mascons


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mascons

(mas -konz) Short for mass concentrations. Positive gravitational anomalies associated with the young circular lunar maria, where relatively dense disk-shaped masses are now known to be located close to the surface: because the gravitational attraction is somewhat higher over these regions, mascons perturb the orbits of lunar satellites. They were produced either by the mare basalt itself as it flooded the basins or by the uplifting of higher-density mantle material during basin excavation. Mascons imply the existence of a rigid lunar crust for at least 3000 million years. The removal of crust during crater formation may also produce negative gravitational anomalies; these are observed in the younger large craters and around the Orientale Basin, which is only partly lava-filled. Because the circular maria are topographic lows, mascons may be partially isostatically compensated, i.e. they may have sunk under their excess density until some sort of equilibrium depth was reached with relation to adjacent material.
References in periodicals archive ?
The Aestuum mascon is more pronounced than Vaporum's, perhaps indicating a thicker lava filling.
GRAIL scientists found the mascons by combining the gravity data from
By eradicating the line between fact and fiction, particular drugs called Mascons have eroded any possibilities for sustaining the environment as well as for supporting the natural and creative mind.
Some computer models suggest that the combined stresses from this and the mascon could produce the strange radial ridge patterns we see.
Computations by Jet Propulsion Laboratory geophysicists suggest that the mascon can be explained by a dense layer 10 to 20 km thick somewhere between 3 and 50 km deep.
All previously known mascons are near-side impact basins topped with mare basalts several kilometers thick (presumably representing the excess mass).