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Data Set ID:
NSIDC-0113

Micrometeorites from the South Pole Water Well, Version 1

Micrometeorites dated between 1100 A.D. to 1500 A.D. were collected from the bottom of the South Pole Water Well in December 1995. Element analyses of 181 cosmic glass spherule and micrometeorite samples are in ASCII text and Excel spreadsheet format. Scanning Electron Microscope (SEM) images of the spherules and micrometeorites are in TIFF format. Data are available via ftp.

Geographic Coverage

Spatial Coverage:
  • N: -90, S: -90, E: 0, W: 0

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 December 1995 to 31 December 1995
Temporal Resolution: Not specified
Parameter(s):
  • Rocks/Minerals > Meteorites > Micrometeorites
Platform(s) GROUND-BASED OBSERVATIONS
Sensor(s): ELECTRON MICROPROBES, SCANNING ELECTRON MICROSCOPES, SEDIMENT TRAPS
Data Format(s):
  • Microsoft Excel
  • TIFF
  • ASCII Text
Version: V1
Data Contributor(s): Susan Taylor

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.

Taylor, S. 2002. Micrometeorites from the South Pole Water Well, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: http://dx.doi.org/10.7265/N5R49NQK. [Date Accessed].

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Detailed Data Description

Format

Following is a list of files for this data set:

GlassOxide.txt and GlassOxide.xls: Tab-delimited ASCII text and Excel spreadsheet files, respectively, with diameter and element analyses of 181 glass cosmic spherules recovered in 1995. Each sample's label identifies the number of the mount and the particle number within the mount.

SP-95-8.txt and SP-95-8.xls: Tab-delimited ASCII text and Excel spreadsheet files, respectively, with diameter, and element analyses of 94 cosmic spherules on the "SP-95-8" mount.

TIFF images of glass spherules and micrometeorites are located in the "micrometeorite_classes" and "unusual_spherules" directories.

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File Size

TIFF images range in file size from 89.3 KB to 1.0 MB.

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Spatial Coverage

Micrometeorite samples were collected from the bottom of the South Pole Water Well, which supplies potable water to the Amundsen-Scott South Pole Station.

Study Area Location Map:

South Pole map

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Temporal Coverage

Micrometeorites dated between 1100 A.D. to 1500 A.D. were collected in December 1995.

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Parameter or Variable
Parameter Description:

Micrometeorites are extraterrestrial particles, generally less than 1 mm, that have survived atmospheric entry. They range from unmelted or partially melted particles that retain their original mineralogy, to melted cosmic spherules, some of which have lost most of their mass by vaporization. See the TIFF images located in the "micrometeorite_classes" and "unusual_spherules" directories for classes of spherules extracted from the South Pole Water Well (Taylor 2002).

Sample Data Record:

Following is the first five lines of data from "GlassOxide.txt." Blank values indicate that no measurements were taken for this sample. Columns include:

  • Label: "SP" indicates "South Pole," followed by the number of the mount and the particle number within each mount.
  • Diameter (Dia): in µm
  • Oxide weight percent: The next eight columns list the oxide weight percent of each mineral identified in a given sample.
  • Notes: Additional comments about the sample
Label Dia Si02 Ti02 Al203 Cr02 FeO MnO NiO MgO CaO Total Notes
BCR-1 54.60 2.25 13.13 0.01 12.09 0.17 0.01 3.47 7.14 92.87 BCR-1
SP-18-1 666 50.13 1.10 25.25 0.04 14.31 0.01 0.03 1.22 3.02 95.10
SP-18-4 472 52.03 0.21 3.16 0.02 9.88 0.37 0.02 33.13 1.77 100.59
SP-18-8 451 56.78 0.11 2.38 0.03 9.40 0.42 0.00 27.01 3.80 99.93
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Software and Tools

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Data Acquisition and Processing

Taylor, Lever, and Govoni traveled to the Amundsen-Scott South Pole Station in December 1995 to retrieve micrometeorite samples larger than 50 µm from the bottom of the South Pole Water Well. Micrometeorites form a lag deposit on the well bottom as they are melted out of the ice during continuous drilling of the well.

The researchers designed a collector that suctioned and internally filtered terrestrial and extraterrestrial particles from the bottom of the well. They operated the collector from the surface with a waterproof electromechanical cable and underwater video system. Suctioning particles by entraining them in a water stream prevented compositional bias in the samples. To avoid clogging the filter with terrestrial particles, they used a fabric filter with a 53 µm opening, which limited collection to particles larger than 53 µm. They collected about 200 g of predominantly terrestrial material from 7% of the well bottom area.

The researchers removed particles from the collector by backflushing them from the filter into funnels and wet-sieving them into stainless steel sieves. They sorted the samples by size (50 µm - 106 µm, 106 µm - 150 µm, 250 µm - 425 µm, and >425 µm), and, using a binocular microscope, separated cosmic spherules from the terrestrial material. Major element analyses were conducted for 181 glass cosmic spherules with a Scanning Electron Microscope/Energy Dispersive Analysis through X-ray (SEM/EDAX) system at the University of Washington. An automatic fluorescence (ZAF) program and mineral standards were used to quantify the data from the SEM/EDAX system. The following minerals were identified in the micrometeorites: SiO2, TiO2, Al2O3, CrO2, FeO, MnO, NiO, and MgO.

Ninety-four cosmic spherules from the SP-95-8 mount were analyzed with a JSM-6400 microprobe at the Natural History Museum in Vienna, Austria. The electron images were taken with a Zeiss DSM962 scanning electron microscope (SEM) at Dartmouth College. Diameters of all particles were measured with a reticle using a binocular light microscope at 10x to 50x magnification. The SEM images do not yield an accurate size because, in most cases, the widest part of the spherule may be under the epoxy surface (Taylor et al. 1997).

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References and Related Publications

Contacts and Acknowledgments

Susan Taylor
Cold Regions Research and Engineering Laboratory
U.S. Army Corps Engineers
Hanover, NH  USA

Document Information

Document Creation Date:

September 2002

Document Revision Date:

September 2002

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