# NEW PAPER OUT ON THE COUPLED DYNAMICS OF ICE, MELTWATER, AND TILL
The majority of glaciers and ice sheets flow on a bed of loose and
thawed sediments. These sediments are weakened by pressurized glacial
meltwater, and their lubrication accelerates the ice movement. In
formerly-glaciated areas of the world, for example Northern Europe,
North America, and in the forelands of the Alps, the landscape was
reshaped and remolded by past ice moving the sediments along with
its flow. Sediment movement is also observed under current glaciers,
both the fast-moving ice streams of the Greenland and Antarctic ice
sheets, but also smaller glaciers in the mountainous areas of Alaska,
northern Scandinavia, and elsewhere. The movement of sediment could
be important for the progression of glaciations, and influence how
resilient marine-terminating ice streams are against sea-level rise.
Today, the Nature-group journal Communications Earth & Environment
published my paper on sediment beneath ice. Together with co-authors
Liran Goren, University of the Negev (Israel), and Jenny Suckale,
Stanford University (California, USA), we present a new computer
model that simulates the coupled mechanical behavior of ice, sediment,
and meltwater. We calibrate the model against real materials, and
provide a way for including sediment transport in ice-flow models.
We also show that water-pressure variations with the right frequency
can create create very weak sections inside the bed, and this greatly
enhances sediment transport. I designed the freely-available program
cngf-pf for the simulations.
## Abstract
Water pressure fluctuations control variability in sediment
flux and slip dynamics beneath glaciers and ice streams
Rapid ice loss is facilitated by sliding over beds consisting
of reworked sediments and erosional products, commonly referred
to as till. The dynamic interplay between ice and till reshapes
the bed, creating landforms preserved from past glaciations.
Leveraging the imprint left by past glaciations as constraints
for projecting future deglaciation is hindered by our incomplete
understanding of evolving basal slip. Here, we develop a continuum
model of water-saturated, cohesive till to quantify the interplay
between meltwater percolation and till mobilization that governs
changes in the depth of basal slip under fast-moving ice. Our
model explains the puzzling variability of observed slip depths
by relating localized till deformation to perturbations in
pore-water pressure. It demonstrates that variable slip depth
is an inherent property of the ice-meltwater-till system, which
could help understand why some paleo-landforms like grounding-zone
wedges appear to have formed quickly relative to current
till-transport rates.
## Metrics
It is a substantial task to prepare a scientific publication. The
commit counts below mark the number of revisions done during
preparation of this paper:
- Main article text: 239 commits
- Supplementary information text: 35 commits
- Experiments and figures: 282 commits
- Simulation software: 354 commits
## Links and references:
- Publication on journal webpage (open access):
https://doi.org/10.1038/s43247-020-00074-7
- Source code for producing figures: git://src.adamsgaard.dk/cngf-pf-exp1
- Simulation software: git://src.adamsgaard.dk/cngf-pf
