About this image
This THEMIS visible image illustrates the complex terrains within Terra Meridiani. This general region is one of the more complex on Mars, with a rich array of sedimentary, volcanic, and impact surfaces that span a wide range of martian history. This image lies at the eastern edge of a unique geologic unit that was discovered by the Mars Global Surveyor Thermal Emission Spectrometer (TES) Science Team to have high concentrations of a unique mineral called grey (crystalline) hematite. As discussed by the TES Science Team, this mineral typically forms by processes associated with water, and this region appears to have undergone alteration by hydrothermal (hot water) or other water-related processes. As a result of this evidence for water activity, this region was selected for further exploration by Opportunity, one of NASA's Mars Exploration Rovers. The brightness and texture of the surface varies remarkably throughout this image. These differences are associated with different rock layers or units, and can be used to map the occurrence of these layers. The number of layers indicates that extensive deposition by volcanic and sedimentary processes has occurred in this region. Since that time, however, extensive erosion has occurred to produce the patchwork of different layers exposed across the surface. Several distinct layers can be seen within the ~20 km diameter crater at the bottom (south) of the image, indicating that this crater once contained layers of sedimentary material that has since been removed. THEMIS infrared images of this region show that many of these rock layers have distinctly different temperatures, indicating that the physical properties vary from layer to layer. These differences suggest that the environment and the conditions under which these layers were deposited or solidified varied through time as these layers were formed. UPDATE: Opportunity successfully landed and has spent over a year investigating the Meridiani region. As TES had indicated with the discovery of hemitite, this region does contain numerous minerals that, on Earth, form in a water rich environment.
Please see the THEMIS Data Citation Note for details on crediting THEMIS images.