This data set contains c-axis fabric measurements and grain area from the physical properties samples taken from the main West Antarctic Ice Sheet (WAIS) Divide ice core, WDC06A , Antarctica.
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C-axis Fabric from Physical Properties Samples of the WAIS Divide Ice Core, Version 1
Geographic Coverage
Spatial Coverage: |
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Spatial Resolution: |
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Temporal Coverage: |
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Temporal Resolution: | Varies |
Parameter(s): |
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Platform(s) | Laboratory |
Sensor(s): | ACFA |
Data Format(s): |
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Version: | V1 |
Data Contributor(s): | Donald Voigt, Richard Alley, Joan Fitzpatrick |
Metadata XML: | View Metadata Record |
Data Citation
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.
Voigt, D. E., J. Fitzpatrick, and R. Alley. 2015. C-axis Fabric from Physical Properties Samples of the WAIS Divide Ice Core, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5W093VM. [Date Accessed].Literature Citation
As a condition of using these data, we request that you acknowledge the author(s) of this data set by referencing the following peer-reviewed publication.
Fitzpatrick, J. et al. 2014. Physical properties of the WAIS Divide ice core, Journal of Glaciology. 60. 1181-1198. http://dx.doi.org/10.3189/2014JoG14J100
Detailed Data Description
This data set contains c-axis fabric measurements and grain area from the physical properties samples taken from the main WAIS Divide ice core, WDC06A , Antarctica ( Figure 1). The sample interval was 20 m and represents samples from 140 m depth to the bottom of the core at 3405 m depth. The c-axis measurements were obtained from 10 cm by 10 cm thin sections on the automated c-axis analyzer designed and built by Larry Wilen (Wilen 2003).

Data are provided in tab-delimited text (.txt), and images are in jpeg (.jpg) and bitmap (.bmp) formats. A database of analyzed sections is in Microsoft Excel (.xls) format.
Data are available on the FTP site in the ftp://sidads.colorado.edu/pub/DATASETS/AGDC/nsidc0605_voigt/ directory. Within this directory, there are 83 folders, one for each nominal depth, containing seven to eight files each and one Microsoft Excel spreadsheet, Database of Analyzed Sections.xls. See Table 1 for descriptions of the files within each folder and the database spreadsheet.
File Type | Format | Description |
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Information | .txt | contains date and time the section was run for this analysis, the scaling factor of the image (mm/pixel), the actual depth of the sample, and any other special information about the sample |
C-Axes | .txt | contains the grain number, theta, phi and the R² value for the grain. Grains for which the program was unable to calculate a c-axis are labeled as "grain not analyzable." The R² value is a value for the quality of the measurement of a particular grain. |
Area | .txt | contains the area of each grain in square pixels. The mm/pixel calibration can be used to determine the area in mm2 |
Edge File Image | .bmp | image of the edge file used to pick grains |
Labeled Image | .bmp | image of the thin section with the grains numbered |
Unlabeled Image | .jpg | an unlabeled image of the thin section |
Horizontal Schmidt Plot Image | .jpg | image of the horizontally rotated thin section, unfiltered by R² |
Schmidt Plot Image | .jpg | image of vertically rotated thin section around the core's axis so the major axis of the data set is parallel to X. The value for rotation is given in the table, Database of Analyzed Sections.xls, as azimuth |
Database of Analyzed Sections | .xls | provides the section number, top depth and bottom depth, the azimuth and the eigenvalues of each section |
This section explains the file naming convention used for the three text (.txt) files in this data set with examples.
Example File Names:
1264 Section Info.txt
1264 area.txt
1264 c-axes.txt
#### xxxxxxx.txt
Refer to Table 2 for the valid values for the file name variables listed above.
Where:
Variable | Description |
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#### | Sample number |
xxxxxxx |
indicates the type of information for each section: |
This section explains the file naming convention used for the two bitmap image files (.bmp) in this data set with examples.
Example File Names:
1264 edges.bmp
1264 labeled picture.bmp
#### edges/labeled picture(or picture).bmp
Refer to Table 3 for the valid values for the file name variables listed above.
Where:
Variable | Description |
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#### | Sample number |
edges | image of the edge file used to pick grains |
labeled picture/picture | image of the thin section with the grains numbered |
This section explains the file naming convention used for the vertical Schmidt Plot image files in this data set with an example.
Example File Names:
SP of 15.05 WDC06A 1264 VTS.JPEG
SP of xx.xx WDC06A #### VTS.jpeg(or jpg)
Refer to Table 4 for the valid values for the file name variables listed above.
Where:
Variable | Description |
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SP of | Schmidt plot of |
xx.xx | time stamp (24-hour clock) of sample |
WDC06A | WAIS Divide Core number |
#### | sample number |
VTS | Vertical Thin Section |
This section explains the file naming convention used for the horizontal Schmidt Plot image files in this data set with an example.
Example File Names:
1264 horizontal SP.jpg
#### horizontal SP.jpg (or jpeg)
Refer to Table 5 for the valid values for the file name variables listed above.
Where:
Variable | Description |
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#### | sample number |
horizontal | direction of the sample to the X-axis |
SP | Schmidt plot |
This section explains the file naming convention used for the unlabeled image files in this data set with an example.
Example File Names:
1264 VTS unlabeled picture.JPEG
#### VTS unlabeled picture.jpg (or jpeg)
Refer to Table 6 for the valid values for the file name variables listed above.
Where:
Variable | Description |
---|---|
#### | sample number |
VTS | Vertical Thin Section |
unlabeled picture | image of grains without numbers |
Data files range from 1 KB to 973 KB.
WAIS Divide, Antarctica: 79.467° S, 112.085° W
Spatial Resolution
Core depths range from 140 m - 3405 m with core samples 10 cm long taken every 20 m
Data collected 01 August 2011 to 01 October 2014
Data extend from 67748 cal yr BP to 480 cal yr BP
Temporal Resolution
Temporal resolution for the data varies.
Ice fabric (c-axis angle measurements)
Ice core records
Software and Tools
The data can be accessed using any text editor, image editing software, and Microsoft Excel.
Data Acquisition and Processing
Processing Steps
Fabric was measured on the automated c-axis fabric analyzer located at Penn State University, designed and built by Larry Wilen. Raw data is in the form of multiple images of the ice thin section taken at defined angles under cross polarized light. The images are analyzed to determine position of the extinction minimum of each grain within the thin section, this being the orientation of the c-axis of that grain. During processing, the area of each analyzed grain is also measured.
Automatic C-Axis Fabric Analyzer
References and Related Publications
Contacts and Acknowledgments
Donald E. Voigt
Penn State University
Department of Geosciences
209 Deike Bldg
University Park, PA 16802
Richard B. Alley
Penn State University
Department of Geosciences
517B Deike Bldg
University Park, PA 16802
Joan J. Fitzpatrick
Geosciences and Environmental Change Science Center
USGS
Box 25046, MS 980
Denver, CO 80225
This research was supported by NSF Antarctic Earth Sciences Grant Number ANT-10-43528.
Document Information
DOCUMENT CREATION DATE
December 2014
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