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Data Set ID:

Microstructural Location and Composition of Impurities in Polar Ice Cores, Version 1

This data set contains measurements of impurities and ions in three polar ice cores: the Vostok 5G ice core and the Byrd ice core from Antarctica, and the Greenland Ice Sheet Project 2 (GISP2) D core. Parameters include sample depth, grain size, ion concentration, and ice core impurity information. Measurements were made using Ion Chromatography (IC), optical microscopy, and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM/EDS).

Data are available via FTP in Microsoft Excel (.xls)and Microsoft Word (.doc) formats.

Geographic Coverage

Spatial Coverage:
  • N: 72.583333, S: 72.583333, E: -38.466667, W: -38.466667

  • N: -72.466667, S: -72.466667, E: 106.8, W: 106.8

  • N: -80.016667, S: -80.016667, E: -119.516667, W: -119.516667

Spatial Resolution: Not Specified
Temporal Coverage:
  • 1 January 1999 to 30 December 2005
Temporal Resolution: Not specified
  • Ice Core Records > Ice Core Air Bubbles
  • Ice Core Records
  • Glaciers/Ice Sheets > Ice Sheets
  • Ice Core Records > Ions
  • Ice Core Records > Particulate Matter
Platform(s) LABORATORY
Data Format(s):
  • Microsoft Excel
Version: V1
Data Contributor(s): Ian Baker, Rachel Obbard

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.

Baker, I. and R. Obbard. 2010. Microstructural Location and Composition of Impurities in Polar Ice Cores, Version 1. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: [Date Accessed].

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Detailed Data Description


Data are in Microsoft Excel (.xls) format.

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File and Directory Structure

Data are available on the FTP site in the directory. Within this directory, there are five Microsoft Excel (.xls) spreadsheets, and one Microsoft Word (.doc) file. The contents of these data files are described in Table 1.

Table 1. File Description
File Name Description
GISP2_&_Byrd_Core_Impurity_Data.xls This file contains information on the location of the most prevalent elements found in impurities in the GISP-2 D and Byrd cores. Note that hydrogen and nitrogen are undetectable by the EDS (too light) and oxygen is ubiquitous (found in every spectra) and hence not analyzed
GISP2_Impurities_Inclusions.xls This file contains data on elements and ions identified in ice core impurities. Measurements were made using Ion Chromatography (IC), optical microscopy, and Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM/EDS).
GISP2_Selected_Ions.xls This file contains measurements of ions (Na, NH4, K, Mg, Ca, Cl, NO3, SO4) in samples from the Vostok 5G ice core.
Vostok_5G_ Grain_Size_Linear_Intercept.xls This file contains grain size measurements made using the linear intercept method.
Vostok_5G_ Grain_Size.xls This file contains grain size area measurements, made using optical microscopy.
Vostok_5G_Grain_Size_Notes.doc This file contains observation notes related to the samples used for grain size measurement.
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File Naming Convention

Files are named according to the following convention and as described in Table 2:

Example File Name: GISP2_Selected_Ions.xls



Table 2. File Naming Convention
Variable Description
IceCore Name of ice core:
  • GISP2: Greenland Ice Sheet Project 2 Ice Core D
  • Vostok_5G: Vostok 5G Ice Core
  • Byrd: Byrd Ice Core
Parameter Measurement type.
  • Impuritiesand Inclusions: Data on ions and elements in ice core impurities, determined by IC, optical microscopy, and SEM/EDS.
  • Grain Size: Grain size in area, determined by optical microscopy
  • Selected Ions: Ion measurements in parts per billion (ppb), determined by IC
.xls Microsoft Excel file extension

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File Size

The files range in size from 20 KB to 272 KB.

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The total data volume is approximately 600 KB.

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Spatial Coverage

The data are from three ice cores, the Vostok 5G and the Byrd ice cores from Antarctica, and the Greenland Ice Sheet Project 2 (GISP2) D core. The geographical locations are as follows:

Southernmost Latitude: 80°01'S
Northernmost Latitude: 80°01'S
Westernmost Longitude: 119°31'W
Easternmost Longitude: 119°31'W

Vostok 5G
Southernmost Latitude: 72°28'S
Northernmost Latitude: 72°28'S
Westernmost Longitude: 106°48'E
Easternmost Longitude: 106°48'E

Southernmost Latitude: 72°35'N
Northernmost Latitude: 72°35'N
Westernmost Longitude: 38°28'W
Easternmost Longitude: 38°28'W

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Temporal Coverage

Data were collected during laboratory experiments and observations, conducted from 1995 to 2005.

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Parameter or Variable

Parameters include sample depth (m), grain size (mm^2), ion concentration (ppb), and ice core impurity information (ppb).

Parameter Description

Parameter Description
Table 3. Parameter Descriptions
Sample Depth Sample Depth, in meters
Grain Size Grain size measurements in square millimeters (mm^2), measured using optical microscopy and the linear intercept method
Impurities Elements and ions in ice core impurities
Ion Concentration Ion concentration for Na, NH4, K, Mg, Ca, Cl, NO3, SO4, in ppb

Sample Data Records

Ratio of Impurity Counts  by Depth to the Number of Spectra Collected at That Depth Normalized to Cl
Table 4. Sample Record from GISP2_&_Byrd_Core_Impurity_Data.xls
Ion 94 214 341 2750 2850 2950
Cl 0.187807814 0.173361059 0.153660939 0.164331838 0.156506512 0.164331838 1
Na 0.179271096 0.158914304 0.102440626 0.046951954 0 0.140855861 0.62843384
S 0.068293751 0.08668053 0.136587501 0.140855861 0.031301302 0.023475977 0.487194922
Table 5. Sample Record from GISP2_Impurities_Inclusions.xls
SAMPLE DATA Impurity Ion Concentration (ppb) Elements in Relaxation Figures
DEPTH (m) DEPTH (m) Age (yrBP) SO4 NO3 Cl Ca Mg K NH4 Na GB Filaments Dust found vapor fig GBPores #/mmthick Area (mm^2) Total Area COMMENTS
94 94(3) 94 73.04 71.93 10.99 7.62 1.43 2.15 5.22 4.14
150.10-150.13 146.466(1) 481 30.80 103.85 7.73 4.88 1.36 2.02 20.62 1.20 yes none
249.0-249.03 246.466(1) 911 22.93 74.76 9.64 0.58 0.25 1.28 4.53 1.21 0.51 0.0101 0.0051 "black vf"
GISP2 Ion Chromatography Data (ppb)
Table 6. Sample Record from GISP2_Selected_Ions.xls
Ion grain interior grain boundary IDL*
94 m 214m 341m 2750m 2850m 2950m 2950m
Na 950.57 13.62 29.03 38.16 14.78 67.35 158.21 10
V3311_A Measured and Marked
Table 7. Sample Record from Vostok_5G_Grain_Size.xls
1 85.04
2 65.57
Vostok 248m
Table 8. Sample Record fromVostok_5G_Grain_Size_Linear_Intercept.xls
Linear Intercept Method
Actual (mm) Scale (mm)
Down 145 61
Across 140 58.89655172
No. Grains
Chord Down Across
1 22 19
2 25 19
3 21 22
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Software and Tools

Data are accessible using standard spreadsheet software.

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Data Acquisition and Processing

Data Source

Ice core samples were obtained from the National Ice Core Laboratory (NICL) in Denver, Colorado, USA.

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Data Acquisition Methods

Data acquisition methods are described in detail in Obbard and Baker, 2007, Cullen and Baker, 2000 and 2001, and Baker et. al., 2003. See the references listed below.

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Sensor or Instrument Description

Ion chromatography data were acquired using Dionex guard and separator columns for anions and cations.

Scanning Electron Microscope (SEM) data are from the Dartmouth Environmental Scanning Electron Microscope (ESEM): JEOL 5310LV.

Energy Dispersive Spectroscopy (EDS) data were acquired using a germanium detector with aluminum coated polyimide window.

Additional notes on methods are available in each data file, and in the related references, listed below and in the data files.

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References and Related Publications

Contacts and Acknowledgments

Dr. Ian Baker
Thayer School of Engineering
Dartmouth College
8000 Cummings Hall 
Hanover, NH 03755

Dr. Rachel Obbard
Thayer School of Engineering
Dartmouth College
8000 Cummings Hall 
Hanover, NH 03755


This research was supported by NSF OPP grants 0440523 and 09980379.

Document Information


21 January 2010


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