Current Research Interests

Mössbauer spectroscopy of Martian and Mars-analog minerals -

The MER Athena spacecraft are still collecting Mössbauer spectra of the surface of Mars, even after two years on the surface. These spectra are being analyzed and used to constrain mineralogy and evolution of the surface of Mars, and to look for evidence of water.

To properly analyze these Martian spectra, Mössbauer spectra of terrestrial materials at a range of temperatures are being collected and analyzed, using a Mössbauer spectrometer at Mount Holyoke College in Massachusetts. These data are publicly available at http://www.mtholyoke.edu/courses/mdyar/marsmins/.

Error analyses of Mössbauer spectra fitting and comparison between different Mössbauer spectral fitting programs -

Mössbauer spectra are being used to constrain and sometimes even identify minerals on Mars. To do this it is vital to understand the sources of error involved, so that meaningful confidence levels can be placed on interpretations. In addition, information on how spectra analyzed with different Mössbauer spectral analysis programs is not currently available, and I am currently collecting such data.

Selected Publications

Velocity scales for Mars Mössbauer data, David G. Agresti, M. Darby Dyar, and Martha W. Schaefer, Hyperfine Interactions (2006) in press.

Mössbauer spectroscopy of Earth and planetary materials , M. D. Dyar, D. G. Agresti, M. W. Schaefer, C. A. Grant, and E. C. Sklute, Annual Reviews of Earth and Planetary Science (2006).

Mössbauer spectroscopy of Mars-analog rocks from an acid saline sedimentary environment, M. W. Schaefer, M. D. Dyar, and K. C. Benson, LPSC XXXIV, abs. #1690 (2003).

Mineral Spectroscopy: A Tribute to Roger G. Burns, Geochemical Society Special Publication No. 5, eds. M. D. Dyar, M. W. Schaefer, and C. McCammon, (1996).

Worlds Apart, A Textbook in Planetary Sciences, G. J. Consolmagno, S. J., M. W. Schaefer, Prentice-Hall, Englewood Cliffs, NJ, 323 pp. (1994).