| NSF Org: |
OPP Office of Polar Programs (OPP) |
| Recipient: |
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| Initial Amendment Date: | September 11, 2012 |
| Latest Amendment Date: | March 4, 2015 |
| Award Number: | 1043761 |
| Award Instrument: | Standard Grant |
| Program Manager: |
thomas wilch
OPP Office of Polar Programs (OPP) GEO Directorate for Geosciences |
| Start Date: | September 15, 2012 |
| End Date: | August 31, 2015 (Estimated) |
| Total Intended Award Amount: | $886,972.00 |
| Total Awarded Amount to Date: | $1,004,386.00 |
| Funds Obligated to Date: |
FY 2015 = $117,414.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
110 INNER CAMPUS DR AUSTIN TX US 78712-1139 (512)471-6424 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
110 INNER CAMPUS DR AUSTIN TX US 78712-1139 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ANT Earth Sciences |
| Primary Program Source: |
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| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.078 |
ABSTRACT
Intellectual Merit:
The PIs propose to use airborne geophysics to provide detailed geophysical mapping over the Marie Byrd Land dome of West Antarctica. They will use a Basler equipped with advanced ice penetrating radar, a magnetometer, an airborne gravimeter and laser altimeter. They will test models of Marie Byrd Land lithospheric evolution in three ways: 1) constrain bedrock topography and crustal structure of central Marie Byrd Land for the first time; 2) map subglacial geomorphology of Marie Byrd Land to constrain landscape evolution; and 3) map the distribution of subglacial volcanic centers and identify active sources. Marie Byrd Land is one of the few parts of West Antarctica whose bedrock lies above sea level; as such, it has a key role to play in the formation and decay of the West Antarctic Ice Sheet (WAIS), and thus on eustatic sea level change during the Neogene. Several lines of evidence suggest that the topography of Marie Byrd Land has changed over the course of the Cenozoic, with significant implications for the origin and evolution of the ice sheet.
Broader impacts:
This work will have important implications for both the cryospheric and geodynamic communities. These data will also leverage results from the POLENET project. The PIs will train both graduate and undergraduate students in the interpretation of large geophysical datasets providing them with the opportunity to co-author peer-reviewed papers and present their work to the broader science community. This research will also support a young female researcher. The PIs will conduct informal education using their Polar Studies website and contribute formally to K-12 curriculum development. The research will incorporate microblogging and data access to allow the project?s first-order hypothesis to be confirmed or denied in public.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Summary of the project: Coastal Marie Byrd Land (MBL) is a region of ice-covered West Antarctica that had previously been unexplored. It is a critical region in that it is one of the few parts of West Antarctica where the underside of the overlying ice sheet lies above sea level, and thus is stable, while much of the rest of West Antarctica Ice Sheet is susceptible to collapse. The remnant ice cap on MBL is likely where the West Antarctic Ice Sheet grows back from when the rest collapses during warm periods. However, volcanoes in MBL and some exposed, eroded outcrops indicate that the bedrock of MBL might have changed elevation over geological time.
The Geophysical Investigation of Marie Byrd Land Evolution (GIMBLE) project completed two expeditions across the coastal Marie Byrd Land sector of West Antarctica in 2013 and 2014. We used an ski equipped DC-3T Basler aircraft to survey from two USAP field camps in the interior of the West Antarctic Ice Sheet. The aircraft carried an advanced ice penetrating radar to examine the ice layers and the underside of the ice sheet, a magnetometer to indicate the composition and structure of underlying rocks, and a three-axis stabilized gravimeter to measure the density and crustal structure of the underlying crust.
Intellectual merit: The first season was based out of Byrd Field Camp, and in part resurveyed sites that had been measured using POLENET seismometers which give an independent measurement of crustal structure. A major finding was confirming the site of a recent subglacial volcano over a site of ongoing deep earthquakes on the southern edge of the MBL highlands. This was consistent with high localized geothermal heat flow in MBL, consistent with POLENETs identification of a possible mantle hotspot under MBL from seismic data. Geothermal heat flow is significant for ice sheet evolution in that it melts the underside of the ice sheet, providing water and lubrication to ice flow. Between field seasons GIMBLE assisted with working up radar data over nearby Thwaites Glacier which identified regions of high basal melting of the ice sheet and again indicated high localized geothermal heat flow in this region.
The second season of GIMBLE operated out of WAIS Divide field camp and created a high resolution grid of the interior of the MBL. We found that the character of the buried landscape changes abruptly between the ocean edge of the MBL and the interior between the volcanoes. We interpret both landscapes as predating the current ice sheet. The coastal region consists of an ancient planed-off surface that broke and rotated as MBL was stretched by tectonic forces well before ice came to West Antarctica. The interior records the inception of ice driven erosion, with rough mountain peaks surrounded by very deep glacial valleys that appear to be associated with major volcanoes.
We also found evidence for a major water sheet under the ice near the MBL highland, at the point where a two major Antarctic Ice streams start. Again, this is likely evidence for local enhanced melting by geothermal heat flow.
Broader Impacts: GIMBLE has had the opportunity to work with a range of graduate students, undergraduates and high school students, in planning the survey design, participating in the field work, and analyzing the data. Data is also in the process of being released.
Last Modified: 12/02/2015
Modified by: Duncan A Young
