About MOCAAS

A Mars Orbital Catalog of Aqueous Alteration Signatures

This projects provides and maintains a global repository of aqueous minerals on Mars. The repository comes in various formats: databases, vectorial entries, and geographic map layers.

It was started in the early 2010s based on the orbital dataset of the OMEGA near-infrared imaging spectrometer and has since incorporated data from a similar instrument, CRISM.

Université Paris-Saclay - Institut d'Astrophysique Spatiale is responsible for the OMEGA instrument onboard the ESA Mars Express probe. JHU-APL is responsible for the CRISM instrument onboard the NASA Mars Reconnaissance Orbiter probe.




Accessing the database

Access to the standard database can be found here:
New - March 2024 ! The database (raster format) can now be visualized on JMARS:
Current database version: November 2023
 Currently, only the raster data are available. These are tiled, geo-referenced, geotiff files

Download database

The geotiff maps are separated according to the instrument used to map the aqueous minerals: OMEGA and CRISM. The native pixel size for OMEGA maps is 500 m, and 100 m for CRISM. Each map is color-coded according to mineral composition.
Maps cover non-polar latitudes of Mars (up to +/- 70°). Polar maps are also available (contact us for more information).
Aqueous mineral composition is provided in terms of "spectral-mineral" classes (see publication for details) and summarized here:

RED : Fe/Mg-rich phyllosilicates (clays)
GREEN: Poly hydrated and hydroxilated sulfate salts (or locally: zeolites)
BLUE: Mono hydrated sulfate salts
ORANGE: Carbonate salts (or locally: serpentine group phyllosilicates)
CYAN: Al-rich phyllosilicates (clays) and hydrated (opalized) silica

A more detailed version of the database is available, including a higher resolution mineral database as well as refined mineralogical analyses on the global-scale data. Contact us for more information.

Citing the database

Please refer to the following publication when using this dataset :
A Mars orbital catalog of aqueous alteration signatures (MOCAAS), J. Carter et al., Icarus, 389, 115164 (2023) doi: 10.1016/j.icarus.2022.115164





High resolution local maps

High resolution maps are available for select sites of interest. These are sampled at 10m/pix and use map-projected data from CRISM targeted and multispectral products. Note that georeferencing errors in the data geometry files do not make the maps suitable to pinpoint mineral detections at the meter scale, subsequent corrections are required to acheive this.
// Click on the images to download the raster bundles \\

Gale crater - Mt. Sharp

Nili Fossae - Jezero crater

Oxia Planum

Mawrth Vallis



Contribute

Do you want to help us improve this database ? Become part of the MOCAAS project ! Contact us for more information.





Future prospects

New versions of the database are foreseen, as well as new interfaces:

  • Yearly updates of the OMEGA and CRISM based datasets
  • Incorporate the anhydrous salt detections based on the TES (MGS) and THEMIS (ODY) instruments
  • A new portal for contributors to suggest new mineral deposits or alter the existing database (similar to the HiRISE HiWish interface)


    • Contact information

    John Carter
    IAS, Bat 121, Paris-Sud University, 91405 Orsay, France
    john.carter@ias.u-psud.fr