posted on 2019-04-04, 13:36authored byCostanza Morino, Susan J. Conway, Thorsteinn Saemundsson, Jon Kristinn Helgason, John HillierJohn Hillier, Frances E.G. Butcher, Matthew Balme, Colm J. Jordan, Tom Argles
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.
Funding
This work has been funded by a postgraduate studentship grant (NE/L002493/1) from the
Central England Natural Environment Research Council Training Alliance (CENTA). This
project forms part of and is funded by a British Geological Survey BUFI CASE Studentship
(GA/14S/024, Ref: 284).
History
Department
Geography and Environment
Published in
Earth and Planetary Science Letters
Volume
516
Pages
136-147
Citation
MORINO, C. .... et al., 2019. Molards as an indicator of permafrost degradation and landslide processes. Earth and Planetary Science Letters, 516, pp.136-147.
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/
Acceptance date
2019-03-27
Publication date
2019-04-17
Notes
This is an Open Access article. It is published by Elsevier under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/