Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica
Abstract We report the discovery of a large accumulation of micrometeorites (MMs) in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The MMs are present in abundances of ~600 particles kg −1 of moraine sediment and include a near‐comple...
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crwiley:10.1111/maps.13107 2024-06-23T07:47:22+00:00 Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica Genge, Matthew J. van Ginneken, Matthias Suttle, Martin D. Harvey, Ralph P. Science and Technology Facilities Council 2018 http://dx.doi.org/10.1111/maps.13107 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.13107 https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.13107 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Meteoritics & Planetary Science volume 53, issue 10, page 2051-2066 ISSN 1086-9379 1945-5100 journal-article 2018 crwiley https://doi.org/10.1111/maps.13107 2024-06-11T04:52:20Z Abstract We report the discovery of a large accumulation of micrometeorites (MMs) in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The MMs are present in abundances of ~600 particles kg −1 of moraine sediment and include a near‐complete collection of MM types similar to those observed in Antarctic blue ice and within bare‐rock traps in the Antarctic. The size distribution of the observed particles is consistent with those collected from snow collections suggesting the moraine has captured a representative collection of cosmic spherules with significant loss of only the smallest particles (<100 μm) by wind. The presence of microtektites with compositions similar to those of the Australasian strewn field suggests the moraine has been accumulating for 780 ka with dust‐sized debris. On the basis of this age estimate, it is suggested that accumulation occurs principally through ice sublimation. Direct infall of fines is suggested to be limited by snow layers that act as barriers to accumulation and can be removed by wind erosion. MM accumulation in many areas in Antarctica, therefore, may not be continuous over long periods and can be subject to climatic controls. On the basis of the interpretation of microtektites as Australasian, Larkman Nunatak deposit is the oldest known supraglacial moraine and its survival through several glacial maxima and interglacial periods is surprising. We suggest that stationary ice produced by the specific ice flow conditions at Larkman Nunatak explains its longevity and provides a new type of record of the East Antarctic ice sheet. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Wiley Online Library Antarctic The Antarctic East Antarctic Ice Sheet Bare Rock ENVELOPE(-45.589,-45.589,-60.704,-60.704) Larkman Nunatak ENVELOPE(179.383,179.383,-85.767,-85.767) Grosvenor Mountains ENVELOPE(175.000,175.000,-85.667,-85.667) Meteoritics & Planetary Science 53 10 2051 2066 |
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Open Polar |
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Wiley Online Library |
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crwiley |
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English |
description |
Abstract We report the discovery of a large accumulation of micrometeorites (MMs) in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The MMs are present in abundances of ~600 particles kg −1 of moraine sediment and include a near‐complete collection of MM types similar to those observed in Antarctic blue ice and within bare‐rock traps in the Antarctic. The size distribution of the observed particles is consistent with those collected from snow collections suggesting the moraine has captured a representative collection of cosmic spherules with significant loss of only the smallest particles (<100 μm) by wind. The presence of microtektites with compositions similar to those of the Australasian strewn field suggests the moraine has been accumulating for 780 ka with dust‐sized debris. On the basis of this age estimate, it is suggested that accumulation occurs principally through ice sublimation. Direct infall of fines is suggested to be limited by snow layers that act as barriers to accumulation and can be removed by wind erosion. MM accumulation in many areas in Antarctica, therefore, may not be continuous over long periods and can be subject to climatic controls. On the basis of the interpretation of microtektites as Australasian, Larkman Nunatak deposit is the oldest known supraglacial moraine and its survival through several glacial maxima and interglacial periods is surprising. We suggest that stationary ice produced by the specific ice flow conditions at Larkman Nunatak explains its longevity and provides a new type of record of the East Antarctic ice sheet. |
author2 |
Science and Technology Facilities Council |
format |
Article in Journal/Newspaper |
author |
Genge, Matthew J. van Ginneken, Matthias Suttle, Martin D. Harvey, Ralph P. |
spellingShingle |
Genge, Matthew J. van Ginneken, Matthias Suttle, Martin D. Harvey, Ralph P. Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
author_facet |
Genge, Matthew J. van Ginneken, Matthias Suttle, Martin D. Harvey, Ralph P. |
author_sort |
Genge, Matthew J. |
title |
Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
title_short |
Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
title_full |
Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
title_fullStr |
Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
title_full_unstemmed |
Accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at Larkman Nunatak, Antarctica |
title_sort |
accumulation mechanisms of micrometeorites in an ancient supraglacial moraine at larkman nunatak, antarctica |
publisher |
Wiley |
publishDate |
2018 |
url |
http://dx.doi.org/10.1111/maps.13107 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fmaps.13107 https://onlinelibrary.wiley.com/doi/pdf/10.1111/maps.13107 |
long_lat |
ENVELOPE(-45.589,-45.589,-60.704,-60.704) ENVELOPE(179.383,179.383,-85.767,-85.767) ENVELOPE(175.000,175.000,-85.667,-85.667) |
geographic |
Antarctic The Antarctic East Antarctic Ice Sheet Bare Rock Larkman Nunatak Grosvenor Mountains |
geographic_facet |
Antarctic The Antarctic East Antarctic Ice Sheet Bare Rock Larkman Nunatak Grosvenor Mountains |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_source |
Meteoritics & Planetary Science volume 53, issue 10, page 2051-2066 ISSN 1086-9379 1945-5100 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1111/maps.13107 |
container_title |
Meteoritics & Planetary Science |
container_volume |
53 |
container_issue |
10 |
container_start_page |
2051 |
op_container_end_page |
2066 |
_version_ |
1802651463944503296 |