Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake
Chemical, stable isotope and natural abundance radionuclide analysis of cores taken through sediments below Lake Bonney, Taylor Valley, Antarctica, show evidence of multiple episodes of flooding by meltwaters from Taylor Glacier and desiccation to brines sufficiently concentrated to produce ice free...
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ftunivwaikato:oai:researchcommons.waikato.ac.nz:10289/12837 2023-05-15T14:00:42+02:00 Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake Croall, Jacob Grant Hendy, Chris H. Hall, Brenda L. 2019-09-06T02:20:38Z application/pdf https://hdl.handle.net/10289/12837 en eng The University of Waikato https://hdl.handle.net/10289/12837 All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated. Thesis 2019 ftunivwaikato 2022-03-29T15:15:56Z Chemical, stable isotope and natural abundance radionuclide analysis of cores taken through sediments below Lake Bonney, Taylor Valley, Antarctica, show evidence of multiple episodes of flooding by meltwaters from Taylor Glacier and desiccation to brines sufficiently concentrated to produce ice free conditions. The last three identified desiccation events date 1550 ± 40, 800 ± 100 and 450 ± 160 yr B.P. and match the last three periods of sustained cooling identified by isotope changes in the Taylor Dome ice core. Similar cooling events have been identified by other authors elsewhere in Antarctica. The desiccation events have produced dramatic changes in the sediment character of Lake Bonney East Lobe, but show little impact in the West Lobe. In East Lobe halite, hydrohalite, gypsum, and aragonite are precipitated and extreme isotopic enrichment of carbon (up to 813C of +12.0%0) occurred as aragonite was forced from solution by rapid freezing of the brine over winter. Reflooding events were often associated with algal blooms and resulted in radical changes in the 180/1 60 ratio in the water column. It is speculated that Taylor Glacier retreated to expose a 250 m deep subglacial depression during the last glacial maximum allowing Glacial Lake Washburn to extend westwards to perhaps Cavendish Rocks. The reduced Taylor Glacier enabled Taylor Dome to lower causing deposition of more 180 enriched ice than would otherwise have been expected. Taylor Glacier and Taylor Dome have continued to advance throughout the Holocene. Thesis Antarc* Antarctic Antarctica ice core Taylor Glacier The University of Waikato: Research Commons Antarctic Glacial Lake ENVELOPE(-129.463,-129.463,58.259,58.259) Taylor Valley ENVELOPE(163.000,163.000,-77.617,-77.617) Bonney ENVELOPE(162.417,162.417,-77.717,-77.717) Taylor Glacier ENVELOPE(162.167,162.167,-77.733,-77.733) Lake Bonney ENVELOPE(-25.588,-25.588,-80.361,-80.361) Taylor Dome ENVELOPE(157.667,157.667,-77.667,-77.667) Washburn ENVELOPE(-86.133,-86.133,-77.617,-77.617) Cavendish Rocks ENVELOPE(161.400,161.400,-77.833,-77.833) |
institution |
Open Polar |
collection |
The University of Waikato: Research Commons |
op_collection_id |
ftunivwaikato |
language |
English |
description |
Chemical, stable isotope and natural abundance radionuclide analysis of cores taken through sediments below Lake Bonney, Taylor Valley, Antarctica, show evidence of multiple episodes of flooding by meltwaters from Taylor Glacier and desiccation to brines sufficiently concentrated to produce ice free conditions. The last three identified desiccation events date 1550 ± 40, 800 ± 100 and 450 ± 160 yr B.P. and match the last three periods of sustained cooling identified by isotope changes in the Taylor Dome ice core. Similar cooling events have been identified by other authors elsewhere in Antarctica. The desiccation events have produced dramatic changes in the sediment character of Lake Bonney East Lobe, but show little impact in the West Lobe. In East Lobe halite, hydrohalite, gypsum, and aragonite are precipitated and extreme isotopic enrichment of carbon (up to 813C of +12.0%0) occurred as aragonite was forced from solution by rapid freezing of the brine over winter. Reflooding events were often associated with algal blooms and resulted in radical changes in the 180/1 60 ratio in the water column. It is speculated that Taylor Glacier retreated to expose a 250 m deep subglacial depression during the last glacial maximum allowing Glacial Lake Washburn to extend westwards to perhaps Cavendish Rocks. The reduced Taylor Glacier enabled Taylor Dome to lower causing deposition of more 180 enriched ice than would otherwise have been expected. Taylor Glacier and Taylor Dome have continued to advance throughout the Holocene. |
author2 |
Hendy, Chris H. Hall, Brenda L. |
format |
Thesis |
author |
Croall, Jacob Grant |
spellingShingle |
Croall, Jacob Grant Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
author_facet |
Croall, Jacob Grant |
author_sort |
Croall, Jacob Grant |
title |
Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
title_short |
Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
title_full |
Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
title_fullStr |
Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
title_full_unstemmed |
Late Holocene cool climate episodes, recorded on Lake Bonney, an Antarctic amplifier lake |
title_sort |
late holocene cool climate episodes, recorded on lake bonney, an antarctic amplifier lake |
publisher |
The University of Waikato |
publishDate |
2019 |
url |
https://hdl.handle.net/10289/12837 |
long_lat |
ENVELOPE(-129.463,-129.463,58.259,58.259) ENVELOPE(163.000,163.000,-77.617,-77.617) ENVELOPE(162.417,162.417,-77.717,-77.717) ENVELOPE(162.167,162.167,-77.733,-77.733) ENVELOPE(-25.588,-25.588,-80.361,-80.361) ENVELOPE(157.667,157.667,-77.667,-77.667) ENVELOPE(-86.133,-86.133,-77.617,-77.617) ENVELOPE(161.400,161.400,-77.833,-77.833) |
geographic |
Antarctic Glacial Lake Taylor Valley Bonney Taylor Glacier Lake Bonney Taylor Dome Washburn Cavendish Rocks |
geographic_facet |
Antarctic Glacial Lake Taylor Valley Bonney Taylor Glacier Lake Bonney Taylor Dome Washburn Cavendish Rocks |
genre |
Antarc* Antarctic Antarctica ice core Taylor Glacier |
genre_facet |
Antarc* Antarctic Antarctica ice core Taylor Glacier |
op_relation |
https://hdl.handle.net/10289/12837 |
op_rights |
All items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated. |
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1766270018747629568 |