Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills
Indiana University-Purdue University Indianapolis (IUPUI) : In January 2007, 26 samples of till from 6 different moraines along the Reedy Glacier, East Antarctica were collected with the goal of differentiating between these samples and till collected from the base of the Whillans, Kamb, and Bindsch...
Main Author: | |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
IUPUI University Library
2008
|
Subjects: | |
Online Access: | https://dx.doi.org/10.7912/c2/510 https://scholarworks.iupui.edu/handle/1805/1695 |
id |
ftdatacite:10.7912/c2/510 |
---|---|
record_format |
openpolar |
spelling |
ftdatacite:10.7912/c2/510 2023-05-15T13:33:53+02:00 Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills Kramer, Katie L. 2008 https://dx.doi.org/10.7912/c2/510 https://scholarworks.iupui.edu/handle/1805/1695 en eng IUPUI University Library Antarctica Ice Stream Till Reedy Glacier Geology -- Antarctica Glaciers -- Antarctica Ice streams -- Antarctica CreativeWork article 2008 ftdatacite https://doi.org/10.7912/c2/510 2022-03-10T11:39:41Z Indiana University-Purdue University Indianapolis (IUPUI) : In January 2007, 26 samples of till from 6 different moraines along the Reedy Glacier, East Antarctica were collected with the goal of differentiating between these samples and till collected from the base of the Whillans, Kamb, and Bindschadler Ice Streams of West Antarctica. The ability to differentiate between East and West Antarctic ice will allow us to constrain ice flow into the central Ross Sea during the Last Glacial Maximum (LGM), which has implications for more accurate reconstructions of the Ross Ice Sheet and its behavior. Moraines sampled from the head of Reedy Glacier give insight to the geology beneath the EAIS, and may be representative of what the glacier is eroding from its bed. Samples along the trunk of the glacier capture representative rock types eroded along the length of Reedy Glacier. At each moraine 3 replicate sub-sites were selected for collection to represent the diversity of material within each moraine. Comparisons are based on the composition of pebbles, particle size distributions, and sand petrography. Analysis of the pebble fraction shows that each sub-site contains similar rock types, however, the concentration of each rock type varies as much as 25-35%. Similar variation is also seen within the sub-site sand fraction. Both the pebble and sand fraction reflect the mapped bedrock geology. The dominant pebble types are coarse-grained felsic and intermediate igneous rocks, as well as quartzite. Similarly felsic igneous grains, quartzite, quartz, and feldspar characterize the sand fraction. Particle size analysis shows that v Reedy Glacier till averages 85% sand. The subglacial West Antarctic samples contain approximately 30% sand, and equal amounts of silt and clay, approximately 35% each. An observation of the sand fraction from beneath the West Antarctic Ice Streams shows composition similar to tills from Reedy Glacier. However, tills from the base of the West Antarctic Ice Streams contain up to 75% polymict grains, and in contrast, these grains are absent in the tills from Reedy Glacier. These sand-sized polymict grains dominate material from the base of Whillans and Bindschadler Ice Streams, whereas material from the base of Kamb Ice Stream contains grains of felsic igneous, quartz, feldspar, and few to no polymict grains. In addition to the polymict grains, the sand fraction in the ice stream cores contains trace fragments of sedimentary, and volcanic rocks, both of which are absent from the Reedy Glacier sand fraction. However, polymict grains are believed to represent a process occurring beneath the ice sheet, rather than indicate provenance. It is difficult to differentiate between the two tills, as both contain high concentrations of felsic-intermediate igneous lithics, quartz, and feldspar. The central Ross Sea contains sediment similar in rock type and mineralogy as seen within sediments from both Reedy Glacier, and the base of the ice streams of West Antarctica. Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Ice Sheet Kamb Ice Stream Reedy Glacier Ross Sea West Antarctica DataCite Metadata Store (German National Library of Science and Technology) Antarctic East Antarctica Ross Sea West Antarctica Whillans ENVELOPE(-64.250,-64.250,-84.450,-84.450) Kamb Ice Stream ENVELOPE(-145.000,-145.000,-82.250,-82.250) Reedy Glacier ENVELOPE(-134.000,-134.000,-85.500,-85.500) |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Antarctica Ice Stream Till Reedy Glacier Geology -- Antarctica Glaciers -- Antarctica Ice streams -- Antarctica |
spellingShingle |
Antarctica Ice Stream Till Reedy Glacier Geology -- Antarctica Glaciers -- Antarctica Ice streams -- Antarctica Kramer, Katie L. Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
topic_facet |
Antarctica Ice Stream Till Reedy Glacier Geology -- Antarctica Glaciers -- Antarctica Ice streams -- Antarctica |
description |
Indiana University-Purdue University Indianapolis (IUPUI) : In January 2007, 26 samples of till from 6 different moraines along the Reedy Glacier, East Antarctica were collected with the goal of differentiating between these samples and till collected from the base of the Whillans, Kamb, and Bindschadler Ice Streams of West Antarctica. The ability to differentiate between East and West Antarctic ice will allow us to constrain ice flow into the central Ross Sea during the Last Glacial Maximum (LGM), which has implications for more accurate reconstructions of the Ross Ice Sheet and its behavior. Moraines sampled from the head of Reedy Glacier give insight to the geology beneath the EAIS, and may be representative of what the glacier is eroding from its bed. Samples along the trunk of the glacier capture representative rock types eroded along the length of Reedy Glacier. At each moraine 3 replicate sub-sites were selected for collection to represent the diversity of material within each moraine. Comparisons are based on the composition of pebbles, particle size distributions, and sand petrography. Analysis of the pebble fraction shows that each sub-site contains similar rock types, however, the concentration of each rock type varies as much as 25-35%. Similar variation is also seen within the sub-site sand fraction. Both the pebble and sand fraction reflect the mapped bedrock geology. The dominant pebble types are coarse-grained felsic and intermediate igneous rocks, as well as quartzite. Similarly felsic igneous grains, quartzite, quartz, and feldspar characterize the sand fraction. Particle size analysis shows that v Reedy Glacier till averages 85% sand. The subglacial West Antarctic samples contain approximately 30% sand, and equal amounts of silt and clay, approximately 35% each. An observation of the sand fraction from beneath the West Antarctic Ice Streams shows composition similar to tills from Reedy Glacier. However, tills from the base of the West Antarctic Ice Streams contain up to 75% polymict grains, and in contrast, these grains are absent in the tills from Reedy Glacier. These sand-sized polymict grains dominate material from the base of Whillans and Bindschadler Ice Streams, whereas material from the base of Kamb Ice Stream contains grains of felsic igneous, quartz, feldspar, and few to no polymict grains. In addition to the polymict grains, the sand fraction in the ice stream cores contains trace fragments of sedimentary, and volcanic rocks, both of which are absent from the Reedy Glacier sand fraction. However, polymict grains are believed to represent a process occurring beneath the ice sheet, rather than indicate provenance. It is difficult to differentiate between the two tills, as both contain high concentrations of felsic-intermediate igneous lithics, quartz, and feldspar. The central Ross Sea contains sediment similar in rock type and mineralogy as seen within sediments from both Reedy Glacier, and the base of the ice streams of West Antarctica. |
format |
Article in Journal/Newspaper |
author |
Kramer, Katie L. |
author_facet |
Kramer, Katie L. |
author_sort |
Kramer, Katie L. |
title |
Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
title_short |
Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
title_full |
Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
title_fullStr |
Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
title_full_unstemmed |
Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills |
title_sort |
provenance study of reedy glacier and west antarctic ice stream tills |
publisher |
IUPUI University Library |
publishDate |
2008 |
url |
https://dx.doi.org/10.7912/c2/510 https://scholarworks.iupui.edu/handle/1805/1695 |
long_lat |
ENVELOPE(-64.250,-64.250,-84.450,-84.450) ENVELOPE(-145.000,-145.000,-82.250,-82.250) ENVELOPE(-134.000,-134.000,-85.500,-85.500) |
geographic |
Antarctic East Antarctica Ross Sea West Antarctica Whillans Kamb Ice Stream Reedy Glacier |
geographic_facet |
Antarctic East Antarctica Ross Sea West Antarctica Whillans Kamb Ice Stream Reedy Glacier |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Kamb Ice Stream Reedy Glacier Ross Sea West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Kamb Ice Stream Reedy Glacier Ross Sea West Antarctica |
op_doi |
https://doi.org/10.7912/c2/510 |
_version_ |
1766046711407443968 |