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Tephra in Siple and Taylor Dome Ice Cores

Data Set Summary

This data set consists of electron microprobe geochemical analyses of 86 glass shard samples 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 glass shards are in TIFF format. Data are available via ftp.

Citing These Data:

Please cite these data as follows:

Dunbar, N. 2002. Tephra in Siple and Taylor Dome Ice Cores. Boulder, CO: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N50P0WXF.

Also, please consult and cite the following related publication:

Dunbar, N., G. Zielinski, and D. Voisins. 2003. Tephra layers in the Siple Dome and Taylor Dome Ice Cores, Antarctica: Sources and correlations. Journal of Geophysical Research 108 B8) ECV 6-1.

Overview Table

Category Description
Parameter(s) Electron microprobe geochemical analyses of glass shards
Backscattered electron images of tephra samples
Spatial coverage Tephra samples were collected from Siple and Taylor Domes, Antarctica.
Temporal coverage Ice cores were taken during the 1999-2000 Antarctic field season.
Data format Geochemical analyses of tephra are in tab-delimited ASCII and Excel formats. Electron images of tephra samples are in TIFF format.
File sizes Geochemical analyses in ASCII format: 5 KB
Geochemical analyses in Excel format: 37 KB
Electron images in TIFF format: 139 KB to 890 KB
Procedures for obtaining data Data are available via ftp.

Table of Contents

1. Contacts and Acknowledgments
2. Detailed Data Description
3. Data Access and Tools
4. Data Acquisition and Processing
5. References and Related Publications
6. Document Information

1. Contacts and Acknowledgments:

Investigator Name(s) and Affiliation(s):

Nelia W. Dunbar
New Mexico Institute of Mining and Technology
E&ES Department
Socorro, NM 87801 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

Acknowledgments:

This research was supported by NSF grant OPP-9615167 ("Volcanic Record from the Siple and Taylor Dome Ice Cores, Antarctica").

2. Detailed Data Description:

Format and File Sizes:

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.

Spatial Coverage:

Tephra samples were collected from Siple Dome (81°S, 148°W) and Taylor Dome (77° 48' S, 158° 43' E).

Study Area Location Map:

Siple and Taylor Domes, Antarctica

Temporal Coverage:

Cores were taken during the 1999-2000 field season.

Parameter or Variable:

Data consist of electron microprobe analyses of glass shards where compositionally-consistent samples were present. The following variables are reported:

3. Data Access:

Data are available via ftp.

Related Data Collections:

Please see the Ice Core Gateway for other Antarctic ice core data.

4. 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 1sigma, 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

5. References and Related Publications:

Dunbar, N., R. Esser, W. McIntosh, G. Zielinski, and P. Kyle. 1998. Englacial tephra layers in West Antarctica: Implications for the history of the West Antarctic Ice Sheet. 4th Annual West Antarctic Ice Sheet Workshop. ABSTRACT.

Dunbar, N., R. Esser, and W. McIntosh. 1998. Englacial tephra layers in West Antarctica: Implications for the history of the West Antarctic Ice Sheet: Antarctic Journal of the U.S. XXXIII- Review 1998.

Dunbar, N., R. Esser, W. McIntosh, P. Kyle, and G. Zielinski. 1997. Englacial tephra layers in the East and West Antarctic ice sheets: Indicators of glacial flow patterns on ice sheet margins. EOS, Transactions of the American Geophysical Union 78: F250. ABSTRACT.

Dunbar, N., W. McIntosh, R. Esser, T. Wilch, and G. Zielinski. 1998. Direct dating and geochemical correlations of englacial tephra layers at two sites in West Antarctica: Proceedings of the West Antarctic Ice Sheet Meeting Chapman Conference, Sept. 13-18, p. 18-19. ABSTRACT.

McIntosh, W. and T. Wilch. 1995. Late Pleistocene (223-125 ka) Plinian eruptions in Marie Byrd Land: Potential time horizons in West Antarctic ice cores. VII International Symposium of Antarctic Earth Sciences, Siena, Italy. p. 261.

Wilch, T., W. McIntosh, and N. Dunbar. 1999. Late Quaternary volcanic activity in Marie Byrd Land: potential 40Ar/39Ar-dated time horizons in future West Antarctic ice and marine cores. Geological Society of America Bulletin 111: 1563-1580. ABSTRACT.

Zielinksi, G. and N. Dunbar. 1998. Volcanic Record from the Siple and Taylor Domes, Antarctica: WAISCORES Meeting, Sept. 10, 1998.

6. Document Information:

Document Creation Date:

June 2002

Document Revision Date:

July 2002

Document Curator:

NSIDC writers, nsidc@nsidc.org

Document URL:

http://nsidc.org/data/docs/agdc/nsidc0110_dunbar/index.html