A series of troughs extends diagonally (southwest-northeast) across this high-resolution image of the interior of the Caloris basin. The troughs are graben: structures that developed where horizontal forces pulled the crust apart, causing valleys to form as sections of rock dropped down between two inward-dipping faults. Pulling-apart ("extensional") deformation is much less common on Mercury than is compressional deformation. However, a large number of graben are found within Caloris. This network of graben, named Pantheon Fossae, is the subject of a blog essay recently posted on the website of The Planetary Society.

This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.

Date acquired: January 19, 2012
Image Mission Elapsed Time (MET): 235472082
Image ID: 1285755
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: 27.3°
Center Longitude: 160.7° E
Resolution: 24 meters/pixel
Scale: The scene is about 43 km (27 mi.) across
Incidence Angle: 76.8°
Emission Angle: 54.9°
Phase Angle: 131.8°
North is up in this image.

The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. MESSENGER acquired over 150,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.

For information regarding the use of images, see the MESSENGER image use policy.