Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica
We report the discovery of a large accumulation of micrometeorites in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The micrometeorites are present in abundances of ~600 particles Kg-1 of moraine sediment and include a near complete c...
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ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/57892 2023-05-15T14:02:50+02:00 Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica Genge, MJ Van Ginneken, M Suttle, M Harvey, R Science and Technology Facilities Council (STFC) Science and Technology Facilities Council (STFC) 2018-03-12 http://hdl.handle.net/10044/1/57892 https://doi.org/10.1111/maps.13107 unknown Wiley Meteoritics and Planetary Science © 2018 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. CC-BY 2066 2051 Science & Technology Physical Sciences Geochemistry & Geophysics DEEP-SEA SEDIMENTS COSMIC SPHERULES TRANSANTARCTIC MOUNTAINS BLUE ICE ACCRETION RATE SOUTH-POLE DUST COLLECTION FLUX MICROTEKTITES 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology Journal Article 2018 ftimperialcol https://doi.org/10.1111/maps.13107 2018-11-08T23:38:36Z We report the discovery of a large accumulation of micrometeorites in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The micrometeorites are present in abundances of ~600 particles Kg-1 of moraine sediment and include a near complete collection of micrometeorite 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 m) 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 in-fall of fines is suggested to be limited by snow layers that act as barriers to accumulation and can be removed by wind erosion. Micrometeorite 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 South pole South pole Imperial College London: Spiral Antarctic Bare Rock ENVELOPE(-45.589,-45.589,-60.704,-60.704) East Antarctic Ice Sheet Grosvenor Mountains ENVELOPE(175.000,175.000,-85.667,-85.667) Larkman Nunatak ENVELOPE(179.383,179.383,-85.767,-85.767) South Pole The Antarctic Transantarctic Mountains Meteoritics & Planetary Science 53 10 2051 2066 |
institution |
Open Polar |
collection |
Imperial College London: Spiral |
op_collection_id |
ftimperialcol |
language |
unknown |
topic |
Science & Technology Physical Sciences Geochemistry & Geophysics DEEP-SEA SEDIMENTS COSMIC SPHERULES TRANSANTARCTIC MOUNTAINS BLUE ICE ACCRETION RATE SOUTH-POLE DUST COLLECTION FLUX MICROTEKTITES 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology |
spellingShingle |
Science & Technology Physical Sciences Geochemistry & Geophysics DEEP-SEA SEDIMENTS COSMIC SPHERULES TRANSANTARCTIC MOUNTAINS BLUE ICE ACCRETION RATE SOUTH-POLE DUST COLLECTION FLUX MICROTEKTITES 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology Genge, MJ Van Ginneken, M Suttle, M Harvey, R Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
topic_facet |
Science & Technology Physical Sciences Geochemistry & Geophysics DEEP-SEA SEDIMENTS COSMIC SPHERULES TRANSANTARCTIC MOUNTAINS BLUE ICE ACCRETION RATE SOUTH-POLE DUST COLLECTION FLUX MICROTEKTITES 0201 Astronomical And Space Sciences 0402 Geochemistry 0403 Geology |
description |
We report the discovery of a large accumulation of micrometeorites in a supraglacial moraine at Larkman Nunatak in the Grosvenor Mountains of the Transantarctic Range in Antarctica. The micrometeorites are present in abundances of ~600 particles Kg-1 of moraine sediment and include a near complete collection of micrometeorite 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 m) 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 in-fall of fines is suggested to be limited by snow layers that act as barriers to accumulation and can be removed by wind erosion. Micrometeorite 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 (STFC) Science and Technology Facilities Council (STFC) |
format |
Article in Journal/Newspaper |
author |
Genge, MJ Van Ginneken, M Suttle, M Harvey, R |
author_facet |
Genge, MJ Van Ginneken, M Suttle, M Harvey, R |
author_sort |
Genge, MJ |
title |
Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
title_short |
Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
title_full |
Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
title_fullStr |
Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
title_full_unstemmed |
Accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at Larkman Nunatak, Antarctica |
title_sort |
accumulation mechanisms of micrometeorites in an ancient supra-glacial moraine at larkman nunatak, antarctica |
publisher |
Wiley |
publishDate |
2018 |
url |
http://hdl.handle.net/10044/1/57892 https://doi.org/10.1111/maps.13107 |
long_lat |
ENVELOPE(-45.589,-45.589,-60.704,-60.704) ENVELOPE(175.000,175.000,-85.667,-85.667) ENVELOPE(179.383,179.383,-85.767,-85.767) |
geographic |
Antarctic Bare Rock East Antarctic Ice Sheet Grosvenor Mountains Larkman Nunatak South Pole The Antarctic Transantarctic Mountains |
geographic_facet |
Antarctic Bare Rock East Antarctic Ice Sheet Grosvenor Mountains Larkman Nunatak South Pole The Antarctic Transantarctic Mountains |
genre |
Antarc* Antarctic Antarctica Ice Sheet South pole South pole |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet South pole South pole |
op_source |
2066 2051 |
op_relation |
Meteoritics and Planetary Science |
op_rights |
© 2018 The Authors. Meteoritics & Planetary Science published by Wiley Periodicals, Inc. on behalf of The Meteoritical Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
op_rightsnorm |
CC-BY |
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_ |
1766273234835079168 |