This data set consists of electron microprobe geochemical analyses of glass shards sampled from Siple Dome and Taylor Dome ice cores during the 1999-2000 field season. Geochemical data are in tab-delimited ASCII and Excel formats. Backscattered electron images of tephra samples are in TIFF format. Data are available via ftp.
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Tephra in Siple and Taylor Dome Ice Cores, Version 1
Geographic Coverage
Spatial Coverage: |
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Spatial Resolution: | Not Specified |
Temporal Coverage: |
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Temporal Resolution: | Not specified |
Parameter(s): |
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Platform(s) | GROUND-BASED OBSERVATIONS |
Sensor(s): | CORING DEVICES, ELECTRON MICROPROBES |
Data Format(s): |
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Version: | V1 |
Data Contributor(s): | Nelia Dunbar |
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.
Dunbar, N. 2002. Tephra in Siple and Taylor Dome Ice Cores, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N50P0WXF. [Date Accessed].Detailed Data Description
Geochemical analyses are in tab-delimited ASCII and Excel formats.
- "sipleA_tephra.txt" (ASCII file, 5 KB)
- "sipleA_tephra.xls" (Excel file, 37 KB)
- "sipleA*.tif" (TIFF files of backscattered electron images, 139 KB to 890 KB)
Geochemical analyses have following data fields:
- Depth of samples (m). If the sample name contains "filter" then depth is given in the "Top depth in core" column.
- Number of geochemical analyses per sample
- Mean and standard deviation of geochemical composition in percentage weight (normalized to 100 percent)
Note: the number next to the sample name (for example, "sipleA 34.4-34.7") indicates the sample depth in meters.
Tephra samples were collected from Siple Dome (81° S, 148° W) and Taylor Dome (77° 48' S, 158° 43' E).
Study Area Location Map
Cores were taken during the 1999-2000 field season.
Data consist of electron microprobe analyses of glass shards where compositionally-consistent samples were present. The following variables are reported:
- Depth of samples (m). If the sample name contains "filter" then depth is given in the "Top depth in core" column.
- Number of geochemical analyses per sample
- Mean and standard deviation of geochemical composition in percentage weight (normalized to 100 percent)
Software and Tools
Data Acquisition and Processing
Electron microprobe analyses and backscatter electron images were processed with a Cameca SX-100 microprobe. Geochemical quantities are reported in percentage weight and normalized to 100 percent. Na2O is normalized to the value obtained by neutron activation analysis. Analytical precision, based on replicate analyses of standard reference materials of similar composition to the unknowns, is as follows (in percentage weight):
SiO2±0.47
TiO2±0.03
FeO±0.06
MnO±0.06
MgO±0.07
CaO±0.02
Na2O±0.55
K2O±0.27
P2O5±0.02
Cl±0.07
Preprocessing for electron microprobe analysis was conducted by irradiating neutron activation samples at the University of Missouri Research Reactor. Separated samples were analyzed at the New Mexico Institute of Mining and Technology. Irradiation lasted approximately 40 hours at a flux of 2.5 x 1013N cm-2 s-1. Analytical errors, based on replicate analysis of samples, to 1σ, are as follows:
Major elements (percentage weight):
FeO ± 0.01
Na2O ± 0.04
Trace elements (ppm):
Sc±0.04
Cr±12
Co±0.13
Ni±1
Zn±1
As±0.7
Br±0.07
Rb±0.8
Sr±0.7
Sb±0.1
Cs±1.4
Ba±10
La±1.8
Ce±1.4
Nd±0.7
Sm±0.07
Eu±0.14
Tb±0.02
Yb±0.07
Lu±0.01
Hf±0.12
Ta±0.04
Ta±0.04
W±0.05
U±0.02
Th±1
References and Related Publications
Contacts and Acknowledgments
Nelia W. Dunbar
New Mexico Institute of Mining and Technology
E&ES Department
Socorro, NM 87801 USA
This research was supported by NSF grant OPP-9615167 ("Volcanic Record from the Siple and Taylor Dome Ice Cores, Antarctica").
Document Information
DOCUMENT CREATION DATE
June 2002
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