DOCSLIB.ORG

Niels Schrøder 2.Indd

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Niels Schrøder 2.Indd The Journal of Transdisciplinary Environmental Studies vol. 3, no. 1, 2004 10,000 Years of Climate Change and Human Impact on the Environment in the Area Surrounding Lejre. N. Schrøder, L. Højlund Pedersen, R. Juel Bitsch. Department of Environment, Technology and Social Studies, Roskilde University. Denmark. E-mail: [email protected] Abstract: The classical site for Holocene studies of the impact of humans and climatic changes – Lejre (Denmark) and its surroundings – has been re-examined. A detailed geological/geophysi- cal mapping of the area and geochemical/palynological analysis of two selected cores confirms that climate change has been the decisive factor behind the main changes in human activities in the area. It also confirms that the Blytt-Sernander model fits very well with the climatic proxies from the Lejre area. Finally, it is concluded that the Holocene climatic history of the Lejre area and of Greenland are closely correlated with strong ties to global causes of climate change. Key words: Holocene, climatic change, geology, archaeology, pollen, Blytt-Sernander model. Introduction framework of the detailed geological mapping of the For more than 350 years, the area around Lejre has area, and to compare the results with the national been a classical object of investigations into natural archaeological database (www.dkconline.dk), in order history with the aim of studying the interaction to clarify this problem. Also we will present data that between human activity and environmental change shows that the Blytt-Sernander model of Holocene (Worm 1642, Anchersen 1745, Dau 1829, Forch- climatic change fits well with the climatic indicators hammer et al. 1852-1856, Rørdam 1900). During in the Lejre area. the last 25 years, Roskilde University has made de- tailed geological/geophysical mapping of the area. In recent years, there has been a debate concerning The Blytt-Sernander model the establishment of a national park in the Roskilde For more than one hundred years, vegetational Fjord/Lejre area, the main aim of which would be inferred climatic changes have provided the basis to communicate knowledge about the interaction for subdividing the NW European Holocene. Until between its natural and cultural histories. During the recently, the Blytt-Sernander model based on peat same period, the authors of this article have finished stratigraphy has been the dominant theory. Blytt pollen and geochemical analysis of cores from a drill (1876) explained the occurrence of tree-stumps hole in Roskilde Fjord (RF6), and from a drill hole layers as evidence of an alternation between dry in lake Kornerup. and rainy periods, due to the work of Sernander It has been debated if the climatic (environmental) (1908) the model gained a better foundation and changes have been the effect of human activity, or won general acceptance. whether the changing human activity has been the The Blytt-Sernander model divided the last 10,000 effect of climatic change (Bondesen 1998, Diamond years of the Holocene into four phases: Boreal 1998). It will be one aim of this paper to interpret (dry), Atlantic (humid), Subboreal (dry and warm) the analytical data from the two drill holes in the and Subatlantic (humid and cool). The transitions The Journal of Transdisciplinary Environmental Studies, ISSN 1602-2297 http://www.journal-tes.dk/ Schrøder el al.: 10,000 years of climate change and human impact on the environment....... Figure 1. Location of the Lejre study area – figures 2, 3,18-21 and the Roskilde area – figures 14-17. between the periods were considered rather abrupt. analysis) of the marine core (RF6). Furthermore, the Sernander even believed that the Subboreal-Sub- lithological changes are synchronous with the shift in atlantic represented a climatic catastrophe – the pollen zones. Therefore, we employ these zonings in Fimbul winter of the Sagas. the description of the Holocene climate. Moreover, With the subsequent development of palynology, as the results of the analysis show the changes in pollen zones were fitted to the Blytt- Sernander vegetation that define the transition between the periods. However, the Atlantic period was divided periods are the result of climatic change that must in two zones the Early Atlantic Period and the Full cover much greater areas than Sjælland. Atlantic Period (Jessen 1937, Jørgensen 1963). We observe the same development in vegetation change in the two sites. However, the chemical With the application of 14C dating it has become analysis of cores from Lake Kornerup mainly shows clear that the changes in vegetation were time-trans- the impact of human activity on the landscape gressive (Magnerud et al., 1982), and some geolo- (Schrøder et al. 1996), while the chemical analysis gists have since used the Blytt-Sernander periods of the cores from Roskilde Fjord reflects changes in as crono stratigraphic units only. In addition, the salinity, tides and rainfall. archaeologists are now rejecting the theory of the This reflection of more general climatic indicators “catastrophic” period-shifts. Jørgen Jensen (2003 is due to the very unique environment around drill p.23-24), in his monumental and authoritative hole RF6 in Roskilde Fjord. As seen on the maps, review of Danish prehistory, sees the Subboreal- the inner part of Roskilde Fjord is configured as an Subatlantic change as just one of many cyclic cli- evaporation pan, in the middle of Sjælland, with matic variations, which is in contrast to the former fluctuating inflows of seawater and freshwater. authoritative review of Danish prehistory (Brønsted 1940,1977) in particular, he opposes the popular description of climatic change presented by Martin Data and interpretation methods A. Hansen (1952) a writer (and amateur archaeolo- Drill hole analysis, gist) who lived in and interpreted the prehistory of Core samples from the drill holes in Roskilde Fjord the Lejre area. (RF6) and Lake Kornerup were recovered in 5cm Consequently, the Blytt-Sernander periodisation is thickness. now falling into disuse. However, the scheme was established to describe the situation in Scandinavia, Pollen analysis: Pollen were counted in 40 levels and in this investigation, the Blytt-Sernander climat- in Roskilde Fjord (RF6). In every level 500 – 600 ic zones show up clearly in the lithology (chemical pollen were counted. In Lake Kornerup pollen were 2 The Journal of Transdisciplinary Environmental Studies (TES) counted in 62 levels. In every level about 1000 pollen Hydrogeological modelling were counted. All samples had well preserved pollen The distribution of wetlands on the palaeo-geo- (Højlund Pedersen 2003). graphical maps of figures 14 to 16 has been deter- Dating: In this study, the Blytt-Sernander climatic mined from hydrogeological models, based on the zones have been established using the traditional pol- geological maps, and calibrated by the modelling len indicators namely the distinct elm-fall at the Full of the known effects of the establishment of the Atlantic/Subboreal transition, and the rise of Beech groundwater pumping in 1936 (see fig. 4). It has also at the Subboreal/Subatlantic transition. In dating been determined by the observed rise of groundwater the zones, we follow the investigations in Store Bælt level in Lake Kornerup (figure 5) and in Lavringe (Christensen et al.1997). However, 14C datings in (Sørensen 1986) from Boreal to Full Atlantic. RF6 of both the top of Boreal (AAR-3347) and the bottom of Early Atlantic (AAR-3346) confirmed the Archaeological and historical data date of 7000 BC. Similarly, dating the elm-fall in The archaeological Mesolithic settlement data shown both RF6 (AAR-3345) and Lake Kornerup (AAR- in figures 14 to 16 and the data on stone graves from 6263) confirmed the date of 3800 BC. the Neolithic period and grave mounds from the Bronze Age (figures 18 to 19) are from the national Chemical analysis: 40 levels in Roskilde Fjord (RF6) archaeological database (www.dkconline.dk). Some were analysed for: grave mounds may be from the Iron Age, but known Ba, Ca, Sr, Mg, Fe, Mn, Cr, Zn, Pb, Cd, Cu, Ni, iron ages mounds have been ignored. Co, Hg (Enøe 2003). Destruction was undertaken in a Milestone, MLS- The mapping of villages around 600 AD and of 1200 MEGA microwave oven, using the following villages and manor houses in 1682 AD (figures 20 sequence of chemical reagents: HNO3 (65% Su- to 21) is based on the Hartkorn (land tax) of the prapur), H2O2 (30%, p.a.). This solution in exact 1682 (Pedersen 1928) and on place name studies volume with deionizated water was then analysed (Jørgensen 1996). on AAS, (Varian, SpectrAA 250 Plus). Standards The Hartkorn (land tax) valuation of 1682 seems were made from a Stock-standard solution with the also to be a useful geological mapping tool. The concentration 1000 mg/L, BDH Spectrsol. Hg was valuators were specifically asked to judge the “good- measured on Hydrid system VGA 76 on the same ness” of the soil by noticing the clay content. It is Varian, using 25% SnCl2 in 20% HCl suprapur therefore worth noting that the areas with the high quality. tax are the areas affected by the last ice movements on Sjælland (see figure 3b). Lodgement (bottom) till Geological mapping being dominant in the areas affected by the Isefjord During the last 25 years, Roskilde University has and Great Belt glaciers could explain it. Whereas made detailed geological/geophysical mapping of the the central Sjælland was dominated by stagnant ice area in order to provide a basis for a more sustain- - and flow till. able use of the groundwater and mineral resources in the area (see figures 2-3, for review and reference list see Schrøder 1997). Roskilde Fjord has also been mapped in detail (for review and reference list see Bondesen 2002). The configuration of the former coastlines (figures 14 and 15) is based partly on drill hole information (Bondesen 1988).
Load more

Recommended publications
  • Schmitz, M. D. 2000. Appendix 2: Radioisotopic Ages Used In
    Appendix 2 Radioisotopic ages used in GTS2020 M.D. SCHMITZ 1285 1286 Appendix 2 GTS GTS Sample Locality Lat-Long Lithostratigraphy Age 6 2s 6 2s Age Type 2020 2012 (Ma) analytical total ID ID Period Epoch Age Quaternary À not compiled Neogene À not compiled Pliocene Miocene Paleogene Oligocene Chattian Pg36 biotite-rich layer; PAC- Pieve d’Accinelli section, 43 35040.41vN, Scaglia Cinerea Fm, 42.3 m above base of 26.57 0.02 0.04 206Pb/238U B2 northeastern Apennines, Italy 12 29034.16vE section Rupelian Pg35 Pg20 biotite-rich layer; MCA- Monte Cagnero section (Chattian 43 38047.81vN, Scaglia Cinerea Fm, 145.8 m above base 31.41 0.03 0.04 206Pb/238U 145.8, equivalent to GSSP), northeastern Apennines, Italy 12 28003.83vE of section MCA/84-3 Pg34 biotite-rich layer; MCA- Monte Cagnero section (Chattian 43 38047.81vN, Scaglia Cinerea Fm, 142.8 m above base 31.72 0.02 0.04 206Pb/238U 142.8 GSSP), northeastern Apennines, Italy 12 28003.83vE of section Eocene Priabonian Pg33 Pg19 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 14.7 m above base of 34.50 0.04 0.05 206Pb/238U 14.7, equivalent to Ancona, northeastern Apennines, 13.6011 E section MAS/86-14.7 Italy Pg32 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 12.9 m above base of 34.68 0.04 0.06 206Pb/238U 12.9 Ancona, northeastern Apennines, 13.6011 E section Italy Pg31 Pg18 biotite-rich layer; MASS- Massignano (Oligocene GSSP), near 43.5328 N, Scaglia Cinerea Fm, 12.7 m above base of 34.72 0.02 0.04 206Pb/238U
    [Show full text]
  • 1 TIMESCALE for CLIMATIC EVENTS of SUBBOREAL/SUBATLANTIC TRANSITION RECORDED at the VALAKUPIAI SITE, LITHUANIA Jacek Pawlyta1,2
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by BSU Digital Library RADIOCARBON, Vol 49, Nr 2, 2007, p 1–9 © 2007 by the Arizona Board of Regents on behalf of the University of Arizona TIMESCALE FOR CLIMATIC EVENTS OF SUBBOREAL/SUBATLANTIC TRANSITION RECORDED AT THE VALAKUPIAI SITE, LITHUANIA Jacek Pawlyta1,2 • Algirdas Gaigalas3 • Adam MichczyÒski1 • Anna Pazdur1 • Aleksander Sanko4 ABSTRACT. Oxbow lake deposits of the Neris River at the Valakupiai site in Vilnius (Lithuania) have been studied by dif- ferent methods including radiocarbon dating. A timescale was attained for the development of the oxbow lake and climatic events recorded in the sediments. 14C dates obtained for 24 samples cover the range 990–6500 BP (AD 580 to 5600 BC). Medieval human activity was found in the upper part of the sediments. Mollusk fauna found in the basal part of the terrace indicate contact between people living in the Baltic and the Black Sea basins. Mean rates were calculated for erosion of the river and for accumulation during the formation of the first terrace. INTRODUCTION This work presents the results of radiocarbon dating of samples collected at the Valakupiai site, near Vilnius in eastern Lithuania (54°43′58″N, 25°18′33″E; 98.5 m asl) (Figure 1). Special attention was paid to the remnant oxbow lake in the Neris River valley and to the lake-bog deposits filling it. Detailed study of the deposits delivered specific information that enabled paleoecological recon- struction of the site, as well as a description of the geochronological evolution of the oxbow lake and accompanying climatic events.
    [Show full text]
  • Pollen-Based Quantitative Land-Cover Reconstruction for Northern Asia Covering the Last 40 Ka Cal BP
    Clim. Past, 15, 1503–1536, 2019 https://doi.org/10.5194/cp-15-1503-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Pollen-based quantitative land-cover reconstruction for northern Asia covering the last 40 ka cal BP Xianyong Cao1,a, Fang Tian1, Furong Li2, Marie-José Gaillard2, Natalia Rudaya1,3,4, Qinghai Xu5, and Ulrike Herzschuh1,4,6 1Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, Potsdam 14473, Germany 2Department of Biology and Environmental Science, Linnaeus University, Kalmar 39182, Sweden 3Institute of Archaeology and Ethnography, Siberian Branch, Russian Academy of Sciences, pr. Akad. Lavrentieva 17, Novosibirsk 630090, Russia 4Institute of Environmental Science and Geography, University of Potsdam, Karl-Liebknecht-Str. 24, 14476 Potsdam, Germany 5College of Resources and Environment Science, Hebei Normal University, Shijiazhuang 050024, China 6Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24, Potsdam 14476, Germany apresent address: Key Laboratory of Alpine Ecology, CAS Center for Excellence in Tibetan Plateau Earth Sciences, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China Correspondence: Xianyong Cao ([email protected]) and Ulrike Herzschuh ([email protected]) Received: 21 August 2018 – Discussion started: 23 October 2018 Revised: 3 July 2019 – Accepted: 8 July 2019 – Published: 8 August 2019 Abstract. We collected the available relative pollen produc- pollen producers. Comparisons with vegetation-independent tivity estimates (PPEs) for 27 major pollen taxa from Eura- climate records show that climate change is the primary fac- sia and applied them to estimate plant abundances during the tor driving land-cover changes at broad spatial and temporal last 40 ka cal BP (calibrated thousand years before present) scales.
    [Show full text]
  • Holocene Climate As Reflected by a Malacological Sequence at Verri&Res,France
    Holocene climate as reflected by a malacological sequence at Verri&res,France NICOLE LIMONDIN AND DENIS-DIDIER ROUSSEAU Limondin, N. & Rousseau, D.-D. 1991 (September): Holocene climate as reflected by a malacological Born sequence at Verrieres, France. Boreas, VOI. 20, pp. 207-229. OSIO. ISSN 03m-9483. Though numerous analyses have been made of Holocene pollen sequences, they come from similar environmental contexts, mainly peat deposits. Land snails can provide good palaeoecological and palaeoclimatical data in different drier environmental settings. The Verrieres deposits, located in the Seine Valley, southeast of Paris, provide rich and abundant malacofaunas. We compare the well-defined local biostratigraphy with other mollusc stratigraphies from Burgundy, the closest site to the studied region. Multivariate analysis of the malacofaunas indicates that temperature and moisture did not always vary in parallel during the Holocene. On the other hand, Verrieres malacofaunas reflect the main Holocene changes, as observed in the classical pollen series, confirming the reliability of the local biostratigraphy. The Younger Dryas in Verrieres was cold and dry. This was followed by the Preboreal phase, which is not well preserved at Verritres, but shows cool and humid conditions. The Boreal and Subboreal both show a cold and moist event bounded by two temperature phases. The Atlantic is also divided into two temperate phases by a cool and moist event. The Subatlantic shows temperature oscillations with cool peaks, but moisture shows a continuous trend to dryness. Nicole Limondin and Denis-Didier Rousseau, URA CNRS 157, Centre des Sciences de la Terre, Uniuersitd de Bourgogne, 6 Bd Gabriel, 21100 Dijon. France; Rousseau's present address: Lamont Doherg Geological Observatory of Columbia University, Palisades, N.Y.
    [Show full text]
  • Formal Ratification of the Subdivision of the Holocene Series/ Epoch
    Article 1 by Mike Walker1*, Martin J. Head 2, Max Berkelhammer3, Svante Björck4, Hai Cheng5, Les Cwynar6, David Fisher7, Vasilios Gkinis8, Antony Long9, John Lowe10, Rewi Newnham11, Sune Olander Rasmussen8, and Harvey Weiss12 Formal ratification of the subdivision of the Holocene Series/ Epoch (Quaternary System/Period): two new Global Boundary Stratotype Sections and Points (GSSPs) and three new stages/ subseries 1 School of Archaeology, History and Anthropology, Trinity Saint David, University of Wales, Lampeter, Wales SA48 7EJ, UK; Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, Wales SY23 3DB, UK; *Corresponding author, E-mail: [email protected] 2 Department of Earth Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario LS2 3A1, Canada 3 Department of Earth and Environmental Sciences, University of Illinois, Chicago, Illinois 60607, USA 4 GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölveg 12, SE-22362, Lund, Sweden 5 Institute of Global Change, Xi’an Jiaotong University, Xian, Shaanxi 710049, China; Department of Earth Sciences, University of Minne- sota, Minneapolis, MN 55455, USA 6 Department of Biology, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada 7 Department of Earth Sciences, University of Ottawa, Ottawa K1N 615, Canada 8 Centre for Ice and Climate, The Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, DK-2100, Copenhagen, Denmark 9 Department of Geography, Durham University, Durham DH1 3LE, UK 10
    [Show full text]
  • The Danish Fish Fauna During the Warm Atlantic Period (Ca
    Atlantic period fish fauna and climate change 1 International Council for the CM 2007/E:03 Exploration of the Sea Theme Session on Marine Biodiversity: A fish and fisheries perspective The Danish fish fauna during the warm Atlantic period (ca. 7,000- 3,900 BC): forerunner of future changes? Inge B. Enghoff1, Brian R. MacKenzie2*, Einar Eg Nielsen3 1Natural History Museum of Denmark (Zoological Museum), University of Copenhagen, DK- 2100 Copenhagen Ø, Denmark; email: [email protected] 2Technical University of Denmark, Danish Institute for Fisheries Research, Department of Marine Ecology and Aquaculture, Kavalergården 6, DK-2920 Charlottenlund, Denmark; email: [email protected] 3Technical University of Denmark, Danish Institute for Fisheries Research, Department of Inland Fisheries, DK-8600 Silkeborg, Denmark; email: [email protected] *corresponding author Citation note: This paper has been accepted for publication in Fisheries Research. Please see doi:10.1016/j.fishres.2007.03.004 and refer to the Fisheries Research article for citation purposes. Abstract: Vast amounts of fish bone lie preserved in Denmark’s soil as remains of prehistoric fishing. Fishing was particularly important during the Atlantic period (ca. 7,000-3,900 BC, i.e., part of the Mesolithic Stone Age). At this time, sea temperature and salinity were higher in waters around Denmark than today. Analyses of more than 100,000 fish bones from various settlements from this period document which fish species were common in coastal Danish waters at this time. This study provides a basis for comparing the fish fauna in the warm Stone Age sea with the tendencies seen and predicted today as a result of rising sea temperatures.
    [Show full text]
  • SECTION C 12 Timescales
    SECTION c 12 Timescales The timescales adopted in geomorphology fall well within the c.4.6 billion years of Earth history, with some being a mere season or even a single event. In addition to continuous timescales, discrete periods of Earth history have been utilized. Six hierarchical levels are formally defined geologically, and these embrace the external or allogenic drivers for the long-term intrinsic or autogenic processes that have fashioned the Earth’s surface, some parts of which still bear ancient traces, whereas others have been fashioned more recently or are currently active. Contemporary problems demand attention to be given to recent timescales, the Quaternary and the Holocene, although these are less formally partitioned. Geomorphology- focused classifications have also been attempted with short, medium and long timescales conceived in relation to system states. An outstanding chal- lenge is to reconcile research at one timescale with results from another. Table 12.1 Historical naming of the geological epochs Eon Era Epoch Date Origin Phanerozoic Cenozoic Holocene 1885 3rd Int.Geol. Congress Pleistocene 1839 C. Lyell Pliocene 1833 C. Lyell Miocene 1833 C. Lyell Oligocene 1854 H.E. von Beyrich Eocene 1833 C. Lyell Palaeocene 1874 W.P. Schimper Mesozoic Cretaceous 1822 W.D. Conybeare/J.Phillips Jurassic 1839 L. von Buch Triassic 1834 F.A. von Albertini Palaeozoic Permian 1841 R.I. Murchison Carboniferous 1822 W.D. Conybeare/J.Phillips Devonian 1839 A.Sedgwick/R.I.Murchison Silurian 1839 R.I. Murchison Ordovician 1879 C. Lapworth Cambrian 1835 A. Sedgwick Precambrian Informal For contemporary usage see Figure 12.1; the Holocene and the Pleistocene are now taken to be epochs within the Quaternary Period, and earlier epochs are within the Palaeogene and Neogene Periods in the Cenozoic.
    [Show full text]
  • 113 Radiocarbon Dating of Buried Holocene Soils In
    RADIOCARBON, Vol 44, Nr 1, 2002, p 113–122 © 2002 by the Arizona Board of Regents on behalf of the University of Arizona RADIOCARBON DATING OF BURIED HOLOCENE SOILS IN SIBERIA Lyubov A Orlova1 • Valentina S Zykina Institute of Geology, Siberian Branch of the Russian Academy of Sciences, Koptuyg Ave. 3, Novosibirsk 630090, Russia ABSTRACT. We have constructed a detailed chronological description of soil formation and its environments with data obtained on radiocarbon ages, palynology, and pedology of the Holocene buried soils in the forest steppe of western and cen- tral Siberia. We studied a number of Holocene sections, which were located in different geomorphic situations. Radiocarbon dating of materials from several soil horizons, including soil organic matter (SOM), wood, peat, charcoal, and carbonates, revealed three climatic periods and five stages of soil formation in the second part of the Holocene. 14C ages of approximately 6355 BP, 6020 BP, and 5930 BP showed that the longest and most active stage is associated with the Holocene Climatic Opti- mum, when dark-grey soils were formed in the forest environment. The conditions of birch forest steppe favored formation of chernozem and associated meadow-chernozem and meadow soils. Subboreal time includes two stages of soil formation corresponding to lake regressions, which were less intense than those of the Holocene Optimum. The soils of that time are chernozem, grassland-chernozem, and saline types, interbedded with thin peat layers 14C dated to around 4555 BP, 4240 BP and 3480 BP, and 3170 BP. Subatlantic time includes two poorly developed hydromorphic paleosols formed within inshore parts of lakes and chernozem-type automorphic paleosol.
    [Show full text]
  • Alphabetical List
    LIST E - GEOLOGIC AGE (STRATIGRAPHIC) TERMS - ALPHABETICAL LIST Age Unit Broader Term Age Unit Broader Term Aalenian Middle Jurassic Brunhes Chron upper Quaternary Acadian Cambrian Bull Lake Glaciation upper Quaternary Acheulian Paleolithic Bunter Lower Triassic Adelaidean Proterozoic Burdigalian lower Miocene Aeronian Llandovery Calabrian lower Pleistocene Aftonian lower Pleistocene Callovian Middle Jurassic Akchagylian upper Pliocene Calymmian Mesoproterozoic Albian Lower Cretaceous Cambrian Paleozoic Aldanian Lower Cambrian Campanian Upper Cretaceous Alexandrian Lower Silurian Capitanian Guadalupian Algonkian Proterozoic Caradocian Upper Ordovician Allerod upper Weichselian Carboniferous Paleozoic Altonian lower Miocene Carixian Lower Jurassic Ancylus Lake lower Holocene Carnian Upper Triassic Anglian Quaternary Carpentarian Paleoproterozoic Anisian Middle Triassic Castlecliffian Pleistocene Aphebian Paleoproterozoic Cayugan Upper Silurian Aptian Lower Cretaceous Cenomanian Upper Cretaceous Aquitanian lower Miocene *Cenozoic Aragonian Miocene Central Polish Glaciation Pleistocene Archean Precambrian Chadronian upper Eocene Arenigian Lower Ordovician Chalcolithic Cenozoic Argovian Upper Jurassic Champlainian Middle Ordovician Arikareean Tertiary Changhsingian Lopingian Ariyalur Stage Upper Cretaceous Chattian upper Oligocene Artinskian Cisuralian Chazyan Middle Ordovician Asbian Lower Carboniferous Chesterian Upper Mississippian Ashgillian Upper Ordovician Cimmerian Pliocene Asselian Cisuralian Cincinnatian Upper Ordovician Astian upper
    [Show full text]
  • The Ulmus Fall at the Transition Atlanticum-Subboreal in Pollen Diagrams 1
    Palaeogeography, Palaeoclimatology, Palaeoecology Elsevier Publishing Company, Amsterdam - Printed in The Netherlands THE ULMUS FALL AT THE TRANSITION ATLANTICUM-SUBBOREAL IN POLLEN DIAGRAMS 1 H. A. TEN HOVE g Division of Palaeobotany and Pollenmorphology, Botanical Museum and Herbarium, Utrecht (The Netherlands) (Received September 26, 1968) SUMMARY The views of previous authors on the elm fall, especially backgrounded by TAUBER'S (1965) theory on differential pollen dispersion, are discussed. Five possible explanations are given: climate, competition and edaphical factors, human influence, diseases, selective pollen filtering. For the time being the present author concludes that the most probable explanation for the elm fall is human influence, eventually in interaction with a change in climate. Depending on local, edaphic and ecological conditions, the various factors which may be held responsible for the elm fall, are probably of unequal importance for different regions. INTRODUCTION Following JESSEN (1934) and IVERSEN (1941) most pollenstratigraphers put a zone-boundary at the considerable fall of Ulmus at the end of the Atlantic (zone VIia/VIlb: MITCHELL, 1941; GODWIN, 1948; JESSEN, 1949; zone VII/VIII: JESSEN, 1938; FIRBAS, 1949). The Subboreal thus is defined solely in terms of vegetation development (compare also WATERBOLK, 1954). Many 14C dates indicate that the Ulmus fall occurred between 3,900 B.C. and 2,600 B.C.; 50~ of these dates comprise the period between 3,150 B.C. and 3,350 B.C. GODWIN (1960) and NILSSON (1964) summarized all available dates. The Ulmus fall In the following part five explanations of the elm fall, that were expounded in the past, are discussed.
    [Show full text]
  • Cabrera's Vole Microtus Cabrerae
    Cabrera’s Vole Microtus cabrerae Thomas, 1906 and the subgenus Iberomys during § the Quaternary: Evolutionary implications and conservation Jose´ Antonio Garrido-Garcı´a *, Ramo´ n C. Soriguer-Escofet Estacio´ n Biolo´gica de Don˜ana, Consejo Superior de Investigaciones Cientı´ficas (CSIC), Avda. Americo Vespuccio s/n, 41092, Sevilla, Spain A B S T R A C T Keywords: Iberomys The corological evolution of the species of the subgenus Iberomys and, specifically, of Microtus cabrerae, Microtus cabrerae are described. Iberomys appeared in the Iberian Peninsula during the Lower Pleistocene and then reached Pleistocene southern France and Italy during the Middle Pleistocene. M. cabrerae established itself as an Iberian Holocene endemic during the final glacial period and subsequently occupied South-Eastern France. This latter Biogeography population and those found along the Mediterranean coast survived until the Subatlantic period. Thus, it Conservation is concluded that Iberomys is endemic to the European sector of the western Mediterranean Basin, but once was found over much more of the Iberian Peninsula, Italy and France. The Iberian Peninsula is, nevertheless, fundamental in its life history as its evolutionary centre and the origin of expansions into other areas. On the other hand, it is possible to locate the centre of origin of the subgenus Iberomys at a regional scale (the Iberian Peninsula) and adapt its evolutionary cycle to a Symmetrical Model. The contraction of the range of M. cabrerae during the Holocene is not related to the Subboreal climatic crisis; rather, it took place during the Subatlantic and could be related to the expansion of agriculture, which probably destroyed many of its habitats.
    [Show full text]
  • Timescale for Climatic Events of Subboreal/Subatlantic Transition Recorded at the Valakupiai Site, Lithuania
    RADIOCARBON, Vol 49, Nr 2, 2007, ρ 889-897 © 2007 by the Arizona Board of Regents on behalf of the University of Arizona TIMESCALE FOR CLIMATIC EVENTS OF SUBBOREAL/SUBATLANTIC TRANSITION RECORDED AT THE VALAKUPIAI SITE, LITHUANIA Jacek Pawlyta1'2 · Algirdas Gaigalas3 · Adam Michczynski1 · Anna Pazdur1 · Aleksander Sanko4 ABSTRACT. Oxbow lake deposits of the Neris River at the Valakupiai site in Vilnius (Lithuania) have been studied by dif- ferent methods including radiocarbon dating. A timescale was attained for the development of the oxbow lake and climatic events recorded in the sediments. ,4C dates obtained for 24 samples cover the range 990-6500 BP (AD 580 to 5600 BC). Medieval human activity was found in the upper part of the sediments. Mollusk fauna found in the basal part of the terrace indicate contact between people living in the Baltic and the Black Sea basins. Mean rates were calculated for erosion of the river and for accumulation during the formation of the first terrace. INTRODUCTION This work presents the results of radiocarbon dating of samples collected at the Valakupiai site, near Vilnius in eastern Lithuania (54°43'58"N, 25°18'33"E; 98.5 m asl) (Figure 1). Special attention was paid to the remnant oxbow lake in the Neris River valley and to the lake-bog deposits filling it. Detailed study of the deposits delivered specific information that enabled paleoecological recon- struction of the site, as well as a description of the geochronological evolution of the oxbow lake and accompanying climatic events. One can recognize separate dynamic phases formed during the course of development of the oxbow lake.
    [Show full text]