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The Viking X ray fluorescence experiment - Analytical methods and early resultsTen samples of the Martian regolith have been analyzed by the Viking lander X ray fluorescence spectrometers. Because of high-stability electronics, inclusion of calibration targets, and special data encoding within the instruments the quality of the analyses performed on Mars is closely equivalent to that attainable with the same instruments operated in the laboratory. Determination of absolute elemental concentrations requires gain drift adjustments, subtraction of background components, and use of a mathematical response model with adjustable parameters set by prelaunch measurements on selected rock standards. Bulk fines at both Viking landing sites are quite similar in composition, implying that a chemically and mineralogically homogeneous regolith covers much of the surface of the planet. Important differences between samples include a higher sulfur content in what appear to be duricrust fragments than in fines and a lower iron content in fines taken from beneath large rocks than those taken from unprotected surface material. Further extensive reduction of these data will allow more precise and more accurate analytical numbers to be determined and thus a more comprehensive understanding of elemental trends between samples.
Document ID
19780027534
Document Type
Reprint (Version printed in journal)
Authors
Clark, B. C., III (Martin Marietta Aerospace Denver, CO, United States)
Castro, A. J. (Martin Marietta Aerospace Denver, CO, United States)
Rowe, C. D. (Martin Marietta Planetary Sciences Laboratory Denver, Colo., United States)
Baird, A. K. (Pomona College Claremont, Calif., United States)
Rose, H. J., Jr. (Martin Marietta Aerospace Denver, CO, United States)
Toulmin, P., III (Martin Marietta Aerospace Denver, CO, United States)
Christian, R. P. (U.S. Geological Survey Reston, Va., United States)
Kelliher, W. C. (NASA Langley Research Center Hampton, Va., United States)
Keil, K. (Martin Marietta Aerospace Denver, CO, United States)
Huss, G. R. (New Mexico, University Albuquerque, N. Mex., United States)
Date Acquired
August 9, 2013
Publication Date
September 30, 1977
Publication Information
Publication: Journal of Geophysical Research
Volume: 82
Subject Category
LUNAR AND PLANETARY EXPLORATION
Funding Number(s)
CONTRACT_GRANT: NAS1-9000
CONTRACT_GRANT: NAS1-11858
CONTRACT_GRANT: NASA ORDER L-9717
CONTRACT_GRANT: NAS1-11855
Distribution Limits
Public
Copyright
Other