Molards as an indicator of permafrost degradation and landslide processes

Morino, Costanza; Conway, Susan J.; Sæmundsson, Þorsteinn; Helgason, Jón Kristinn; Hillier, John; Butcher, Frances E.G.; Balme, Matthew R.; Jordan, Colm; Argles, Tom. 2019 Molards as an indicator of permafrost degradation and landslide processes. Earth and Planetary Science Letters, 516. 136-147. https://doi.org/10.1016/j.epsl.2019.03.040

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Official URL: http://dx.doi.org/10.1016/j.epsl.2019.03.040

Abstract/Summary

Molards have been defined in the past as conical mounds of debris that can form part of a landslide's deposits. We present the first conclusive evidence that molards in permafrost terrains are cones of loose debris that result from thawing of frozen blocks of ice-rich sediments mobilised by a landslide, and hence propose a rigorous definition of this landform in permafrost environments. We show that molards can be used as an indicator of permafrost degradation, and that their morphometry and spatial distribution give valuable insights into landslide dynamics in permafrost environments. We demonstrate that molards are readily recognisable not only in the field, but also in remote sensing data; surveys of historic aerial imagery allow the recognition of relict molards, which can be used as an indicator of current and past permafrost conditions. The triggering of landslides as a result of permafrost degradation will arguably occur more often as global atmospheric temperatures increase, so molards should be added to our armoury for tracking climate change, as well as helping us to understand landslide-related hazards. Finally, we have also identified candidate molards on Mars, so molards can inform about landscape evolution on Earth and other planetary bodies.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.epsl.2019.03.040
ISSN:	0012821X
Date made live:	16 Aug 2019 14:32 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/524795

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.epsl.2019.03.040

ISSN:

0012821X

Date made live:

16 Aug 2019 14:32 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/524795