MEX OMEGA Global Maps (DDRGM)

DDRGM – Global Maps

Instrument: Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité

PDS Data Set ID: MEX-M-OMEGA-5-DDR-GLOBAL-MAPS-V1.0

DOI: Mars Express DOI Overview Page

For more information about OMEGA DDRGM products, see the OMEGA Product EAICD.

The Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité (OMEGA) Global Maps (DDRGM) data products are high-level map products derived from observation data. The data set currently contains 8 global maps of the surface albedo and minerals on Mars. Together they constitute a unique atlas that will enable users to study the surface of Mars in a global context, providing an unparalleled view into its history and identifying regions of strong interest for future exploration.

The maps included are:

  • NIR Albedo Map: This is a near-infrared (NIR) 1.08 micrometer albedo map. Consistent with previous space and ground-based observations, it shows that the bright regions are localized in the northern hemisphere over the regions of Tharsis, Arabia Terra, and Elysium. In the southern highlands, the regions with the highest albedo are found over the Hellas basin and the region of Promethei.

  • Ferric Oxide Map: The identification of ferric oxide (Fe3+), the mineral phase of iron, is made by means of the 0.53 micrometer absorption band. Ferric oxides are both present within the bulk crust and lava outflows, and within the dust oxidized by alteration at the surface.

  • Dust Map: This map indicates the presence of ferric oxides in the form of nanoparticles (a few tens of nm in size), responsible for the red color of Mars. They are interpreted to be the result of a surface highly oxidizing alteration, dominated by an atmospheric interaction, without liquid water playing a role.

  • Hydrated Mineral Map: This map shows individual sites where hydrated minerals, formed only in the presence of water, were detected by MEX/OMEGA and MRO/CRISM instruments. More than ten different hydrous minerals have been found on Mars, with many occurrences found in the same site. The distribution of hydrated minerals shows that aqueous alteration began very early in Mars’ history, more than 4 Gyrs ago. Their presence shows that in its ancient history Mars has harbored at least transient habitable conditions, and this map indicates sites with well-preserved records of them.

  • Olivine Maps (3 maps): Olivine and pyroxene tell the story of volcanism, with differences in the chemical composition of the solidified lavas representing the evolution of the temperature and pressure inside the planet. Some of the most pristine olivines are found around impact craters that have excavated very ancient samples of the mantle from below the crust. Olivine has a broad, complex absorption centered near 1 micrometer that varies in width, position, and shape with grain size and Fo number. Three different spectral parameters are used to detect olivine with:

    • rich Mg content and/or small grain size and/or low abundance

    • high iron content and/or large grain size and/or high abundance

    • large Fe content and/or with large grain size and/or with high abundance

  • Pyroxene Map: The identification of pyroxene is made by means of the 2 micrometer absorption band. Like olivine, pyroxene results from volcanic processes that trace the evolution of the planet’s interior, its chemical composition acting as a tracer of the evolution of the temperature and pressure inside the planet. The widespread pyroxene-bearing terrains result from magmatic and volcanic processes, translating the evolution of Mars upper mantle and crust.

Reference for NIR Albedo, Ferric Oxide, Dust, Olivine, and Pyroxene maps: Ody et al., 2012, doi:10.1029/2012JE004117

Reference for Hydrated Mineral map: Carter et al., 2013, doi:10.1029/2012JE004145

OMEGA DDRGM products have the following file names:

ttt_ppp_MAP.IMG (with detached PDS label)

where:

ttt = map type

ALBEDO_R1080 = NIR Albedo

FERRIC_BD530 = Ferrix Oxide

FERRIC_NNPHS = Dust

HYDROUS_SITES = Hydrated Mineral

OLIVINE_OSP1 = Olivine 1

OLIVINE_OSP2 = Olivine 2

OLIVINE_OSP3 = Olivine 3

PYROXENE_BD2000 = Pyroxene

ppp = projection type

EQU = simple cylindrical

GEO = planetocentric

The hydrated mineral map product also includes a comma separated value map file, .CSV.

In ODE, DDRGM products have the following Product IDs:

TTT_PPP_MAP