U-Pb Analyses of Zircons from the Popigai Impact Structure, Russia: First Results

Abstract

Zircons were extracted from impact melt rock samples from the 35.7 Ma Popigai impact structure in Russia. U-Pb SHRIMP age dating of four zircons resulted in ages of 1982 Ma for two of the zircons and younger ages for the other two grains. Minimum age estimates of the younger grains can be derived from their 912 and 306 Ma 207Pb / 206Pb ages. No shock features are obvious in these grains; thus, the Pb loss could be recent. The older ages represent ages of zircon derived from the target lithology. No evidence for resetting of the isotopic system at 35 Ma in the zircons was found in this pilot study.