During the September 1988 Mars opposition, we obtained new high spatial (100--150 km) and spectral (Δλ/λ=1%) resolution near-IR telescopic charge-coupled device images of Mars from Pic-du-Midi Observatory. These images allow the association of spectral units with morphologic surface units on Mars, especially within the dark regions which exhibit much greater variability than the bright regions. Mineralogical interpretation of the data leads to a global description of the surface state of alteration consistent with the spatial distribution of bright and dark regions, with the bright regions being more altered than the dark. Within the less altered regions, Fe2+ crystal field absorption bands are detected, indicative of the presence of mafic minerals (Opx, Cpx, Ol) in agreement with a likely crustal basaltic composition. The most conspicuous Fe2+ absorption features are clearly related to the volcanic regions of the Syrtis Major Shield and Hesperia Planum unit. The strongest observed absorptions due to olivine and clinopyroxene are spatially associated with the restricted central caldera complex of Nili-Meroe Paterae (within Syrtis Major) and the Tyrrhena Patera unit (within Hesperia Planum) and indicate an ultramafic composition. ¿ American Geophysical Union 1990