Kamensk crater

Kamensk crater is an impact crater located 10 to 15 km to the nord of Kamensk-Shakhtinsky town in Rostov Oblast, Russia. It is 25 km in diameter and the age is estimated to be 49.0 ± 0.2 million years old (Eocene). The crater is not exposed at the surface. It may have formed at the same time as the smaller and nearby Gusev crater.

Description
Six laser total-fusion analyses of the Kamensk impact glass have a weighted-mean age of 49.2 ± 0.1 Ma relative to sanidine from the Taylor Creek Rhyolite of New Mexico, that has an age of 27.92 Ma relative to a K-Ar age of 162.9 ± 0 Ma for a primary fluence-monitor standard SB-3 biotite or of 513.9 Ma for an international hornblende standard MMhb-1. This isotopic age of the Kamensk glass recalculated using a reference age for MMhb-1 of 520.4 Ma is 49.9 ± 0.1 Ma.