Granicus Valles and Tinjar Valles
This image, taken by the High Resolution Stereo Camera (HRSC) on board Mars Express, shows the region of Granicus Valles and Tinjar Valles. The HRSC obtained this image during orbit 1383 at a ground resolution of approximately 23.7 metres per pixel. The image is centred at 26.8° N and 135.7° E and has been rotated 90 degrees counter-clockwise, so that north is to the left.
The northwest-aligned Granicus Valles and Tinjar Valles may have been formed partly through the action of subsurface water, due to a process known as sapping. The two valleys are part of the Utopia-Planitia region, an area thought to be covered by a layer of lava that flowed from the northwest flanks of Elysium Mons into the Utopia-Planitia Basin.
Elysium Mons lies southeast of the imaged region and is the largest volcano on the Elysium Planitia, the second largest volcanic region on Mars after the Tharsis region. The large volcano rises 12.5 kilometres above the surrounding plain.
Today, the once-smooth volcanic plain is incised by channels of variable size and appearance, including Granicus Valles (towards the southwest) and Tinjar Valles (towards the north). Both channel systems evolve from a single main channel entering the image scene from southeast (upper right). The impressive sinuous lava channel emanates from the mouth of a circular drainage area, and runs to the Elysium rise trending into a graben (terrain dissected by tectonic deformation).
This narrow, straight, 4-km wide and 120-km long graben is interpreted as the source of both lava flows and debris flows that carved Granicus and Tinjar Valles. Similar Elysium flank grabens at higher elevations lack outflow channels. This elevation dependence leads scientists to suggest that subsurface water, released by volcanic activity, has later played a role in shaping the channels visible today.
The colour scene was derived from the three HRSC-colour channels and the nadir channel. Image resolution has been decreased for use on the internet.
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 IGO License.