Experimental study of the degradation of ice-cemented sediment produced by landslides into molards
Doctorate Full Doctorate
Earth & Universe
Host institution
Other institution
Doctoral school
Physics, Engineering Sciences, Materials, Energy (PSIME) - ED 591


This thesis topic is part of the ANR Permolards (2019-2024), whose aim is to use molards as markers of mountain permafrost degradation. Molards are debris cones that result from the thawing of blocks of frozen sediment. The blocks of frozen sediments are mobilised from hillslopes by landslides and hence molards are associated with landslide deposits. Molards cannot form without the interstitial ice that cements the original material, allowing it to behave as a solid during transport. Once the ice thaws, the blocks lose their cohesion, causing the material to collapse into molards. These landforms are an indicator of the recent and ongoing degradation of permafrost. Their spatial and geomorphological characteristics reflect the dynamics of the landslides that formed them. This project aims to highlight the importance of molards in terms of climate change and natural hazard, as molards can reveal how permafrost degradation occurs and evolves, and provide information on the dangers of landslides in cold environments. Case studies in Greenland, Canada and Iceland. The thesis focuses on the experimental part of the larger project ANR Permolards. The PhD student will be given the opportunity to participate in the fieldwork in Canada and Iceland, exchange with numerical modellers (IPGP, LMV) and develop their own numerical models.

Skills required

In order to carry out the planned experiments, the doctoral student will have to: - carry out literature searches and use the information to inform the cold room experiments; - use the results from preliminary experiments currently being performed on 30 cm initial blocks to refine the experimental protocol to make it applicable to larger molards; - training will be provided in cold room experimental techniques (management of freeze/thaw cycles, continuous data acquisition of temperatures and water content); - Calibration of the thermal camera; - quantify the topographic modifications of the simulated molards using available photogrammetry and GIS software (Photomodeler, Agisoft Metashape, ArcGIS 10, qGIS, CloudCompare); - analysis of monitoring data, including processing and analysis of the data acquired by continuous measurements (temperature, water content) and punctual measurements (beginning of freezing, end of freezing, middle of thaw in thermal and photogrammetric data). Required skills The candidate should have a background in geoscience and/or geophysics. Basic knowledge of periglacial processes would be an advantage. Experience in GIS and/or photogrammetry will be appreciated, as well as experience in programming. A good level of English is expected, as it is necessary for exchanges within an international team. As part of his/her thesis, the doctoral student will be required to participate in a field mission in Canada in the summer of 2023. This thesis will be done within the framework of the ANR Permolards research project. The candidate should be motivated by working with several teams (M2C laboratories in Caen, LPG in Nantes, Geops in Orsay, EDYTEM in Chambéry).


Climate change, permafrost, molard, mass wasting, physical modelling, cold room

Funded offer

Funding type
Contrat Doctoral


Application deadline 10/05/21

Duration36 months

Start date15/09/21

Creation date15/03/21


Level of french requiredC2 (proficiency)

Level of English requiredC1 (advanced)


Annual tuition fee0 € / year

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