Open Session - SWISS GEOSCIENCE MEETINGs

Figure 1. General ice flow direction during LGM and lateglacial phases in the Greina region.
6.
Geomorphological map of the Greina region (Central Swiss Alps)
Fontana Georgia*, Scapozza Cristian*, Reynard Emmanuel*
*Institut de Géographie, Université de Lausanne, Anthropole, CH–1015 Lausanne (Georgia.Fontana@unil.ch)
The Greina is a high mountain region located in the Central Swiss Alps. In spite of the interesting geomorphological features
of the region, no scientific research was carried out in this field until now. The aim of this research was to realise a geomorphological
map of the Greina region, in order to reconstitute the morphogenesis of the area and to make available basis
information for the promotion of the geomorphological heritage of the Greina region (Fontana 2008).
The geomorphological map was realised using the guidelines developed at the Institute of Geography of Lausanne University
(Schoeneich et al. 1998). The method allows the realisation of morphogenetic maps and is particularly interesting for morphogenesis
reconstitutions.
The Greina region presents a rich geomorphological diversity including structural, fluvial, gravitative, karstic, glacial, periglacial
and organic landforms. The landform distribution is largely dependent on geological structure. From a tectonic
point of view, the northern part of the study area belongs to the Gothard Massiv. This tectonic unit is composed of crystalline
rocks, especially gneiss. Crystalline rocks are quite resistant to erosion and still conserve the traces of glacial erosion. Roches
moutonnées and striations are therefore very frequent. The tectonic units situated southern of the Gothard Massiv include
its sedimentary cover and some lower Penninic nappes. The autochthon sedimentary cover is mostly composed of dolomitic
rocks, which present several karstic landforms, like dolines and residual landforms. The parautochton sedimentary cover
and the lower Penninic nappes include several lithologies. Calcschists are very frequent: as these rocks are sensitive to the
action of frost, erosional glacial landforms are quite rare, whereas talus slopes are very frequent. As clays are a product of
calcschists weathering, well-developed solifluxion lobes are also visible.
Thanks to the geomorphological map and to other field observations, the general morphogenesis of the Greina region during
the Lateglacial and the Holocene could be reconstituted (for the Lateglacial, see Fontana et al. 2008). During the Holocene,
glacial processes became less important, whereas gravitative, fluvial and periglacial processes strongly shape the current
183
Symposium 6: Apply! Snow, ice and Permafrost Science + Geomorphology