View in EDS

Radar‐Derived Crystal Orientation Fabric Suggests Dynamic Stability at the Summit of Hercules Dome.

Saved in:
Bibliographic Details
Title: Radar‐Derived Crystal Orientation Fabric Suggests Dynamic Stability at the Summit of Hercules Dome.
Authors: Hills, B. H.1,2 (AUTHOR) benjamin.hills@mines.edu, Holschuh, N.3 (AUTHOR), Hoffman, A. O.4 (AUTHOR), Horlings, A. N.1,5 (AUTHOR), Erwin, E.6,7 (AUTHOR), Kirkpatrick, L. R.1 (AUTHOR), Fudge, T. J.1 (AUTHOR), Steig, E. J.1 (AUTHOR), Christianson, K.1 (AUTHOR)
Source: Journal of Geophysical Research. Earth Surface. Mar2025, Vol. 130 Issue 3, p1-22. 22p.
Subject Terms: *Interglacials, *Antarctic ice, *Ice sheets, *Glacial Epoch, Ice crystals, Ice shelves
Abstract: Hercules Dome is a prospective ice‐core site due to its setting in the bottleneck between East and West Antarctica. If ice from the last interglacial period has been preserved there, it could provide critical insight into the history of the West Antarctic Ice Sheet. The likelihood of a continuous, well‐resolved, easily interpretable climate record preserved in ice extracted from Hercules Dome depends in part on the persistence of ice‐flow dynamics at the divide. Significant changes in ice drawdown on either side of the divide, toward the Ross or Ronne ice shelves, could change the relative thickness of layers and the deposition environment represented in the core. Here, we use radar sounding to survey the ice flow at Hercules Dome. Repeated radar acquisitions show that vertical velocities are consistent with expectations for an ice divide with a frozen bed. Polarimetric radar acquisitions capture the ice‐crystal orientation fabric (COF) which develops as ice strains, so it depends on both the pattern of ice flow and the time over which flow has been consistent. We model the timescales for COF evolution, finding that the summit of Hercules Dome has been dynamically stable in its current configuration, at least over the last five thousand years, a time period during which the Antarctic ice sheet was undergoing significant retreat at its margins. The evident stability may result from a prominent bedrock ridge under the divide, which had not been previously surveyed and has therefore not been represented in the bed geometry of coarsely resolved ice‐sheet models. Plain Language Summary: Hercules Dome is a localized high point in the ice surface between East and West Antarctica. Based on present‐day flow patterns highlighted in prior work, there is reason to believe that ice from 130 thousand years ago may be preserved there. The old ice would give insight on behavior of the West Antarctic Ice Sheet during a prior warm period in Earth's history. However, if the ice flow patterns near Hercules Dome have changed over time, the old ice may not be preserved in a state which can be easily interpreted. To study the ice flow, we use radar measurements of (i) vertical movement, and (ii) crystal orientation. The orientations of crystals change over time as the ice is stretched, so they can reveal information about ice flow and how long it has been consistent. We find that the ice flow at the summit of Hercules Dome has been consistent for at least the last five thousand years, as the Antarctic Ice Sheet shrank coming out of the last ice age. This stability is likely caused by a large ridge of rock beneath the ice, which had not been discovered until now. Key Points: We constrain present and past ice dynamics at Hercules Dome, East Antarctica, using measurements of ice flow and crystal orientation fabric (COF)We find evidence of divide flow in both vertical velocities and COF, particularly at the summit of Hercules DomeModels of COF suggest that divide orientation, position, and shape have been dynamically stable since at least 5 ka [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Earth Surface is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: GreenFILE
FullText Text:
  Availability: 0
Header DbId: 8gh
DbLabel: GreenFILE
An: 184045645
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Radar‐Derived Crystal Orientation Fabric Suggests Dynamic Stability at the Summit of Hercules Dome.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Hills%2C+B%2E+H%2E%22">Hills, B. H.</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<i> benjamin.hills@mines.edu</i><br /><searchLink fieldCode="AR" term="%22Holschuh%2C+N%2E%22">Holschuh, N.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Hoffman%2C+A%2E+O%2E%22">Hoffman, A. O.</searchLink><relatesTo>4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Horlings%2C+A%2E+N%2E%22">Horlings, A. N.</searchLink><relatesTo>1,5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Erwin%2C+E%2E%22">Erwin, E.</searchLink><relatesTo>6,7</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Kirkpatrick%2C+L%2E+R%2E%22">Kirkpatrick, L. R.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Fudge%2C+T%2E+J%2E%22">Fudge, T. J.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Steig%2C+E%2E+J%2E%22">Steig, E. J.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Christianson%2C+K%2E%22">Christianson, K.</searchLink><relatesTo>1</relatesTo> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Earth+Surface%22">Journal of Geophysical Research. Earth Surface</searchLink>. Mar2025, Vol. 130 Issue 3, p1-22. 22p.
– Name: Subject
  Label: Subject Terms
  Group: Su
  Data: *<searchLink fieldCode="DE" term="%22Interglacials%22">Interglacials</searchLink><br />*<searchLink fieldCode="DE" term="%22Antarctic+ice%22">Antarctic ice</searchLink><br />*<searchLink fieldCode="DE" term="%22Ice+sheets%22">Ice sheets</searchLink><br />*<searchLink fieldCode="DE" term="%22Glacial+Epoch%22">Glacial Epoch</searchLink><br /><searchLink fieldCode="DE" term="%22Ice+crystals%22">Ice crystals</searchLink><br /><searchLink fieldCode="DE" term="%22Ice+shelves%22">Ice shelves</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Hercules Dome is a prospective ice‐core site due to its setting in the bottleneck between East and West Antarctica. If ice from the last interglacial period has been preserved there, it could provide critical insight into the history of the West Antarctic Ice Sheet. The likelihood of a continuous, well‐resolved, easily interpretable climate record preserved in ice extracted from Hercules Dome depends in part on the persistence of ice‐flow dynamics at the divide. Significant changes in ice drawdown on either side of the divide, toward the Ross or Ronne ice shelves, could change the relative thickness of layers and the deposition environment represented in the core. Here, we use radar sounding to survey the ice flow at Hercules Dome. Repeated radar acquisitions show that vertical velocities are consistent with expectations for an ice divide with a frozen bed. Polarimetric radar acquisitions capture the ice‐crystal orientation fabric (COF) which develops as ice strains, so it depends on both the pattern of ice flow and the time over which flow has been consistent. We model the timescales for COF evolution, finding that the summit of Hercules Dome has been dynamically stable in its current configuration, at least over the last five thousand years, a time period during which the Antarctic ice sheet was undergoing significant retreat at its margins. The evident stability may result from a prominent bedrock ridge under the divide, which had not been previously surveyed and has therefore not been represented in the bed geometry of coarsely resolved ice‐sheet models. Plain Language Summary: Hercules Dome is a localized high point in the ice surface between East and West Antarctica. Based on present‐day flow patterns highlighted in prior work, there is reason to believe that ice from 130 thousand years ago may be preserved there. The old ice would give insight on behavior of the West Antarctic Ice Sheet during a prior warm period in Earth's history. However, if the ice flow patterns near Hercules Dome have changed over time, the old ice may not be preserved in a state which can be easily interpreted. To study the ice flow, we use radar measurements of (i) vertical movement, and (ii) crystal orientation. The orientations of crystals change over time as the ice is stretched, so they can reveal information about ice flow and how long it has been consistent. We find that the ice flow at the summit of Hercules Dome has been consistent for at least the last five thousand years, as the Antarctic Ice Sheet shrank coming out of the last ice age. This stability is likely caused by a large ridge of rock beneath the ice, which had not been discovered until now. Key Points: We constrain present and past ice dynamics at Hercules Dome, East Antarctica, using measurements of ice flow and crystal orientation fabric (COF)We find evidence of divide flow in both vertical velocities and COF, particularly at the summit of Hercules DomeModels of COF suggest that divide orientation, position, and shape have been dynamically stable since at least 5 ka [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Journal of Geophysical Research. Earth Surface is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=8gh&AN=184045645
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1029/2023JF007588
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 22
        StartPage: 1
    Subjects:
      – SubjectFull: Interglacials
        Type: general
      – SubjectFull: Antarctic ice
        Type: general
      – SubjectFull: Ice sheets
        Type: general
      – SubjectFull: Glacial Epoch
        Type: general
      – SubjectFull: Ice crystals
        Type: general
      – SubjectFull: Ice shelves
        Type: general
    Titles:
      – TitleFull: Radar‐Derived Crystal Orientation Fabric Suggests Dynamic Stability at the Summit of Hercules Dome.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Hills, B. H.
      – PersonEntity:
          Name:
            NameFull: Holschuh, N.
      – PersonEntity:
          Name:
            NameFull: Hoffman, A. O.
      – PersonEntity:
          Name:
            NameFull: Horlings, A. N.
      – PersonEntity:
          Name:
            NameFull: Erwin, E.
      – PersonEntity:
          Name:
            NameFull: Kirkpatrick, L. R.
      – PersonEntity:
          Name:
            NameFull: Fudge, T. J.
      – PersonEntity:
          Name:
            NameFull: Steig, E. J.
      – PersonEntity:
          Name:
            NameFull: Christianson, K.
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 03
              Text: Mar2025
              Type: published
              Y: 2025
          Identifiers:
            – Type: issn-print
              Value: 21699003
          Numbering:
            – Type: volume
              Value: 130
            – Type: issue
              Value: 3
          Titles:
            – TitleFull: Journal of Geophysical Research. Earth Surface
              Type: main
ResultId 1