Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica
Evidence of Antarctic ice sheet behavior and paleoenvironment is often approached from proxy records because there is a dearth of direct records from Antarctica itself. The studies presented here seek to augment our knowledge of translations of the West Antarctic Ice Sheet’s (WAIS) marine terminat...
Main Author: | |
---|---|
Format: | Text |
Language: | unknown |
Published: |
LSU Scholarly Repository
2010
|
Subjects: | |
Online Access: | https://repository.lsu.edu/gradschool_dissertations/3150 https://doi.org/10.31390/gradschool_dissertations.3150 https://repository.lsu.edu/context/gradschool_dissertations/article/4149/viewcontent/uc.pdf |
id |
ftlouisianastuir:oai:repository.lsu.edu:gradschool_dissertations-4149 |
---|---|
record_format |
openpolar |
spelling |
ftlouisianastuir:oai:repository.lsu.edu:gradschool_dissertations-4149 2024-09-15T17:45:03+00:00 Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica Chow, Juan Manuel 2010-01-01T08:00:00Z application/pdf https://repository.lsu.edu/gradschool_dissertations/3150 https://doi.org/10.31390/gradschool_dissertations.3150 https://repository.lsu.edu/context/gradschool_dissertations/article/4149/viewcontent/uc.pdf unknown LSU Scholarly Repository https://repository.lsu.edu/gradschool_dissertations/3150 doi:10.31390/gradschool_dissertations.3150 https://repository.lsu.edu/context/gradschool_dissertations/article/4149/viewcontent/uc.pdf LSU Doctoral Dissertations diatoms Ross Sea West Antarctic Ice Sheet Pliocene Antarctica Earth Sciences text 2010 ftlouisianastuir https://doi.org/10.31390/gradschool_dissertations.3150 2024-08-08T04:27:17Z Evidence of Antarctic ice sheet behavior and paleoenvironment is often approached from proxy records because there is a dearth of direct records from Antarctica itself. The studies presented here seek to augment our knowledge of translations of the West Antarctic Ice Sheet’s (WAIS) marine termination based on direct biostratigraphic evidence. Diatom analyses were conducted from two areas of Ross Sea, Antarctica. In the first study, diatoms were used to constrain the age of diamictons from five seismic units in the Eastern Basin and thus expand our knowledge of WAIS behavior during the Southern Hemisphere Last Glacial Maximum (LGM). All five units have a late Pliocene diatom assemblage. The absence of a late Pleistocene diatom assemblage indicates that the Eastern Basin LGM could not have been at ca. 20 kyrs. Moreover, differences in diatom assemblages indicate that units previously assigned to a single phase of LGM advance and post-LGM retreat must have included two temporally distinct grounding events. In the second study, diatoms were used to assess the uniformity of a till sheet by comparing the assemblage from the topset bed to that of the interior of the till sheet. The analysis suggests that the till sheet as observed from seismic data is homogeneous, and helps support the validity of studies made by using short sediment cores that sample only the upper part of the till sheet. In the third study, diatoms from diatomite units from south of Ross Island were used to provide paleoenvironmental information about the early Pliocene. The diatom assemblages have no modern analogues, but they do indicate that sea surface temperatures were much warmer in the early Pliocene compared to the present, there was enhanced ice sheet ablation, and katabatic winds were absent at least during the diatom growth season. Text Antarc* Antarctic Antarctica Ice Sheet Ross Island Ross Sea LSU Digital Commons (Louisiana State University) |
institution |
Open Polar |
collection |
LSU Digital Commons (Louisiana State University) |
op_collection_id |
ftlouisianastuir |
language |
unknown |
topic |
diatoms Ross Sea West Antarctic Ice Sheet Pliocene Antarctica Earth Sciences |
spellingShingle |
diatoms Ross Sea West Antarctic Ice Sheet Pliocene Antarctica Earth Sciences Chow, Juan Manuel Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
topic_facet |
diatoms Ross Sea West Antarctic Ice Sheet Pliocene Antarctica Earth Sciences |
description |
Evidence of Antarctic ice sheet behavior and paleoenvironment is often approached from proxy records because there is a dearth of direct records from Antarctica itself. The studies presented here seek to augment our knowledge of translations of the West Antarctic Ice Sheet’s (WAIS) marine termination based on direct biostratigraphic evidence. Diatom analyses were conducted from two areas of Ross Sea, Antarctica. In the first study, diatoms were used to constrain the age of diamictons from five seismic units in the Eastern Basin and thus expand our knowledge of WAIS behavior during the Southern Hemisphere Last Glacial Maximum (LGM). All five units have a late Pliocene diatom assemblage. The absence of a late Pleistocene diatom assemblage indicates that the Eastern Basin LGM could not have been at ca. 20 kyrs. Moreover, differences in diatom assemblages indicate that units previously assigned to a single phase of LGM advance and post-LGM retreat must have included two temporally distinct grounding events. In the second study, diatoms were used to assess the uniformity of a till sheet by comparing the assemblage from the topset bed to that of the interior of the till sheet. The analysis suggests that the till sheet as observed from seismic data is homogeneous, and helps support the validity of studies made by using short sediment cores that sample only the upper part of the till sheet. In the third study, diatoms from diatomite units from south of Ross Island were used to provide paleoenvironmental information about the early Pliocene. The diatom assemblages have no modern analogues, but they do indicate that sea surface temperatures were much warmer in the early Pliocene compared to the present, there was enhanced ice sheet ablation, and katabatic winds were absent at least during the diatom growth season. |
format |
Text |
author |
Chow, Juan Manuel |
author_facet |
Chow, Juan Manuel |
author_sort |
Chow, Juan Manuel |
title |
Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
title_short |
Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
title_full |
Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
title_fullStr |
Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
title_full_unstemmed |
Diatom stratigraphy defining ice sheet grounding chronology, Ross Sea, Antarctica |
title_sort |
diatom stratigraphy defining ice sheet grounding chronology, ross sea, antarctica |
publisher |
LSU Scholarly Repository |
publishDate |
2010 |
url |
https://repository.lsu.edu/gradschool_dissertations/3150 https://doi.org/10.31390/gradschool_dissertations.3150 https://repository.lsu.edu/context/gradschool_dissertations/article/4149/viewcontent/uc.pdf |
genre |
Antarc* Antarctic Antarctica Ice Sheet Ross Island Ross Sea |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Ross Island Ross Sea |
op_source |
LSU Doctoral Dissertations |
op_relation |
https://repository.lsu.edu/gradschool_dissertations/3150 doi:10.31390/gradschool_dissertations.3150 https://repository.lsu.edu/context/gradschool_dissertations/article/4149/viewcontent/uc.pdf |
op_doi |
https://doi.org/10.31390/gradschool_dissertations.3150 |
_version_ |
1810492749076496384 |