Relative dating cratering distribution
Cartoon strip of the formation of impact craters and, subsequently, secondary craters.
From left to right, shows the timeline of a mass impacting a body, ejecta propagating from the initial impact, shock wave motion and the resulting cratered surface.
We discuss the conversion of production function polynomials between common presentations, and the statistical uncertainty of the determined ages with respect to the non-linear chronology function, and a minor refinement of data binning.
] One of the major goals of planetary exploration is to determine the surface histories of the solid planets and satellites.
In practice, this procedure requires an accurate assessment of the initial abundances of the isotopes produced in the radioactive decay.
The problem becomes intricate if more than one event that affected the radiogenic isotope systems has occurred during the evolution of the rock.
We describe the procedure to fit a cumulative production function polynomial to a partial crater size–frequency distribution.
The oldest terrestrial rocks, found in the Precambrian shield of Greenland, are about 3.8 billion years old. The youngest extensive stratigraphic units dated by isotopic methods are the mare basalts, which range in age from about 3.3 to 3.8 billion years.
SECONDARY CRATERING: AGE-DATING Secondary cratering may be important or dominant for forming smaller craters on Mars.
If so, then the presumption of randomness (spatially/temporally) is wrong, undercutting long used methods of relative and absolute age-dating of geologic units on Mars.
The crater density is expected to be maximum at the apex of the orbital motion and decrease with the increase of the angular distance from the apex.
The ratio of the density at the apex (maximum) to that of the antapex (minimum) depends on the average encounter velocity of impactors to the satellite.