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.
DOWNLOADING DATA VIA FTP
Data can be downloaded through a Web browser or command line via FTP. When using a Web browser, the FTP link first directs you to an Optional Registration Form that if filled out, will allow you to receive notifications about updates or processing changes related to that specific data set. After completing the Optional Registration Form, the FTP directory becomes available. For additional help downloading data through an FTP client, go to the How to access data using an FTP client support page.
Siple Dome Core Date from Measurement of the d18O of Paleoatmospheric Oxygen, Version 1
|Spatial Resolution:||Not Specified|
|Temporal Resolution:||Not specified|
|Platform(s)||GROUND STATIONS, GROUND-BASED OBSERVATIONS, LABORATORY|
|Data Contributor(s):||Michael Bender, James White|
|Metadata XML:||View Metadata Record|
As a condition of using these data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.Bender, M. 2003. Siple Dome Core Date from Measurement of the d18O of Paleoatmospheric Oxygen, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5TX3C95. [Date Accessed].
Detailed Data Description
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 as Microsoft Excel (.
xls) and Word (.
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:
|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:
The file names for the Microsoft Excel data files are
d18Oatm2.xls. The file name for the Microsoft Word data file is
The data set contains three files ranging in size from 52 KB to 235 KB.
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
Data were obtained during three Antarctic field seasons in 1996 to 1999.
Data was analyzed at 1,000 to 1,500 years (1–1.5 kyr) before present (ybp) resolution
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|
Gas and Ice Age versus Depth Chronology
|top depth, m||Gas Age
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
Linearly Interpolated Gas Chronology
Ice Core Timescale (dD vs. Ice Age)
Ice Core Timescale (d18Oatm vs. Gas Age)
|Ice depth of gas sample
top depth, m
d 18Oatm, ppt
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 δ18Oatmtimescale and accuracy of the constraints of the Siple Dome control depths.
Software and Tools
Data are accessible using standard spreadsheet and word processing document software.
The total volume of the data set is 528 KB.
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.
References and Related Publications
Contacts and Acknowledgments
Dr. Michael Bender
Department of Geosciences
M48 Guyot Hall
Princeton, NJ 08544
Dr. James White
University of Colorado
Boulder, CO 80309
Document Creation Date
28 December 2009