scholarly journals Die spät- und frühpostglaziale Vegetationsentwicklung im Umkreis der Alpen. Bemerkungen zur Arbeit von H. Zoller: „Pollenanalystische Untersuchungen zur Vegetationsgeschichte der insurbischen Schweiz“, 1960

1962 ◽  
Vol 12 (1) ◽  
pp. 9-17
Author(s):  
Gerhard Lang

Abstract. Based upon newer papers a brief summary is given on Late-glacial and Pre-boreal vegetational history at the western and northern border of the Alps; the effects of the Bölling- and especially the Alleröd-oscillation are demonstrated. Proceeding of that the different results by H. Zoller (I960) in Southern Switzerland are examined and the arguments for another dating of his two Late-glacial pollen diagramms are discussed. According to that the first afforestation in the lowlands at the southern border of the Alps occured not in the Allerod but already in the Boiling period; the „Piottino-oscillation", associated with the Gschnitz-Stadium, is probably not a new discovered Pre-boreal climatic oscillation, but corresponds to the Alleröd-oscillation. Therefore it seems not necessary to doubt the synchronism of Younger Dryas and Schlußvereisung in the Alps.

1999 ◽  
Vol 28 ◽  
pp. 135-140 ◽  
Author(s):  
Hanns Kerschner ◽  
Susan Ivy-Ochs ◽  
Christian Schlüchter

AbstractThe former glacier at the type locality of the “Gschnitz Stadial” of the Alpine Late-glacial chronology is interpreted from a paleoglaciological and paleoclimatological point of view. The equilibrium-line altitude, ice flux through selected cross sections and mass-balance gradients are calculated from reconstructed glacier topography. They are used to determine total net ablation and accumulation and precipitation under the assumption of steady-state. The former temperature at the ELA and temperature change is estimated using various glacier—climate models. Precipitation was less than one-third of today’s values, and summer temperature was roughly 10°C lower than today. The climate during the Gschnitz Stadial appears to have been cold and continental, and was more similar to full glacial conditions than to the Younger Dryas climate in the Alps. This is further evidence for an older age of the Gschnitz Stadial.


1981 ◽  
Vol 15 (2) ◽  
pp. 160-170 ◽  
Author(s):  
U. Eicher ◽  
U. Siegenthaler ◽  
S. Wegmüller

AbstractThe sequence of vegetation phases in the late Glacial was studied in a sediment section from the bog Tourbière de Chirens by means of pollen analysis. 18O/16O ratios of samples of lacustrine marl, obtained from the same profile, reflect variations of 18O/16O in precipitation and thus provide an additional, independent paleoclimatic record. The observed 18O/16O variations agree well with the climatic history as deduced from pollen analysis. The climatic transition from the Oldest Dryas to the Bølling period sensu lato, as well as the beginning and end of the Younger Dryas cold phase, is marked by abrupt changes in the 18O/16O ratio which were observed also in other regions of the Alps. These drastic climatic changes probably took place simultaneously over large areas of Central Europe and occurred within short time spans.


Nature ◽  
1986 ◽  
Vol 323 (6085) ◽  
pp. 247-250 ◽  
Author(s):  
Robert J. Mott ◽  
Douglas R. Grant ◽  
Ralph Stea ◽  
Serge Occhietti

The Holocene ◽  
2021 ◽  
pp. 095968362110116
Author(s):  
Lucie Juřičková ◽  
Jakub Menšík ◽  
Jitka Horáčková ◽  
Vojen Ložek

The Alps are an important hotspot of species diversity and endemism, as well as a presumed glacial refugium of several species’ groups including land snails. The recent ranges of Alpine endemics are well known, but their fluctuations during the postglacial period mirroring local climate changes are understudied. By analysing five Late Glacial and Holocene mollusc successions from two areas in the southernmost part of the Bohemian Massif (Czech Republic) situated about 100 km north of the Alps, we reveal details of these fluctuations. The Alpine endemic rocky dweller Chilostoma achates had reached the southern part of the Bohemian Massif already in the Late Glacial and disappeared in the Mid-Holocene canopy forest optimum. On the contrary, the northern boundaries of Alpine canopy forest epigeic snails extended further north than today at the turn of the Middle and Late-Holocene, pointing to a more favourable forest microclimate. The earliest known occurrences of several temperate canopy forest central European species, especially Causa holosericea and Discus perspectivus, imply the role of different areas in the Alps as their glacial refugia.


2020 ◽  
Vol 6 (50) ◽  
pp. eaba4844
Author(s):  
Brice R. Rea ◽  
Ramón Pellitero ◽  
Matteo Spagnolo ◽  
Philip Hughes ◽  
Susan Ivy-Ochs ◽  
...  

The Younger Dryas (YD) was a period of rapid climate cooling that occurred at the end of the last glaciation. Here, we present the first palaeoglacier-derived reconstruction of YD precipitation across Europe, determined from 122 reconstructed glaciers and proxy atmospheric temperatures. Positive precipitation anomalies (YD versus modern) are found along much of the western seaboard of Europe and across the Mediterranean. Negative precipitation anomalies occur over the Fennoscandian ice sheet, the North European Plain, and as far south as the Alps. This is consistent with a more southerly and zonal storm track, which is linked to a concomitant southern location of the Polar Frontal Jet Stream, generating cold air outbreaks and enhanced cyclogenesis, especially over the eastern Mediterranean. This atmospheric configuration resembles the modern Scandinavian (SCAND) circulation over Europe (a blocking high pressure over Scandinavia pushing storm tracks south and east), and by analogy, a seasonally varying palaeoprecipitation pattern is interpreted.


2016 ◽  
Vol 11 (17) ◽  
Author(s):  
Miguel Ángel Vázquez Ruiz

Resumen:El proceso de globalización de los procesos económicos, a primera vista sugiere un mundo de dimensiones homogéneas, muy interrelacionado entre sí y con igualdad de oportunidades de desarrollo para todos los países. Pero la realidad se desenvuelve en otra lógica: la globalización impulsa dinámicas muy segmentadas, donde el mundo vive las paradojas de la conformación de bloques regionales entre países y de regiones diferenciadas al interior de estos. En este sentido, uno de los espacios donde en la actualidad, por una razón u otra, se dan relaciones peculiares, son las fronterizas. Hay países donde los vínculos fronterizos se expresan como conflictos étnicos y religiosos; en cambio en otros, las conexiones más importantes son de índole económica y demográfica. Este es el caso de la frontera entre México y Estados Unidos, espacio donde se reproduce una de las relaciones binacionales más intensas entre países. En el presente artículo, se pretende avanzar en hacer una relectura de la frontera norte de México y sur de Estados Unidos, considerándola una región integrada por dos subregiones: la estadounidense y la mexicana. Para ello, se pasa revista a los más importantes enfoques teóricos para entender esa realidad, y se propone su revisión a la luz de las constantes modificaciones en ésta, que conducen a agotamientos muy rápidos en los "paradigmas" de análisis que cada autor del tema utiliza. Este planteamiento se documenta con la aportación de elementos cuantitativos y cualitativos acerca de las partes que configuran la región y, particularmente, se destacan las distintas modalidades de corredores económicos como medios de vinculación entre las "subregiones". Se plantea también reflexionar acerca de aspectos poco estudiados en estas últimas, como sería el perfil de los actores empresariales, básico para entender sus niveles de competitividad en la globalización a partir de una plataforma regional.Palabras clave: Globalización, Zonas fronterizas, Frontera México-Estados Unidos, Corredores económicos, Economía fronteriza.Abstract:The globalization of economic processes, at first sight, suggests a very inter- related world of homogenous dimensions, with equal opportunities of development for all countries. But reality comes about with another logic: globalization furthers very segmented dynamics, where the world experiences the paradox of the establishment of regional blocks among countries and regions that are differentiated within such blocks. In this sense, border areas are one of the spaces where presently, due to one reason or another, peculiar relations occur. There are countries where border ties are expressed as ethnic and religious conflicts, whereas, there are others, in which the most important connections are of an economic and demographic nature. This is the case of the Mexico-US border, space where one of the most intense binational relations between countries takes place. This article intends to review Mexico?s northern border and the United States southern border, considering it a region integrated by two subregions: the one of the United States and the one of Mexico. For such purpose, the most important theoretical approaches is reviewed in order to understand said reality. Its review is proposed in view of its constant modifications that lead to very fast depletions in the "paradigms" of analysis used by each author who writes about the subject. This statement is documented with the contribution of qualitative and quantitative elements about the parts that form the region, particularly underscoring the different modalities of economic corridors as means to link the "subregions". Statements are also made that lead to reflect on aspects that have been little studied in the latter, such as the pro file of the business actors, that is basic to understand their levels of competitiveness in globalization as of a regional platform .Key words: Globalization, Borderlines, USA-Mexico borderline, Economic corridors, Borderline economics.


1996 ◽  
Vol 46 (1) ◽  
pp. 144-151
Author(s):  
Wolfgang Zech ◽  
Rupert Bäumler ◽  
Oksana Savoskul ◽  
Anatoli Ni ◽  
Maxim Petrov

Abstract. Soil geographic studies were carried out in the Oigaing valley between Ugamsky and Pskemsky range NE of Tashkent (W-Tienshan, Republic of Uzbekistan) with special regard to the Pleistocene and Holocene glaciation. Clear end moraines of the last main glaciation are preserved at the junction of Maidan and Oigaing river at 1500-1600 m a.s.l. They show intensively weathered soils with a depth of more than 80 cm. Similar deposits ol presumably Pleistocene or late glacial origin are also located upvalley at the embouchure of numerous side valleys (Beschtor, Tekesch, Aütor) into the main valley of Oigaing. All side valleys are characterized by late glacial ground and end moraines in 2500-2700 m a.s.l. showing intensively weathered brown colored soils of 30-40 cm depth. Further moraines of Holocene or recent origin are located approach of the recent glaciers which descend to 3000-3200 m. They show shallow, initial soils, and presumably correspond with glacial advances during the so-called "Little Ice Age" with a maximum advance at about 1850 in the Alps, and in the middle Holocene at about 2000 or 4000 a BP. Highly weathered, and rubefied interglacial soils developed from old Quaternary gravel are preserved above high glacial ice marginal grounds of the last main glaciation (>2850 m a.s.l.) in the lower side valley of the Barkrak river. In the upper valley huge drift could be shown above the ice marginal grounds, but without typical forms of morainic deposits. They give evidence for older glaciations with a greater extent compared with the last main glaciation. However, no corresponding moraines are present in the working area.


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.


Radiocarbon ◽  
2004 ◽  
Vol 46 (2) ◽  
pp. 933-941 ◽  
Author(s):  
Irina P Panyushkina ◽  
Steven W Leavitt ◽  
Alex Wiedenhoeft ◽  
Sarah Noggle ◽  
Brandon Curry ◽  
...  

The abrupt millennial-scale changes associated with the Younger Dryas (YD) event (“chronozone”) near the dawn of the Holocene are at least hemispheric, if not global, in extent. Evidence for the YD cold excursion is abundant in Europe but fairly meager in central North America. We are engaged in an investigation of high-resolution environmental changes in mid-North America over several millennia (about 10,000 to 14,000 BP) during the Late Glacial–Early Holocene transition, including the YD interval. Several sites containing logs or stumps have been identified and we are in the process of initial sampling or re-sampling them for this project. Here, we report on a site in central Illinois containing a deposit of logs initially thought to be of YD age preserved in alluvial sands. The assemblage of wood represents hardwood (angiosperm) trees, and the ring-width characteristics are favorable to developing formal tree-ring chronologies. However, 4 new radiocarbon dates indicate deposition of wood may have taken place over at least 8000 14C yr (6000–14,000 BP). This complicates the effort to develop a single floating chronology of several hundred years at this site, but it may provide wood from a restricted region over a long period of time from which to develop a sequence of floating chronologies, the timing of deposition and preservation of which could be related to paleoclimatic events and conditions.


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