Xavier Allègre

Different generation of controlled moraines in the glacier foreland of Midtdalsbreen, Norway

Date, time and venue: 28th of March, at 16:00, in Högbomsalen
Supervisor: Benedict Reinardy
Examiner: Arjen Stroeven
Master's Programme in Glaciology and Polar Environments
Degree Project in Physical Geography and Quaternary Geology, 45 credits

Presentation language: English

Satellite imagery coupled with careful field investigations were used in the foreland of the Midtdalsbreen outlet glacier with the aim of finding small (< 3m) controlled moraines deposited against a supposedly 'LIA' bigger moraine (>5 m). Both the controlled moraines and other landforms throughout the glacier foreland indicate that the ice geometry for Midtdalsbreen shortly after the LIA was such that the snout of the glacier was a thin sheet of ice flowing against the previously deposited LIA moraine. What could at first glimpse appears like steeply dipping beds -or highly impacted by permafrost- sedimentology, within the interpreted controlled moraines, reveals instead the presence of thin ice either during or shortly after the LIA maximum for the eastern part of Hardangerjøkul and also some parts of Norway eventually. It is possible to observe developing dirt-cones that are protecting an ice-core directly up above the multi-directional fracture planes of the snout of the present-days glacier. These dirt-cones later evolve into these sedimentological hummocky units with steeply dipping layers within the paleo-landscape. These constrain the thickness of ice of the Midtdalsbreen glacier snout after the LIA as well as the glacier dynamic during melting: this later would have had to operate first by downwasting and then by backwasting in order to have sufficient time to deposit the, later to be, controlled moraines, by the means of a thin ice sheet.