Interpreting the cratering record: Mercury to Ganymede and Callisto
1982
The large-crater populations on the terrestrial planets differ markedly
from those on the Galilean satellites. On the densely cratered terrains of
Mercury, Mars, and the Moon, the crater populations > 8 km diameter
bear fundamental similarities to one another. These similarities encompass
both the shape of their crater curves (i.e., their size-frequency
distribution functions) and their overall crater densities. We argue that
these similarities reflect the attributes of the ancient impacting
population and are not, as sometimes hypothesized, the result of crater
saturation. The densely cratered terrains of Ganymede and Callisto, and
the grooved terrains of Ganymede, have some similarities with each
other but bear few common attributes with those on the terrestrial
planets. Some of the differences between the crater populations on
Ganymede and Callisto apparently result from differences in the
physical states of their icy crusts during and soon after the period of
late heavy bombardment. The emplacement of the grooved terrain
clearly altered the young crater population on Ganymede, and some
evidence exists that a similar alteration of the most ancient crater
population also occurred. We are unable to reconcile the observed
crater populations on Ganymede and Callisto (modified by any of the
proposed mechanisms) with an initial population similar to that of the
terrestrial plants, suggesting that a different reservoir of impacting
bodies cratered surfaces in the inner and outer solar system. Devolving
from this interpretation are constraints on the origins of both of the
impacting populations and strong cautions about extrapolating time
scales derived from the lunar cratering record to the Galilean satellites.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
0
References
37
Citations
NaN
KQI