Journal cover Journal topic
E&G Quaternary Science Journal An open-access journal of the German Quaternary Association
Journal topic
Volume 48, issue 1
E&G Quaternary Sci. J., 48, 23-37, 1998
https://doi.org/10.3285/eg.48.1.03
© Author(s) 1998. This work is distributed under
the Creative Commons Attribution 3.0 License.
E&G Quaternary Sci. J., 48, 23-37, 1998
https://doi.org/10.3285/eg.48.1.03
© Author(s) 1998. This work is distributed under
the Creative Commons Attribution 3.0 License.

  01 Jan 1998

01 Jan 1998

Surface geometry of the Last Glacial Maximum (LGM) in the southeastern Swiss Alps (Graubünden) and its paleoclimatological significance

Duri Florineth Duri Florineth

Abstract. Using detailed field evidence provided by trimlines on former nunataks, erratic boulders and the orientations of glacial striae, the surface geometry in the accumulation area during the Last Glacial Maximum was reconstructed for the area of SE Switzerland and adjacent Italy. Collectively, the trends of trimline elevations, flowlines deduced from glacial striae and bedrock morphology along the longitudinal valleys and their tributaries indicate that the former accumulation area consisted of an ice dome with the ice divide located over the area enclosed by Schlarignia, Cinuos-chel, Livigno and Piz Bernina. It attained a minimum altitude of approximately 3000 m. Modelling the topography of the ice surface using a Geographical Information System (GIS) is consistent with these results. The paleoclimatological signal included in this surface geometry was used to draw conclusions about the main atmospheric paleocireulation patterns and to outline the principal precipitation areas for the Alps during the last glaciation. It followed from this that ice build-up was principally related to dominating precipitation by southerly circulation (foehn). The prevaleance of foehn circulation most likely reflects a southward shift of the North Atlantic polar atmospheric front and of the accompanied storm track due to the advancing margin of sea ice. There exists good agreement between these assumptions and (a) results of global circulation models for the time of the LGM; (b) estimations of basal shear stress values and flow velocities for Ice Age glaciers; and (c) interpretations of paleowind indicators.

Publications Copernicus
Download
Citation