Julien CARCAILLET

Last News

28/05/2024

Research & Development

I dedicate my work to the quantitative study of processes affecting the earth’s surface. More specifically, as a specialist in cosmogenic nuclide dating, I use my expertise to provide chronological information on landscape morphogenesis and associated internal and external mechanisms.
I am developing research to enhance dating techniques based on the physicochemical evolution of rock surfaces.
Furthermore, I am responsible for the Geo-Thermo-Chronology platform

Personal "active" research projects

– Spatial and temporal distribution of extreme rock-ice avalanches in the Cordillera Blanca, Peru.

The Cordillera Blanca in Peru, with its many peaks over 6000m and several hundred white glaciers, is still the most glaciated intertropical mountain range in the world. In connection with global warming, the retreat of the cryosphere associated with the degradation of permafrost is contributing to an increase in associated gravity hazards (e.g. serac falls, GLOFS, moraine building collapses, rock avalanches) that can reach towns and villages in downstream valleys. These hazards have been responsible for tens of thousands of victims since the 1950s.
In this context, this thesis project aims to produce an inventory of ancient rock avalanches within the Cordillera Blanca in order to better assess their spatial distribution, frequency of occurrence and magnitude, particularly in relation to past climatic oscillations (from the Holocene to the late Pleistocene). Various geochronological approaches (cosmogenic nuclides, OSL, 14C) will be combined with high-resolution geomorphological work (DEM analysis, drone, field mapping) to characterize and date these major event deposits. These long-term series of geomorphological archives will then be put into perspective with the glacial fluctuations documented over these periods to better understand the context of occurrence of these extreme avalanches and their possible link with cryosphere fluctuations during the last glacial/interglacial climatic transitions.

Technical challenge : hazard assessment on a broad time scale, TCN dating, Andean geomorphology
Funding : CNES, PEPR IRiMa, BQR ISTerre.
Participants :

  • S. Zerathe, J. Carcaillet, B. Lehmann ISTerre, Grenoble
  • T. Condom IGE, Grenoble
  • INAIGEM, Huaraz (Pe), INGEMMET, Lima (Pe)

– Did high-altitude summits serve as vegetation refugia during Pleistocene glaciations ?

Nunataks, i.e. summits protruding from ice sheets during LGM, have been key physical features alpine landscapes since the onset of Pleistocene. Whether nunataks served as vegetation refugia through glacial periods remains a controversial issue with high relevance to understand how climate change impacts biodiversity. We aim at testing the hypothesis of nunatak plant refugia by means of community genomics focusing on six plant species specialized to high altitude cliffs, coupled with geomorphological and geochronological estimation of past glacier extent and thickness. This project will set up sampling campaigns in data-deficient areas, to increase plant sampling for genomics and rock sampling for geochronology (Terrestrial cosmogenic nuclide). We will develop an unprecedented model-based test of quaternary scenarios of demography and range shifts of several high altitude plant species, by working at two distinct scales (Ecrins massif and entire Alps) and integrating together paleo-glacier delimitation, paleo-climatic reconstructions, hindcasting of past species ranges, genomic data (ddRAD-seq) and coalescence simulations.

Technical challenge : Schmidt Hammer dating, TCN dating
Funding : REFUGIA, LABEX OSUG.
Participants :

  • S. Lavergne, F. Boucher, S. Ibanez LECA, Grenoble
  • J. Carcaillet, P. Valla, S. Zerathe ISTerre, Grenoble
  • R. Delunel EVS, Lyon