STRATIGRAFIA DELLA SEQUENZA CATAGLACIALE NEI COLLI DI IVREA E DATI POLLINICI PRELIMINARI SUI DEPOSITI LACUSTRI DI CHIAVERANO (TORINO)

Abstract

Forno M. G., Gianotti F., Grosso F. & Pini R., Stratigraphy of the cataglacial sequence in the “Colli d’Ivrea” area and preliminary pollen data of the Chiaverano lacustrine deposits (Torino). (IT ISSN 0394-3356, 2007).
The geological history of the Ivrea Morainic Amphitheatre (AMI) and of the “Colli d’Ivrea” area is currently under detailed revision. The
Colli d’Ivrea area is located in the marginal left sector of the inner depression of the amphitheatre, some hundreds meters above the
present-day incision of the Dora Baltea River. This area, well-known for the occurrence of subglacial bedrock landforms, is characterized by widespread roches moutonnées. The geological survey of this area revealed that these landforms are locally accompanied by a depositional record, locally developed, not recognized by previous authors: this record is testified by the presence of frontal and concentric morainic ridges, some meters-high, discontinuously preserved. The morainic evidence suggests a glacial lobe in progressive withdrawal, connected to an inner position of the glacier compared to the main ridges.
The preliminary pollen analysis of the Tomalino lacustrine-palustrine deposits (Chiaverano) and the comparison with another pollen
record from the amphitheatre (Lago Sirio) suggest that lacustrine sedimentation locally developed since the first part of the Late-Glacial Interstadial of Bølling-Allerød.