H2O- and OH-bearing minerals in the martian regolith: Analysis of 1997 observations from HST/NICMOS

E. Z.Noe Dobrea, J. F. Bell, M. J. Wolff, K. D. Gordon

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We have analyzed observations of the Acidalia hemisphere of Mars taken by the Hubble Space Telescope's Near-Infrared Camera Multi-Object Spectrograph (HST/NICMOS) during July of 1997 (Ls = 152°, northern martian summer). The data consist of images at ∼ 60 km/pixel resolution, using both narrow-and medium-band filters specifically selected to allow us to study the hydration state of the martian surface. Calibration was performed by comparison to Phobos-2 ISM observations of overlapping regions, and atmospheric gas correction was performed by modeling the atmosphere for each pixel using a line-by-line radiative transfer code coupled with the MOLA altimetry data. Our results indicate the presence of at least three spectrally different large-scale (> 1000 km diameter) terrains corresponding to the dark regions of northern Acidalia, the southern hemisphere classical dark terrain, and the classical intermediate terrain adjacent to southern Acidalia. We also identified two other spectrally unique terrains, corresponding to the northern polar ice cap, and to the southern winter polar hood. Comparisons with mineral spectra indicate the possibility of different H2O- or OH-bearing (i.e., hydroxides and/or hydrates) minerals existing both in northern Acidalia and in the nearby intermediate albedo terrain. Hydrated minerals do not appear to be spectrally important components of the southern hemisphere dark terrains imaged by HST in 1997.

Original languageEnglish (US)
Pages (from-to)1-20
Number of pages20
Issue number1
StatePublished - Nov 2003
Externally publishedYes


  • Mars
  • Mineralogy
  • Spectroscopy
  • Surface

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'H2O- and OH-bearing minerals in the martian regolith: Analysis of 1997 observations from HST/NICMOS'. Together they form a unique fingerprint.

Cite this