Siple Dome Core Date from Measurement of the d18O of Paleoatmospheric Oxygen
Summary
This data set is part of the West Antarctic Ice Sheet Cores (WAISCORES) project, an NSF-funded project to understand the influence of the West Antarctic ice sheet on climate and sea level change. WAISCORES researchers acquired and analyzed ice core samples from the Siple Dome, in the Siple Coast region, West Antarctica. This data set includes a timescale record for the Siple Dome ice core. This chronology is derived by measuring the delta oxygen-18 of paleoatmospheric oxygen (δ18Oatm) then correlating those measurements to the Greenland Ice Sheet Project 2 (GISP2) record by adjusting the Siple Dome timescale so that its curve of δ18Oatm coincided with that of GISP2. The replicate samples were measured at 1 to 1.5 kiloyear (kyr) resolution for the length of the core. Because of core relaxation and cracking at the surface associated with gas loss and a small fractionation of O isotopes associated with loss of O2, the δ18Oatm, timescale and accuracy of the constraints of the Siple Dome control depths are subject to limited error. Data are available via FTP in Microsoft Excel (.xls) and Word (.doc) file formats.
Citing These Data
The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.
The following example shows how to cite the use of this data set in a publication. List the principal investigators, year of data set release, publisher: NSIDC, and digital media.
Bender, M. 2004. Siple Dome Core Date from Measurement of the d18O of Paleoatmospheric Oxygen. Boulder, Colorado, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5TX3C95.
Overview Table
| Category | Description |
|---|---|
| Data format | Microsoft Excel (.xls) and Word (.doc) files |
| Spatial coverage and resolution |
Southernmost Latitude: 81°S Northernmost Latitude: 81°S Westernmost Longitude: 149°W Easternmost Longitude: 149°W |
| Temporal coverage and resolution | Data collection: Three Antarctic field seasons in 1996 to 1999. Data resolution: 100,000 to 100,500 years before present (ybp) |
| File naming convention |
d18Oatm.xls d18Oatm2.xls d18Oatm.doc |
| File size | The data set is 528 KB total. |
| Parameter(s) | Paleoatmospheric oxygen concentration (δ18Oatm) in parts per trillion (ppt, 1012) Gas age in kiloannum (ka) or kiloyears (kyr) Ice age in kiloannum (ka) or kiloyears (kyr) |
| Procedures for obtaining data | Data are available via FTP. |
Table of Contents
- Contacts and Acknowledgments
- Detailed Data Description
- Data Access and Tools
- Data Acquisition and Processing
- References and Related Publications
- Document Information
1. Contacts and Acknowledgments
Investigator(s)
Dr. Michael Bender
Princeton University
Department of Geosciences
M48 Guyot Hall
Princeton, NJ 08544
USA
Dr. James White
INSTAAR
450 UCB
University of Colorado
Boulder, CO 80309
USA
Technical Contact
NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
e-mail: nsidc@nsidc.org
Acknowledgements
This research was supported by NSF Office of Polar Programs.
2. Detailed Data Description
Format
Data are available as Microsoft Excel (.xls) and Word (.doc) files.
File and Directory Structure
Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/waiscores/bender/ directory. Table 1 lists the files in this directory:
| File Name | Description |
|---|---|
|
d18Oatm.xls d18Oatm2.xls |
Analytical data for paleoatmospheric oxygen, gas and ice age data, and constrained timescale of ice core chronology |
| d18Oatm.doc | Graphical representation of time series records, in kiloyears (kyr), for Siple Dome, constrained with Vostok and GISP2 measurements, including:
|
File Naming Convention
The file names for the Microsoft Excel data files are d18Oatm.xls and d18Oatm2.xls. The file name for the Microsoft Word data file is d18Oatm.doc.
File Size
The data set contains three files ranging in size from 52 KB to 235 KB.
Spatial Coverage
Ice core data were collected at the Siple Dome site in the Siple Coast region of Antarctica.
Southernmost Latitude: 81°S
Northernmost Latitude: 81°S
Westernmost Longitude: 149°W
Easternmost Longitude: 149°W
Temporal Coverage
Data were obtained during three Antarctic field seasons in 1996 to 1999.
Temporal Resolution
Data was analyzed at 1,000 to 1,500 years (1–1.5 kyr) before present (ybp) resolution.
Parameter or Variable
Parameters for ice core chronology analysis include the top depth in meters (m), the delta deuterium ratio (δD) of ice core samples as provided by James White, the delta oxygen-18 ratio of paleoatmospheric oxygen (δ18Oatm) in parts per trillion (ppt), the gas age and ice age in kiloannum (ka), and the linearly interpolated gas age and ice age in kiloyears (kyr).
Sample Data Record
Below is a sample record of the ice core chronology analysis data from d18Oatm2.xls. The ice core chronology analysis is separated into six sample records: deuterium analysis from James White, gas and ice age versus depth chronology, paleoatmospheric delta oxygen-18 ratio analysis, linearly interpolated gas chronology, and ice core timescale. The ice core timescale is separated into deuterium (δD) versus ice age and paleoatmospheric delta oxygen-18 (δ18Oatm) versus gas age for plotting. Only the first four data records are shown for each sample record.
Deuterium Analysis from James White:
| top depth, m | d D |
| 382.234 | -218.8 |
| 382.794 | -217.4 |
| 393.832 | -210.5 |
| 394.332 | -226.0 |
Gas and Ice Age versus Depth Chronology:
| top depth, m |
Gas Age ka |
Ice Age ka |
| 382.234 | 6.1 | 6.7 |
| 382.794 | 6.1 | 6.7 |
| 393.832 | 6.3 | 6.9 |
| 394.332 | 6.3 | 6.9 |
Paleoatmospheric Delta Oxygen-18 Ratio Analysis:
|
Ice depth of gas sample top depth, m |
d 18Oatm-a, ppt | d 18Oatm-b, ppt |
means of reps d 18Oatm, ppt |
| 59.575 | 0.04 | 0.06 | 0.05 |
| 119.339 | -0.11 | -0.01 | -0.06 |
| 179.459 | 0.03 | -0.01 | 0.01 |
| 239.502 | 0.00 | 0.02 | 0.01 |
Linearly Interpolated Gas Chronology:
|
Gas Age control pt. (kyr) |
Gas Age linear interp. (kyr) |
Ice Age (kyr) |
| 1.0 | 1.6 | |
| 1.9 | 2.5 | |
| ... | ... | ... |
| 69.5 | 69.5 | 70.1 |
| 71.0 | 71.6 |
Ice Core Timescale (dD vs. Ice Age):
| Siple_ice_age | Siple_dD |
| 6.7 | -218.8 |
| 6.7 | -217.4 |
| 6.9 | -210.5 |
| 6.9 | -226.0 |
Ice Core Timescale (d18Oatm vs. Gas Age):
|
Ice depth of gas sample top depth, m Siple_gas_depth |
Gas Age linear interp. Siple_gas_ageSIPLE_D18OATM |
mean d 18Oatm, ppt Siple_18Oatm |
| 59.575 | 1.0 | 0.05 |
| 119.339 | 1.9 | -0.06 |
| 179.459 | 2.9 | 0.01 |
| 239.502 | 3.8 | 0.01 |
Error Sources
Gas loss due to core relaxation and cracking at the surface and a small fractionation of O isotopes associated with loss of O2 both contribute to the error in the δ18Oatm timescale and accuracy of the constraints of the Siple Dome control depths.
3. Data Access and Tools
Data Access
Data are available via FTP.
Volume
The total volume of the data set is 528 KB.
Software and Tools
Data are accessible using standard spreadsheet and word processing document software.
Related Data Collections
- Concentration and Isotopic Composition of O2 and N2 in Trapped Gases of the Vostok Ice Core
- Vostok Ice Core Chemistry, Timescale, Isotope, and Temperature Data
- Trapped Gas Composition and Chronology of the Vostok Ice Core
- Methane Measurements from the GISP2 and Siple Dome Ice Cores
4. Data Acquisition and Processing
Analysis of ice core samples followed the sample processing methods described in Brook et al., 2005, to obtain measurements of the oxygen isotope ratio of paleoatmospheric O2 (δ18Oatm) and the deuterium isotope ratio. Samples were then calculated for gas age and ice age to obtain the gas chronology and subjected to linear interpolation to constrain the timescale to correlate with the GISP2 record. The experimental effort involved measuring the δ18O of O2, δ15N of N2, and the O2/N2 ratio in replicate samples, at 1 to 1.5 kyr resolution for the length of the core. For more information on data acquisition methods, see the researchers' notes in the Major Findings and the References and Related Publications listed below.
5. References and Related Publications
Bender, M. L., G. Floch, J. Chappellaz, M. Suwa, J. M. Barnola, T. Blunier, G. Dreyfus, J. Jouzel, and F. Parrenin. 2006. Gas Age–Ice Age Differences and the Chronology of the Vostok Ice Core, 0–100 ka. Journal of Geophysical Research 111:D21115: doi:10.1029/2005JD006488.
Bender, M. L., B. Malaize, J. Orchardo, T. Sowers, and J. Jouzel. 1999. High Precision Correlations of Greenland and Antarctic Ice Core Records Over the Last 100 kyr. In Mechanisms of Global Climate Change, eds. P. U. Clark, R. S. Webb, and L. D. Keigwin. American Geophysical Union Geophysical Monograph 112:149–164.
Brook, E. J., J. W. C. White, A. Schilla, M. Bender, B. Barnett, J. Severinghaus, K. Taylor, R. Alley, and E. Steig. 2005. Timing of Millennial-scale Climate Change at Siple Dome, West Antarctica, During the Last Glacial Period. Quaternary Science Reviews 24:1333-1343: doi:10.1016/j.quascirev.2005.02.002.
Schilla, A. 2007. The Stable Isotopes and Deuterium Excess from the Siple Dome Ice Core: Implications for the Late Quaternary Climate and Elevation History of the Ross Sea Region, West Antarctica. Ph.D. Dissertation, Department of Geological Sciences, University of Colorado.
Schilla, A., T. Popp, J. W. C. White, M. Bender, E. Brook, E. Steig, and K. Taylor. 2002. Stable Isotope Record From Siple Dome, Antarctica. Eos, Transactions, American Geophysical Union 83(19):A32B-12.
Sowers, T., M. Bender, and D. Raynaud. 1989. Elemental and Isotopic Composition of Occluded O2 and N2 in Polar Ice. Journal of Geophysical Research 94: 5137-5150.
Table 2 list related documents that are available on the NSIDC Web site.
| Document | Description | URL |
|---|---|---|
| WAISCORES | Project Web site | http://nsidc.org/data/waiscores/ |
| Antarctic Glaciological Data Center | Data center Web site | http://nsidc.org/agdc/ |
| WAISCORES: Findings by Bender | Major Findings Web page | http://nsidc.org/data/waiscores/findings/bender_findings.html |
6. Document Information
Acronyms
The acronyms used in this document are listed in Table 3.
| Acronym | Description |
|---|---|
| D18OATM | Delta oxygen-18 ratio of paleoatmospheric oxygen, δ18Oatm |
| DD | Delta deuterium ratio, δD |
| .DOC | Microsoft Word document file extension |
| FTP | File Transfer Protocol |
| GISP2 | Greenland Ice Sheet Project 2 |
| KA | Kiloannum, 103 |
| KYR | Kiloyears, 103 |
| NSF | National Science Foundation |
| NSIDC | National Snow and Ice Data Center |
| ‰ | Per mil, one part per thousand, 10-3 |
| URL | Uniform Resource Locator |
| WAISCORES | Western Divide West Antarctic Ice Cores |
| .XLS | Microsoft Excel spreadsheet file extension |
| YBP | Years before present |
Document Creation Date
28 December 2009
Document URL
http://nsidc.org/data/docs/agdc/nsidc0123_bender/index.html
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