Gassendi crater -- clue on the thermal history of Mare Humorum

July 06, 2006

This mosaic of two images, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows the inside of crater Gassendi on the Moon.

AMIE obtained these images on 13 January 2006, one minute apart from each other, from a distance of about 1220 kilometres (top frame) and 1196 kilometres (bottom frame) from the surface, with a ground resolution of 110 and 108 metres per pixel, respectively.

The area shown in the top image is centred at a latitude of 16.2º South and longitude 40.2º West, while the bottom images is centred at a latitude of 17.9º South and longitude 40.2º West.

Gassendi is an impact feature located on the near side of the Moon, at the northern edge of Mare Humorum. The crater is actually much larger than the field of view visible in this image. The hills on the lower right of the mosaic are the central peak of the crater, with a height of roughly 1.2 kilometres. The crater almost fully visible on the top is called 'Gassendi A'.

Gassendi is a scientifically interesting site because it offers lunar landers the possibility of sampling ancient highland rocks (in the crater's central peak) as well as providing ages for both the Humorum impact basin and the Gassendi crater itself. However, because the terrain just outside the crater is quite rough, if a crew landed in this region, it would be pretty difficult to reach Gassendi's central peaks for sampling. Gassendi was considered as one of the three potential sites for the Apollo 17 mission, that eventually touched ground in the Taurus-Littrow valley.

The age of Gassendi crater is estimated to be about 3.6 thousand million years (with an error of plus or minus 700 million years).

When observed through spectroscopic analysis, crater Gassendi presents a 'behaviour' very different from any other lunar crater (Mikhail 1979). High resolution studies performed in the near-infrared light (Chevrel and Pinet 1990, 1992) indicated the presence of extrusive volcanic material (that is volcanic material flowing out from the surface and then crystallising) limited to the southern portion of Gassendi's floor, which is adjacent to Mare Humorum.

The interpretation of these data suggested that the central part of the crater, including the peak complex, may have a more 'mafic' nature (that is a composition of rocks coming from the solidification of magma which are rich rich in iron and magnesium silicates, such as olivine and pyroxene), with a higher pyroxene component than surrounding highlands.

The data interpretation also suggested that extensive extrusive volcanism may have occurred within the eastern portion of the floor, as also indicated by the significant presence of pyroxene that also corresponds to visible volcanic features. The western part of the crater floor, away from the geometric continuation of the western edge of Mare Humorum, is composed of highlands-rich material.

The difference between the western and eastern side of the Gassendi floor-fractured crater may be strongly linked to the early thermal history of Mare Humorum.

The crater is named after Pierre Gassendi (1592-1655), French philosopher, scientist and mathematician. In 1631, Gassendi became the first person to observe the transit of a planet across the Sun, viewing the transit of Mercury which Kepler had predicted.

European Space Agency

Related Moon Articles from Brightsurf:

New mineral discovered in moon meteorite
The high-pressure mineral Donwilhelmsite, recently discovered in the lunar meteorite Oued Awlitis 001 from Apollo missions, is important for understanding the inner structure of the earth.

First measurements of radiation levels on the moon
In the current issue (25 September) of the prestigious journal Science Advances, Chinese and German scientists report for the first time on time-resolved measurements of the radiation on the moon.

Researchers develop dustbuster for the moon
A team led by the University of Colorado Boulder is pioneering a new solution to the problem of spring cleaning on the moon: Why not zap away the grime using a beam of electrons?

First global map of rockfalls on the Moon
A research team from ETH Zurich and the Max Planck Institute for Solar System Research in Göttingen counted over 136,000 rockfalls on the moon caused by asteroid impacts.

Going nuclear on the moon and Mars
It might sound like science fiction, but scientists are preparing to build colonies on the moon and, eventually, Mars.

Astronaut urine to build moon bases
The modules that the major space agencies plan to erect on the Moon could incorporate an element contributed by the human colonizers themselves: the urea in their pee.

How moon jellyfish get about
With their translucent bells, moon jellyfish (Aurelia aurita) move around the oceans in a very efficient way.

Does crime increase when the moon is full?
Noting that anecdotal beliefs can affect public policies and practices, a 'pracademics' team from NYU's Marron Institute of Urban Management worked with public safety personnel to examine the commonly held axiom that crime rises with the full moon -- and found that the evidence is just not there.

Soil on moon and Mars likely to support crops
Researchers at Wageningen University & Research in the Netherlands have produced crops in Mars and moon soil simulant developed by NASA.

Are we prepared for a new era of field geology on the moon and beyond?
Space agencies must invest more resources on field geology training of astronauts to take full advantage of scientific opportunities on the moon and other planetary bodies, Kip Hodges and Harrison Schmitt urge, in an Editorial.

Read More: Moon News and Moon Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to