One of the most famous terrestrial impact craters is the "Barringer Crater" also known as the "Meteor Crater" in Arizona (USA) (Fig. 1). It has a diameter of 1.186 km and an age of 49,000 years. Other terrestrial craters can be found for example in Mexico (Chicxulub Crater), in Africa (Aorounga Crater, Roter Kamm Crater), in Canada (e.g. Manicouagan Crater, Clearwater Lakes, Deep Bay), and in Australia (Gosses Bluff) [Pilkington & Grieve, 1992; www.solarviews.com/eng/tercrate.htm ].
Like other bodies with a solid surface but without a thick protecting atmosphere and efficient erosion processes, Mars is blotched by innumerable impact craters of various sizes and shapes. Crater diameters predominantly depend on impact energy, whereas the type and morphology of a crater may also be determined by the substrate [Carr et al., 1977]. Most of the Martian craters can be found in the ancient terrains of the southern highlands. Fig. 2 presents a relative young and fresh impact crater in Utopia Planitia on Mars.
The crater size-frequency distribution can be used as an age-dating technique for geological surfaces [Neukum, 1983]. The basic concept is that older surfaces exhibit a large number of huge impact craters, whereas younger surfaces are dominated by small impact craters. Large craters are few or lacking entirely because the abundance of big projectiles declined as the age of the universe increased. The surfaces on Mars have been dated by this technique [Hartmann and Neukum, 2001].
Last update: 09/06/2010 10:42
