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Preliminary results of spectral reflectance studies of tycho craterThe preliminary analysis and interpretation of near infrared spectra obtained for both the interior and exterior deposits associated with the Tycho crater is presented. Specific objectives were: (1) to determine the composition and stratigraphy of the highland crust in the Tycho target site; (2) to determine the likely composition of the primary ejecta which may be present in ray deposits; (3) to investigate the nature of spectral units defined in previous studies; (4) to further investigate the nature and origin of both the bright and dark haloes around the rim crest; and (5) to compare the compositions determined for the Tycho units with those of the Aristarchus crater as well as typical highland deposits. The spectra obtained for the interior areas exhibit similar spectral features. These include relatively strong 1 micron absorption bands whose minima are centered between 0.97 and 0.99 microns and shallow to intermediate continuum slopes. The spectra generally exhibit indications of a 1.3 micron feature consistent with the presence of Fe(2+) bearing plagioclase feldspar. The strong 1 micron absorption features indicate a dominant high Ca clinopyroxene component. Results obtained from the ejecta deposits show that the spectrum of the inner, bright halo is almost identical with those obtained for interior units. The spectrum of the dark halo exhibits a wide, relatively shallow absorption feature centered at 1.01 microns, a 1.3 micron absorption, and a steep continuum slope. This spectrum is interpreted as indicating the presence of pyroxene, Fe-bearing feldspar, and a significant component of Fe-bearing impact melt glass. Finally, the spectra of spots inside Tycho show similarity with certain spectra for Aristarchus. However, the suite of spectra obtained for Tycho exhibits a different trend in terms of band center versus width.
Document ID
19870013997
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Hawke, B. R.
(Hawaii Univ. Honolulu, HI, United States)
Coombs, C. R.
(Hawaii Univ. Honolulu, HI, United States)
Lucey, P. G.
(Hawaii Univ. Honolulu, HI, United States)
Bell, J. F.
(Hawaii Univ. Honolulu, HI, United States)
Jaumann, R.
(Hawaii Univ. Honolulu, HI, United States)
Neukum, G.
(Hawaii Univ. Honolulu, HI, United States)
Pieters, Carle M.
(Brown Univ. Providence, R. I., United States)
Date Acquired
September 5, 2013
Publication Date
May 1, 1987
Publication Information
Publication: NASA, Washington, Reports of Planetary Geology and Geophysics Program, 1986
Subject Category
Lunar And Planetary Exploration
Accession Number
87N23430
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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