Seawater softening of suture zones inhibits fracture propagation in Antarctic ice shelves

Authors Organisations
  • Bernd Kulessa(Author)
    Prifysgol Abertawe | Swansea University
    University of Tasmania
  • Adam D. Booth(Author)
    University of Leeds
  • Martin O’Leary(Author)
    Prifysgol Abertawe | Swansea University
  • Daniel Mcgrath(Author)
    Colorado State University
  • Edward C. King(Author)
    British Antarctic Survey
  • Adrian J. Luckman(Author)
    Prifysgol Abertawe | Swansea University
  • Paul R. Holland(Author)
    British Antarctic Survey
  • Daniela Jansen(Author)
    Prifysgol Abertawe | Swansea University
    Alfred Wegener Institute for Polar and Marine Research
  • Suzanne L. Bevan(Author)
    Prifysgol Abertawe | Swansea University
  • Sarah S. Thompson(Author)
    Prifysgol Abertawe | Swansea University
    University of Tasmania
  • Bryn Hubbard(Author)
Type Article
Original languageEnglish
Article number5491
Number of pages12
JournalNature Communications
Volume10
Issue number1
DOI
Publication statusPublished - 02 Dec 2019
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Abstract

Suture zones are abundant on Antarctic ice shelves and widely observed to impede fracture propagation, greatly enhancing ice-shelf stability. Using seismic and radar observations on the Larsen C Ice Shelf of the Antarctic Peninsula, we confirm that such zones are highly heterogeneous, consisting of multiple meteoric and marine ice bodies of diverse provenance fused together. Here we demonstrate that fracture detainment is predominantly controlled by enhanced seawater content in suture zones, rather than by enhanced temperature as previously thought. We show that interstitial seawater can reduce fracture-driving stress by orders of magnitude, promoting both viscous relaxation and the development of micro cracks, the incidence of which scales inversely with stress intensity. We show how simple analysis of viscous buckles in ice-penetrating radar data can quantify the seawater content of suture zones and their modification of the ice-shelf’s stress regime. By limiting fracture, enhancing stability and restraining continental ice discharge into the ocean, suture zones act as vital regulators of Antarctic mass balance