Ages of Craters and Maria
The only lunar features whose absolute ages are known are those with samples that have been radiometrically analyzed on Earth. The resulting ages are quite accurate but sometimes the geologic event that produced the sample is uncertain.
Most ages are deduced from counting of impact craters that formed on features. These ages are uncertain in that secondary craters may have accidentally been counted, and more importantly, the crater counts are converted to an absolute age by the use of a crater production rate (CPR) that is not know with certainty. The rate has changed thru time (it was much higher before about 3.8 b.y. ago) and it may be different for craters of different diameters. The CPR is calibrated with ages of the handful of radiometric dated samples. The resulting calculated ages are called model ages. Unfortunately, there are different CPRs, resulting in different model ages for the same crater counts. Fortunately, most work no uses t
Most ages are deduced from counting of impact craters that formed on features. These ages are uncertain in that secondary craters may have accidentally been counted, and more importantly, the crater counts are converted to an absolute age by the use of a crater production rate (CPR) that is not know with certainty. The rate has changed thru time (it was much higher before about 3.8 b.y. ago) and it may be different for craters of different diameters. The CPR is calibrated with ages of the handful of radiometric dated samples. The resulting calculated ages are called model ages. Unfortunately, there are different CPRs, resulting in different model ages for the same crater counts. Fortunately, most work no uses t
Absolute Ages
North Ray Crater, Apollo 16
South Ray Crater, Apollo 16
Apollo 11 maria
Apollo 12 maria
Apollo 14 maria
Apollo 15 maria
Apollo 17 maria
Apollo 16 Cayley Plains
Apollo 16 Descartes Formation
Copernicus
Tycho
Imbrium Basin
Model Ages
| Lunar Crater |
Model Age, B.Y. |
Std Dev. B.Y. |
Feature Dated |
Reference |
| Vavilov |
1.7 |
0.1 |
original floor |
Kirchoff et al 2013 |
| Hayn |
1.8 |
0.4 |
original floor |
Kirchoff et al 2013 |
| Aristoteles |
2.7 |
0.8 |
floor |
Kirchoff et al 2013 |
| Theophilus |
3.0 |
0.6 |
original floor |
Kirchoff et al 2013 |
| Geminus |
3.2 |
0.4 |
original floor |
Kirchoff et al 2013 |
