N/W Melas Chasma (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

This HiRISE image covers a portion of the Wallrock and Canyon Floor in South-Western Melas Chasma.

Along the Floor of Melas Chasma is an unusual Blocky Deposit composed of light-toned Blocks in a darker matrix. The HR provided by the HiRISE camera reveals Layers only a few meters thick in some of the light-toned Blocks. The Blocks vary in size but most fall between approx. 100 up to 500 mts in diameter. Although most Blocks appear rounded, others have angular edges and can be very elongate. The morphologies of the Blocks suggest ductile deformation, such as from a flow or by tectonic disruption after emplacement. Aeolian Ripples are interspersed between the Blocks in the darker Matrix.

Small valleys can be seen along the Wallrock. The Wallrock is a mixture of two geologic units that differ mainly in their reflectance. The light-toned unit appears to be thinner and only exposed in localized spots. Several of the light-toned Deposits are seen only in the Valleys, suggesting they were either deposited or are exposed by erosion.