Data Set Overview
      =================
      This data set contains 166 laboratory spectra of 108 meteorite
      samples, as reported by M. J. Gaffey in Gaffey (1976)
      [GAFFEY1976]. This in turn was based on his PhD thesis work
      (Gaffey 1974 [GAFFEY1974]).
 
      The meteorites selected for this work represented nearly all types
      and subclasses then identified in terrestrial collections. Gaffey
      (1976) demonstrates that the meteorite spectra are diagnostic not
      only of class, but also of composition, abundance and mineral
      phase distribution. As such, they represent a useful standard for
      interpretation of spectral reflectance observations of asteroids.
 
 
      Parameters
      ==========
      The spectrum files list wavelength, reflectance and error, where
      available. Reflectance values have not been scaled. An index to
      the spectrum files is provided. The index file includes some
      notations made by Gaffey during the coarse of recording the
      spectra.
 
      Note that the wavelength range varies slightly from spectrum to
      spectrum, mainly from extrema being dropped where errors became
      excessive.
 
 
      Processing
      ==========
      The details of the data processing are reported in Gaffey (1976)
      [GAFFEY1976].
 
 
      Modification History
      ====================
      Version 1 of this data set was reviewed and accepted in 1999. At
      the end of 2000 the data set came under scrutiny as a candidate
      for inclusion in the Small Bodies Data Base, at which time a
      substantial upgrade was undertaken. Tasks performed included:
 
        o  Meteorite names were edited for spelling.
 
        o  Names were checked against the 'Catalogue of Meteorites'
           (CoM), Graham et al. (1985) [GRAHAMETAL1985] for both
           spelling and specificity. Where the original name was
           ambiguous (as, for example, with ''Babb's Mill''), the
           correct association was determined by matching types and
           sources, and the name in this data set changed to include the
           appropriate modifiers.
 
        o  Meteorite types were checked against the CoM and updated as
           required.
 
        o  The data set includes a number of composite spectra averaging
           over several samples of the same type, without listing the
           specific meteorites involved. It was discovered that two
           identical spectra were provided for each of these composites.
           The duplicate spectra have been removed.
 
        o  Upon further checking it was discovered that the
           combined spectrum for Grueneberg & Ochansk was also
           included twice. The duplicate data were deleted.
 
        o  Information about the number of samples averaged to
           produce many of the spectra was extracted from the
           notes field of the index file into a separate column.
 
        o  Abbreviations in the notes field of the index file were
           expanded by referencing the original paper and thesis.
           Gaffey was contacted by SBN personnel to clear up
           additional questions regarding these notes.
 
        o  The filename was moved from the last column of the
           index to the first.
 
        o  The index file is now provided in three sort orders:
           'nameindx.tab' is sorted on meteorite name;
           'fileindx.tab' is sorted on file name; and
           'typeindx.tab' is sorted on meteorite type.
 
        o  Gaffey (1974) [GAFFEY1974] contained a table in
           Appendix 1 that listed each sample analyzed, its source and
           in many cases a quality code indicating the condition of the
           sample. The lines corresponding to spectra in this data set
           were keypunched from the printed thesis into a sample list
           file. The names and types were edited as above to conform to
           the CoM. The resulting file was then sorted in two different
           orders and added to the dataset. The 'namelist.tab' file
           lists sample information in name order, while 'typelist.tab'
           lists the same information in order of meteorite type (as in
           the original thesis).
 
        o  New labels were created for the individual spectra.
           The new labels include some additional descriptive
           information, plus extrema for the wavelength and reflectance
           values to facilitate plotting. The name of the particular
           sample, as indicated in the index file, has also been
           incorporated into the label information.
 
        o  Two spectra (for Rose City) discovered to be missing
           from the archived data set were recovered and restored. Upon
           inspection it was discovered that these two spectra were
           duplicates of each other. Only one has been included.
 
      Note that, apart from the duplicate files that were deleted and
      the missing file added, no spectrum data was itself changed during
      the upgrade process.

Coverage and Quality
      ====================
      Gaffey (1976) includes the following description regarding the
      sources and selection of meteorite samples:
 
        In order to obtain the broadest possible representation of the
        meteorite types as well as the widest coverage of each type,
        more than 150 individual meteorite samples were selected. The
        bulk of these samples were provided by Edward Olsen (Field
        Museum, Chicago) and Clifford Frondel (Harvard University).
        Additional specimens were provided by Carleton Moore (Arizona
        State University) and Karl Turekien (Yale University). Specimens
        were chosen to be as fresh as possible (interior fragments,
        clean, no discernible alteration). The Specimens selected
        represent all but 3 of the approximately 40 meteorite types. The
        three excluded types, all stony irons, present special sample
        preparation problems and are best handled by modeling techniques
        ... . Despite these quality controls, detailed microscopic
        examination of the samples and of the powder formed by crushing
        them as well as examination of the measured spectra indicated
        that approximately a quarter of the samples exhibited signs of
        alteration or contamination. These were eliminated from the
        final selection used in establishing the meteorite class
        spectral characteristics.
 
      The NOTES column in the index file frequently contains remarks
      regarding any observed alteration or oxidation noted in a
      particular sample.
 
 
      Review
      ======
      Version 1.0 of this data set was reviewed on April 9, 1999.
      Version 2.0 of this data set was reviewed on May 10, 2002.