Reliable glacial chronologies for many of the major LGM piedmont glaciers on the southern side of the Alps have been recently established based on radiocarbon and cosmogenic nuclide dating. However, less is known on the timing of the Last Glacial Maximum in the central part of the southern Alps, where the Toce/Ticino and Adda glacier systems remain chronologically unconstrained. Scattered radiocarbon ages are available (Scapozza et al. 2014), but do not yield information on LGM maximum advance(s) or final glacier retreat from the forelands. This is particularly unfortunate as the glaciers of the central southern Alps were linked to the major Alpine ice domes. The present study aims to overcome this gap of knowledge. Mapping and cosmogenic nuclide dating of the Verbano lobe will give insights into the timing and extent of the Last Glacial Maximum and possible (re)advances of the Toce/Ticino glacier system. So far, thirty rock samples from glacially deposited boulders have been collected for surface exposure dating on the western part of the piedmont lobe, both north and south of Verbania. First Beryllium-10 ages have been determined. Preliminary results show that one of the outermost lateral moraines, that was lately believed to have formed prior to LGM (Bini et al. 2009), is clearly of LGM age. The LGM extent of the Verbano lobe must have been significantly larger than proposed by Bini et al. (2009). The present data set together with field evidence further suggests a glacier re-advance following LGM that ceased with a rapid meltdown of the glacier. References: Bini et al. 2009, Federal Office of Topography, Swisstopo. Scapozza et al. 2014, Geomorphologie 4, 307-322.
First steps towards a glacial chronology of the Verbano lobe, Italian Alps
Giovanni Monegato;
2019
Abstract
Reliable glacial chronologies for many of the major LGM piedmont glaciers on the southern side of the Alps have been recently established based on radiocarbon and cosmogenic nuclide dating. However, less is known on the timing of the Last Glacial Maximum in the central part of the southern Alps, where the Toce/Ticino and Adda glacier systems remain chronologically unconstrained. Scattered radiocarbon ages are available (Scapozza et al. 2014), but do not yield information on LGM maximum advance(s) or final glacier retreat from the forelands. This is particularly unfortunate as the glaciers of the central southern Alps were linked to the major Alpine ice domes. The present study aims to overcome this gap of knowledge. Mapping and cosmogenic nuclide dating of the Verbano lobe will give insights into the timing and extent of the Last Glacial Maximum and possible (re)advances of the Toce/Ticino glacier system. So far, thirty rock samples from glacially deposited boulders have been collected for surface exposure dating on the western part of the piedmont lobe, both north and south of Verbania. First Beryllium-10 ages have been determined. Preliminary results show that one of the outermost lateral moraines, that was lately believed to have formed prior to LGM (Bini et al. 2009), is clearly of LGM age. The LGM extent of the Verbano lobe must have been significantly larger than proposed by Bini et al. (2009). The present data set together with field evidence further suggests a glacier re-advance following LGM that ceased with a rapid meltdown of the glacier. References: Bini et al. 2009, Federal Office of Topography, Swisstopo. Scapozza et al. 2014, Geomorphologie 4, 307-322.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
