Abstract:
This dataset contains the position and depth of four spatially-extensive Internal Reflecting Horizons (or IRHs) traced on the British Antarctic Survey's PASIN system and NASA Operation IceBridge's MCoRDS2 system across the Pine Island Glacier catchment. Using the WAIS Divide ice-core chronology and a 1-D steady-state model, we assign ages to our four IRHs: (R1) 2.31-2.92 ka, (R2) 4.72 +/- 0.28 ka, (R3) 6.94 +/- 0.31 ka, and (R4) 16.50 +/- 0.79 ka.
This project was funded by the UK Natural Environment Research Council Grant NE/L002558/1
Keywords:
Englacial Stratigraphy, Holocene, ITGC, Ice Penetrating Radar, Pine Island Glacier, Thwaites Glacier, West Antarctica
Bodart, J., Bingham, R., Ashmore, D., Karlsson, N., Hein, A., & Vaughan, D. (2021). Dated radar stratigraphy of the Pine Island Glacier catchment (West Antarctica) derived from BBAS-PASIN (2004-05) and OIB-MCoRDS2 (2016/2018) surveys (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/f2de31af-9f83-44f8-9584-f0190a2cc3eb
| Use Constraints: | This data is covered by a UK Open Government Licence (http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). Further by downloading this data the user acknowledges that they agree with the NERC data policy (http://www.nerc.ac.uk/research/sites/data/policy.asp), and the following conditions: 1. To cite the data in any publication as follows: Bodart, J., Bingham, R., Ashmore, D., Karlsson, N., Hein, A., & Vaughan, D. (2021). Dated radar stratigraphy of the Pine Island Glacier catchment (West Antarctica) derived from BBAS-PASIN (2004-05) and OIB-MCoRDS2 (2016/2018) surveys (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/F2DE31AF-9F83-44F8-9584-F0190A2CC3EB 2. The user recognizes the limitations of data. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data. |
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| Creation Date: | 2021-01-26 |
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| Dataset Progress: | Complete |
| Dataset Language: | English |
| ISO Topic Categories: |
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| Parameters: |
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| Personnel: | |
| Name | PDC BAS |
| Role(s) | Metadata Author |
| Organisation | British Antarctic Survey |
| Name | Prof Robert Bingham |
| Role(s) | Investigator |
| Organisation | University of Edinburgh |
| Name | Dr David Ashmore |
| Role(s) | Investigator |
| Organisation | University of Liverpool |
| Name | Prof David Vaughan |
| Role(s) | Investigator |
| Organisation | British Antarctic Survey |
| Name | Mr Julien Bodart |
| Role(s) | Investigator |
| Organisation | University of Edinburgh |
| Name | Dr Andrew Hein |
| Role(s) | Investigator |
| Organisation | University of Edinburgh |
| Name | Dr Nanna Karlsson |
| Role(s) | Investigator |
| Organisation | Geological Survey of Denmark and Greenland |
| Parent Dataset: | N/A |
| Reference: | Bodart, J.A., Bingham, R.G., Ashmore, D. W., Karlsson, N. B., Hein, A.S., and Vaughan, D. G. 2021. Age-Depth Stratigraphy of Pine Island Glacier Inferred from Airborne Radar and Ice-Core Chronology. Journal of Geophysical Research: Earth Surfaces. doi: 10.1029/2020JF005927 | |
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| Quality: | Uncertainties in IRH depths can be found in the Lineage section and in the paper. Missing values for radar ice thickness are shown as NaN. | |
| Lineage: | Instrumentation and Processing: The main radar data is from the British Antarctic Survey's PASIN system, flown over Pine Island Glacier in the austral season 2004-05. Data were collected with two interleaved radar modes.The first was a deep-sounding, 150 MHz centre-frequency, 4-microseconds, 10 MHz chirp mode and the second was a 150 MHz, 0.1-microseconds pulse mode designed to image shallow IRHs but from which we are also able to recover IRHs deeper (~2 km) in the ice column. The second radar dataset used here is from NASA Operation IceBridge's MCoRDS2 system, flown in two separate surveys over Pine Island Glacier and nearby Thwaites and Institute Ice Stream catchments in 2016 and 2018. The system operated at a centre frequency of 190 MHz and a 50 MHz bandwidth. We used the CReSIS L1B standard products, produced with pulse compression, focused-SAR processing and along-track motion compensation. For the purposes of increasing IRH traceability on the PIG-PASIN data, we quadratically detrended each radar trace, normalised each pixel in a moving vertical window, and then applied a 10-trace horizontal average to reduce incoherent noise. For both the PIG-PASIN and the OIB-MCoRDS2 data, we removed the air-to-ice two-way travel time and shifted the surface elevation to time zero, prior to exporting the data to standard 2-D SEG-Y format for data interpretation. We conducted our IRH tracing in the Schlumberger Petrel 3-D seismic software using a semi-automated tracing algorithm that uses an adjustable window to track the local maxima of received reflected power between traces. Methodology and Results: We identified four prominent Internal Reflecting Horizons (or IRHs) that we term R1-4 in the PASIN and MCoRDS2 radar data. The upper three IRHs (R1-3) were chosen on the basis of high spatial continuity and high signal-to-noise ratio (SNR). We used available crossovers between radar profiles as calibration points to trace the IRHs and relied upon the distinctiveness of our IRHs when tracing between crossovers (see Bodart et al., 2021 for more details). We converted all our IRHs from time domain to depth using a value for the speed of electromagnetic waves through ice of 168.5 m/microseconds and applied a 10 m spatially-invariant firn correction. All our depth measurements are given in depth below the surface (set at 0 m). The maximum uncertainty for the IRHs traced on the PASIN data is +/- 17 m, and +/- 14 m on the IRHs traced on the MCoRDS2 data. More details on how these were calculated can be found in Bodart et al. (2021). The IRHs were dated using intersection with the WAIS divide ice-core and with the use of a steady-state 1-D vertical-strain model. Data Structure: Each CSV file contains six columns: (1) 'X' is the Cartesian x-coordinates in Polar Stereographic South (EPSG: 3031, -71 S) (units: meters). (2) 'Y' is the Cartesian y-coordinates in Polar Stereographic South (EPSG: 3031, -71 S) (units: meters). (3) 'Lon' is the longitudinal coordinate in WGS84 (EPSG: 4326) (units: degrees). (4) '''Lat' is the latitudinal coordinate in WGS84 (EPSG: 4326) (units: degrees). (5) 'Pick' is the pixel number below the ice surface of the radargram of that IRH. (6) 'Depth' is the depth of the IRH below the ice surface (units: meters). (7) 'RadarIceThick' is the ice thickness detected by the radar (units: meters). Missing values for radar ice thickness are shown as NaN. (8) 'FlightID' is the radar flight line number or segment. More information on the naming convention used for the CSVs can be found under 'Storage'. |
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| Temporal Coverage: | |
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| Start Date | 2016-11-09 |
| End Date | 2018-11-07 |
| Start Date | 2004-12-11 |
| End Date | 2005-01-21 |
| Paleo Temporal Coverage: | |
| Paleo Start Date | 16.50 ka |
| Paleo End Date | 2.31 ka |
| Chronostratigraphic Unit | HOLOCENE |
| Spatial Coverage: | |
| Latitude | |
| Southernmost | -81.1 |
| Northernmost | -73.5 |
| Longitude | |
| Westernmost | -112.9 |
| Easternmost | -72.7 |
| Altitude | |
| Min Altitude | N/A |
| Max Altitude | N/A |
| Depth | |
| Min Depth | 204 |
| Max Depth | 2640 |
| Data Resolution: | |
| Latitude Resolution | N/A |
| Longitude Resolution | N/A |
| Horizontal Resolution Range | 1 meter - < 30 meters |
| Vertical Resolution | N/A |
| Vertical Resolution Range | 10 meters - < 30 meters |
| Temporal Resolution | N/A |
| Temporal Resolution Range | N/A |
| Location: | |
| Location | Antarctica |
| Detailed Location | Pine Island Glacier |
| Sensor(s): |
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| Source(s): |
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| Data Collection: | BBAS/AGASEA PASIN survey: season 2004-05 NASA/OIB MCoRDS2 surveys: seasons 2016 and 2018 |
| Distribution: | |
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| Distribution Media | Online Internet (HTTP) |
| Distribution Size | 120 MB |
| Distribution Format | ASCII |
| Fees | N/A |
| Data Storage: | This dataset is comprised of 12x CSV files organised by SurveyName or flightID (for IRHs traced on MCoRDS2 data), as follows: 4x files for IRHs R1-4 traced on PASIN (R1_PASIN, R2_PASIN, R3_PASIN, R4_PASIN) across the Pine Island and upper Thwaites glacier catchments. 3x files for IRHs R1-3 traced on MCoRDS2 flightline 20181022_01 (R1_OIB_20181022_01, R2_OIB_20181022_01, R3_OIB_20181022_01) across the upper Pine Island and Institute Ice Stream glacier catchments. 2x files for IRHs R2-3 traced on MCoRDS2 flightline 20181107_01 (R2_OIB_20181107_01, R3_OIB_20181107_01) across the upper Pine Island Glacier centre flowline. 3x files for IRHs R2-4 traced on MCoRDS2 flightline 20161109 (R2_OIB_20161109_03, R3_OIB_20161109_03, R4_OIB_20161109_03) connecting the Pine Island Glacier with the WAIS Divide ice core and upper Thwaites glacier catchment. There is also 1x read_me text file which explains the data file structure and information on how to cite this dataset. |