scholarly journals Klimazeugen des periglazialen Dauerfrostbodens in Mittel- und Westeuropa: Ein Beitrag zur Rekonstruktion des Klimas der Glaziale des quartären Eiszeitalters

1960 ◽  
Vol 11 (1) ◽  
pp. 121-141 ◽  
Author(s):  
Karlheinz Kaiser

Abstract. Certain periglacial phenomena (ice-wedges, cryoturbations, patterned ground, pingos) are critically investigated with respect to their outer appearance as well as to the causes of their formation, but especially how far they might be used as indicators of an old permafrost. The results for Central and Western Europe have been mapped according to our actual status of knowledge. The attempts hitherto made to reconstruct the climate of the Quaternary glacial periods, have been thoroughly checked. A new calculation of the maximum diminution of Pleistocene temperature gives a value of 15—16° C (bottom temperature) in Central and Western Europe. For the Younger Dryas we still have to expect a temperature depression of 11—12° C. Both values have been found by comparing mean annual temperatures in the border-zone of permafrost at the high-glacial time and during the Younger Dryas with the actual temperatures. This is true on the premise that the active permafrost area can be limited by the — 2° C annual isotherme, both under actual as well as under glacial climatic conditions.

1969 ◽  
Vol 23 ◽  
pp. 29-32
Author(s):  
Ole Bennike ◽  
Esben Lindgård ◽  
Henrik Jønsson Granat ◽  
Richard C. Preece ◽  
Finn Viehberg

Interglacial deposits in Denmark have traditionally been referred to the Cromerian complex (Hareskovian), Holsteinian or Eemian stages. However, based on studies of sediment cores from the deep sea many more than three Quaternary interglacials have been documented, and in other parts of north-western Europe it is becoming increasingly clear that the on-shore Quaternary sequences are much more complex than previously believed. Interglacial deposits are characterised by plant and animal remains indicating longer periods with climatic conditions similar to or warmer than today, whereas interstadial deposits were formed during shorter time spans and usually contain remains of relatively coldadapted, arctic or sub-arctic species. Interglacial and interstadial deposits can be dated more or less precisely, and thus provide information about the relative age of glacial deposits.


2019 ◽  
Vol 15 (2) ◽  
pp. 713-733 ◽  
Author(s):  
Johannes Hepp ◽  
Lorenz Wüthrich ◽  
Tobias Bromm ◽  
Marcel Bliedtner ◽  
Imke Kathrin Schäfer ◽  
...  

Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.


1895 ◽  
Vol 37 (1) ◽  
pp. 127-149
Author(s):  
James Geikie

For many years geologists have recognised the occurrence of at least two boulder-clays in the British Islands and the corresponding latitudes of the Continent. It is no longer doubted that these are the products of two separate and distinct glacial epochs. This has been demonstrated by the appearance of intercalated deposits of terrestrial, freshwater, or, as the case may be, marine origin. Such interglacial accumulations have been met with again and again in Britain, and they have likewise been detected at many places on the Continent, between the border of the North Sea and the heart of Russia. Their organic contents indicate in some cases cold climatic conditions; in others, they imply a climate not less temperate or even more genial than that which now obtains in the regions where they occur. Nor are such interglacial beds confined to northern and north-western Europe. In the Alpine Lands of the central and southern regions of our Continent they are equally well developed. Impressed by the growing strength of the evidence, it is no wonder that geologists, after a season of doubt, should at last agree in the conclusion that the glacial conditions of the Pleistocene period were interrupted by at least one protracted interglacial epoch. Not a few observers go further, and maintain that the evidence indicates more than this. They hold that three or even more glacial epochs supervened in Pleistocene times. This is the conclusion I reached many years ago, and I now purpose reviewing the evidence which has accumulated since then, in order to show how far it goes to support that conclusion.


1998 ◽  
Vol 50 (3) ◽  
pp. 240-251 ◽  
Author(s):  
Julian E. Andrews ◽  
Ashok K. Singhvi ◽  
Ansu J. Kailath ◽  
Ralph Kuhn ◽  
Paul F. Dennis ◽  
...  

Late Pleistocene terrestrial climate records in India may be preserved in oxygen and carbon stable isotopes in pedogenic calcrete. Petrography shows that calcrete nodules in Quaternary sediments of the Thar Desert in Rajasthan are pedogenic, with little evidence for postpedogenic alteration. The calcrete occurs in four laterally persistent and one nonpersistent eolian units, separated by colluvial gravel. Thermoluminescence and infrared- and green-light-stimulated luminescence of host quartz and feldspar grains gave age brackets for persistent eolian units I–IV of ca. 70,000–60,000, ca. 60,000–55,000, ca. 55,000–43,000, and ca. 43,000–∼25,000 yr, respectively. The youngest eolian unit (V) is <10,000 yr old and contains no calcrete. Stable oxygen isotope compositions of calcretes in most of eolian unit I, in the upper part of eolian unit IV, and in the nonpersistent eolian unit, range between −4.6 and −2.1‰ PDB. These values, up to 4.4‰ greater than values from eolian units II and III, are interpreted as representing nonmonsoonal18O-enriched “normal continental” waters during climatic phases when the monsoon weakened or failed. Conversely, 25,000–60,000-yr-old calcretes (eolian units II and III) probably formed under monsoonal conditions. The two periods of weakened monsoon are consistent with other paleoclimatic data from India and may represent widespread aridity on the Indian subcontinent during isotope stages 2 and 4. The total variation in δ13C is 1.7‰ (0.0–1.7‰), and δ13C covaries positively and linearly with δ18O. δ13C values are highest when δ18O values indicate the most arid climatic conditions. This is best explained by expansion of C4grasses at the expense of C3plants at low latitudes during glacial periods when atmospheric pCO2was lowered. C4dominance was overridingly influenced by global change in atmospheric pCO2despite the lowered summer rainfall.


2015 ◽  
Vol 438 ◽  
pp. 34-50 ◽  
Author(s):  
Dominik Pawłowski ◽  
Mateusz Płóciennik ◽  
Stephen J. Brooks ◽  
Tomi P. Luoto ◽  
Krystyna Milecka ◽  
...  

2016 ◽  
Vol 6 ◽  
pp. 690-699 ◽  
Author(s):  
Dorothée G. Drucker ◽  
Wilfried Rosendahl ◽  
Wim Van Neer ◽  
Mara-Julia Weber ◽  
Irina Görner ◽  
...  

2008 ◽  
Vol 1 (8) ◽  
pp. 520-523 ◽  
Author(s):  
Achim Brauer ◽  
Gerald H. Haug ◽  
Peter Dulski ◽  
Daniel M. Sigman ◽  
Jörg F. W. Negendank

2012 ◽  
Vol 151 (1) ◽  
pp. 34-43 ◽  
Author(s):  
K. NI ◽  
A. PACHOLSKI ◽  
D. GERICKE ◽  
H. KAGE

SUMMARYMonitoring ammonia (NH3) emission is time consuming and requires specialized measurement equipment. The measurement time can be reduced if there is a close relationship between time and subsequent cumulated NH3 emission values. A statistical analysis was employed to study the relationship between cumulative NH3 emissions over varying time intervals and final NH3 loss after 3 days of measurement. A large number of multi-plot field experiments on NH3 loss after the application of animal and biogas slurries by trail hoses to crops in Northern Germany were carried out from 2007 to 2010. Based on data from 2007, measured using a passive sampler method, a linear empirical model was developed to calculate final cumulated NH3 loss from intermediate cumulated losses. Linear model fitting showed that cumulative NH3 losses after 24 h were significantly correlated with final cumulated NH3 losses, explaining more than 0·98 of its variation. The linear coefficient was 1·34, implying that c. 0·73 of final NH3 loss occurred within the first 24 h. Validation by datasets obtained from another year (2008), two additional measurement methods and another agro-region (marsh area, 2009/10) resulted in a close agreement of model predictions with measured data within the range of model uncertainty and data variation. The results underpin the feasibility of calculating final NH3 losses from cumulative losses during first 24 h after slurry application and can be used to simplify NH3 loss measurement after the application of liquid slurries in multi-plot field experiments. The slope of the linear relationship is only valid for liquid slurries and the environmental conditions of the present study, which are typical for many agro-regions in north-western Europe, and will have to be adapted for different climatic conditions. A time-efficient measurement of emissions from solid organic fertilizers might require a different time span.


2008 ◽  
Vol 70 (2) ◽  
pp. 131-140 ◽  
Author(s):  
Glen M. MacDonald ◽  
Katrina A. Moser ◽  
Amy M. Bloom ◽  
David F. Porinchu ◽  
Aaron P. Potito ◽  
...  

AbstractSediment records from two lakes in the east-central Sierra Nevada, California, provide evidence of cooling and hydrological shifts during the Younger Dryas stade (YD; ~ 12,900–11,500 cal yr BP). A chironomid transfer function suggests that lake-water temperatures were depressed by 2°C to 4°C relative to maximum temperatures during the preceding Bølling–Allerød interstade (BA; ~ 14,500–12,900 cal yr BP). Diatom and stable isotope records suggest dry conditions during the latter part of the BA interstade and development of relatively moist conditions during the initiation of the YD stade, with a reversion to drier conditions later in the YD. These paleohydrological inferences correlate with similar timed changes detected in the adjacent Great Basin. Vegetation response during the YD stade includes the development of more open and xeric vegetation toward the end of the YD. The new records support linkages between the North Atlantic, the North Pacific, and widespread YD cooling in western North America, but they also suggest complex hydrological influences. Shifting hydrological conditions and relatively muted vegetation changes may explain the previous lack of evidence for the YD stade in the Sierra Nevada and the discordance in some paleohydrological and glacial records of the YD stade from the western United States.


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