Gibran (crater)
Encyclopedia
Gibran is a crater
on Mercury
, which was discovered in January 2008 during the first flyby of the planet by MESSENGER
spacecraft. It contains a large , nearly circular pit crater. Multiple examples of pit craters have been observed on Mercury on the floors of impact craters, leading to the name pit-floor craters for the impact structures that host these features. Unlike impact crater
s, pit craters are rimless, often irregularly shaped, steep-sided, and often display no associated ejecta or lava flows. These pit craters are thought to be evidence of shallow volcanic activity and may have formed when retreating magma caused an unsupported area of the surface to collapse, creating a pit. They are analogs of Earth's volcanic caldera
s. Pit-floor craters may provide an indication of internal igneous processes where other evidence of volcanic processes is absent or ambiguous. The discovery of multiple pit-floor craters augments evidence that volcanic activity has been a widespread process in the geologic evolution of Mercury's crust.
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
on Mercury
Mercury (planet)
Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
, which was discovered in January 2008 during the first flyby of the planet by MESSENGER
MESSENGER
The MErcury Surface, Space ENvironment, GEochemistry and Ranging space probe is a robotic NASA spacecraft in orbit around the planet Mercury. The spacecraft was launched aboard a Delta II rocket in August 2004 to study the chemical composition, geology, and magnetic field of Mercury...
spacecraft. It contains a large , nearly circular pit crater. Multiple examples of pit craters have been observed on Mercury on the floors of impact craters, leading to the name pit-floor craters for the impact structures that host these features. Unlike impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
s, pit craters are rimless, often irregularly shaped, steep-sided, and often display no associated ejecta or lava flows. These pit craters are thought to be evidence of shallow volcanic activity and may have formed when retreating magma caused an unsupported area of the surface to collapse, creating a pit. They are analogs of Earth's volcanic caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
s. Pit-floor craters may provide an indication of internal igneous processes where other evidence of volcanic processes is absent or ambiguous. The discovery of multiple pit-floor craters augments evidence that volcanic activity has been a widespread process in the geologic evolution of Mercury's crust.