TY - JOUR

T1 - Formation of plateau landscapes on glaciated continental margins

AU - Egholm, David L.

AU - Jansen, John D.

AU - Brædstrup, Christian F.

AU - Pedersen, Vivi K.

AU - Andersen, Jane L.

AU - Ugelvig, Sofie V.

AU - Larsen, Nicolaj K.

AU - Knudsen, Mads F.

PY - 2017

Y1 - 2017

N2 - Low-relief plateaus separated by deeply incised fjords are hallmarks of glaciated, passive continental margins. Spectacular examples fringe the once ice-covered North Atlantic coasts of Greenland, Norway and Canada, but low-relief plateau landscapes also underlie present-day ice sheets in Antarctica and Greenland. Dissected plateaus have long been viewed as the outcome of selective linear erosion by ice sheets that focus incision in glacial troughs, leaving the intervening landscapes essentially unaffected. According to this hypothesis, the plateaus are remnants of preglacial low-relief topography. However, here we use computational experiments to show that, like fjords, plateaus are emergent properties of long-term ice-sheet erosion. Ice sheets can either increase or decrease subglacial relief depending on the wavelength of the underlying topography, and plateau topography arises dynamically from evolving feedbacks between topography, ice dynamics and erosion over million-year timescales. This new mechanistic explanation for plateau formation opens the possibility of plateaus contributing significantly to accelerated sediment flux at the onset of the late Cenozoic glaciations, before becoming stable later in the Quaternary.

AB - Low-relief plateaus separated by deeply incised fjords are hallmarks of glaciated, passive continental margins. Spectacular examples fringe the once ice-covered North Atlantic coasts of Greenland, Norway and Canada, but low-relief plateau landscapes also underlie present-day ice sheets in Antarctica and Greenland. Dissected plateaus have long been viewed as the outcome of selective linear erosion by ice sheets that focus incision in glacial troughs, leaving the intervening landscapes essentially unaffected. According to this hypothesis, the plateaus are remnants of preglacial low-relief topography. However, here we use computational experiments to show that, like fjords, plateaus are emergent properties of long-term ice-sheet erosion. Ice sheets can either increase or decrease subglacial relief depending on the wavelength of the underlying topography, and plateau topography arises dynamically from evolving feedbacks between topography, ice dynamics and erosion over million-year timescales. This new mechanistic explanation for plateau formation opens the possibility of plateaus contributing significantly to accelerated sediment flux at the onset of the late Cenozoic glaciations, before becoming stable later in the Quaternary.

U2 - 10.1038/NGEO2980

DO - 10.1038/NGEO2980

M3 - Journal article

AN - SCOPUS:85026639308

VL - 10

SP - 592

EP - 597

JO - Nature Geoscience

JF - Nature Geoscience

SN - 1752-0894

IS - 8

ER -