controlled by glacial advance-retreat patterns. The mappable glacial sequences are undeformed by the underlying anticlines and display several notable features: 1) erosional bases that can often be mapped across the entire shelf, terminating at the shelf edge, 2) little evidence for terminal or retreat moraines on the shelf suggesting very rapid and single phase retreat of the glacier, 3) incomplete glacial sequences due to erosion by later advances, and 4) minimal creation of accommodation space. We investigate the cause of the switch to glacial dominance, the mechanisms and causes of the potentially

  7. Technical Note: Using wavelet analyses on water depth time series to detect glacial influence in high-mountain hydrosystems

    Directory of Open Access Journals (Sweden)

    S. Cauvy-Fraunié

    2013-04-01

    Full Text Available Worldwide, the rapid shrinking of glaciers in response to ongoing climate change is currently modifying the glacial meltwater contribution to hydrosystems in glacierized catchments. Assessing the contribution of glacier run-off to stream discharge is therefore of critical importance to evaluate potential impact of glacier retreat on water quality and aquatic biota. This task has challenged both glacier hydrologists and ecologists over the last 20 yr due to both structural and functional complexity of the glacier-stream system interface. Here we propose a new methodological approach based on wavelet analyses on water depth time series to determine the glacial influence in glacierized catchments. We performed water depth measurement using water pressure loggers over ten months in 15 stream sites in two glacier-fed catchments in the Ecuadorian Andes (> 4000 m. We determined the global wavelet spectrum of each time series and defined the Wavelet Glacier Signal (WGS as the ratio between the global wavelet power spectrum value at a 24 h-scale and its corresponding significance value. To test the relevance of the WGS we compared it with the percentage of the glacier cover in the catchments, a metric of glacier influence often used in the literature. We then tested whether one month data could be sufficient to reliably determine the glacial influence. As expected we found that the WGS of glacier-fed streams decreased downstream with the increasing of non-glacial tributaries. We also found that the WGS and the percentage of the glacier cover in the catchment were significantly positively correlated and that one month data was sufficient to identify and compare the glacial influence between two sites, provided that the water level time series were acquired over the same period. Furthermore, we found that our method permits to detect glacial signal in supposedly non-glacial sites, thereby evidencing glacial meltwater infiltrations. While we specifically

  8. Warm Nordic Seas delayed glacial inception in Scandinavia

    OpenAIRE

    A. Born; Kageyama, M.; K. H. Nisancioglu

    2010-01-01

    We simulate the last glacial inception, 115 000 years ago, with a three dimensional thermomechanical ice sheet model of the Northern Hemisphere, forced by a comprehensive coupled climate model. High oceanic heat transport into the Nordic Seas prevents large scale ice growth over Scandinavia. Glacial inception in the region starts on the highest mountains in the south when sea surface temperatures in the Nordic Seas are reduced by at least 3 °C. Ice growth in Northern Scandinavia requires a co...

  9. Glacial magnetite dissolution in abyssal NW Pacific sediments - evidence for carbon trapping?

    Science.gov (United States)

    Korff, Lucia; von Dobeneck, Tilo; Frederichs, Thomas; Kasten, Sabine; Kuhn, Gerhard; Gersonde, Rainer; Diekmann, Bernhard

    2016-04-01

    The abyssal North Pacific Ocean's large volume, depth, and terminal position on the deep oceanic conveyor make it a candidate site for deep carbon trapping as postulated by climate theory to explain the massive glacial drawdown of atmospheric CO2. As the major basins of the North Pacific have depths of 5500-6500m, far below the modern and glacial Calcite Compensation Depths (CCD), these abyssal sediments are carbonate-free and therefore not suitable for carbonate-based paleoceanographic proxy reconstructions. Instead, paleo-, rock and environmental magnetic methods are generally well applicable to hololytic abyssal muds and clays. In 2009, the international paleoceanographic research cruise SO 202 INOPEX ('Innovative North Pacific Experiment') of the German RV SONNE collected two ocean-spanning EW sediment core transects of the North Pacific and Bering Sea recovering a total of 50 piston and gravity cores from 45 sites. Out of seven here considered abyssal Northwest Pacific piston cores collected at water depths of 5100 to 5700m with mostly coherent shipboard susceptibility logs, the 20.23m long SO202-39-3, retrieved from 5102 m water depth east of northern Shatsky Rise (38°00.70'N, 164°26.78'E), was rated as the stratigraphically most promising record of the entire core transect and selected for detailed paleo- and environmental magnetic, geochemical and sedimentological investigations. This core was dated by correlating its RPI and Ba/Ti records to well-dated reference records and obviously provides a continuous sequence of the past 940 kyrs. The most striking orck magnetic features are coherent magnetite-depleted zones corresponding to glacial periods. In the interglacial sections, detrital, volcanic and even submicron bacterial magnetite fractions are excellently preserved. These alternating magnetite preservation states seem to reflect dramatic oxygenation changes in the deep North Pacific Ocean and hint at large-scale benthic glacial carbon trapping

  10. Was the Sun especially active at the end of the late glacial epoch?

    Science.gov (United States)

    Alekseeva, Liliya

    In their pioneering work, the geophysicists A. Brekke and A. Egeland (1983) collected beliefs of different peoples, associated with northern lights. Our analyses of this collection show that these beliefs are mainly related to the mythological idea of ``abnormal'' deads (dead, childless old maids in Finnish beliefs; killed people; spirits dangerous to children). We find similar motifs in Slavic fairy tales about the ``Thrice-Nine Land,'' regarded as the other world in folkloric studies (in the Land where mobile and agitated warlike girls live, whose Head Girl is characterized by the words ``white snow, pretty light, the prettiest in the World,'' but whose name ``Mariya Morevna'' refers to the word ``mort''; where a river flows with its banks covered by human bones; where the witch Baba-Yaga dwells, being extremely dangerous for children). Moreover, it can be noted that similar narrative fabulous myths deal with the concept of auroral oval northern lights, since some specific features of the natural auroral forms are mentioned there, with their particular spatial orientations (to the North or West). This resembles the manner in which Ancient Greek myths describe the real properties of the heavenly phenomena in a mythological language. It is interesting that myths on the high-latitude northern lights spread even to the South of Europe (and, might be, to India and Iran). This fact can be understood in view of the following. It has been established that, during the late glacial epoch, the environmental and cultural conditions were similar over the area from Pyrenean to the Ural Mountains; the pattern of hunters' settlements outlined the glacial sheet from the outside. Relics of the hunters' beliefs can now be found in Arctic, where the environment and lifestyle remain nearly unchanged. The ethnographer Yu.B. Simchenko (1976) has reconstructed the most archaic Arctic myths. According to them, the World of dead is associated with the world of ice governed by the ``Ice

  11. Technical Analysis of a Ptolemaic Child Sarcophagus and the Identification of Ancient and Modern Reuse

    Science.gov (United States)

    Mallinckrodt, Catherine Scott

    The goals of this project are the technical analysis of a Ptolemaic child coffin lid, development of a conservation strategy, and realization of priority stabilization interventions. Early in the process of evaluation and analysis irregularities in the appearance and structure of the coffin suggested re-use of components. This thesis proposes that there are incidences of ancient and modern reuse of structural elements in this coffin lid, and substantiates this assertion through the results of a technical analysis. Non-destructive and destructive methods of analysis were used including UV induced visible fluorescence, Infrared and Visible-induced luminescence (VIL) imaging. Particle samples were investigated microscopically, and using XRF or X-ray Fluorescence spectroscopy, XRD or X-ray Diffraction, FTIR or Fourier Transform Infrared spectroscopy and GC-MS or Gas Chromatography-Mass Spectrometry technologies were used for elemental and molecular analysis. Egyptology scholars, conservators, and materials scientists were consulted. The text establishes the historical context, and the use and meaning of the artifact. The object is described, the pigment analysis is presented, and prior interventions to the object are elaborated. The collective results of the technical analysis, observation and consultation are interpreted to substantiate the assertion of modern and ancient reuse. Technical analysis supports the observation that face of the deceased is inconsistent with the Ptolemaic period and that is was created in an early dynastic period and reused on this coffin in antiquity. The components of the foot-block are identified as ancient but not associated with this coffin, and 20th century adhesives and hardware are evidence that it is a modern addition. Social and economic demands in antiquity, and also in the post-excavation period of the late 19th and 20th centuries, have motivated alterations to objects of cultural and economic importance. This thesis provides

  12. Amorites in the Early Old Babylonian Period

    NARCIS (Netherlands)

    Boer, Rients de

    2014-01-01

    The Amorites are known throughout the history of the Ancient Near East: they occur in texts from the Ur III empire (2100–2000 bc), but also in the Bible. In the Old Babylonian period (2000–1600 bc), several dynasties of Amorite kings ruled all over the Middle East. They came to power in the early Ol

  13. A high-resolution climatic change since the Late Glacial Age inferred from multi-proxy of sediments in Qinghai Lake

    Institute of Scientific and Technical Information of China (English)

    SHEN; Ji; LIU; Xingqi; Ryo; Matsumoto; WANG; Sumin; YANG; X

    2005-01-01

    Based on multi-proxy analysis of pollen, carbonate, TOC, TN and δ13C of organic matters, a high-resolution climatic evolution of Qinghai Lake since the Late Glacial Age is reconstructed. The results indicate that the boundary between the Last Glacial Maximum and the Late Glacial Age is at about 18.2 cal.ka BP. The warm and wet period, which began at about 15.4 cal.ka BP, culminated at 7.4 cal.ka BP and came to its end at about 4.5 cal.ka BP. After that, the climate gradually became cold and dry. The multi-proxy analysis indicates that the climate fluctuated greatly during the transitional period from the Late glacial Age to the Holocene, and this is in good accordance with that reflected by deep sea cores of North Atlantic, ice cores of Greenland, lake sediments in Europe, loess sequences and Guliya ice core in China. The climatic evolutional characteristic of the Qinghai Lake since the Late Glacial Age shows that the driving force of the East-Asia Monsoon correlates with solar radiation on the ten-thousand-year scale.

  14. Ancient anchorage systems in India with reference to the Gujarat coast

    Digital Repository Service at National Institute of Oceanography (India)

    Gaur, A.S.; Sundaresh; Tripati, S.

    , Kindar Kheda near Mul Dwarka (Visawada) and Kanjetar and Kaj near Mul Dwarka (Kodinar). All the three Dwarka have ancient temples dated to the 10 th -12 th century AD. Nonetheless, these sites were ancient busy ports and perhaps temples were served... and anchoring points along the west coast of India from the protohistoric period (Ray, 2003, 2). The discovery of a large number of stone structures and anchors at Dwarka suggests that it was a busy port during the historical and the medieval times (Gaur, et...

  15. Neoproterozoic Glacial Extremes: How Plausible is the

    Science.gov (United States)

    Peltier, W. R.

    2004-05-01

    The suggestion that the glaciation events of the Neoproterozoic could have been global in extent, so-called "snowball" glaciations, during which the oceans were entirely covered by sea ice and the continents by massive continental ice sheets, is an idea tha is recurrent in the geological and climate dynamics literature. It is an idea that haa both critics and defenders but concensus concerning it's plausiblity has yet to emerge. Previous work on this problem has led to the suggestion that a more likely scenario than the "hard snowball" is one in which open water continues to persist at the equator, thus enabling biological evolution into the Cambrian to proceed, perhaps stimulated by the transition from the cold conditions of the Neoproterozoic to the warm condition of the Cambrian, thus leading to the Cambrian "explosion of life". We will discuss recent extensions of our previous efforts to model the extreme climate of the Neoproterozoic, using both the University of Toronto Glacial Systems Model and the NCAR Community Climate System Model. With an appropriate choice for the albedo of sea ice, the former model conntinues to deliver hysteresis in the surface temperature vs. CO2 concentration space when solar luminosity is reduced by 6% below modern, and thus continues to suggest the existence of the previously hypothesized "CO2 attractor". We argue here that the system could be locked onto this attractor by the strong "out of equilibrium" effects of the carbon cycle recently discussed by Rothman et al. (PNAS, 2003). The open water solution is confirmed as the preferred mode of the system by the detailed CCSM integrations that we have performed.

  16. Sub-glacial Origin of the Hot Springs Bay Valley hydrothermal System, Akutan, Alaska

    Science.gov (United States)

    Stelling, P. L.; Tobin, B.; Knapp, P.

    2015-12-01

    Exploration for geothermal energy in Hot Springs Bay Valley (HSBV) on Akutan Island, Alaska, has revealed a rich hydrothermal history, including what appears to be a stage of peak activity during a significant glacial period. Alteration mineralogy observed in 754 m of drill core recovered from the outflow zone is dominated by chlorite and includes minor smectite clays, a suite of zeolite species and several moderately high-temperature hydrothermal minerals (epidote/clinozoisite, prehnite, adularia and wairakite). The latter minerals each have minimum formation temperatures exceeding 200 oC, and fluid inclusion results in related calcite crystals indicate temperatures of formation to be as high as 275 oC, some 100 oC hotter than the modern boiling point with depth (BPD) curve at that depth (>62 m). In order to maintain liquid temperatures this high, the pressure during mineralization must have been substantially greater (~680 bar), a pressure change equivalent to erosion of ~280 m of rock (ρ=2.5 g/cm3). Although glacial erosion rates are too low (0.034 mm/yr; Bekele et al., 2003) for this amount of erosion to occur in a single glaciation, glacial melting and ablation are substantially more rapid (~100 mm/yr; Bekele et al., 2003; Person et al., 2012). Thus, a more probable scenario than pure erosion is that peak hydrothermal conditions occurred during a large glacial event, with the added pressure from the overlying ice allowing the high temperature minerals to form closer to the ground surface. Subsequent melting of the ice eroded upper tributary valleys and upper levels of the originally smectite-rich alteration assemblage, explaining the paucity of swelling clays in the region. We present mineralogical, fluid inclusion and geochronologic evidence to support these conclusions, and discuss the general implications of sub-glacial hydrothermal system formation and geothermal resource potential. References: Bekele, E., Rostron, B. and Person, M. (2003) Fluid pressure

  17. Provenance changes between recent and glacial-time sediments in the Amundsen Sea embayment, West Antarctica: clay mineral assemblage evidence

    OpenAIRE

    Ehrmann, Werner; Hillenbrand, Claus-Dieter; Smith, James A.; Graham, Alastair G.C.; Kuhn, Gerhard; Larter, Robert D.

    2011-01-01

    The Amundsen Sea embayment is a probable site for the initiation of a future collapse of the West Antarctic Ice Sheet. This paper contributes to a better understanding of the transport pathways of subglacial sediments into this embayment at present and during the last glacial period. It discusses the clay mineral composition of sediment samples taken from the seafloor surface and marine cores in order to decipher spatial and temporal changes in the sediment provenance. The most striking featu...

  18. Glacial climate sensitivity to different states of the Atlantic Meridional overturning circulation : results from the IPSL model

    OpenAIRE

    Kageyama, M.; J. Mignot; D. Swingedouw; Marzin, C.; Alkama, R.; O. Marti

    2009-01-01

    Numerous records from the North Atlantic and the surrounding continents have shown rapid and large amplitude climate variability during the last glacial period. This variability has often been associated to changes in the Atlantic Meridional Overturning Circulation (AMOC). Rapid climate change on the same time scales has also been reconstructed for sites far away from the North Atlantic, such as the tropical Atlantic, the East Pacific and Asia. The mechanisms explaining these climatic respons...

  19. Periodic functions with variable period

    OpenAIRE

    Pryjmak, M. V

    2010-01-01

    The examples of rhythmical signals with variable period are considered. The definition of periodic function with the variable period is given as a model of such signals. The examples of such functions are given and their variable periods are written in the explicit form. The system of trigonometric functions with the variable period is considered and its orthogonality is proved. The generalized system of trigonometric functions with the variable period is also suggested; some conditions of it...

  20. From the Last Interglacial to the Anthropocene: Modelling a Complete Glacial Cycle (PalMod)

    Science.gov (United States)

    Brücher, Tim; Latif, Mojib; Claussen, Martin; Schulz, Michael

    2016-04-01

    We will give a short overview of the national climate modelling initiative (PalMod - Paleo Modelling, www.palmod.de) on the understanding of the climate system dynamics and its variability during the last glacial cycle. PalMod is funded by the German Federal Ministry of Education and Research (BMBF) and its specific topics are: (i) to identify and quantify the relative contributions of the fundamental processes which determined the Earth's climate trajectory and variability during the last glacial cycle, (ii) to simulate with comprehensive Earth System Models (ESMs) the climate from the peak of the last interglacial - the Eemian warm period - up to the present, including the changes in the spectrum of variability, and (iii) to assess possible future climate trajectories beyond this century during the next millennia with sophisticated ESMs tested in such a way. The research is intended to be conducted over a period of 10 years, but with shorter funding cycles. The envisioned approach is innovative in three respects. First, the consortium aims at simulating a full glacial cycle in transient mode and with comprehensive ESMs which allow full interactions between the physical and biogeochemical components of the Earth system, including ice sheets. Second, we shall address climate variability during the last glacial cycle on a large range of time scales, from interannual to multi-millennial, and attempt to quantify the relative contributions of external forcing and processes internal to the Earth system to climate variability at different time scales. Third, in order to achieve a higher level of understanding of natural climate variability at time scales of millennia, its governing processes and implications for the future climate, we bring together three different research communities: the Earth system modeling community, the proxy data community and the computational science community. The consortium consists of 18 partners including all major modelling centers within

  1. Coastal response to simultaneous mid-Holocene climate and sea-level changes: Lessons from ancient Egypt

    Science.gov (United States)

    Hein, C. J.; FitzGerald, D. M.; Milne, G. A.; Bard, K. A.; Fattovich, R.

    2011-12-01

    Coastal evolution during the Holocene has been driven by complex interactions between changes in sea level, climate, and sedimentation processes. Along the Egyptian Red Sea coast, a post-glacial marine transgression drowned a series of wadi channels, flooding their lower reaches to create shallow lagoons. Archeological investigations at one such site, Mersa / Wadi Gawasis, have uncovered the existence of an ancient Egyptian harbor along a carbonate / conglomerate terrace located 600 m landward of the modern shoreline; this discovery documented the world's earliest (3.5 - 4.0 ka) archaeological evidence of long-distance seafaring. This site is interpreted to have been a harbor servicing trade routes along the African Red Sea coast. Sedimentological, malacological, chorological, and foraminiferal analyses indicate that this harbor was located within a low energy, 6 - 8 m deep, tidal embayment that once extended ~1 km inland of the modern shore. A buried coral-beach rock platform and tidal flat sediments are found ubiquitously along the periphery of the paleo-bay and at elevations of up to 1 m above modern mean sea level. Wave-cut notches and erosional terraces observed at 1.1 - 1.8 m above modern sea level along the modern shoreline provide additional evidence of a higher-than-present stand of sea-level during the mid-Holocene. Sea-level predictions generated using a site-specific isostatic model for the northern the Red Sea confirm the presence of 0.5 - 2 m highstand at 5 ka. Reconstructions indicate that the bay at Mersa / Wadi Gawasis reached its maximum surface area prior to the highstand. Preliminary closure was driven by sediment inputs from the adjacent wadi, enhanced by the wetter climate of the African Humid Period, combined with a slowing rate of sea-level rise, thus demonstrating the dominance of sedimentary processes during this period. Following the highstand, slowly falling sea level coincidental with climatic aridization allowed for the establishment

  2. Pollutant lead reveals the pre-Hellenistic occupation and ancient growth of Alexandria, Egypt

    Science.gov (United States)

    Véron, A.; Goiran, J. P.; Morhange, C.; Marriner, N.; Empereur, J. Y.

    2006-03-01

    It is generally accepted that Alexandria ad Aegyptum was founded ex nihilo in 331 BC by Alexander the Great, rapidly growing into one of antiquity's most opulent economic and intellectual centers. However, ancient texts by Strabo (17.1.6) and Pliny (NH 5.11.62) suggest the existence of a pre-Hellenistic settlement named Rhakotis. This literary evidence has fuelled contentious scholarly debate for decades. Here we present new geochemical data from Alexandria's ancient bay sediments, elucidating unequivocal proof for pollutant lead (Pb) input into the harbor during the Egyptian Old Kingdom (2686-2181 BC). A second contamination peak is detected during the Iron Age (1000-800 BC), at the end of the prosperous Ramesses reigns. These findings evidence thriving pre-Hellenistic settlements in Alexandria. During the Greek and Roman periods, we expound the largest Pb pollution ever encountered in ancient city sediments with Pb levels twice as high as those measured in contemporary industrialized estuaries.

  3. Use of x-ray fluorescence and diffraction techniques in studying ancient ceramics of Sri Lanka

    Science.gov (United States)

    Karunaratne, B. S. B.

    2012-07-01

    Ceramics were produced for centuries in Sri Lanka for various purposes. Ancient ceramic articles such as pottery, bricks, tiles, sewer pipes, etc, were made from naturally occurring raw materials. Use of X-ray fluorescence (XRF), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) in characterizing of two ancient ceramic samples from two different archaeological sites in Sri Lanka is presented. The information obtained in this manner is used to figure out the ancient ceramic technology, particularly to learn about the raw materials used, the source of raw materials, processing parameters such as firing temperature or binders used in ceramic production. This information then can be used to explore the archaeometric background such as the nature and extent of cultural and technological interaction between different periods of history in Sri Lanka.

  4. Use of x-ray fluorescence and diffraction techniques in studying ancient ceramics of Sri Lanka

    International Nuclear Information System (INIS)

    Ceramics were produced for centuries in Sri Lanka for various purposes. Ancient ceramic articles such as pottery, bricks, tiles, sewer pipes, etc, were made from naturally occurring raw materials. Use of X-ray fluorescence (XRF), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) in characterizing of two ancient ceramic samples from two different archaeological sites in Sri Lanka is presented. The information obtained in this manner is used to figure out the ancient ceramic technology, particularly to learn about the raw materials used, the source of raw materials, processing parameters such as firing temperature or binders used in ceramic production. This information then can be used to explore the archaeometric background such as the nature and extent of cultural and technological interaction between different periods of history in Sri Lanka.

  5. Synchrotron radiation analysis on ancient Egyptian vitreous materials

    Energy Technology Data Exchange (ETDEWEB)

    Yamahana, Kyoko [Tokai Univ., Hiratsuka, Kanagawa (Japan). Lecture of Egyptian Archaeology

    2000-07-01

    Ancient Egyptian vitreous materials, namely faience and glass, share the same elemental composition. But they appear to have originated separately. Faience objects appear as early as the Predynastic period, and glass was introduced from Mesopotamia during the New Kingdom. These faience and glass objects were not of daily use, rather they were regarded as religious symbols or luxury status goods. Most of the products were coloured blue, but we see an increased use of other colours during the New Kingdom (c.1550-1069BC). This tendency corresponds to the period of both territorial and political expansion of Egypt. A non-destructive SR-XRF experiment at SPring-8 was conducted last winter, aiming to determine the regional trait of elemental composition by examining the pattern and ratio of rare earth elements. As a result, we could observe some distinctive rare earth elements that may indicate regional variation. (author)

  6. Synchrotron radiation analysis on ancient Egyptian vitreous materials

    International Nuclear Information System (INIS)

    Ancient Egyptian vitreous materials, namely faience and glass, share the same elemental composition. But they appear to have originated separately. Faience objects appear as early as the Predynastic period, and glass was introduced from Mesopotamia during the New Kingdom. These faience and glass objects were not of daily use, rather they were regarded as religious symbols or luxury status goods. Most of the products were coloured blue, but we see an increased use of other colours during the New Kingdom (c.1550-1069BC). This tendency corresponds to the period of both territorial and political expansion of Egypt. A non-destructive SR-XRF experiment at SPring-8 was conducted last winter, aiming to determine the regional trait of elemental composition by examining the pattern and ratio of rare earth elements. As a result, we could observe some distinctive rare earth elements that may indicate regional variation. (author)

  7. Studies of Ancient Lice Reveal Unsuspected Past Migrations of Vectors.

    Science.gov (United States)

    Drali, Rezak; Mumcuoglu, Kosta Y; Yesilyurt, Gonca; Raoult, Didier

    2015-09-01

    Lice are among the oldest parasites of humans representing an excellent marker of the evolution and migration of our species over time. Here, we analyzed by real-time polymerase chain reaction (RT-PCR) developed in this study the mitochondrial DNA of seven ancient head louse eggs found on hair remains recovered from two sites in Israel: 1) five nits dating from Chalcolithic period (4,000 bc) were found in the Cave of the Treasure located at Nahal Mishmar, in the Judean Desert and 2) two nits dating from Early Islamic Period (ad 650-810) were found in Nahal Omer in the Arava Valley (between Dead Sea and Red Sea). Our results suggest that these eggs belonged to people originating from west Africa based on identification of the louse mitochondrial sub-clade specific to that region. PMID:26078317

  8. Mycological evidence of coprophagy from the feces of an Alaskan Late Glacial mammoth

    Science.gov (United States)

    van Geel, Bas; Guthrie, R. Dale; Altmann, Jens G.; Broekens, Peter; Bull, Ian D.; Gill, Fiona L.; Jansen, Boris; Nieman, Aline M.; Gravendeel, Barbara

    2011-08-01

    Dung from a mammoth was preserved under frozen conditions in Alaska. The mammoth lived during the early part of the Late Glacial interstadial (ca 12,300 BP). Microfossils, macroremains and ancient DNA from the dung were studied and the chemical composition was determined to reconstruct both the paleoenvironment and paleobiology of this mammoth. Pollen spectra are dominated by Poaceae, Artemisia and other light-demanding taxa, indicating an open, treeless landscape ('mammoth steppe'). Fruits and seeds support this conclusion. The dung consists mainly of cyperaceous stems and leaves, with a minor component of vegetative remains of Poaceae. Analyses of fragments of the plastid rbcL gene and trnL intron and nrITS1 region, amplified from DNA extracted from the dung, supplemented the microscopic identifications. Many fruit bodies with ascospores of the coprophilous fungus Podospora conica were found inside the dung ball, indicating that the mammoth had eaten dung. The absence of bile acids points to mammoth dung. This is the second time that evidence for coprophagy of mammoths has been derived from the presence of fruit bodies of coprophilous fungi in frozen dung. Coprophagy might well have been a common habit of mammoths. Therefore, we strongly recommend that particular attention should be given to fungal remains in future fossil dung studies.

  9. The importance of studying inherited hematological disorders in ancient Anatolian populations

    Directory of Open Access Journals (Sweden)

    Yeşim Doğan Alakoç

    2011-12-01

    Full Text Available Before analysis of DNA from ancient remains was possible, anthropologists studied evolution and migration patterns using data obtained from population genetic studies on modern populations combined with data obtained from morphological evaluations of ancient remains. Currently, DNA analysis of ancient populations is making a valuable contribution to these efforts. Researchers that perform ancient DNA analysis prefer to study polymorphisms on the Y chromosome or mitochondrial DNA because the results are easier to statistically evaluate. To evaluate polymorphisms on diploid genomes, which are more informative, only mutations that have been extensively examined in modern populations should be chosen. The most extensively evaluated mutations are those related to prevalent inherited disorders. As such, beta-thalassemia, sickle cell anemia, FVL mutation of globin and the factor V genes are good candidates for DNA studies in ancient populations. These mutations are common in Anatolia, host to many civilizations since the Paleolithic period. This history makes Anatolia a good place for conducting research that could enhance our understanding of human evolution and migration patterns.

  10. The Vindolanda Tablets and the Ancient Economy

    DEFF Research Database (Denmark)

    Evers, Kasper Grønlund

    model is outlined which takes into account the different economic behaviours revealed by the tablets and attempts to fit them together into one coherent, economic system, whilst also relating the activities to questions of scale in the ancient economy; moreover, the conclusions drawn in the study are......, the aim is to investigate how best to comprehend the economic system attested at Vindolanda and to consider the wider implications for studies of the ancient economy in general. This is accomplished by a three-step approach: first, the nature of the Vindolandan evidence is assessed, and the state of...... research on both studies of the ancient economy and the economy of early Roman Britain is accounted for, so as to highlight the value of the Vindolanda Tablets and lay the ground for the interpretations which follow. Secondly, the economic activities attested by the tablets are analysed in terms of market...

  11. PIXE analysis on an ancient scroll sample

    International Nuclear Information System (INIS)

    For years, scientists have developed several new techniques to read texts of Herculaneum scrolls without destroying them. Recently, the use of a custom built high-resolution CT scanner was proposed to scan and then virtually unroll the scrolls for reading. Identification of any unique chemical signatures in the ancient ink would allow better calibration of the CT scanner to improve the chances of resolving the ink from the burned papyrus background. To support this effort, we carried out one pilot study to see whether the composition of the ink can be obtained from an ancient scroll sample using PIXE technique. PIXE data were collected and analyzed in two different regions of the ancient scroll sample (ink and blank regions). This preliminary work shows that elemental distributions from the ink used in this scroll mainly contained Al, Fe and Ti as well as minor trace amounts of Cr, Cu and Zn. (author)

  12. The ancient Chinese notes on hydrogeology

    Science.gov (United States)

    Zhou, Yu; Zwahlen, François; Wang, Yanxin

    2011-08-01

    The ancient Chinese notes on hydrogeology are summarized and interpreted, along with records of some related matters, like groundwater exploration and utilization, karst springs, water circulation, water conservation and saline-land transformation, mine drainage, and environmental hydrogeology. The report focuses only on the earliest recorded notes, mostly up until the Han Dynasty (206 BC - AD 25). Besides the references cited, the discussion in this report is based mainly on archaeological material, the preserved written classic literature, and some assumptions and/or conclusions that have been handed down in legends to later ages. Although most material relates to ancient China, the lessons learned may have practical significance worldwide. Compared to other contemporary parts of the world, ancient China, without doubt, took the lead in the field of groundwater hydrology. The great achievements and experience of the Chinese ancestors should provide motivation and inspiration for hydrogeologists to carry out their scientific research and exploration passionately and actively.

  13. Twins in Ancient Greece: a synopsis.

    Science.gov (United States)

    Malamitsi-Puchner, Ariadne

    2016-01-01

    This brief outline associates twins with several aspects of life in Ancient Greece. In Greek mythology twins caused ambivalent reactions and were believed to have ambivalent feelings for each other. Very often, they were viewed as the representatives of the dualistic nature of the universe. Heteropaternal superfecundation, which dominates in ancient myths, explains on one hand, the god-like qualities and, on the other hand, the mortal nature of many twins. An assumption is presented that legends referring to twins might reflect the territorial expansions of Ancient Greeks in Northern Mediterranean, around the Black Sea, in Asia Minor, as well as North East Africa. In conclusion, in Greek antiquity, twins have been used as transitional figures between myth and reality. PMID:26135766

  14. The ancient lunar crust, Apollo 17 region

    Science.gov (United States)

    James, O. B.

    1992-01-01

    The Apollo 17 highland collection is dominated by fragment-laden melt rocks, generally thought to represent impact melt from the Serenitatis basin-forming impact. Fortunately for our understanding of the lunar crust, the melt rocks contain unmelted clasts of preexisting rocks. Similar ancient rocks are also found in the regolith; most are probably clasts eroded out of melt rocks. The ancient rocks can be divided into groups by age, composition, and history. Oldest are plutonic igneous rocks, representing the magmatic components of the ancient crust. The younger are granulitic breccias, which are thoroughly recrystallized rocks of diverse parentages. The youngest are KREEPy basalts and felsites, products of relatively evolved magmas. Some characteristics of each group are given.

  15. Chronology of glaciations in the Cantabrian Mountains (NW Iberia) during the Last Glacial Cycle based on in situ-produced 10Be

    Science.gov (United States)

    Rodríguez-Rodríguez, Laura; Jiménez-Sánchez, Montserrat; Domínguez-Cuesta, María José; Rinterknecht, Vincent; Pallàs, Raimon; Bourlès, Didier

    2016-04-01

    The mountain ranges of the Iberian Peninsula preserve a valuable record of past glaciations that may help reconstruct past atmospheric circulation patterns in response to cooling events in the North Atlantic Ocean. Available chronologies for the glacial record of the Cantabrian Mountains, which are mainly based on radiocarbon and luminescence dating of glacial-related sediments, suggest that glaciers recorded their Glacial Maximum (GM) during MIS 3 and experienced a later Last Glacial Maximum (LGM) advance. This LGM extent is not established yet, preventing a fair correlation with available Cosmic Ray Exposure (CRE) based chronologies for the glacial record of the Pyrenees and the Sistema Central. We present a glacial reconstruction and a 10Be CRE chronology for the Porma valley, in the southern slope of the central Cantabrian Mountains. Glacial evidence at the lowest altitudes correspond to erratic boulders and composite moraines whose minimum 10Be CRE age of 113.9 ± 7.1 ka suggests that glaciers were at their maximum extent during MIS 5d, most likely in response to the minima in summertime insolation of the Last Glacial Cycle. Recessional moraines preserved within the glacial maximum limits allow the assessment of subsequent glacier advances or stagnations. The most remarkable advance took place prior to 55.7 ± 4.0 ka (probably at the end of MIS 4), consistently with minimum radiocarbon ages previously reported for lacustrine glacial-related deposits in the Cantabrian Mountains. A limited number of 10Be CRE ages from a composite moraine suggest a possible advance of the Porma glacier coeval with the global LGM; the glacier front attributed to the LGM would be placed within the margins of the previous GM like in the western Pyrenees. Erratic boulders perched on an ice-moulded bedrock surface provided a mean 10Be CRE age of 17.7 ± 1.0 ka, suggesting that part of the recessional moraine sequence corresponds to minor advances or stagnations of the glacier fronts

  16. Overdeepening development in a glacial landscape evolution model with quarrying

    DEFF Research Database (Denmark)

    Ugelvig, Sofie Vej; Egholm, D.L.; Iverson, Neal R.;

    In glacial landscape evolution models, subglacial erosion rates are often related to basal sliding or ice discharge by a power-law. This relation can be justified when considering bed abrasion, where rock debris transported in the basal ice drives erosion. However, the relation is not well suppor......, F02012 (2011). Iverson, N. R. A theory of glacial quarrying for landscape evolution models. Geology, v. 40, no. 8, 679-682 (2012). Schoof, C. The effect of cavitation on glacier sliding. Proc. R. Soc. A , 461, 609-627 (2005).......In glacial landscape evolution models, subglacial erosion rates are often related to basal sliding or ice discharge by a power-law. This relation can be justified when considering bed abrasion, where rock debris transported in the basal ice drives erosion. However, the relation is not well...... supported when considering models for quarrying of rock blocks from the bed. Field observations indicate that the principal mechanism of glacial erosion is quarrying, which emphasize the importance of a better way of implementing erosion by quarrying in glacial landscape evolution models. Iverson (2012...

  17. Symmetries in Images on Ancient Seals

    CERN Document Server

    Sparavigna, Amelia

    2008-01-01

    In this paper, we discuss the presence of symmetries in images engraved on ancient seals, in particular on stamp seals. Mainly used to secure the containers from tampering and for owner's identification, these objects appeared during the 5th millennium BC in Mesopotamia. Usually the seals were engraved with simple images, suitable to communicate an immediate information. Rotational symmetries are already displayed by the most ancient stamp seals, whose images reach a quasi-perfect symmetry in their small circular or ovoid spaces. Bilateral symmetries are quite common in Egyptian scarab seals.

  18. Ancient neurilemmoma: A rare oral tumor

    Directory of Open Access Journals (Sweden)

    J Muruganandhan

    2013-01-01

    Full Text Available Neurilemmomas are benign tumors of neural origin composed of Schwann cell proliferation in characteristic patterns. Ancient neurilemmomas are usually longstanding growths that exhibit degenerative features that could be mistaken for malignancy. They are extremely rare in the oral cavity and present in older individuals of long duration. The authors report a case of ancient neurilemmoma in a young patient with short duration of growth. This unique case presented with remarkable histopathological features with respect to vascularity and atypia associated with degenerative change. It is essential to not mistake these features as malignant transformation so as to avoid radical procedures.

  19. The TL dating of ancient porcelain

    International Nuclear Information System (INIS)

    The age determination of ancient porcelain using the pre-dose technique in TL dating was reported. The variation of beta dose with depth below the surface of the porcelain slice, the thermal activation characteristic (TAC) for 110 degree C peak, the measurement of paleodose and the estimation of annual dose were studied. The results show that this technique is suitable for authenticity testing of ancient porcelain, but both accuracy and precision for porcelain dating are worse than those for pottery, because porcelain differs from pottery on composition, structure and firing temperature. Besides, some complicated factors in the pre-dose technique would be the possible cause of the greater errors

  20. Crevassing and calving of glacial ice

    Science.gov (United States)

    Kenneally, James Patrick

    Calving of ice is a relatively new area of research in the still young field of glaciology. In the short time that calving has been studied, it has been mainly treated as an afterthought, with the predominant mode of thinking being that it will happen so to concern oneself with why is not important. Many studies dealt with observations of calving front positions over time vs. ice velocity in an attempt to quantify the calving rate as the difference between the two, while others have attempted to deduce some empirical relationship between calving rate and variables such as water depth or temperature. This study instead addresses the question of why, where, and when ice will first become crevassed, which is an obviously necessary condition for a later calving event to occur. Previous work examining the causes of calving used ideas put forth from a variety of fields, including civil engineering, materials science, and results from basic physics and mechanics. These theories are re-examined here and presented as part of a larger whole. Important results from the field of fracture mechanics are utilized frequently, and these results can be used as a predictor of ice behavior and intrinsic properties of ice, as well as properties like back stresses induced by local pinning points and resistive shears along glacial ice boundaries. A theory of fracture for a material experiencing creep is also presented with applications to ice shelves and crevasse penetration. Finally, a speculative theory regarding large scale iceberg formation is presented. It is meant mainly as an impetus to further discussion on the topic, with the hope that a model relating crevasse geometries to flow parameters can result in crevasse spacings that could produce the tabular icebergs which are so newsworthy. The primary focus of this thesis is to move away from the "after the fact" studies that are so common in calving research, and instead devote energy to determining what creates the conditions that

  1. The Last Glacial Maximum and Termination in the Torres del Paine Region, Southern South America

    Science.gov (United States)

    Garcia, J.; Hall, B. L.; Kaplan, M. R.; Vega, R. M.; Binnie, S.; Gómez, G.; Santana, F.

    2012-12-01

    Torres del Paine National Park (e.g., Lagos del Toro, Sarmiento and Azul). RV moraines parallel each other and can be tracked continuously for several km along the southern slope of Sierra Contreras in Chile. To the east, in present day Argentina, they constitute concentric wide moraine arcs that include tens of frontal moraine ridges. We collected boulders embedded in the relatively sharp RV I and II moraines for 10Be and 26Al cosmogenic-exposure dating to reconstruct the last glacial period. We also sampled and dated cobbles from the main glaciofluvial plain grading to the outer RV I landforms, to crosscheck with the cosmogenic ages obtained from boulders embedded at moraine tops. Additionally, we present new 10Be cosmogenic ages from boulders in TDP I and TDP IV moraines at Lago del Toro basin, which help us to define the structure of the local termination.

  2. Paleoenvironmental change in central Chile as inferred from OSL dating of ancient coastal sand dunes

    Science.gov (United States)

    Andrade, Belisario; Garcia, Juan L.; Lüthgens, Christopher; Fiebig, Markus

    2013-04-01

    To present day, the climatic and geographic expression of glacials and interglacials in the semiarid coast of central Chile remains unclear. The lack of well dated paleoclimatic records has up to now precluded firm conclusions whether maximum glacials evident in the Andes mountain range probably coincide with wetter (e.g., pluvials) or drier conditions at the coast. The natural region locally known as "Norte Chico" represents a transitional semiarid area between the extreme Atacama Desert to the North and the wetter, Mediterranean-like type of climate, to the South. In this semiarid region of Chile several generations of eolian sand dunes, some of them separated by paleosoils, have been preserved. In addition to the occurrence of paleosoils, thick debris flow deposits in some places overly ancient dune bodies, likely indicating significant environmental changes during the formation of these archives. However, the exact timing of these processes within the mid to late Pleistocene and Holocene is still unclear. A key aspect is that some of the ancient dunes are recently hanging above rocky coastlines, where no supply of sand exists today, likely implying their formation during a lower than present, probably glacio-eustatically induced sea level. The location of the research area in a key mid-latitude region of the eastern Pacific in combination with the preserved landform record offers a chance to reconstruct climatic shifts during the Quaternary by studying the variability of morphogenetic conditions throughout time, in order to promote knowledge about possible forcing factors driving climatic variability. Within this pilot study, samples for optically stimulated luminescence (OSL) dating were taken from three different stratigraphic sections that denote a complex environmental variability as indicated by paleosoils and debris flow units intercalated in ancient sand dunes. First dating results inferred from OSL measurements using a post-IR IRSL (pIRIR) protocol for

  3. Testing Hypotheses About Glacial Cycles Against the Observational Record

    DEFF Research Database (Denmark)

    Kaufmann, Robert; Juselius, Katarina

    2013-01-01

    biological activity reduces CO2 concentrations. Glacial variations in ice volume, as proxied by are driven by changes in CO2 concentrations, global and high latitude solar insolation, latitudinal gradients in solar insolation, and the atmospheric concentration of CO2. The model is able to quantify the......We estimate an identified cointegrated vector autoregression (CVAR) model of the climate system to test hypotheses about the physical mechanisms that may drive glacial cycles during the late Pleistocene. Results indicate that a permanent doubling of CO2 generates a 11.1oC rise in Antarctic...... temeprature. Large variations in atmospheric CO2 over glacial cycles are driven by changes in sea ice and sea surface temperature in southern oceans and marine biological activity. The latter can be represented by a two-step process in which iron dust increases biological activity and the increase in...

  4. Interpretation and preliminary simulation of the 40 ka periodicity of the Quaternary glaciation

    Institute of Scientific and Technical Information of China (English)

    LI Nan; CHEN Xing

    2007-01-01

    More and more proxy records approved that the periodicity of the glacial cycles is about 40 ka before MPT (middle Pleistocene transition) as early as late Tertiary from 3.0 Ma to 0.9 Ma, whereas it changes to about 100 ka after MPT.Summer insolation at high latitude in Northern Hemisphere, usually considered as the main external force for the ice age, is dominated by the 23 ka precession period, which does not match the period of the glacial cycles.In this paper, we define an energy index C and its threshold Ct that indicate the net energy supply and the overall response of the climate system.The difference between these two parameters determines whether the ice sheet melts or not, and accordingly the start and termination of the interglacial stages, as well as the periodicity of glacial oscillations.Based on the energy threshold hypothesis, the preliminary simulation experiments are made to test the period of the glacial cycles and driven factors from a conceptual model.The results indicate that energy index C and threshold Ct can interpret not only the 40 ka periodicity before MPT, but also the quasi-100 ka periodicity after MPT to some extent, and the 40 ka is the basic period of the glacial cycles, which discloses the inherent continuity of climatic change before and after MPT.

  5. Records of solar eclipse observations in ancient China

    Science.gov (United States)

    Han, Yanben; Qiao, Qiyuan

    2009-11-01

    Like ancient people at other places of the world, the ancient Chinese lived in awe of the Sun. As they felt solar eclipses extremely significant events, they closely observed the occurrence of solar eclipse. Ancient astronomers further realized very early that solar eclipses were one of the important astronomical phenomena to revise and improve the ancient calendar. Interestingly, ancient emperors regarded solar eclipses as warnings from heaven that might affect the stability of their throne. Consequently, observing and recording solar eclipses became official, which dated far back to ancient China when numerous relevant descriptions were recorded in historical books. These records contribute substantially to China as an ancient civilization, as well as to the research of the long-term variation of the rotation rate of the Earth during >2000 years before the 17th century. This paper briefly reviews the perception, observations and recording of solar eclipses by ancient Chinese astronomers.

  6. Seasonality controls on glacial erosion in the Himalaya and Karakoram

    Science.gov (United States)

    Scherler, D.; Bookhagen, B.; Strecker, M. R.

    2009-04-01

    The waxing and waning of mountain glaciers during the Quaternary left a clear imprint of glacial erosion in form of deeply incised, U-shaped valleys in many mountain ranges around the world. Temperature changes and the availability of moisture are generally thought of as the limiting factors for the geomorphic work that glaciers accomplish. Here, we present evidence that the seasonality of moisture supply strongly affects glacial flow velocities, and thus the erosional efficiency of glaciers. We used ASTER satellite imagery to measure flow velocities of glaciers in the Himalaya and Karakoram during the last decade. Being situated in the transition between moisture sources rooted in the Indian Summer Monsoon and the Northern Hemisphere Westerlies, this region provides a natural laboratory to study the influence of seasonally different moisture sources on glacier dynamics. We interpret the measured surface velocities to reflect ice flux, and use them as a proxy for glacial erosion. We tie our observations to east-west gradients in climate and how they affect the mass balance of glaciers. In the central Himalaya, glaciers characterized by summer accumulation, flow at generally lower velocities compared to glaciers in the Karakoram in a winter accumulation regime. The data also show that most ice flux occurs near the equilibrium line altitude (ELA), and thereby provide empirical support for focused glacial erosion at distinct, climate controlled altitudinal sectors. These zones are presently located at approx. 4.8-5 +/- 0.5 km in the Karakoram and western Himalaya, and at approx. 5.5 +/- 0.5 km in the central and eastern Himalaya. A mean position of the Quaternary ELA, depressed by approx. 500 m, delineates a zone of focused glacial erosion that corresponds well with areas of western end of the Asian highlands, including the western Himalaya, the Karakoram, eastern Hindukush, and the Pamir. Here, aridity constrains the efficiency of fluvial erosion and we suggest that

  7. Geometric dependency of Tibetan lakes on glacial runoff

    Directory of Open Access Journals (Sweden)

    V. H. Phan

    2013-10-01

    Full Text Available The Tibetan Plateau is an essential source of water for Southeast Asia. The runoff from its ~34 000 glaciers, which occupy an area of ~50 000 km2, feeds Tibetan lakes and major Asian rivers like the Indus and Brahmaputra. Reported glacial shrinkage likely has an impact on the runoff. Unfortunately, accurate quantification of glacial changes is difficult over the high-relief Tibetan Plateau. However, it has recently been shown that it is possible to directly assess water level changes of a significant number of the ~900 Tibetan lakes with an area over 1 km2. This paper exploits different remote sensing products to create drainage links between Tibetan glaciers, lakes and rivers. The results allow us to differentiate between lakes with and without outlet. In addition, we introduce the notion of geometric dependency of a lake on glacial runoff, defined as the ratio between the total area of glaciers draining into a lake and the total area of the lake catchment. We determined these dependencies for all ~900 sufficiently large Tibetan lakes. To do so, we combined three remote sensing products: the CAREERI glacier mask product, a lake mask product based on the MODIS MOD44W water product and the HydroSHEDS river network product derived from Shuttle Radar Topography Mission (SRTM elevation data. Using a drainage network analysis, we determined all drainage links between glaciers and lakes. The results show that 25.3% of the total glacier area directly drains into one of 244 Tibetan lakes. The results also give the geometric dependency of each lake on glacial runoff. For example, there are ten lakes with direct glacial runoff from at least 240 km2 of glacier. Three case studies, including one of the well-studied Nam Tso Lake, demonstrate how the geometric dependency of a lake on glacial runoff can be directly linked to hydrological processes.

  8. Is rate of glacial retreat accelerated in Indian Himalaya? (Invited)

    Science.gov (United States)

    Kulkarni, A. V.

    2013-12-01

    The Himalaya has one of the largest concentration of glaciers and rivers like Indus, Ganga and Bramhputra originate from this region. The snow and glacier melt is an important source of water for these rivers. However, this source of water may get affected in the near future due to changes in the cryosphere. Therefore, retreat of Himalayan glaciers are discussed extensively in scientific and public forums in India. Conventionally health of glaciers is assessed using changes in glacial length, as it is widely measured. However changes in glacial length and loss in areal extent near terminus needs to be interpreted carefully, as these changes can be influenced by numerous terrain and climatically sensitive parameters. The terrain parameters which can influence glacial retreat are slope, area altitude distribution, debris cover and orientation. In addition, climatically sensitive parameters like mass balance, glacial lakes and black carbon can also influence glacier retreat. These multiple influences can produce a complex pattern of glacial retreat. In this paper long-term glacier retreat in three river basins in the Indian Himalaya as Tista, Baspa and Parbati will be discussed. These basins are located in different climatically sensitive regions and each basin has unique dominant process of mass wasting. In addition to terrain parameters, influence of process like formation and expansion of moraine dammed lakes in Tista basin, deposition of black carbon on accumulation area in Baspa basin and debris cover in Parbati basin will also be discussed. This will provide understanding on varying influence of different mass wasting processes on glacial retreat during last five decades in the Indian Himalaya.

  9. Climatic aspects in the building of ancient urban settlements in Israel

    Energy Technology Data Exchange (ETDEWEB)

    Potchter, O. (Dept. of Geography, Tel Aviv Univ. (Israel))

    1991-01-01

    The past presents numerous examples of adaptation in urban planning and building design to climatic conditions in different geographical regions. Each historical period developed its own concepts of urbanization and building design, some were unique and others were adapted from period to period. This research will examine to what extent climatic aspects were considered in the building of ancient urban settlements in Israel in the Hellenistic, Roman and Byzantine periods (300 BC-600 AD). Thus this research considers Persian, Hauran and Nabatean influences on architecture and city planning. (orig.).

  10. An integrated assessment of vulnerability to glacial hazards

    OpenAIRE

    Hegglin, E; Huggel, C.

    2008-01-01

    The Rio Santa valley in the Cordillera Blanca, Peru, has been repeatedly affected by severe glacial flood disasters in the past decades. The continuing high rate of glacier retreat has led to the formation and rapid growth of a large number of glacial lakes. Due to the risk of lake outburst floods, downstream communities are confronted with serious hazards. The regional capital of Huaraz is one of the major sites exposed to these hazards. Mainly due to a lack of resources, no systematic evalu...

  11. Alpine glacial topography and the rate of rock column uplift

    DEFF Research Database (Denmark)

    Pedersen, Vivi Kathrine; Egholm, D.L.; Nielsen, S.B.

    2010-01-01

    The present study investigates the influence of alpine glacial erosion on the morphology and relief distribution of mountain regions associated with varying rock column uplift rates. We take a global approach and analyse the surface area distribution of all mountain regions affected by glacial...... basis of this decay, the analysed mountain regions fall within three distinct groupsprimarily reflecting variations in average values of rock columnuplift rates.Mountain ranges affected by rapid rock column uplift display high above-snowline relief and large decay lengths, whereas inactive orogens have...

  12. Managing the effects of accelerated glacial melting on volcanic collapse and debris flows: Planchon-Peteroa Volcano, Southern Andes

    Science.gov (United States)

    Tormey, Daniel

    2010-11-01

    Glaciated mountains are among the most sensitive environments to climatic changes, and recent work has shown that large-scale glacial melting, including at the end of the Pleistocene, caused a significant increase in the incidence of large volcanic sector collapse and debris flows on then-active volcanoes. With current accelerated rates of glacial melting, glaciated active volcanoes are at an increasing risk of sector collapse, debris flow and landslide. These catastrophic events are Earth's most damaging erosion phenomenon, causing extensive property damage and loss of life. This paper illustrates these effects in well-studied settings, focusing on the end-Pleistocene to Holocene glaciovolcanic growth and destruction of the cone of the active volcano Planchon-Peteroa in the Andean Southern Volcanic Zone at latitude 35° 15' S, along the border between Chile and Argentina. The development of the volcano over the last 14,000 years illustrates how glacial melting and magmatic activity can trigger landslides and sector collapses. Planchon had a large sector collapse that produced a highly mobile and erosive debris avalanche 11,000 years BP, and other slope instabilities during the end-Pleistocene/early Holocene deglaciation. The summit amphitheater left after the sector collapse was subject to alternating periods of glaciation and melting-induced lake formation. Breaching of the moraine dams then formed lahars and landslides originating at the western edge of the summit amphitheater, and the deposits are preserved along the western flank of the volcano. Deep incision of moraine deposits further down the western slope of the volcano indicates that the lahars and landslides were water-rich and had high erosive power. As illustrated by Planchon-Peteroa, the interplay among glacial growth and melting, magmatic activity, and slope stability is complex, but must be accounted for in volcanic hazard assessment. Planchon-Peteroa currently has the southernmost temperate zone

  13. Watermarking ancient documents based on wavelet packets

    Science.gov (United States)

    Maatouk, Med Neji; Jedidi, Ola; Essoukri Ben Amara, Najoua

    2009-01-01

    The ancient documents present an important part of our individual and collective memory. In addition to their preservation, the digitization of these documents may offer users a great number of services like remote look-up and browsing rare documents. However, the documents, digitally formed, are likely to be modified or pirated. Therefore, we need to develop techniques of protecting images stemming from ancient documents. Watermarking figures to be one of the promising solutions. Nevertheless, the performance of watermarking procedure depends on being neither too robust nor too invisible. Thus, choosing the insertion field or mode as well as the carrier points of the signature is decisive. We propose in this work a method of watermarking images stemming from ancient documents based on wavelet packet decomposition. The insertion is carried out into the maximum amplitude ratio being in the best base of decomposition, which is determined beforehand according to a criterion on entropy. This work is part of a project of digitizing ancient documents in cooperation with the National Library of Tunis (BNT).

  14. Microscopical Examination of Ancient Silver Coins

    International Nuclear Information System (INIS)

    The microstructure of three silver coins of the IIId century B.C. from the Illyrian king Monounios, the ancient Greek city of Dyrrachion and of Korkyra was studied with XRF and microscopy. From this investigation it turned out that these coins have different chemical composition and microstructure that imply different minting method

  15. LD Students and the Ancient Mariner.

    Science.gov (United States)

    Cohen, Barbara L.

    1988-01-01

    Synectics, the making of analogies, was used with learning disabled high school seniors to provide them with a creative process that aids in developing a deeper understanding of literature. After studying Coleridge's "Rime of the Ancient Mariner," the students completed a six-step process and produced a short writing assignment. (VW)

  16. Fast neutron activation analysis of ancient mirror

    International Nuclear Information System (INIS)

    About fifty specimens of ancient Chinese bronze mirror from various dynasties are analysed by fast neutron radiated from neutron generator. The contents of copper, tin and lead in the mirror are listed in this paper. Experimental method and measurement equipment are described too

  17. Mitochondrial phylogenomics of modern and ancient equids

    DEFF Research Database (Denmark)

    Vilstrup, Julia T; Seguin-Orlando, Andaine; Stiller, Mathias; Ginolhac, Aurelien; Raghavan, Maanasa; Nielsen, Sandra C A; Weinstock, Jacobo; Froese, Duane; Vasiliev, Sergei K; Ovodov, Nikolai D; Clary, Joel; Helgen, Kristofer M; Fleischer, Robert C; Cooper, Alan; Shapiro, Beth; Orlando, Ludovic Antoine Alexandre

    2013-01-01

    sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy's zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize...

  18. Ancient science in a digital age.

    Science.gov (United States)

    Lehoux, Daryn

    2013-03-01

    Technology is rapidly changing our understanding of ancient science. New methods of visualization are bringing to light important texts we could not previously read; changes in online publishing are allowing unprecedented access to difficult-to-find materials; and online mapping tools are offering new pictures of lost spaces, connectivities, and physical objects. PMID:23789512

  19. Unlocking the Mysteries of Ancient Egypt.

    Science.gov (United States)

    Riechers, Maggie

    1995-01-01

    Describes the work of Egyptologist William Murnane who is recording the ritual scenes and inscriptions of a great columned hall from the days of the pharaohs. The 134 columns, covered with divine imagery and hieroglyphic inscriptions represent an unpublished religious text. Briefly discusses ancient Egyptian culture. Includes several photographs…

  20. A Roman Dodecahedron as an ancient rangefinder

    OpenAIRE

    Sparavigna, Amelia Carolina

    2012-01-01

    Rangefinders are instruments used for ballistics and for surveying in general. I report about some of them, ranging from the ancient Rome to modern methods. In particular, I am discussing the use of Roman Dodecahedra, bronze artifacts of gallo-roman origin, for measuring distance

  1. Precursors of Vocational Psychology in Ancient Civilizations.

    Science.gov (United States)

    Dumont, Frank; Carson, Andrew D.

    1995-01-01

    Examines philosophical theories produced by two ancient civilizations (Eastern Mediterranean and Chinese) for applications to an applied psychology of work. Includes analysis of Egyptians, Semites, and Greeks, with a special emphasis on Plato. Suggests that many basic elements of vocational psychology were present during the first millennium B.C.…

  2. The Roots of Science in Ancient China.

    Science.gov (United States)

    Fisher, Arthur

    1982-01-01

    A 45-year-old research project (culminating in the multivolume "Science and Civilization in China") is examining major scientific innovations in ancient China and attempting to explain why, although the Chinese gained a technological edge in the past, they did not make the forward leap into modern science. (JN)

  3. Planetary science: Traces of ancient lunar water

    Science.gov (United States)

    Hauri, Erik H.

    2013-03-01

    The presence of water in lunar volcanic rocks has been attributed to delivery after the Moon formed. Water detected in rocks from the ancient lunar highlands suggests that the Moon already contained water early in its history, and poses more challenges for the giant impact theory of Moon formation.

  4. A probabilistic model of Ancient Egyptian writing

    OpenAIRE

    Nederhof, Mark Jan; Rahman, Fahrurrozi

    2015-01-01

    This article investigates a probabilistic model to describe how signs form words in Ancient Egyptian writing. This applies to both hieroglyphic and hieratic texts. The model uses an intermediate layer of sign functions. Experiments are concerned with finding the most likely sequence of sign functions that relates a given sequence of signs and a given sequence of phonemes. Postprint

  5. Ancient Pyramids Help Students Learn Math Concepts

    Science.gov (United States)

    Smith, Courtney D.; Stump, Amanda M.; Lazaros, Edward J.

    2010-01-01

    This article presents an activity that allows students to use mathematics and critical-thinking skills to emulate processes used by the ancient Egyptians to prepare the site for the Pyramids of Giza. To accomplish this, they use three different methods. First, they create a square using only simple technological tools that were available to the…

  6. Discovering the Ancient Maya from Space

    Science.gov (United States)

    Sever, T. L.

    2008-01-01

    The Pet6n region of northern Guatemala contains some of the most significant Mayan archeological sites in Latin America. It was in this region that the Maya civilization began, flourished, and abruptly disappeared. Remote sensing technology is helping to locate and map ancient Maya sites that are threatened today by accelerating deforestation and looting. Thematic Mapper, IKONOS, and QuickBird satellite, and airborne STAR-3i and AIRSAR radar data, combined with Global Positioning System (GPS) technology, are successfully detecting ancient Maya features such as sites, roadways, canals, and water reservoirs. Satellite imagery is also being used to map the bajos, which are seasonally flooded swamps that cover over 40% of the land surface. Through the use of various airborne and satellite sensor systems we have been able to detect and map ancient causeways, temples, reservoirs, and land forms, and locate these features on the ground through GPS technology. Recently, we have discovered that there is a strong relationship between a tropical forest vegetation signature in satellite imagery and the location of archeological sites. We believe that the use of limestone and lime plasters in ancient Maya construction affects the moisture, nutrition, and plant species of the surface vegetation. We have mapped these vegetation signatures in the imagery and verified through field survey that they are indicative of archeological sites. Through the use of remote sensing and GIS technology it is possible to identify unrecorded archeological features in a dense tropical forest environment and monitor these cultural features for their protection.

  7. Characteristics of mortars from ancient bridges

    Czech Academy of Sciences Publication Activity Database

    Frankeová, Dita; Slížková, Zuzana; Drdácký, Miloš

    Vol. 7. Dordrecht : Springer, 2012 - (Válek, J.; Hughes, J.; Groot, J.), s. 165-174 ISBN 978-94-007-4634-3 R&D Projects: GA ČR(CZ) GA103/09/2067; GA MŠk(CZ) LA09008 Institutional support: RVO:68378297 Keywords : mortars * ancient bridges * analytical methods Subject RIV: AL - Art, Architecture, Cultural Heritage

  8. The Ancient Kemetic Roots of Library and Information Science.

    Science.gov (United States)

    Zulu, Itibari M.

    This paper argues that the ancient people of Kemet (Egypt), "the black land," built and operated the first major libraries and institutions of higher education in the world. Topics of discussion include the Ancient Egyptians as an African people; a chronology of Ancient Kemet; literature in Kemet; a history of Egyptian Librarianship; the…

  9. Lost-Wax Casting in Ancient China: New Discussion on Old Debates

    Science.gov (United States)

    Zhou, Weirong; Huang, Wei

    2015-07-01

    The possible use of lost-wax casting in China has long been a matter of controversy. Based on the study of pertinent ancient texts concerning the technical origins of lost-wax casting in China, direct examination of questioned ancient Chinese bronzes as well as definite lost-wax castings from both overseas and China, and modern production of objects using piece-mold casting, the authors point out their own conceptual ideas about ancient lost-wax casting as follows. First, the lost-wax casting technique does not have its earliest origins in ancient China but rather from the Sumerians in Mesopotamia, where it was predominantly used to cast small human and animal figures (statuettes). Next, some essential characteristics of the lost-wax casting technique can be identified from the point of view of a distortable soft starting model. The locally deformed shape of lost-wax castings is found to be variable. Finally, it is improper to consider the ease of extraction from the mold as the criterion for distinguishing lost-wax casting from piece-mold casting. It is therefore incorrect to conclude that the three-dimensional openwork decorations present on Chinese bronzes from the Spring and Autumn Period, and the Warring States Period, are fabricated using lost-wax castings.

  10. Balancing Acts Between Ancient and Modern Cities: The Ancient Greek Cities Project of C. A. Doxiadis

    OpenAIRE

    Zarmakoupi, Mantha

    2015-01-01

    This paper examines the inception and development of the Ancient Greek Cities (AGC) research project (1963–77) of Constantinos A. Doxiadis and addresses the novelty of its methodological approach to the study of classical urbanism. With the AGC project, Doxiadis launched a comprehensive study of the ancient Greek built environment to provide an overview of the factors involved in its shaping. The project produced 24 published volumes — the first two laying out the historical and methodologica...

  11. Climate-induced changes to the ancestral population size of two Patagonian galaxiids: the influence of glacial cycling.

    Science.gov (United States)

    Zemlak, Tyler S; Walde, Sandra J; Habit, Evelyn M; Ruzzante, Daniel E

    2011-12-01

    Patagonia is one of the few areas in the Southern Hemisphere to have been directly influenced by Quaternary glaciers. In this study, we evaluate the influence that Quaternary glacial ice had on the genetic diversity of two congeneric fish species, the diadromous Galaxias maculatus and the nondiadromous Galaxias platei, using multilocus estimates of effective population size through time. Mid-Quaternary glaciations had far-reaching consequences for both species. Galaxias maculatus and G. platei each experienced severe genetic bottlenecks during the period when Patagonia ice sheet advance reached its maximum positions c. 1.1-0.6 Ma. Concordant drops in effective size during this time suggest that range sizes were under similar constraints. It is therefore unlikely that coastal (brackish/marine) environments served as a significant refuge for G. maculatus during glacial periods. An earlier onset of population declines for G. platei suggests that this species was vulnerable to modest glacial advances. Declines in effective sizes were continuous for both species and lasted into the late-Pleistocene. However, G. maculatus exhibited a strong population recovery during the late-Quaternary (c. 400,000 bp). Unusually long and warm interglacials associated with the late-Quaternary may have helped to facilitate a strong population rebound in this primarily coastal species. PMID:22077139

  12. Persistent millennial-scale climate variability in the eastern tropical North Pacific over the last two glacial cycles

    Science.gov (United States)

    Arellano-Torres, Elsa; Ganeshram, Raja S.; Pichevin, Laetitia E.; Salas-de-Leon, David Alberto

    2015-06-01

    High-resolution sediment records from the eastern tropical North Pacific (ETNP) spanning the last ~240 ka B.P. were studied to document the nature of millennial-scale climatic events in the tropical Pacific and to investigate teleconnection mechanisms. We present organic carbon (%OC) and diffuse spectral reflectivity records as indicative of upwelling and productivity changes off NW Mexico over the middle to late Pleistocene. The new productivity records document the persistence of abrupt millennial-scale changes over the last two glacial cycles. Detailed spectral and wavelet time series analyses show the predominance of longer climatic cycles (2-6 ka) during the last and the penultimate glacial periods. The persistence of millennial variability during the penultimate glacial, in absence of large ice rafted debris events in the North Atlantic, suggests that freshwater input through ice sheet dynamics is not essential for millennial-scale climate variability. Given the worldwide emerging picture of remarkable similar millennial-scale records over long time periods, we suggest that the pacing of this climate variability may represent a natural resonance in the climate system, amplified by a tightly coupled oceanic and atmospheric teleconnection processes. We present a schematic scenario of millennial-scale climate change depicting the role of the tropical Pacific in this global teleconnection system by linking productivity and upwelling changes in the ETNP with shifts in the position of the Intertropical Convergence Zone and the strength of the subtropical North Pacific High.

  13. Ancient Egypt in our Cultural Heritage?

    Directory of Open Access Journals (Sweden)

    Vera Vasiljević

    2016-02-01

    Full Text Available Inspiration derived from ancient Egypt is usually expressed through the Egyptian motifs in arts and popular culture of the 19th and 20th centuries, as well as through the non-scientific interpretations of the culture, very much based upon the Renaissance ones. The number and variety of material and non-material traces of this fascination are most expressed in the countries where, along with the early support for the institutional development of Egyptology, there existed economically potent educated middle classes (Western and Central Europe, USA, but may also be traced elsewhere. The public fascination by ancient Egypt has not ceased by the times of foundation of Egyptology, marked by the decipherment of the hieroglyphic script in 1822. Until the end of the 20th century Egyptologists have rarely dealt with the prelude to their discipline, limiting their interest to the critical approach to ancient sources and to noting the attempts to interpret the hieroglyphic script and the function of pyramids. However, the rising importance of the reception studies in other disciplines raised the interest of Egyptologists for the "fascination of Egypt", thus changing the status of various modes of expressing "Egyptomania" – they have thus become a part of the cultural heritage, registered, documented, preserved and studied. The research of this kind is only beginning in Serbia. The line of inquiry enhances the knowledge of the scope, manifestations and roles of the interest in Egypt, not limited by the national or political borders. On the other hand, the existence of the cultural heritage similar to the wider European view of ancient Egypt – short remarks by Jerotej Račanin, Kandor by Atanasije Stojković, the usage of architectural motifs derived from Egypt, the emergence of small private collections, to mention several early examples – all show that the research into the reception of ancient Egypt may contribute to the knowledge about the history

  14. Genetic diversity among ancient Nordic populations.

    Directory of Open Access Journals (Sweden)

    Linea Melchior

    Full Text Available Using established criteria for work with fossil DNA we have analysed mitochondrial DNA from 92 individuals from 18 locations in Denmark ranging in time from the Mesolithic to the Medieval Age. Unequivocal assignment of mtDNA haplotypes was possible for 56 of the ancient individuals; however, the success rate varied substantially between sites; the highest rates were obtained with untouched, freshly excavated material, whereas heavy handling, archeological preservation and storage for many years influenced the ability to obtain authentic endogenic DNA. While the nucleotide diversity at two locations was similar to that among extant Danes, the diversity at four sites was considerably higher. This supports previous observations for ancient Britons. The overall occurrence of haplogroups did not deviate from extant Scandinavians, however, haplogroup I was significantly more frequent among the ancient Danes (average 13% than among extant Danes and Scandinavians (approximately 2.5% as well as among other ancient population samples reported. Haplogroup I could therefore have been an ancient Southern Scandinavian type "diluted" by later immigration events. Interestingly, the two Neolithic samples (4,200 YBP, Bell Beaker culture that were typed were haplogroup U4 and U5a, respectively, and the single Bronze Age sample (3,300-3,500 YBP was haplogroup U4. These two haplogroups have been associated with the Mesolithic populations of Central and Northern Europe. Therefore, at least for Southern Scandinavia, our findings do not support a possible replacement of a haplogroup U dominated hunter-gatherer population by a more haplogroup diverse Neolithic Culture.

  15. Evolution of the stable carbon isotope composition of atmospheric CO2 over the last glacial cycle

    Science.gov (United States)

    Eggleston, S.; Schmitt, J.; Bereiter, B.; Schneider, R.; Fischer, H.

    2016-03-01

    We present new δ13C measurements of atmospheric CO2 covering the last glacial/interglacial cycle, complementing previous records covering Terminations I and II. Most prominent in the new record is a significant depletion in δ13C(atm) of 0.5‰ occurring during marine isotope stage (MIS) 4, followed by an enrichment of the same magnitude at the beginning of MIS 3. Such a significant excursion in the record is otherwise only observed at glacial terminations, suggesting that similar processes were at play, such as changing sea surface temperatures, changes in marine biological export in the Southern Ocean (SO) due to variations in aeolian iron fluxes, changes in the Atlantic meridional overturning circulation, upwelling of deep water in the SO, and long-term trends in terrestrial carbon storage. Based on previous modeling studies, we propose constraints on some of these processes during specific time intervals. The decrease in δ13C(atm) at the end of MIS 4 starting approximately 64 kyr B.P. was accompanied by increasing [CO2]. This period is also marked by a decrease in aeolian iron flux to the SO, followed by an increase in SO upwelling during Heinrich event 6, indicating that it is likely that a large amount of δ13C-depleted carbon was transferred to the deep oceans previously, i.e., at the onset of MIS 4. Apart from the upwelling event at the end of MIS 4 (and potentially smaller events during Heinrich events in MIS 3), upwelling of deep water in the SO remained reduced until the last glacial termination, whereupon a second pulse of isotopically light carbon was released into the atmosphere.

  16. Ocean - ice sheet interaction along the NW European margin during the last glacial phases

    Science.gov (United States)

    Becker, L. W. M.; Sejrup, H. P.; Haflidason, H.; Hjelstuen, B. O. B.

    2015-12-01

    The NW European continental margin was repeatedly covered by shelf edge glaciations during the last glacial cycles. Here, we present a compilation of new and previously published data from a SW to NE transect of 8 sediment cores raised along the upper continental slope. This study aims to investigate the interaction between sea surface conditions and the variability seen in the British Irish Ice Sheet (BIIS) and the Fennoscandian Ice Sheet (FIS) during the last 13-40 ka BP. Ice Rafted Debris (IRD) counts, IRD flux data, grain size data, the content of the polar planktonic foraminifera Neogloboquadrina pachyderma (sin) and ∂18O measurements were compiled and combined with new Bayesian age models. From 40-24.5 ka BP the build up and consecutive confluence of the BIIS and the FIS are reflected in sediment composition and flux data. Pulses of large quantities of fine material to the southern part of the transect suggest riverine BIIS related influx. The sediment composition in cores close to the Norwegian channel indicates that the Norwegian Channel Ice Stream (NCIS) was only active between 24.5-18.5 ka BP during the last glacial stage. The planktonic foraminifera data during this period strongly suggests a dependence of NCIS extent variability and pulses in warm Atlantic water entering the Nordic Seas. In the northernmost cores rapidly deposited, laminated sediments and ∂18O spikes in planktonic foraminifera dated to 18.5 ka BP were interpreted as meltwater plume deposits. This may reflect NCIS retreat allowing BIIS and FIS to unzip and route ice dammed lake- and meltwater to the margin. In conclusion, the investigation suggests a close co-variation in extent of marine based parts of the BIIS, the FIS and ocean circulation while demonstrating the strong influence of the local glacial history on standard open marine proxies. This suggests that tuning chronologies of single marine records to ice cores in some regions might be more challenging than previously

  17. Letter to the editor: Genetics and the archaeology of ancient Israel.

    Science.gov (United States)

    Brody, Aaron J; King, Roy J

    2013-12-01

    This letter is a call for DNA testing on ancient skeletal materials from the southern Levant to begin a database of genetic information of the inhabitants of this crossroads region. In this region, during the Iron I period traditionally dated to circa 1200-1000 BCE, archaeologists and biblical historians view the earliest presence of a group that called itself Israel. They lived in villages in the varied hill countries of the region, contemporary with urban settlements in the coastal plains, inland valleys, and central hill country attributed to varied indigenous groups collectively called Canaanite. The remnants of Egyptian imperial presence in the region lasted until around 1150 BCE, postdating the arrival of an immigrant group from the Aegean called the Philistines circa 1175 BCE. The period that follows in the southern Levant is marked by the development of territorial states throughout the region, circa 1000-800 BCE. These patrimonial kingdoms, including the United Kingdom of Israel and the divided kingdoms of northern Israel and Judah, coalesced varied peoples under central leadership and newly founded administrative and religious bureaucracies. Ancient DNA testing will give us a further refined understanding of the individuals who peopled the region of the southern Levant throughout its varied archaeological and historic periods and provide scientific data that will support, refute, or nuance our sociohistoric reconstruction of ancient group identities. These social identities may or may not map onto genetic data, but without sampling of ancient DNA we may never know. A database of ancient DNA will also allow for comparisons with modern DNA samples collected throughout the greater region and the Mediterranean littoral, giving a more robust understanding of the long historical trajectories of regional human genetics and the genetics of varied ancestral groups of today's Jewish populations and other cultural groups in the modern Middle East and Mediterranean

  18. Reconstruction of late glacial climates from the groundwater archive: Cl- and 36Cl in the Carrizo aquifer, Texas

    International Nuclear Information System (INIS)

    The climate history (temperature and precipitation minus evapotranspiration) of southern Texas was reconstructed for the past 35 ka, on the basis of groundwater data from the Carrizo aquifer. Palaeotemperatures derived from noble gases dissolved in groundwater indicate a mean annual temperature 5 deg. C lower than today for the last glacial maximum. Recharge rates (a measure of precipitation minus evapotranspiration) were estimated from Cl- and from 36Cl concentrations after performing corrections for variations of atmospheric Cl- and 36Cl deposition rates. The two lines of evidence are consistent and indicate that the recharge rate between 16 and 20 ka was up to to 100% higher than today. The occurrence of high lake levels in the Great Basin during that period suggests that the shift to a better climate during the late glacial was a common feature of the southwestern and southern United States of America. (author). 22 refs, 3 figs, 1 tab

  19. The Influence of Glacial Ice Sheets on Atlantic Meridional Overturning Circulation Through Atmospheric Circulation Change under Glacial Climate

    Science.gov (United States)

    Sherriff-Tadano, S.; Abe-Ouchi, A.; Yoshimori, M.; Oka, A.; Chan, W. L.

    2014-12-01

    It is well known that glacial ice sheets (Laurentide, Fennoscandian and Antarctic ice sheets) exert a large influence on the climate including the atmospheric circulation. Moreover, recent climate modeling studies suggest that glacial ice sheets have a large impact on the Atlantic meridional overturning circulation (AMOC). However, the process by which the ice sheets impact on the AMOC is not yet fully understood. On the other hand, recent studies showed that surface wind changes play a crucial role on changes to the AMOC under glacial climate. Therefore, in this study, we investigate in detail, the process by which the ice sheet modifies the AMOC through surface wind change. Here we conduct numerical experiments using an atmospheric general circulation model (AGCM) and an ocean general circulation model (OGCM) separately. Our method consists of 2 steps. First, from AGCM experiments, we evaluate the effect of glacial ice sheets on the surface wind. Second, from OGCM experiments, we evaluate the influence of the wind stress change on the AMOC by applying the surface wind change as a boundary condition, while leaving other boundary conditions (surface heat and water fluxes) unchanged. In addition, we conduct several sensitivity experiments. Using the AGCM, we explore individual ice sheet effect, ice sheet topography effect and albedo effect on surface wind change. Moreover, using the OGCM, we change the surface wind gradually or apply the surface wind change only at a specific region in order to explore the wind change effect in detail. We find that glacial ice sheets largely intensify the AMOC by surface wind change under glacial climate. Compare to other regions, it reveals that the wind change at the North Atlantic (NA) is a key region. There, the northern glacial ice sheet topography intensifies the Icelandic Low and anti-cyclonic circulation over the Laurentide ice sheet. However, this wind effect is effective only when the NA is not widely covered by sea ice

  20. A major glacial-interglacial change in aeolian dust composition inferred from Rare Earth Elements in Antarctic ice

    OpenAIRE

    Gabrielli, Paolo; Wegner, Anna; Petit, Jean Robert; Delmonte, Barbara; De Deckker, Patrick; Gaspari, Vania; Fischer, Hubertus; Ruth, Urs; Kriews, Michael; Boutron, Claude; Cescon, Paolo; Barbante, Carlo

    2010-01-01

    We present the first Rare Earth Elements (REE) concentration record determined in 294 sections of an Antarctic ice core (EPICA Dome C), covering a period from 2.9 to 33.7 kyr BP. REE allow a detailed quantitative evaluation of aeolian dust composition because of the large number of variables (i.e. 14 elements). REE concentrations match the particulate dust concentration profile over this period and show a homogeneous crustal-like composition during the last glacial stage (LGS), with only a sl...

  1. Climate Change, Glacier Retreat and Sediment Waves: Evidences from Fans in the Fox Glacial valley (New Zealand) and Analogical Modeling

    Science.gov (United States)

    Gomez, C. A.; Purdie, H.

    2015-12-01

    As global climate continues warm, mountain environments are changing, and rates of glacial retreat are unprecedented. The hydrologic implications of this rapid ice retreat and changing climate conditions have been the focus of numerous studies, but the consequent effects on the sediment cascade in valleys and tributaries has received considerably less attention. In the present study, we investigated the role of glacial recession on sediment mobilization and deposition in a mountain valley catchment at Fox Glacier, New Zealand. In particular, we analyze the role of glacier recession on the formation of sediment fans in the main valley. Emphasis was put on the role of sediment, impounded by the glacier in side tributaries, becoming rapidly available for remobilization as the glacier retreats. The method is based on field observations, and measurements using high resolution GNSS (Trimble R8 survey grade differential GNSS) and photogrammetric methods using Structure from Motion based on ground-, helicopter- and UAV- photographs. Field observations were conducted in the period 2014 - 2015, and have been complimented with analogic modeling in the laboratory, in order to comprehend the processes driving rapid fan formation. The analogic model reproduced the retreat of the glacier and the response of a tributary, with simulations for both glaciated and de-glaciated conditions. For similar hydrologic and slope parameters, the fans created after glacial retreat have shown an acceleration in their formation of up to 12 times compared to fanes created without glacial influence. Field observations within the period 2013 - 2015 of Straight Creek Fan (Fox Valley, New Zealand) have confirmed laboratory simulations, with the fan growing to a radius superior to 200 m and a valley-long width superior to 450 m. As glaciers continue to retreat, it can be expected that sediment surges will occur in affected valleys, without the requirements of other forcing like earthquake or extreme

  2. Periodicity, the Canon and Sport

    Directory of Open Access Journals (Sweden)

    Thomas F. Scanlon

    2015-10-01

    Full Text Available The topic according to this title is admittedly a broad one, embracing two very general concepts of time and of the cultural valuation of artistic products. Both phenomena are, in the present view, largely constructed by their contemporary cultures, and given authority to a great extent from the prestige of the past. The antiquity of tradition brings with it a certain cachet. Even though there may be peripheral debates in any given society which question the specifics of periodization or canonicity, individuals generally accept the consensus designation of a sequence of historical periods and they accept a list of highly valued artistic works as canonical or authoritative. We will first examine some of the processes of periodization and of canon-formation, after which we will discuss some specific examples of how these processes have worked in the sport of two ancient cultures, namely Greece and Mesoamerica.

  3. 76 FR 50476 - Application To Export Electric Energy; Glacial Energy of Texas, Inc.

    Science.gov (United States)

    2011-08-15

    ... Application To Export Electric Energy; Glacial Energy of Texas, Inc. AGENCY: Office of Electricity Delivery.... (Glacial) has applied for authority to transmit electric energy from the United States to Mexico pursuant...)). On July 14, 2011, DOE received an application from Glacial for authority to transmit electric...

  4. Glacial melting: an overlooked threat to Antarctic krill

    Science.gov (United States)

    Fuentes, Verónica; Alurralde, Gastón; Meyer, Bettina; Aguirre, Gastón E.; Canepa, Antonio; Wölfl, Anne-Cathrin; Hass, H. Christian; Williams, Gabriela N.; Schloss, Irene R.

    2016-01-01

    Strandings of marine animals are relatively common in marine systems. However, the underlying mechanisms are poorly understood. We observed mass strandings of krill in Antarctica that appeared to be linked to the presence of glacial meltwater. Climate-induced glacial meltwater leads to an increased occurrence of suspended particles in the sea, which is known to affect the physiology of aquatic organisms. Here, we study the effect of suspended inorganic particles on krill in relation to krill mortality events observed in Potter Cove, Antarctica, between 2003 and 2012. The experimental results showed that large quantities of lithogenic particles affected krill feeding, absorption capacity and performance after only 24 h of exposure. Negative effects were related to both the threshold concentrations and the size of the suspended particles. Analysis of the stomach contents of stranded krill showed large quantities of large particles ( > 106 μm3), which were most likely mobilized by glacial meltwater. Ongoing climate-induced glacial melting may impact the coastal ecosystems of Antarctica that rely on krill. PMID:27250339

  5. Glacial Influences on Solar Radiation in a Subarctic Sea.

    Science.gov (United States)

    Understanding macroscale processes controlling solar radia­tion in marine systems will be important in interpreting the potential effects of global change from increasing ultraviolet radiation (UV) and glacial retreat. This study provides the first quantitative assessment of UV i...

  6. Luminescence dating of ancient Darhad basin, Mongolia

    Science.gov (United States)

    Cheul Kim, Jin; Yi, Sangheon; Lim, Jaesoo; Kim, Ju-Yong

    2016-04-01

    Darhad basin is located in the northern Mongolia, in the western end of the Baikal Rift Zone. In contrast to the neighboring Lake Hovsgol, Mongolia's largest and deepest lake, the Darhad is a drained lake basin. It is ~100 km long (north-south), 20-40 km wide and covered by sediments which locally exceed 500 m thickness (Zorin et al., 1989). Darhad basin is characterized by alternating episodes of expansion and desiccation that are closely related with the Pleistocene damming events. Previous studies of the Darhad Basin suggest that the last paleolake was dammed by a large glacier or the sediments (Selivanov, 1967, 1968; Krivonogov et al., 2005; Gillespie et al., 2008). Especially, recent expansion of the paleolake might be caused by the two glacial maxima during MIS 4 and 2. However, glacier-dammed lakes might be short-lived, dried up and permafrost occurred in the drained basin during the Holocene period. The uppermost paleolake sediments (13.2 m depth) are exposed following the curvature of the meandering river (called "Hodon outcrop"). It is considered the most likely site for the youngest paleolake sediments because it is distributed in the northern middle part of the paleolake. Krivonogov et al. 2012 described the Hodon outcrop with the sedimentological and chronological data. Age dating of 16 samples (11 mollusk shells, 5 wood fragments) indicated that Hodon outcrop sediments were deposited between 10.1±7 and 4.9±5 ka. However, the ages obtained on shells much older dates than the matched wood samples because of ingestion of old carbon by mollusks. The age difference between shells and wood fragments is a minimum of 1.73 ka and a maximum of 3.41 ka (average 2.5 ka). In this case, 14C ages from shells should be corrected with appropriate correction factor. However, the old carbon effects could vary temperally and spatially in the Darhad paleolake. The limited number of the 14C ages from wood fragments result in a simple linear trend in the depth-age curve

  7. XPS and XRF depth patina profiles of ancient silver coins

    International Nuclear Information System (INIS)

    Ancient silver coins of different historical periods going from IV cent. B.C. up to recent XIX century, coming from different Mediterranean countries have been investigated with different surface physical analyses. X-ray photoelectron spectroscopy (XPS) analysis has been performed by using electron emission induced by 1.4 keV X-rays. X-ray fluorescence (XRF) analysis has been devoted by using 30 keV electron beam. Scanning electron microscopy (SEM) has been employed to analyze the surface morphology and the X-ray map distribution by using a 30 keV microbeam. Techniques were used to investigate about the patina composition and trace elements as a function of the sample depth obtained coupling XPS to 3 keV argon ion sputtering technique.

  8. XPS and XRF depth patina profiles of ancient silver coins

    Energy Technology Data Exchange (ETDEWEB)

    Caridi, F., E-mail: fcaridi@unime.it [Facoltà di Scienze MM. FF. NN., Università di Messina, V.le F. Stagno D’Alcontres 31, Messina (Italy); INFN-Sez. CT, Gr. coll. di Messina, V.le F. Stagno D’Alcontres 31, Messina (Italy); Torrisi, L. [Dip.to di Fisica, Università di Messina, V.le F. Stagno D’Alcontres 31, Messina (Italy); INFN-Laboratori Nazionali del Sud, V. S. Sofia 62, 95123 Catania (Italy); Cutroneo, M. [Dip.to di Fisica, Università di Messina, V.le F. Stagno D’Alcontres 31, Messina (Italy); Barreca, F. [Advanced and Nanomaterials Research S.r.l., V.le F. Stagno D’Alcontres 31, Messina (Italy); Gentile, C. [Dip.to di Fisica, Università di Messina, V.le F. Stagno D’Alcontres 31, Messina (Italy); Serafino, T. [Dip.to di Fisica della materia e ingegneria elettronica, V.le F. Stagno D’Alcontres 31, Messina (Italy); Castrizio, D. [Dip.to di Scienze dell’Antichità, Università di Messina (Italy)

    2013-05-01

    Ancient silver coins of different historical periods going from IV cent. B.C. up to recent XIX century, coming from different Mediterranean countries have been investigated with different surface physical analyses. X-ray photoelectron spectroscopy (XPS) analysis has been performed by using electron emission induced by 1.4 keV X-rays. X-ray fluorescence (XRF) analysis has been devoted by using 30 keV electron beam. Scanning electron microscopy (SEM) has been employed to analyze the surface morphology and the X-ray map distribution by using a 30 keV microbeam. Techniques were used to investigate about the patina composition and trace elements as a function of the sample depth obtained coupling XPS to 3 keV argon ion sputtering technique.

  9. Studies of modern and ancient solar energetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, R.C.

    1998-10-01

    Modern solar energetic particles (SEPs) have been studied for about 50 years by satellites and ground-based observations. These measurements indicate much about the nature of SEPs but cover too short a period to quantify the probabilities of very large solar particle events. Many SEPs have high enough energies to make nuclides in material in which they interact. Some nuclides measured in lunar samples have been used to extend the record about SEPs back several million years. Some new measurements of modern SEPs during the last solar cycle and new results for nuclides made by SEPs in lunar samples are presented and their implications discussed. Both the modern and ancient records need to be improved, and methods to get a better understanding of solar energetic particles are discussed. The SEP average fluxes from both sets of records are similar, and both sets can be used to show that huge fluxes of SEPs are very rare.

  10. Palaeoceanography & Palaeoclimate during the penultimate Glacial-Interglacial transition in the Black Sea - Termination II

    Science.gov (United States)

    Wegwerth, Antje; Dellwig, Olaf; Kaiser, Jérôme; Bard, Edouard; Ménot, Guillemette; Nowaczyk, Norbert; Plessen, Birgit; Schnetger, Bernhard; Shumilovskikh, Lyudmila; Arz, Helge

    2013-04-01

    The epicontinental Black Sea is very sensitive to environmental changes thus forming an ideal archive of regional climate change and teleconnective responses to the coupled North Atlantic ocean-atmosphere system. Here we focus on the climatic and hydrological evolution of the SE Black Sea during the glacial-interglacial transition of Termination II to the Eemian (~134-122 ka BP) by using different geochemical and sedimentological proxies. Long-term cold conditions during the ending penultimate glacial are provided by TEX86 derived summer sea-surface temperatures (SST) of around 9°C and are thus considerable lower than present values of about 23°C. Coastal ice formation during extreme winters accounted for huge discharge of ice rafted debris (IRD) until 130.5 ka BP. Milder more humid conditions during this period are indicated for instance by elevated Cr/Al values typical for an ultramafic Pontic Mountain source (Piper and Calvert, 2011) thereby suggesting an increased sediment load mainly from the east-Anatolian rivers Kizilirmak and Yesilirmak. The abrupt disappearance of IRD along with increasing δ18O, Mg/Ca, and Sr/Ca of benthic ostracods (Candona spp.) resulted from slightly rising temperatures (SST 11°C) until 128.8 ka BP. Thereafter, SST rapidly increased within less than 500 years to about 25°C revealing a dramatic change from glacial to interglacial conditions. First analyses of U/Ca-ratios of ostracods show sharply increasing values not before ~128.3 ka BP, synchronous to the appearance of larval Mytilus galloprovincialis shells, due to the Mediterranean transgression into the Black Sea. The simultaneous increase of TOC and Mo/Al of the bulk sediment indicates the development of oxygen-deficient bottom waters and Eemian sapropel formation favoured by the establishment of a halocline shortly after the Mediterranean-Black Sea reconnection. About 500 years after the temperature maximum, the continental environment responded to the warming by elevated

  11. Initiation age and incision rates of inner gorges: Do they record multiple glacial-interglacial cycles?

    Science.gov (United States)

    Delunel, Romain; Casagrande, Jan; Schlunegger, Fritz; Akçar, Naki; Kubik, Peter W.

    2015-04-01

    gorges over multiple interglacial cycles and a relative preservation of Alpine landscapes during glacial periods.

  12. Thermal Conductivity of Triphenyl Phosphite's Liquid, Glassy, and Glacial States.

    Science.gov (United States)

    Krivchikov, Alexander I; Andersson, Ove

    2016-03-17

    The thermal conductivity κ and heat capacity per unit volume ρCp of triphenyl phosphite (TPP) were measured under different pressure and temperature conditions, and with time during the sluggish liquid to glacial state transformation at temperatures about 15 K above the glass transition temperature. As the transformation slowly proceeds during several hours, ρCp decreases monotonically from that of the liquid state to a value close to that of the vitrified state. Concurrently, κ increases nonmonotonically with an intermediate local maximum followed by a minimum, before the final rise to a higher κ. The properties of the ultimately formed glacial state depend on the thermal history, which implies that the state formed under these conditions is a heterogeneous mixture of nanocrystals and mainly amorphous-like solid, and that the relative amount and microstructure depend on the conditions of the transformation. The nonmonotonic changes in phonon propagation during the liquid to glacial transformation suggest microstructural changes which are consistent with a liquid-liquid transformation and sluggish growth of nanocrystals within amorphous-like solid domains. The isobaric thermal conductivity of the as-formed glacial state shows a reversible step increase, just prior to crystallization on heating, which deviates from the typical behavior of glasses, liquids, and crystals. An increase in pressure shifts the step to higher temperatures and suppresses crystallization, which reveals another reversible rise in κ and Cp. These results show that increased molecular mobility in the glacial state increases and suggest reduced thermal resistance at boundaries or that the motions carry heat. PMID:26916579

  13. Analysis of some ancient glass samples unearthed in Sichuan area by PIXE

    International Nuclear Information System (INIS)

    Proton induced X-ray emission (PIXE) technique is an effective method for the chemical composition analysis of ancient glass samples without destruction. Chemical composition of the ancient glass samples dated from the Warring States Period (770-476 B.C.) to the Six Dynasties Period (220-589 A.D.), which were unearthed in Sichuan area, was quantitatively determined by the PIXE technique. The results show that the glass Bi (disc) and the glass eye beads of the Warring States Period all belong to the PbO-BaO-SiO2 system. According to the composition and shape, we infer that these glass Bi and eye beads were made in China. Whereas, the chemical compositions of the glass ear pendants and beads of the Six Dynasties Period are varied, including K2O-CaO-SiO2, K2O-SiO2 and other glass systems, Based on the obtained results and those from literatures, some questions related to the technical propagation of the ancient Chinese glass are discussed. (authors)

  14. Historical distribution of Sundaland’s Dipterocarp rainforests at Quaternary glacial maxima

    Science.gov (United States)

    Cannon, Charles H.; Hijmans, Robert J.; Piessens, Thomas; Saw, Leng Guan; van Welzen, Peter C.; Slik, J. W. Ferry

    2014-01-01

    The extent of Dipterocarp rainforests on the emergent Sundaland landmass in Southeast Asia during Quaternary glaciations remains a key question. A better understanding of the biogeographic history of Sundaland could help explain current patterns of biodiversity and support the development of effective forest conservation strategies. Dipterocarpaceae trees dominate the rainforests of Sundaland, and their distributions serve as a proxy for rainforest extent. We used species distribution models (SDMs) of 317 Dipterocarp species to estimate the geographic extent of appropriate climatic conditions for rainforest on Sundaland at the last glacial maximum (LGM). The SDMs suggest that the climate of central Sundaland at the LGM was suitable to sustain Dipterocarp rainforest, and that the presence of a previously suggested transequatorial savannah corridor at that time is unlikely. Our findings are supported by palynologic evidence, dynamic vegetation models, extant mammal and termite communities, vascular plant fatty acid stable isotopic compositions, and stable carbon isotopic compositions of cave guano profiles. Although Dipterocarp species richness was generally lower at the LGM, areas of high species richness were mostly found off the current islands and on the emergent Sunda Shelf, indicating substantial species migration and mixing during the transitions between the Quaternary glacial maxima and warm periods such as the present. PMID:25385612

  15. A new bathymetry of the Northeast Greenland continental shelf: Constraints on glacial and other processes

    Science.gov (United States)

    Arndt, Jan Erik; Jokat, Wilfried; Dorschel, Boris; Myklebust, Reidun; Dowdeswell, Julian A.; Evans, Jeffrey

    2015-10-01

    A new digital bathymetric model (DBM) for the Northeast Greenland (NEG) continental shelf (74°N-81°N) is presented. The DBM has a grid cell size of 250 m × 250 m and incorporates bathymetric data from 30 multibeam cruises, more than 20 single-beam cruises and first reflector depths from industrial seismic lines. The new DBM substantially improves the bathymetry compared to older models. The DBM not only allows a better delineation of previously known seafloor morphology but, in addition, reveals the presence of previously unmapped morphological features including glacially derived troughs, fjords, grounding-zone wedges, and lateral moraines. These submarine landforms are used to infer the past extent and ice-flow dynamics of the Greenland Ice Sheet during the last full-glacial period of the Quaternary and subsequent ice retreat across the continental shelf. The DBM reveals cross-shelf bathymetric troughs that may enable the inflow of warm Atlantic water masses across the shelf, driving enhanced basal melting of the marine-terminating outlet glaciers draining the ice sheet to the coast in Northeast Greenland. Knolls, sinks, and hummocky seafloor on the middle shelf are also suggested to be related to salt diapirism. North-south-orientated elongate depressions are identified that probably relate to ice-marginal processes in combination with erosion caused by the East Greenland Current. A single guyot-like peak has been discovered and is interpreted to have been produced during a volcanic event approximately 55 Ma ago.

  16. A multi-proxy palaeoecological and palaeoclimatic record within full glacial lacustrine deposits, western Tennessee, USA

    Science.gov (United States)

    Grimley, D.A.; Daniel, L.; Kaplan, S.W.; Yansa, C.H.; Curry, B. Brandon; Oches, E.A.

    2009-01-01

    The Fulton Section, along the Mississippi River in western Tennessee, USA, is a 1km continuous exposure (~20m vertically) of Quaternary fluvial and lacustrine deposits, inset within Eocene sediments and buried by thick loess. Fossiliferous slackwater lake sediments record maximum aggradation during the last two major glaciations, with deposition between ca. 190-140 ka and 24-1814C ka BP, based on amino acid and radiocarbon chronology, respectively. During the onset of full glacial conditions (ca. 24-22 14C ka BP), a relatively permanent shallow lake environment is indicated by ostracods, aquatic molluscs, and both pollen and macrofossils of aquatic plants. By 21.8 14C ka BP, increasing emergent plants, amphibious gastropods (Pomatiopsis) and heavier ??18O compositions suggest marsh-like conditions in a periodically drying lake. The surrounding uplands consisted of Picea-Pinus woodlands mixed with cool-temperate hardwoods (e.g. Quercus, Populus, Carya), grasses and herbs. More open conditions ensued ca. 20 14C ka BP, with loess and slopewash gradually infilling the former lake by 18 14C ka BP. Modern analogue analyses of ostracods and palaeontological evidence imply a full glacial climate similar to today's mixed-boreal zone in central Minnesota, USA, about 98C cooler in mean annual temperature than present-day western Tennessee. Copyright ?? 2009 John Wiley & Sons, Ltd.

  17. Reconstruction of paleocoastlines for the northwestern South China Sea since the Last Glacial Maximum

    Institute of Scientific and Technical Information of China (English)

    HARFF; Jan; MEYER; Michael

    2009-01-01

    The range of relative sea level rise in the northwestern South China Sea since the Last Glacial Maximum was over 100 m. As a result, lowland regions including the Northeast Vietnam coast, Beibu Gulf, and South China coast experienced an evolution from land to sea. Based on the principle of reconstructing paleogeography and using recent digital elevation model, relative sea level curves, and sediment accumulation data, this paper presents a series of paleogeographic scenarios back to 20 cal. ka BP for the northwestern South China Sea. The scenarios demonstrate the entire process of coastline changes for the area of interest. During the late glacial period from 20 to 15 cal. ka BP, coastline slowly retreated, causing a land loss of only 1×104 km2, and thus the land-sea distribution remained nearly unchanged. Later in 15-10 cal. ka BP coastline rapidly retreated and area of land loss was up to 24×104 km2, causing lowlands around Northeast Vietnam and South China soon to be underwater. Coastline retreat continued quite rapidly during the early Holocene. From 10 to 6 cal. ka BP land area had decreased by 9×104 km2, and during that process the Qiongzhou Strait completely opened up. Since the mid Holocene, main controls on coastline change are from vertical crustal movements and sedimentation. Transgression was surpassed by regression, resulting in a land accretion of about 10×104 km2.

  18. Reconstruction of paleocoastlines for the northwestern South China Sea since the Last Glacial Maximum

    Institute of Scientific and Technical Information of China (English)

    YAO YanTao; HARFF Jan; MEYER Michael; ZHAN WenHuan

    2009-01-01

    The range of relative sea level rise in the northwestern South China Sea since the Last Glacial Maximum was over 100 m. As a result, lowland regions including the Northeast Vietnam coast, Beibu Gulf, and South China coast experienced an evolution from land to sea. Based on the principle of recon structing paleogeography and using recent digital elevation model, relative sea level curves, and sediment accumulation data, this paper presents a series of paleogeographic scenarios back to 20 cal. ka BP for the northwestern South China Sea. The scenarios demonstrate the entire process of coastline changes for the area of interest. During the late glacial period from 20 to 15 cal. ka BP, coastline slowly retreated, causing a land loss of only 1 ×104 km2, and thus the land-sea distribution remained nearly unchanged. Later in 15--10 cal. ka BP coastline rapidly retreated and area of land loss was up to 24×104 km2, causing lowlands around Northeast Vietnam and South China soon to be underwater. Coastline retreat continued quite rapidly during the early Holocene. From 10 to 6 cal. ka BP land area had decreased by 9×104 km2, and during that process the Qiongzhou Strait completely opened up. Since the mid Holocene, main controls on coastline change are from vertical crustal movements and sedimentation. Transgression was surpassed by regression, resulting in a land accretion of about 10×104 km2.

  19. Antireflectance coating on shielding window glasses using glacial acetic acid at ambient temperature

    International Nuclear Information System (INIS)

    High density lead glasses having thickness of several centimeters and large dimensions are used as shielding windows in hot cells. To improve visibility, the reflection of light from its optically polished surfaces needs to be minimized to improve transmission as absorption of light in the thick glasses can not be avoided. Antireflectance coating of a material having low refractive index is required for this purpose. Selective leaching of lead at ambient temperature in glacial acetic acid develops a silica rich leached layer on glass surface. Since silica has low refractive index, the leached layer serves as antireflectance coating. Two optically polished discs of shielding window glasses were leached in glacial acetic acid at ambient temperature for 2, 5 and 10 days and their reflectance and transmittance spectra were taken to find effect of leaching. For transparent glass transmittance could be improved from 78.76% to 85.31% after 10 days leaching. Reflectance from the glass could be decreased from 12.48 to 11.67%. For coloured glass transmittance improved from 87.77% to 88.24% after 5 days leaching while reflectance decreased from 12.28% to 5.6% during same period. Based on data generated, 10 days leaching time is recommended for developing anti reflectance coating on transparent shielding window glass and 5 days for coloured shielding window glass. The procedure can be used for shielding windows of any dimensions by fabrication a PVC tank of slightly high dimensions and filling with acetic acid (author)

  20. Glacial cycles and the growth and destruction of Alaska volcanoes

    Science.gov (United States)

    Coombs, M. L.; Calvert, A. T.; Bacon, C. R.

    2014-12-01

    Glaciers have affected profoundly the growth, collapse, preservation, and possibly, eruptive behavior of Quaternary stratovolcanoes in Alaska. Holocene alpine glaciers have acted as effective agents of erosion on volcanoes north of ~55 °N and especially north of 60 °N. Cook Inlet volcanoes are particularly vulnerable as they sit atop rugged intrusive basement as high as 3000 m asl. Holocene glaciers have swept away or covered most of the deposits and dome lavas of frequently active Redoubt (60.5 °N); carved through the flanks of Spurr's active vent, Crater Peak (61.3 °N); and all but obscured the edifice of Hayes (61.6 °N), whose Holocene eruptive history is known almost exclusively though far-traveled tephra and flowage deposits. Relationships between Pleistocene eruptive histories, determined by high-precision Ar-Ar dating of lava flows, and marine oxygen isotope stages (MIS) 2-8 (Bassinot et al., 1994, EPSL, v. 126, p. 91­-108) vary with a volcano's latitude, size, and elevation. At Spurr, 26 ages cluster in interglacial periods. At Redoubt, 28 ages show a more continual eruptive pattern from the end of MIS 8 to the present, with a slight apparent increase in output following MIS 6, and almost no preservation before 220 ka. Veniaminof (56.2 °N) and Emmons (55.5°N), large, broad volcanoes with bases near sea level, had voluminous eruptive episodes during the profound deglaciations after MIS 8 and MIS 6. At Akutan (54.1 °N), many late Pleistocene lavas show evidence for ice contact; ongoing dating will be able to pinpoint ice thicknesses. Furthest south and west, away from thick Pleistocene ice on the Alaska Peninsula and mainland, the Tanaga volcanic cluster (51.9 °N) has a relatively continuous eruptive record for the last 200 k.y. that shows no clear-cut correlation with glacial cycles, except a possible hiatus during MIS 6. Finally, significant edifice collapse features have been temporally linked with deglaciations. A ~10-km3 debris

  1. Influence of rapid glacial tongue treat on surface area of the Palcacocha glacial lake in the Cordillera Blanca, Peru

    Czech Academy of Sciences Publication Activity Database

    Vilímek, V.; Klimeš, Jan

    Tokyo : United Nations University, 2007, s. 9-11. [International Symposium on Landslide Risk Analysis and Sustainable Disaster Management )IPL 2007). Tokyo (JP), 21.01.2007-24.01.2007] Institutional research plan: CEZ:AV0Z30460519 Keywords : glacial retreat * Peru * Cordillera Blanca Subject RIV: DB - Geology ; Mineralogy

  2. Terrestrial evidence of melting of the Antarctic ice sheet during the last glacial period

    OpenAIRE

    Sawagaki, Takanobu; Hirakawa,Kazuomi

    2002-01-01

    Antarctica at the close of a millennium : proceedings of the 8th international symposium on Antarctic earth sciences, Wellington, New Zealand, July 1999, Edited by: J.A. Gamble, D.N.B. Skinner, and S. Henrys (Royal Society of New Zealand Bulletin, 35), ISBN: 1-877264-06-7, pp.404-414

  3. Deposition of Mn-Cu-Ni-enriched sediments during glacial period in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    Borole, D.V.

    factor of 20) down the core, with a pronounced maximum at depths of 78 cm and 26 cm, corresponding to 390 + or - 80 and 320 + or - 60 kyr BP, respectively. The depthwise variation of Mn content matches closely that of cold water subtropical fauna...

  4. Timing of millennial-scale climate change in Antarctica and Greenland during the last glacial period

    DEFF Research Database (Denmark)

    Blunier, T; Brook, E J

    2001-01-01

    Antarctica preceded the onset of Greenland warmings by 1500 to 3000 years. In general, Antarctic temperatures increased gradually while Greenland temperatures were decreasing or constant, and the termination of Antarctic warming was apparently coincident with the onset of rapid warming in Greenland. This...

  5. Comparison of northern and central Greenland ice cores records of methanesulfonate covering the last glacial period

    DEFF Research Database (Denmark)

    Jonsell, U.; Hansson, M. E.; Siggaard-Andersen, M-L-;

    2007-01-01

    MS- concentrations were higher during the cold marine isotopic stages (MIS) 2 and 4 and lower during the warm MIS 5. This long-term trend in MS-, which is similar to the inverse of the corresponding trend in d 18O, is not detected in the GISP2 MS- record. A systematic response in MS- concentrations...

  6. A numerical solution to define channel heads and hillslope parameters from digital topography of glacially conditioned catchments

    Science.gov (United States)

    Salcher, Bernhard; Baumann, Sebastian; Kober, Florian; Robl, Jörg; Heiniger, Lukas

    2016-04-01

    The analysis of the slope-area relationship in bedrock streams is a common way for discriminating the channel from the hillslope domain and associated landscape processes. Spatial variations of these domains are important indicators of landscape change. In fluvial catchments, this relationship is a function of contributing drainage area, channel slope and the threshold drainage area for fluvial erosion. The resulting pattern is related to climate, tectonic and underlying bedrock. These factors may become secondary in catchments affected by glacial erosion, as it is the case in many mid- to high-latitude mountain belts. The perturbation (i.e. the destruction) of an initial steady state fluvial bedrock morphology (where uplift is balanced by surface lowering rates) will tend to become successively larger if the repeated action of glacial processes exceeds the potential of fluvial readjustment during deglaciated periods. Topographic change is associated with a decrease and fragmentation of the channel network and an extension of the hillslope domain. In case of glacially conditioned catchments discrimination of the two domains remains problematic and a discrimination inconsistent. A definition is therefore highly needed considering that (i) a spatial shift in the domains affect the process and rate of erosion and (ii) topographic classifications of alpine catchments often base on channel and hillslope parameters (i.e.channel or hillslope relief). Here we propose a novel numerical approach to topographically define channel heads from digital topography in glacially conditioned mountain range catchments in order to discriminate the channel from the hillslope domain. We analyzed the topography of the southern European Central Alps, a region which (i) has been glaciated multiple times during the Quaternary, shows (ii) little lithological variations, is (iii) home of very low erodible rocks and is (iv) known as a region were tectonic processes have largely ceased. The

  7. Thermal and spectroscopic analysis of ancient potteries

    International Nuclear Information System (INIS)

    The present work is focused on the characterization study of ancient pottery shreds excavated recently from Sembiankandiyur in India. The study is intended to identify the firing temperature, firing conditions and morphology of the ancient pottery samples. The samples were analyzed using FTIR, XRD and TG-DTA. FTIR and XRD studies were used in mineralogical characterization of potteries. The firing temperature and conditions were interpreted by studying the difference in mineral composition in the samples using FTIR and XRD. TG-DTA is considered the complementary technique to elucidate the firing temperature from the thermal characteristic reactions such as dehydration, decomposition and transformations of minerals in the course of controlled firing of the samples. The results showed that all the samples fired in a oxidizing condition and firing temperature also inferred.(authors)

  8. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    Science.gov (United States)

    Akyuz, Sevim; Akyuz, Tanil; Mukhamedshina, Nuranya M.; Mirsagatova, A. Adiba; Basaran, Sait; Cakan, Banu

    2012-05-01

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)-Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry.

  9. Macroculture, Athletics and Democracy in ancient Greece

    OpenAIRE

    Economou, Emmanouel/Marios/Lazaros; Kyriazis, Nicholas

    2012-01-01

    In the present essay we examine whether and how sports affected the emergence of democracy as a political phenomenon in Classical Greece. To achieve this we introduce in a model the concept of macroculture as a complex of mutually supporting values, norms and beliefs in various areas of human activity, like athletics, war, politics, etc. Then, we proceed through a historical review on the history of sports in Ancient Greece and we investigate various aspects of how and under which terms athle...

  10. Ancient Egypt in our Cultural Heritage?

    OpenAIRE

    Vera Vasiljević

    2016-01-01

    Inspiration derived from ancient Egypt is usually expressed through the Egyptian motifs in arts and popular culture of the 19th and 20th centuries, as well as through the non-scientific interpretations of the culture, very much based upon the Renaissance ones. The number and variety of material and non-material traces of this fascination are most expressed in the countries where, along with the early support for the institutional development of Egyptology, there existed economically potent ed...

  11. Science in the Study of Ancient Egypt

    OpenAIRE

    Zakrzewski, Sonia; Shortland, Andrew; Rowland, Joanne

    2016-01-01

    Egyptology has been dominated by the large quantity of written and pictorial material available. This amazing archaeology has opened up a wonderful view of the ancient Egyptian world. The importance of hieroglyphics and texts, and their interpretation, has led to other areas of archaeology playing much less prominence in the study of Egypt. Perhaps most notable in this is relative lack of the application of analytical science to answer Egyptian questions. This problem has been compounded by d...

  12. Parallel OCR for Ancient Greek Critical Editions

    OpenAIRE

    Del Grosso, Angelo; Boschetti, Federico

    2012-01-01

    This project is focused on the parallelization of OCR processes applied to Ancient Greek critical editions. Two experiments have been performed. The first experiment is related to parameters differently tuned on the nodes of the grid, in order to identify the best combination that improves the accuracy of the recognition. The second experiment concerns the application of OCR with the best parameters on sample pages by a divide et impera strategy. Results related to the performances of the par...

  13. HTLV-1: ancient virus, new challenges

    OpenAIRE

    Marzieh Rahimzadegan; Farshid Abedi; Seyed Abodolrahim Rezaei; Reza Ghadimi

    2014-01-01

    Human T-lymphotropic virus (HTLV-1) is an ancient pathogen for human being but arising and recognized recently. The routes of transmission are vertical (mainly by breastfeeding), unsafe sexual contacts and through contaminated blood components specially in whom need frequent and repeated blood transfusions such as permanent anemia due to blood loss in hemophilia and major thalassemia. Patients who should undergo hemodialysis in their lifelong are another instance for increased risk of HTLV-1 ...

  14. A first 10Be cosmogenic glacial chronology from the High Atlas, Morocco, during the last glacial cycle.

    Science.gov (United States)

    Fink, David; Hughes, Philip; Fenton, Cassie

    2014-05-01

    Glacial geomorphological mapping, 10Be cosmogenic exposure ages of 21 erratics from cirque-valley systems and paleo-glacier climate modelling in the High Atlas Mountains, Morocco (31.1° N, 7.9° W), provides new and novel insights as to the history and evolution of the largest desert region on Earth. The Atlas Mountains display evidence of extensive and multiple Late Pleistocene glaciations whose extent is significantly larger than that recognised by previous workers. The largest glaciers formed in the Toubkal massif where we find 3 distinct phases of glacial advances within the last glacial cycle. The oldest moraines occurring at the lowest elevations have yielded eight 10Be ages ranging from 30 to 88 ka. Six of eight samples from moraines at intermediate elevations gave ages of 19 to 25 ka (2 outliers) which correlates well with the global Last Glacial Maximum (ca. 26-21 ka) and the last termination during marine isotope stage 2. Five erratics from the youngest and most elevated moraines yielded a suite of normally distributed exposure ages from 11 to 13 ka which supports a correlation with the northern hemisphere Younger Dryas (12.9-11.7 ka). The glacial record of the High Atlas effectively reflects moisture supply to the north-western Sahara Desert and can provide an indication of shifts between arid and pluvial conditions. The plaeo equilibrium line altitudes (ELA) of these three glacier phases was more than 1000 m lower than the predicted ELA based on today's temperatures. Glacier-climate modelling indicates that for each of these glacier phases climate was not only significantly cooler than today, but also much wetter. The new evidence on the extent, timing and palaeoclimatic significance of glaciations in this region has major implications for understanding moisture transfer between the North Atlantic Ocean and the Sahara Desert during Pleistocene cold stages.

  15. Modeling the Glacial Buzzsaw in the Patagonian Andes

    Science.gov (United States)

    Brandon, M. T.; Tomkin, J. H.

    2006-12-01

    Modeling the Glacial Buzzsaw in the Patagonian Andes The concept of a "glacial buzzsaw" was spawned by Steve Porter's observation in 1977 and 1988 that the "equilibrium line altitude" (ELA) for alpine glaciation in the Andes parallels the summit elevations of the range. The modern ELA in the Patagonian Andes drops from about 4.5 km at 30 S to about 1 km at 50 S, due to colder temperatures at higher latitudes. The summit elevations decrease steadily by a similar amount over this 2200 km distance. The landscape of the western side of the Patagonian Andes clearly shows that it has long been dominated by glacial erosion. Locally preserved tills indicate that alpine glaciation was active at 7 to 4.6 Ma, if not earlier. The idea of a glacial buzzsaw is that erosion by alpine glaciers is aggressive enough to limit the height of a mountain range. Fission-track cooling ages indicate modest long-term erosion rates (~0.5 to 1 km/Ma) for the Patagonian Andes, which precludes the possibility that the range was trimmed down to size by Quaternary- age glaciations. Furthermore, the range shows clear evidence of growth by continental subduction and tectonic accretion along its eastern margin. Evidence for recent tectonic shortening is based on the observation that the range has an approximately constant taper, as expected for a critical wedge. The width of the range decreases southward in parallel with the decreasing summit elevations. We have developed a general analytical model for coupled wedge growth and glacial erosion that accounts for much of the tectonic evolution of the Patagonian Andes. The model is based on an actively accreting wedge that maintains a constant taper geometry. The size of the wedge is controlled by competition between accretion and glacial erosion. Recent work by one of us (JHT) and Gerard Roe shows that the erosional yield caused by alpine glaciation is approximately proportional to the local elevation difference between the summit of the range and the

  16. Millennial-scale climate variability in response to changing glacial and orbital boundary conditions during the Mid-Pleistocene transition

    Science.gov (United States)

    Ferretti, Patrizia; Crowhurst, Simon; Drysdale, Russell; Bajo, Petra; Barbante, Carlo

    2016-04-01

    The Mid-Pleistocene transition represents perhaps the most important climate transition in the Quaternary period, yet it is one of the most poorly understood. Although the exact timing and mechanism of the onset of the "100 kyr" regime remain a matter of debate, it is well established that the overall periodicity of the glacial-interglacial cycles changed from a dominant 41 kyr obliquity periodicity prior to ~0.9 Ma to a dominant late Pleistocene 100 kyr variance. This change in the frequency domain was associated with an increase in the amplitude of global ice volume variations that, superimposed on a long-term climatic trend towards more glacial conditions over millions of years, produced some of the most extreme glaciations recorded. This interval of time has often been considered to be important in relation to long-term Milankovitch-scale climate variability. In contrast, here, special emphasis will be placed on assessing the presence and the characteristics of the suborbital-scale variability, and reconstructing the evolution of millennial-scale climate variability as the average climate state evolve toward generally colder conditions with larger ice sheets, and the spectral character of climate variability shifted from dominantly 41 kyr to 100 kyr. Appealing evidence suggests that millennial-scale climate variability is amplified during times of intense forcing changes, but this rapid variability has not been thoroughly explored yet at the time when the major changes in climate periodicity occurred. To address these questions, we have examined the record of climatic conditions from Marine Isotope Stages 25 to 16 (~970-650 ka) using high-resolution stable isotope records from benthic and planktonic foraminifera from a sedimentary sequence in the North Atlantic (Integrated Ocean Drilling Program Expedition 306, Site U1313) in order to assess millennial-scale changes in sea-surface and deep-water conditions, the dynamics of thermohaline deep-water circulation

  17. Spatial distribution of an ancient agricultural oasis in Juyan, northwestern China

    Science.gov (United States)

    Hu, Ningke; Li, Xin

    2014-09-01

    Activities related to agricultural cultivation are some of the major human drivers of landscape change on the Earth's surface. Archaeological remains can provide qualitative evidence for studies of past agricultural development and environmental conditions. The ancient Juyan Oasis, which once flourished along the historic Silk Road, was a typical oasis of downstream inland river basins in the arid zone of northwestern China. Historical records and archaeological discoveries have qualitatively shown that the oasis supported extensive agricultural activities in this historical period from the Han Dynasty to the early Ming Dynasty (B.C. 202-A.D. 1375), which can be traced back to 2,000 years ago. In this study, different types of archaeological remains (including archaeological sites, ground surface artifacts, ancient cultivation ruins, and agricultural irrigation canals) that were obtained and identified from previous archaeological reports, field inspections, and remote sensing imagery were used to determine the spatial extent of the agricultural oasis in the historical period of interest. Our approach used multiple data sources in order to increase the accuracy and reliability of the results compared to previous studies. Our results distinctly suggested that much of the oasis was cultivated during the historical periods considered. Additionally, the arable land area in the historical period considered was roughly estimated to be approximately (3.39-4.75) × 104 ha. These findings regarding the spatial distribution of this ancient agricultural oasis and its arable land were reasonably determined to represent the ancient agricultural development that occurred in the Juyan Oasis better than results obtained from single sources of data.

  18. Decadal-scale variations in geomagnetic field intensity from ancient Cypriot slag mounds

    OpenAIRE

    Shaar, R; Tauxe, L.; Ben-Yosef, E; V. Kassianidou; Lorentzen, B; Feinberg, JM; Levy, TE

    2015-01-01

    © 2015. American Geophysical Union. All Rights Reserved. Geomagnetic models based on direct observations since the 1830s show that the averaged relative change in field intensity on Earth's surface over the past 170 years is less than 4.8% per decade. It is unknown if these rates represent the typical behavior of secular variations due to insufficient temporal resolution of archaeomagnetic records from earlier periods. To address this question, we investigate two ancient slag mounds in Cyprus...

  19. Logistic Growth for the Nuzi Cuneiform Tablets: Analyzing Family Networks in Ancient Mesopotamia

    OpenAIRE

    Ueda, Sumie; Makino, Kumi; Itoh, Yoshiaki; Tsuchiya, Takashi

    2013-01-01

    We reconstruct the year of publication of each cuneiform tablet of the Nuzi society in ancient Mesopotamia. The tablets, are on land transaction, marriage, loan, slavery contracts etc. The number of tablets seem to increase by logistic growth until saturation. It may show the dynamics of concentration of lands or other properties into few powerful families in a period of about twenty years. We reconstruct family trees and social networks of Nuzi and estimate the publication years of cuneiform...

  20. Population continuity or population change: formation of the ancient Egyptian state

    OpenAIRE

    Zakrzewski, Sonia R.

    2007-01-01

    The origins of the ancient Egyptian state and its formation have received much attention, through analysis of mortuary contexts, skeletal material, and trade. Genetic diversity was analyzed by studying craniometric variation within a series of six time-successive Egyptian populations in order to investigate the evidence for migration over the period of the development of social hierarchy and the Egyptian state. Craniometric variation, based upon 16 measurements, was assessed through principal...

  1. Glacially induced stresses in sedimentary rocks of northern Poland

    Science.gov (United States)

    Trzeciak, Maciej; Dąbrowski, Marcin

    2016-04-01

    During the Pleistocene large continental ice sheets developed in Scandinavia and North America. Ice-loading caused bending of the lithosphere and outward flow in the mantle. Glacial loading is one of the most prominent tectono-mechanical event in the geological history of northern Poland. The Pomeranian region was subjected several times to a load equivalent of more than 1 km of rocks, which led to severe increase in both vertical and horizontal stresses in the upper crustal rocks. During deglaciation a rapid decrease in vertical stress is observed, which leads to destabilization of the crust - most recent postglacial faults scarps in northern Sweden indicate glacially induced earthquakes of magnitude ~Mw8. The presence of the ice-sheet altered as well the near-surface thermal structure - thermal gradient inversion is still observable in NW Poland. The glacially related processes might have left an important mark in the sedimentary cover of northern Poland, especially with regard to fracture reopening, changes in stress state, and damage development. In the present study, we model lithospheric bending caused by glacial load, but our point of interest lies in the overlying sediments. Typical glacial isostatic studies model the response of (visco-) elastic lithosphere over viscoelastic or viscous asthenosphere subjected to external loads. In our model, we introduce viscoelastic sedimentary layers at the top of this stack and examine the stress relaxation patterns therein. As a case study for our modelling, we used geological profiles from northern Poland, near locality of Wejherowo, which are considered to have unconventional gas potential. The Paleozoic profile of this area is dominated by almost 1 km thick Silurian-Ordovician shale deposits, which are interbedded with thin and strong limestone layers. This sequence is underlain by Cambrian shales and sandstones, and finally at ~3 km depth - Precambrian crystalline rocks. Above the Silurian there are approximately

  2. Sediment core and glacial environment reconstruction - a method review

    Science.gov (United States)

    Bakke, Jostein; Paasche, Øyvind

    2010-05-01

    Alpine glaciers are often located in remote and high-altitude regions of the world, areas that only rarely are covered by instrumental records. Reconstructions of glaciers has therefore proven useful for understanding past climate dynamics on both shorter and longer time-scales. One major drawback with glacier reconstructions based solely on moraine chronologies - by far the most common -, is that due to selective preservation of moraine ridges such records do not exclude the possibility of multiple Holocene glacier advances. This problem is true regardless whether cosmogenic isotopes or lichenometry have been used to date the moraines, or also radiocarbon dating of mega-fossils buried in till or underneath the moraines themselves. To overcome this problem Karlén (1976) initially suggested that glacial erosion and the associated production of rock-flour deposited in downstream lakes could provide a continuous record of glacial fluctuations, hence overcoming the problem of incomplete reconstructions. We want to discuss the methods used to reconstruct past glacier activity based on sediments deposited in distal glacier-fed lakes. By quantifying physical properties of glacial and extra-glacial sediments deposited in catchments, and in downstream lakes and fjords, it is possible to isolate and identify past glacier activity - size and production rate - that subsequently can be used to reconstruct changing environmental shifts and trends. Changes in average sediment evacuation from alpine glaciers are mainly governed by glacier size and the mass turnover gradient, determining the deformation rate at any given time. The amount of solid precipitation (mainly winter accumulation) versus loss due to melting during the ablation-season (mainly summer temperature) determines the mass turnover gradient in either positive or negative direction. A prevailing positive net balance will lead to higher sedimentation rates and vice versa, which in turn can be recorded in downstream

  3. Ancient DNA reveals male diffusion through the Neolithic Mediterranean route.

    Science.gov (United States)

    Lacan, Marie; Keyser, Christine; Ricaut, François-Xavier; Brucato, Nicolas; Duranthon, Francis; Guilaine, Jean; Crubézy, Eric; Ludes, Bertrand

    2011-06-14

    The Neolithic is a key period in the history of the European settlement. Although archaeological and present-day genetic data suggest several hypotheses regarding the human migration patterns at this period, validation of these hypotheses with the use of ancient genetic data has been limited. In this context, we studied DNA extracted from 53 individuals buried in a necropolis used by a French local community 5,000 y ago. The relatively good DNA preservation of the samples allowed us to obtain autosomal, Y-chromosomal, and/or mtDNA data for 29 of the 53 samples studied. From these datasets, we established close parental relationships within the necropolis and determined maternal and paternal lineages as well as the absence of an allele associated with lactase persistence, probably carried by Neolithic cultures of central Europe. Our study provides an integrative view of the genetic past in southern France at the end of the Neolithic period. Furthermore, the Y-haplotype lineages characterized and the study of their current repartition in European populations confirm a greater influence of the Mediterranean than the Central European route in the peopling of southern Europe during the Neolithic transition. PMID:21628562

  4. Ice stream behaviour in the western sector of the North Sea during the end of the last glacial cycle

    Science.gov (United States)

    Roberts, David; Evans, David; Clark, Chris; Bateman, Mark; Livingstone, Stephen; Medialdea, Alicia; Cofaigh, Colm O.; Grimoldi, Elena; Callard, Louise; Dove, Dayton; Stewart, Heather; Davies, Bethan; Chiverell, Richard

    2016-04-01

    During the last glacial cycle the East coast of the UK was overrun by the British-Irish Ice Sheet (BIIS) flowing eastwards and southwards. In recent years it has become evident that several ice streams including the Tweed, Tyne, and Stainmore Gap ice streams, as well as the late stage North Sea Lobe (NSL), all played a role in shaping the glacial landscape during this period, but understanding the flow phasing of these ice streams during advance and collapse has proved challenging. Here we present new data from the seafloor collected during recent work undertaken by the Britice Chrono and Glanam project teams during cruise JC123 in the North Sea. Sub-bottom seafloor data together with new swath data clearly show that the final phases of the collapse of the NSL were controlled by ice sourced from the Firth of Forth ice stream which deglaciated in a NNW trajectory. Other ice streams being fed from the west (e.g. Stainmore, Tyne, Tweed) were not influential in final phase ice retreat from the southern North Sea. The Forth ice imprint is characterised by several grounding zone/till wedges marking dynamic, oscillatory retreat of the ice as it retreated along an offshore corridor between North Yorkshire and Northumberland. Repeated packages of tills, ice marginal and glaciomarine sediments, which drape glacially scoured bedrock terrain and drumlins along this corridor, point to marine inundation accompanying ice retreat. New TCN ages suggest decoupling of the Tyne Gap ice stream and NSL between 17.8 and 16.5 ka and this coincides with rapid, regional collapse of the NSL between 17.2 and 16.0 ka along the Yorkshire and Durham coasts (new OSL ages; Britice Chrono). Hence, both the central and northern sectors of the BIIS were being strongly influenced by marine margin instability during the latter phases of the last glacial cycle.

  5. Multiple glacial refugia for cool-temperate deciduous trees in northern East Asia: the Mongolian oak as a case study.

    Science.gov (United States)

    Zeng, Yan-Fei; Wang, Wen-Ting; Liao, Wan-Jin; Wang, Hong-Fang; Zhang, Da-Yong

    2015-11-01

    In East Asia, temperate forests are predicted to have retracted southward to c. 30° N during the last glacial maximum (LGM) based on fossil pollen data, whereas phylogeographic studies have often suggested glacial in situ survival of cool-temperate deciduous trees in their modern northern ranges. Here we report a study of the genetic diversity and structure of 29 natural Mongolian oak (Quercus mongolica) populations using 19 nuclear simple sequence repeat (nSSR) loci and four chloroplast DNA fragments. Bayesian clustering analysis with nSSRs revealed five groups, which were inferred by approximate Bayesian computation (ABC) to have diverged in multiple refugia through multiple glacial-interglacial cycles. Analysis of chloroplast DNA variation revealed four lineages that were largely but incompletely geographically disjunct. Ecological niche modelling (ENMs) indicated a southward range shift of the oak's distribution at the LGM, although high suitability scores were also evident in the Changbai Mts. (Northeast China), the Korean Peninsula, areas surrounding the Bohai Sea, and along the coast of the Russian Far East. In addition, endemic chloroplast DNA haplotypes and nuclear lineages occurred in high-latitude northern areas where the ENM predicted no suitable habitat. The combined evidence from nuclear and chloroplast DNA, and the results of the ENM clearly demonstrate that multiple northern refugia, including cryptic ones, were maintained across the current distributional range of the Mongolian oak during the LGM or earlier glacial periods. Though spatially limited, postglacial expansions from these refugia have led to a pattern of decreased genetic diversity with increasing latitude. PMID:26439083

  6. Modeling glacial flow on and onto Pluto's Sputnik Planum

    CERN Document Server

    Umurhan, O M; Moore, J M; Earle, A M; Binzel, R P; Stern, S A; Schenk, P M; Beyer, R A; White, O L; NImmo, F; McKinnon, W B; Ennico, K; Olkin, C B; Weaver, H A; Young, L A

    2016-01-01

    Observations of Pluto's surface made by the New Horizons spacecraft indicates present-day nitrogen ice glaciation in and around the basin known as Sputnik Planum. Motivated by these observations, we have developed an evolutionary glacial flow model of solid nitrogen ice taking into account its published thermophysical and rheologies properties. This model assumes that glacial ice layers flow laminarly and have low aspect ratios which permits a vertically integrated mathematical formulation. We assess the conditions for the validity of laminar nitrogen ice motion by revisiting the problem of the onset of solid-state buoyant convection of nitrogen ice for a variety of bottom thermal boundary conditions. Subject to uncertainties in nitrogen ice rheology, nitrogen ice layers are estimated to flow laminarly for thicknesses less than 400-1000 meters. The resulting mass-flux formulation for when the nitrogen ice flows as a laminar dry glacier is characterized by an Arrhenius-Glen functional form. The flow model deve...

  7. The distribution of glacial erratics in the Northeast Atlantic

    International Nuclear Information System (INIS)

    A detailed study of all the available information on glacial erratics has been carried out. This has included an examination of 288 dredge hauls, 1164 sediment cores and 176 camera runs. Sufficient data have now been collected to provide an estimate of the impact risk of a point projectile with a glacial erratic, down to oxygen isotope stage 5 (127,000 years) in three areas of the North East Atlantic. 1. Porcupine seabight (50 deg N, 14 deg W) 0.460%; 2. King's Trough Flank (42 deg N, 24 deg W) 0.502%; 3. Great Meteor East (31 deg N, 25 deg W) 0.015%. These estimates are for all erratics larger than 1.5 cm diameter and apply only down to oxygen isotope stage 5. If estimates are required at greater depths than this, it is proposed that a detailed study of a long core should be undertaken. (author)

  8. A study on provenance relation between Jiaotanxia ancient Guan porcelain and Qingliangsi ancient Ru porcelain by NAA

    International Nuclear Information System (INIS)

    11 samples of ancient Chinese Ru porcelain from Qingliangsi kiln, 23 samples of ancient Chinese Guan porcelain from Jiaotanxia kiln and 4 samples of modern archaized Guan porcelain were obtained to determine the contents of elements in each of them by neutron activation analysis (NAA). The NAA data were further analyzed using fuzzy cluster analysis to obtain the fuzzy cluster trend diagrams for the bodies' samples and the glazes samples respectively. The analysis shows that the raw material origins of the Jiaotanxia ancient Chinese Guan porcelain bodies samples are very concentrated; those of the Qingliangsi ancient Chinese Ru porcelain bodies samples are a little dispersed; those of ancient Chinese Guan porcelain glazes samples are relatively concentrated; those of ancient Chinese Ru porcelain glazes samples are dispersed; and the origins of the raw material of ancient Chinese Guan porcelain glazes samples are obviously different from those of ancient Chinese Ru porcelain glazes samples. The bodies samples and glazes samples of Jiaotanxia ancient Chinese Guan porcelain and those of Qingliangsi ancient Chinese Ru porcelain have some difference but can be compared with each other. (authors)

  9. "Pleistocene Park" - A Glacial Ecosystem in a Warming World

    Science.gov (United States)

    Zimov, N.; Zimov, S. A.

    2011-12-01

    Most people if asked what association they have to the phrase - ice age, will answer - "Mammoth". But mammoths are not only big wooly elephants which went extinct in the beginning of Holocene. They were also part of a great ecosystem, the Northern Steppe or Mammoth Ecosystem, which was the world's largest ecosystem for hundreds thousand of years. This ecosystem, with extremely high rates of biocycling, could maintain animal densities which can be hardly found anywhere in the modern world. Northern steppe played an important role in shaping the glacial climate of the planet. High albedo grasslands reflected a much bigger portion of sun heat back to the atmosphere. Cold soils and permafrost served as sinks of carbon, helping to keep greenhouse gas concentration in the atmosphere at low levels. In the beginning of Holocene, simultaneously with wave of human expansion, an extinction wave took place. Tens of megafauna species became extinct at that time worldwide, while ones that resisted the extinction substantially dropped in numbers. The Northern Steppe ecosystem became imbalanced. Without large numbers of herbivores grazing and trampling the pasture, trees, shrubs and moss invaded grasslands. Within just a few hundreds years the mammoth ecosystem was gone, replaced by much lower productivity ecosystems. Already 14 thousand year ago, by simply increasing hunting pressure, humans managed to dramatically change Earth's appearance. We propose that by artificially maintaining a high animal density and diversity on a limited territory for extended period of time, it will be possible to reverse the shift, reestablishing the productive Northern Steppe ecosystem. Moss, shrubs and tree sprouts are not able to resist grazing pressure so they will be quickly replaced by grasses and herbs. Animals digesting all aboveground biomass would accelerate nutrition cycling and consequently increase bioproductivity. Higher bioproductivity would increase evapotranspiration, keeping soils

  10. Oceanographic Influences on the Style and Timing of Glacial-Interglacial Change in Western Beringia

    Science.gov (United States)

    Brigham-Grette, J.; Glushkova, O. Y.; Anderson, P.; Lozhkin, A.; Gualtieri, L.

    2004-12-01

    Late Cenozoic glacial/interglacial change imposed on the Bering Strait region radical changes in paleogeography unique to the Northern Hemisphere. A forested middle Pliocene Arctic gave way to the first major glaciation of the northern hemisphere. Glacial and marine deposits found interbedded along the coasts of Alaska and Chukotka record a number of critical transitions in the evolution of Northern Hemisphere climate. Glacial periods across much of Beringia during the early and middle Pleistocene were at least an order of magnitude more extensive than during the Last Glacial Maximum (LGM) for reasons that remain unclear but must be related to fundamental changes in moisture flux. Valley glaciers (not ice sheets) dominated the landscape of central and western Beringia throughout the Quaternary, though some valley glaciers reached the sea. Eurasian ice sheets to the west and perhaps extensive sea ice over parts of the deep Bering Sea prevented vapor flux to Beringia creating pervasive aridity, limiting the size of ice sheets and the distribution of deep snow cover especially during the LGM. Interglacial periods repeatedly flooded the Bering Strait, rapidly changing the configuration of the coastlines, altering regional continentality, and reinvigorating the exchange of water masses between the North Pacific, Arctic Ocean and North Atlantic. During the last interglacial (MIS 5e) the winter sea ice limit was as much as 800 km further north than now, and summer sea ice may be been periodically absent. Treeline was hundreds of kilometers further north, notably eliminating tundra across Chukotka to the Arctic Ocean. The fragmented coastal record of the Bering Strait registers clear evidence for the rapid initiation of valley glaciation and the deposition of glaciomarine sediments at or near the end of warm interglacial periods including Stage 11 (or 9), but especially the substage 5e/5d transition and the substage 5a/4 transition in parts of coastal Chukotka. The Flaxman

  11. Towards Constraining Glacial Isostatic Adjustment in Greenland Using ICESat and GPS Observations

    DEFF Research Database (Denmark)

    Nielsen, Karina; Sørensen, Louise Sandberg; Khan, Shfaqat Abbas;

    2014-01-01

    . We find, that the temporal behavior of the ICESat-based modeled elastic response agrees well with the GPS observations at the sites KELY, QAQ1, and SCOR. This suggests, that our elastic models are able to resolve the temporal changes in the observed uplift, which indicates that the elastic uplift......Constraining glacial isostatic adjustment (GIA) i.e. the Earth’s viscoelastic response to past ice changes, is an important task, because GIA is a significant correction in gravity-based ice sheet mass balance estimates. Here, we investigate how temporal variations in the observed and modeled...... pattern of elastic crustal displacements shows pronounced variation during the observation period, where an increase in elastic displacement is found at the northwest coast of Greenland, while a decrease is found at the southeast coast. This pattern of temporal changes is supported by the GPS observations...

  12. Limiting factors for vegetation development during the early late glacial in Denmark

    DEFF Research Database (Denmark)

    Mortensen, Morten Fischer; Odgaard, Bent Vad; Jessen, Cathrine

    Slotseng, a small basin in southern Jutland, is the first Danish site with a bio- and chronostratigraphy that unambiguously reflects the environment of the earliest late glacial, the Bølling period. Results of pollen and macrofossil analyses show that the vegetation of the Bølling and Older Dryas.......g. climate change, soil erosion or soil development. In an attempt to identify the most important factors determining the temporal variation of the pollen record at Slotseng, redundancy analysis (RDA) was applied to subsets of pollen data representing a moving window of 20 samples at a time (1-20, 2-21, 3......-22, etc.). Sediment age was used as a covariable and explanatory variables representing environmental change were soil nitrogen, R, and light (all inferred from the Ellenberg indices estimated from macrofossil results), LOI, SUS, sediment accumulation rate, presence of tree-birch macrofossils, sediment...

  13. Glacial geomorphological maps of the Glasgow region, western central Scotland

    OpenAIRE

    Rose, Jim

    2008-01-01

    This paper presents a 1:25,000 scale geomorphological map of the Glasgow region, western central Scotland, an area that was glaciated during the Last Glacial Maximum and, in part, during the Younger Dryas glaciation. The text accompanying the map sets out the historical context of the mapping exercise and describes the process of geomorphological mapping at 1:10,560 scale. The text outlines briefly the results of the mapping exercise, in terms of the map evidence recorded and the interpretati...

  14. Interferometric swath processing of Cryosat data for glacial ice topography

    OpenAIRE

    Gray, L.; Burgess, D.; L. Copland; Cullen, R; N. Galin; Hawley, R.; V. Helm

    2013-01-01

    We have derived digital elevation models (DEMs) over the western part of the Devon Ice Cap in Nunavut, Canada, using "swath processing" of interferometric data collected by Cryosat between February 2011 and January 2012. With the standard ESA (European Space Agency) SARIn (synthetic aperture radar interferometry) level 2 (L2) data product, the interferometric mode is used to map the cross-track position and elevation of the "point-of-closest-approach" (POCA) in sloping glacial...

  15. Radiometric age constraints for glacial terminations IX and VII

    OpenAIRE

    Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Karner, D.; 2Department of Geology, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA 94985, U.S.A.; Marra, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Renne, P.; 3Berkeley Geochronology Center, 2455 Ridged Road, Berkeley, CA 94720, U.S.A. and Department of Earth and; Roberts, A.; 4National Oceanography Centre, Southampton, University of Southampton, European Way, Southampton SO14; Weaver, R.; 4National Oceanography Centre, Southampton, University of Southampton, European Way, Southampton SO14

    2006-01-01

    Buried sedimentary aggradational sections deposited between 800 ka and 600 ka in the Tiber River coastal alluvial plain have been studied using borecores from around Rome. 40Ar/39Ar ages on sanidine and/or leucite from intercalated tephra layers and paleomagnetic investigation of clay sections provide geochronologic constraints on the timing of aggradation of two alluvial sections, demonstrating that they were deposited in response to glacio–eustatic sea level rise caused by Glacial ...

  16. Estimating groundwater recharge through glacial till at Bacon Hall, Shropshire

    OpenAIRE

    Macdonald, D.M.J.

    1995-01-01

    A study was undertaken to obtain estimates for recharge to groundwater through glacial till. The work was carried out in support of the Hydrogeological Classification of Superficial Clays programme; a cofunded programme of research between BGS and the National Rivers Authority. Estimates were made using data from Bacon Hall, one of a series of sites used to monitor the Shropshire Groundwater Scheme. The sites are instrumented to measure the effect on soil moisture due to the pu...

  17. Molecular evidence for an active endogenous microbiome beneath glacial ice

    OpenAIRE

    Hamilton, Trinity L.; Peters, John W.; Mark L. Skidmore; Boyd, Eric S.

    2013-01-01

    Geologic, chemical and isotopic evidence indicate that Earth has experienced numerous intervals of widespread glaciation throughout its history, with roughly 11% of present day Earth's land surface covered in ice. Despite the pervasive nature of glacial ice both today and in Earth's past and the potential contribution of these systems to global biogeochemical cycles, the composition and phylogenetic structure of an active microbial community in subglacial systems has yet to be described. Here...

  18. Thermoluminescence dating of late-glacial sand sediments

    International Nuclear Information System (INIS)

    Ten Late-Glacial sediments were dated by the regeneration method combined with the plateau criteria. The thermoluminescence (TL) dates were compared with independent dates assessed indirectly by radiocarbon dating or varve chronology. For comparison, the 14C dates were calibrated by adding 1000 yr to the conventional results. Eight TL dates agreed with the 14C dates within the uncertainty of the TL dates (± 1 ka), one was overestimated and one underestimated. (author)

  19. Design and development of an ancient Chinese document recognition system

    Science.gov (United States)

    Peng, Liangrui; Xiu, Pingping; Ding, Xiaoqing

    2003-12-01

    The digitization of ancient Chinese documents presents new challenges to OCR (Optical Character Recognition) research field due to the large character set of ancient Chinese characters, variant font types, and versatile document layout styles, as these documents are historical reflections to the thousands of years of Chinese civilization. After analyzing the general characteristics of ancient Chinese documents, we present a solution for recognition of ancient Chinese documents with regular font-types and layout-styles. Based on the previous work on multilingual OCR in TH-OCR system, we focus on the design and development of two key technologies which include character recognition and page segmentation. Experimental results show that the developed character recognition kernel of 19,635 Chinese characters outperforms our original traditional Chinese recognition kernel; Benchmarked test on printed ancient Chinese books proves that the proposed system is effective for regular ancient Chinese documents.

  20. Elemental Records of the Penultimate Glacial-Interglacial Cycle in the Cariaco Basin, Venezuela

    Science.gov (United States)

    Gibson, K.; Peterson, L. C.

    2010-12-01

    Studies of sediment records from the anoxic Cariaco Basin have shown that the tropics experienced millennial-scale climatic and hydrologic changes that were synchronous with high-latitude climate changes during the last glacial-interglacial (G-IG) cycle. New elemental data collected by scanning-XRF from Ocean Drilling Program (ODP) Hole 1002C during Marine Isotope Stage (MIS) 6 and MIS 7 extend this record in time and provide insights into basin sedimentation and tropical climate under boundary conditions that differ from those of the most recent G-IG cycle. Fluctuations of the redox-sensitive metal Mo show millennial-scale variability in MIS 7 and early MIS 6 sediments that are similar in nature to Mo excursions associated with the D/O events of the last G-IG cycle. High sedimentary Mo levels coincide with warm interstadial conditions and record periods of deep basin anoxia. During the last G-IG cycle, D/O events are clearly captured in proxies for terrigenous (Fe, Ti) and biogenic (Ca) sedimentation. While the same can be said for the penultimate G-IG cycle, significant differences exist. Terrigenous input peaks in early MIS 6 and decreases steadily throughout the glacial period into MIS 5e. Though increased terrigenous input during MIS 6 is consistent with lowered glacial sea level and the proximity of local rivers to the basin’s edge, the lack of a response in terrigenous sedimentation to the abrupt rise in sea level during Termination II contrasts markedly with what is observed across Termination I. In addition, during MIS 6, terrigenous sedimentation appears to peak during warm interstadial-like intervals, while in MIS 7, this relationship reverses. The converse is true for biogenic sedimentation, with peaks seen during cool stages of MIS 6, and warm phases of MIS 7. A switch in boundary conditions at this time, such as an increase in ice volume, may trigger a threshold response to sea level that results in differing patterns of millennial

  1. Swath-bathymetric Mapping of Glacial Landforms in the Central Pine Island Trough, West Antarctica

    Science.gov (United States)

    Jakobsson, M.; Anderson, J. B.; Nitsche, F. O.; Gyllencreutz, R.; Kirshner, A. E.; Kirchner, N.; O'regan, M. A.; Mohammad, R.; Eriksson, B.

    2011-12-01

    The Pine Island Glacier drains the West Antarctic Ice Sheet into the Amundsen Sea. During the Last Glacial Maximum (LGM), the Pine Island Glacier extended nearly 500 km from its present location, across the continental shelf to the shelf break. The Oden-Southern-Ocean 2009/2010 (OSO0910) expedition with Swedish icebreaker Oden carried out swath-bathymetric mapping and chirp sonar profiling of the mid-shelf section of Pine Island Trough. Since the bay was virtually ice free during the 2010 austral summer, the swath-bathymetric mapping could be conducted as a systematic survey which covered a coherent area of 4,140 km^2 of the mid-shelf glacial trough. The swath-bathymetric mapping and chirp sonar profiling were carried out with Oden's hull-mounted Kongsberg 12 kHz EM122 1°x1° multibeam echo sounder and integrated SBP 120 3°x3° chirp sonar. From these data we present new insights into to the glacial dynamics during the deglaciation of the mid-continental shelf since LGM. The landforms imaged in Pine Island Trough indicate stepwise retreat of the Pine Island Ice Stream punctuated by periods of grounding line stability and a minor advance followed by episodes of rapid retreat. Notably, directions of mapped mega scale lineations clearly show that the Pine Island Ice Stream changed its flow path during the advance. This advance followed a massive ice shelf break-up and grounding line retreat inferred from mapped corrugation ridges and iceberg plow ridges previously reported by Jakobsson et al., (2011). The periods of grounding line stability during the deglaciation are marked by sediment accumulations in the form of grounding zone wedges. Some of these wedges are here mapped to their full extents and in sufficient detail to characterize spatial dimensions and to estimate the volume of deposited sediment. Considering a range of sediment flux rates from the paleo-Pine Island Ice Stream we estimate that the largest and most clearly defined grounding zone wedge located

  2. A brief history of corneal transplantation: From ancient to modern

    Directory of Open Access Journals (Sweden)

    Alexandra X Crawford

    2013-01-01

    Full Text Available This review highlights many of the fundamental concepts and events in the development of corneal transplantation - from ancient times to modern. Tales of eye, limb, and even heart transplantation appear in ancient and medieval texts; however, in the scientific sense, the original concepts of corneal surgery date back to the Greek physician Galen (130-200 AD. Although proposals to provide improved corneal clarity by surgical interventions, including keratoprostheses, were better developed by the 17 th and 18 th centuries, true scientific and surgical experimentation in this field did not begin until the 19 th century. Indeed, the success of contemporary corneal transplantation is largely the result of a culmination of pivotal ideas, experimentation, and perseverance by inspired individuals over the last 200 years. Franz Reisinger initiated experimental animal corneal transplantation in 1818, coining the term "keratoplasty". Subsequently, Wilhelmus Thorne created the term corneal transplant and 3 years later Samuel Bigger, 1837, reported successful corneal transplantation in a gazelle. The first recorded therapeutic corneal xenograft on a human was reported shortly thereafter in 1838-unsurprisingly this was unsuccessful. Further progress in corneal transplantation was significantly hindered by limited understanding of antiseptic principles, anesthesiology, surgical technique, and immunology. There ensued an extremely prolonged period of debate and experimentation upon the utility of animal compared to human tissue, and lamellar versus penetrating keratoplasty. Indeed, the first successful human corneal transplant was not performed by Eduard Zirm until 1905. Since that first successful corneal transplant, innumerable ophthalmologists have contributed to the development and refinement of corneal transplantation aided by the development of surgical microscopes, refined suture materials, the development of eye banks, and the introduction of

  3. Lake sediment multi-taxon DNA from North Greenland records early post-glacial appearance of vascular plants and accurately tracks environmental changes

    DEFF Research Database (Denmark)

    Epp, L. S.; Gussarova, C.; Boessenkool, S.;

    2015-01-01

    temperatures. Lake sediments contain DNA paleorecords of the surrounding ecosystems and can be used to retrieve a variety of organismal groups from a single sample. In this study, we analyzed vascular plant, bryophyte, algal (in particular diatom) and copepod DNA retrieved from a sediment core spanning the...... phases, and distinct temporal changes in plant presence were recovered. The plant DNA was mostly in agreement with expected vegetation history, but very early occurrences of vascular plants, including the woody Empetrum nigrum, document terrestrial vegetation very shortly after glacial retreat. Our study...... core. Our DNA record was stratigraphically coherent, with no indication of leaching between layers, and our cross-taxon comparisons were in accordance with previously inferred local ecosystem changes. Authentic ancient plant DNA was retrieved from nearly all layers, both from the marine and the limnic...

  4. Glacial aridity in central Indonesia coeval with intensified monsoon circulation

    Science.gov (United States)

    Konecky, Bronwen; Russell, James; Bijaksana, Satria

    2016-03-01

    The Last Glacial Maximum was cool and dry over the Indo-Pacific Warm Pool (IPWP), a key region driving global oceanic-atmospheric circulation. Both low- and high-latitude teleconnections with insolation, ice sheets, and sea level have been suggested to explain the pervasive aridity observed in paleoecological and geomorphic data. However, proxies tracking the H- and O-isotopic composition of rainfall (e.g., speleothems, sedimentary biomarkers) suggest muted aridity or even wetter conditions than the present, complicating interpretations of glacial IPWP climate. Here we use multiproxy reconstructions from lake sediments and modern rainfall isotopic measurements from central Indonesia to show that, contrary to the classical "amount effect," intensified Australian-Indonesian monsoon circulation drove lighter H- and O-isotopic composition of IPWP rainfall during the LGM, while at the same time, dry conditions prevailed. Precipitation isotopes are particularly sensitive to the apparent increase in monsoon circulation and perhaps also decreased moisture residence time implied by our data, explaining contrasts among proxy records while illuminating glacial IPWP atmospheric circulation, a key target for climate models.

  5. Deformed glacial deposits of Passamaquoddy Bay area, New Brunswick

    International Nuclear Information System (INIS)

    The New Brunswick-Maine border area, centred around Passamaquoddy Bay, is characterized by a distinctly higher level of seismic activity compared with the very low level background activity of the region. In this same general area, post-glacial deformation including faulting, has been observed in glaciofluvial and ice contact deposits and the possibility that these structures may in some way related to neotectonic movements in the area has been suggested. A study was undertaken to document these structures and to investigate their origin. The studies show that structures related to collapse of sediments due to melting of buried ice masses are the most prominent post-depositional structures in the glacial sediments. A second group of structures includes failure phenomena such as slumping. These require the action of a mechanism leading to reduction of sediment strength which could be achieved by seismic shaking. However, such failure phenomena could also be brought about by non-seismic processes, thus a unique interpretation of the origin of these structures is difficult, if not impossible. Since seismic shaking is the most effective, regionally extensive trigger of a broad group of failure phenomena in soft sediments, the related structures are usually spread over a large area, but are restricted to a very short time gap. Although the establishment of such space and time relationships may be feasible, for example in extensive lake deposits, it is difficult to do so in patchy laterally variable deposits such as the glacial deposits in Passamaquoddy Bay area

  6. Origin and Distribution Of Glacial Lakes: A Case Study In Tista Basin, India

    Science.gov (United States)

    Kulkarni, A. V.

    2015-12-01

    Himalayan glaciers are experiencing retreat due to changes in the temperature and precipitation pattern. Retreating glaciers depending upon the underlying bed topography can cause lake formation near terminus. Therefore formation and draining of lakes in the glaciated terrain of Himalaya is commonly observed. However, few lakes became stable under suitable geomorphologic conditions and grow sufficiently large to threaten population and infrastructure in downstream. In this investigation changes in glacial lakes in Tista basin were studied using satellite images for a period between 1989 and 2010. The Tista basin in Sikkim covers approximately 7096 sq km area and the total glaciated area is 501± 29 sq km. During the period of investigation the lake area is increased from 6.6 ± 0.8 km2 to 9.6 ± 1.1 km2 due to formation of new lakes and also due to expansion of existing lake. Out of 23 lakes, 16 showed variable increase in area. We have also observed formation of stable proglacial lake due to coalescence of small supra glacial lakes on Changsang and South Lhonak Glacier. The size of lake near South Lhonak Glacier was increased from 18 to 126 ha from 1978 to 2014 (Figure). Therefore detail field investigations were carried out to understand volume and extent of ice in end moraine. The water volume was estimated as 53 million m3 using bathymetric survey and ice at the core of terminal moraines was mapped using resistivity survey. These investigations suggests a possibility of catastrophic outburst flood, if moraine dam breached under extreme weather conditions. Therefore, mitigation strategy is needed to improve safety of people living in the region. In addition, numerous remote sensing based investigations have mapped more than 300 lakes in the glaciated terrain in India, therefore, a national program to monitor glacier lakes and strategy to mitigate possible disaster is needed. Figure: Expansion of the lake near South Lhonak glacier from year 1990 to 2014.

  7. Modelling the Eurasian Ice Sheet through a full (Weichselian) glacial cycle

    Science.gov (United States)

    Siegert, Martin J.; Dowdeswell, Julian A.; Hald, Morten; Svendsen, John-Inge

    2001-11-01

    Recently acquired glacial geological and oceanographic datasets provide information on the Weichselian glaciations of Scandinavia and the Eurasian Arctic. A numerical ice-sheet model, forced by global sea level and solar insolation changes, was run to reconstruct ice sheets compatible with these data. A 'maximum' reconstruction assumes that the modern-type temperature distribution across the Eurasian Arctic is reduced by 10 °C at three stages during the Weichselian, which are related to minimum levels of solar insolation. Conversely, a 'minimum' model incorporates a reduction in temperature of only 5 °C in Early and Middle Weichselian time. The 'maximum' reconstruction employs the relatively larger sea-level fall suggested by the δ18O deep-sea record, while the 'minimum' run uses the more conservative sea-level estimate from New Guinea coral reef terraces. The maximum model predicts three major glacial advances in the Weichselian. These compare well to geological evidence for ice-sheet growth during the Early, Middle and Late Weichselian. Geological evidence for the Late Weichselian ice sheet is compatible with either reconstruction if ice growth across the Taymyr Peninsula is curtailed. The models show that ice-sheet advance caused by the interaction of sea level and solar insolation changes yields a time-dependent ice volume function similar to that established from the geological record. Periods of seasonally open water within the seas bordering the Eurasian Arctic generally occur prior to glaciation, and may provide a source of precipitation for ice-sheet growth. In contrast, periods of ice-rafted debris deposition and depletion in surface-ocean δ18O in sea-floor sediments compare well with the model's determination of ice-sheet decay and melting.

  8. Improving access to endogenous DNA in ancient bones and teeth

    OpenAIRE

    Damgaard, Peter B.; Ashot Margaryan; Hannes Schroeder; Ludovic Orlando; Eske Willerslev; Allentoft, Morten E.

    2015-01-01

    Poor DNA preservation is the most limiting factor in ancient genomic research. In the majority of ancient bones and teeth, endogenous DNA molecules represent a minor fraction of the whole DNA extract, rendering shot-gun sequencing inefficient for obtaining genomic data. Based on ancient human bone samples from temperate and tropical environments, we show that an EDTA-based enzymatic ‘pre-digestion’ of powdered bone increases the proportion of endogenous DNA several fold. By performing the pre...

  9. Advances in structural mechanics of Chinese ancient architectures

    Institute of Scientific and Technical Information of China (English)

    Maohong YU; Yoshiya ODA; Dongping FANG; Junhai ZHAO

    2008-01-01

    Chinese ancient architectures are valuable heritage of ancient culture of China. Many historical building have been preserved up to now. The researches on the structural mechanics of ancient architectures show the different aspects of structure and mechanics. Systematical studies on the structural mechanics of ancient architectures have been carried out at Xi'an Jiaotong University since 1982. It is related with the need of repair of some national preservation relics in Xi'an. These studies include: 1) Ancient wooden structures including three national preservation relics Arrow Tower at North City Gate, City Tower at East City Gate, and Baogao Temple in Ningbao, Zhejiang province. 2) Ancient tall masonry building, the Big Goose Pagoda and Small Goose Pagoda in Xi'an. 3) Mechanical characteristics of ancient soil under foundation and city wall; the influence of caves in and under the ancient City Wall on the stability of the wall. 4) The typical Chinese ancient building at the center of city: the Bell Tower and Drum tower. 5) The behavior of Dou-Gong and Joggle joint of Chinese ancient wooden structure. 6) The mechanical behavior of ancient soils under complex stress state. A new systematical strength theory, the unified strength theory, is used to analyze the stability of ancient city wall in Xi'an and foundation of tall pagoda built in Tang dynasty. These researches also concern differential settlements of Arrow Tower and resistance to earthquake of these historical architecture heritages. Some other studies are also introduced. This paper gives a summary of these researches. Preservation and research are nowadays an essential requirement for the famous monuments, buildings, towers and others. Our society is more and more conscious of this necessity, which involves increasing activities of restoration, and then sometimes also of repair, mechanical strengthening and seismic retrofitting. Many historical buildings have in fact problems of structural strength and

  10. Piracy in the Ancient World: from Minos to Mohammed

    OpenAIRE

    P.C. de Souza

    1992-01-01

    This thesis is an historical analysis of the phenomenon of piracy in the ancient world from the Bronze Age to the Arab conquests. It is based on detailed examination and discussion of the ancient sources. There is a short introduction (Part One) which establishes the scope of the enquiry, defines the subject and surveys modern scholarly literature. Part Two (The Image of Ancient Piracy) consists of a study of the Greek and Latin vocabulary for piracy, and six separate studie...

  11. Unriddling of ancient-medieval culture by PIXE

    International Nuclear Information System (INIS)

    Some examples are given for unriddling of ancient-medieval culture by PIXE. Effectiveness of PIXE to analyze art and archaeological objects is also explained. Objects employed here are 1) red, yellow, blue and white pigments painted on sun-dried bricks excavated in Egypt, 2) ancient glass beads used in the Near East, 3) South American mummy hair, 4) ancient slag excavated from Kansai-district, Japan 5) ink used by Galileo Galilei and 6) Renaissance style enameled gold jewelry. (author)

  12. Connecting Philosophy of Ancient Egyptians to Modern Thinking

    OpenAIRE

    Aminuddin Hassan; Nurul A.A.K. Anuar; Norhasni Z. Abiddin

    2012-01-01

    Problem statement: Associating any knowledge from ancient Egyptians to modern civilization and thinking was important and had its own value. The process of understanding knowledge related to ancient Egyptians is actually based on the nature of philosophical thought. Approach: In the discussion of ancient Egypt philosophy, it is important to look at it from the perspectives of the four branches of philosophy; metaphysics, epistemology, axiology and logic. Metaphysics has two elements, which ar...

  13. Study on Prohibitions of Ancient Chinese Costumes in Black Series

    OpenAIRE

    Xiaomeng Qu

    2013-01-01

    China is a historical country with extensive and profound civilization, in which the Chinese Costume has always been a brilliant feature. Black series occupies an important position in the color institution of ancient Chinese Costumes. The prohibition on black series costumes also has a significant meaning in ancient China. By discussing prohibitions related to black series in ancient Chinese costume institution, this paper studied two typical colors used by people of different classes as the...

  14. Geography, Writing System and History of Ancient Civilizations

    OpenAIRE

    Mo, Pak-Hung

    2013-01-01

    We find an undiscovered effect of geography on the choices of writing system in ancient civilizations that in turn drive their courses of historical evolution. The fates of the ancient civilizations were predetermined by the causation spirals generated by the writing system chosen by their ancient ancestors. Understanding the mechanism can enlighten our present political choices that in turn determine the future course of humankind evolution. It can also inspire us about the clue to build an ...

  15. Re-discovering ancient wheat varieties as functional foods

    OpenAIRE

    Cooper, Raymond

    2015-01-01

    With the gluten-free food market worth almost $1.6 bn in 2011, there is every reason for renewed interest in ancient grains. This resurgent interest is expressed in re-discovering ancient varieties as functional foods. In particular, people affected by celiac disease have to avoid all gluten in their diet and several ancient grains may offer an important alternative.

  16. A phase-transition model for the rise and collapse of ancient civilizations: A pre-ceramic Andean case study

    Science.gov (United States)

    Flores, J. C.

    2015-12-01

    For ancient civilizations, the shift from disorder to organized urban settlements is viewed as a phase-transition simile. The number of monumental constructions, assumed to be a signature of civilization processes, corresponds to the order parameter, and effective connectivity becomes related to the control parameter. Based on parameter estimations from archaeological and paleo-climatological data, this study analyzes the rise and fall of the ancient Caral civilization on the South Pacific coast during a period of small ENSO fluctuations (approximately 4500 BP). Other examples considered include civilizations on Easter Island and the Maya Lowlands. This work considers a typical nonlinear third order evolution equation and numerical simulations.

  17. Migration of vascular plant species to a recent wood adjoining ancient woodland

    Directory of Open Access Journals (Sweden)

    Zbigniew Dzwonko

    2014-02-01

    Full Text Available Woodland communities can be restored by natural succession in sites adjoining ancient woodlands which can act as seed sources for trees, shrubs and woodland herbs. The influence of dominant tree species and the distance from an adjacent ancient oak-hornbeam woodland upon the floristic composition of species in a recent pine wood planted on dry rendzina soil were studied. It was found that, in spite of a 52-year long succession, the border between woods was sharp and the composition of species in the recent wood were significantly different than in the adjacent ancient woodland. Canonical correspondence analysis (CCA showed that the distance to the ancient woodland had a significant influence on species distributions in the recent wood. The numbers of species from the Querco-Fagetea class, vegetatively reproducing species and myrmecochores decreased with this distance, whereas the numbers of anemochores increased. The migration rate of many woodland species, calculated on occurrence of the farthest individuals was very slow, varying from 0.0 m year-1 to 0.38 m year-1. The restoration of the field layer vegetation in the studied pine wood was much slower than in recent deciduous woods on rich and moist soils where the migration rate of some species exceeded 1.50 m year-1. Recent woods adjacent to ancient woodlands can be more effectively colonised by woodland species only when they are dominated by broad-leaved trees with quickly decomposing litter, and the spatial continuity of these woods persists for a long period.

  18. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    Energy Technology Data Exchange (ETDEWEB)

    Akyuz, Sevim, E-mail: s.akyuz@iku.edu.tr [Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul (Turkey); Akyuz, Tanil [Physics Department, Science and Letters Faculty, Istanbul Kultur University, Atakoy Campus, Bakirkoy 34156, Istanbul (Turkey); Mukhamedshina, Nuranya M.; Mirsagatova, A. Adiba [Institute of Nuclear Physics, Uzbek Academy of Sciences, 702132, Ulugbek, Tashkent (Uzbekistan); Basaran, Sait; Cakan, Banu [Department of Restoration and Conservation of Artefacts, Letters Faculty, Istanbul University, Vezneciler, Istanbul (Turkey)

    2012-05-15

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)-Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry. - Highlights: Black-Right-Pointing-Pointer INAA was performed to determine elemental compositions of ancient glass fragments. Black-Right-Pointing-Pointer Basic, coloring/discoloring elements and impurities have been determined. Black-Right-Pointing-Pointer PCA discriminated the glasses depending on their chronological order. Black-Right-Pointing-Pointer The thermal history of the glass samples was determined by FTIR spectrometry.

  19. Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

    International Nuclear Information System (INIS)

    Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)–Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry. - Highlights: ► INAA was performed to determine elemental compositions of ancient glass fragments. ► Basic, coloring/discoloring elements and impurities have been determined. ► PCA discriminated the glasses depending on their chronological order. ► The thermal history of the glass samples was determined by FTIR spectrometry.

  20. Using Ancient DNA to Understand Evolutionary and Ecological Processes

    DEFF Research Database (Denmark)

    Orlando, Ludovic Antoine Alexandre; Cooper, Alan

    2014-01-01

    Ancient DNA provides a unique means to record genetic change through time and directly observe evolutionary and ecological processes. Although mostly based on mitochondrial DNA, the increasing availability of genomic sequences is leading to unprecedented levels of resolution. Temporal studies of...... modern populations. Importantly, the complex series of events revealed by ancient DNA data is seldom reflected in current biogeographic patterns. DNA preserved in ancient sediments and coprolites has been used to characterize a range of paleoenvironments and reconstruct functional relationships in...... paleoecological systems. In the near future, genome-level surveys of ancient populations will play an increasingly important role in revealing, calibrating, and testing evolutionary processes....