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.
Please cite these data as follows:
Taylor, S. 2002. Micrometeorites from the South Pole Water Well. Boulder, CO, USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N50P0WXF.
|Parameter(s)||Diameter (µm), element composition (%), and scanning electron microscope (SEM) images of micrometeorites and glass cosmic spherules|
|Spatial coverage||Amundsen-Scott South Pole Station, Antarctica|
|Temporal coverage||Micrometeorites dated between 1100 A.D. to 1500 A.D. were collected in December 1995.|
|Data format||Element analyses: ASCII and Excel formats
SEM images: TIFF format
|File sizes||GlassOxide.txt: 12.8 KB
GlassOxide.xls: 43.4 KB
SP-95-8.txt: 9.5 KB
SP-95-8.xls: 35.8 KB
SEM images: 89.3 KB - 1.0 MB
|Procedures for obtaining data||Data are available via ftp.|
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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. See derived images for a description of the various spherule types. TIFF images range in file size from 89.3 KB to 1.0 MB.
Micrometeorite samples were collected from the bottom of the South Pole Water Well, which supplies potable water to the Amundsen-Scott South Pole Station.
Micrometeorites dated between 1100 A.D. to 1500 A.D. were collected in December 1995.
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 derived images for classes of spherules extracted from the South Pole Water Well (Taylor 2002).
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
Data are available via ftp.
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).
Taylor, S. "Cosmic Dust from the South Pole." 25 March 2002. Environmental Sciences Branch, Cold Regions Research and Engineering Laboratory. http://www.crrel.usace.army.mil/es/research/micrometeorites.htm
Accessed 17 September 2002.
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