Mercury is resplendent with flooded impact craters and basins, and Tolstoj can be counted among them. This image shows a portion of that basin's flooded floor, and highlights a good example of the Law of Superposition. The crater to the left clearly post-dates the lava within Tolstoj, as it appears fresh, unfilled, and its ejecta sits atop the surrounding smooth volcanic plains. Yet the crater to the right is barely visible, with only its rim escaping burial by those same volcanic plains. These observations indicate that the crater on the right was formed after the Tolstoj basin, but before the basin was flooded by volcanic material. Finally, the crater on the left formed. A classic Mercurian one-two!
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 250-meter/pixel (820 feet/pixel) morphology base map or the 1-kilometer/pixel (0.6 miles/pixel) color base map. It is not possible to cover all of Mercury's surface at this high resolution during MESSENGER's one-year mission, but several areas of high scientific interest are generally imaged in this mode each week.
Date acquired: October 10, 2012
Image Mission Elapsed Time (MET): 258339504
Image ID: 2737706
Instrument: Narrow Angle Camera (NAC) of the Mercury Dual Imaging System (MDIS)
Center Latitude: -13.7°
Center Longitude: 196.3° E
Resolution: 100 meters/pixel
Scale: The crater just left of center is 25 km (16 mi.) in diameter.
Incidence Angle: 67.4°
Emission Angle: 37.9°
Phase Angle: 105.3°
North is down 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. Visit the Why Mercury? section of this website to learn more about the key science questions that the MESSENGER mission is addressing. During the one-year primary mission, MDIS acquired 88,746 images and extensive other data sets. MESSENGER is now in a year-long extended mission, during which plans call for the acquisition of more than 80,000 additional images to support MESSENGER's science goals.
For information regarding the use of images, see the MESSENGER image use policy.