Event stratigraphic in the Late Eocene, type section is at Massignano in Italy
Impact breccia from the Popigai crater
Impact melt rock from the Popigai crater
The Late Eocene - Early Eocene is a period of major change in the global Earth System, marked by a drastic cooling and the development of Antarctic ice sheets. The Late Eocene is also characterized by a high flux of fine and coarse extraterrestrial material on Earth; as attested by helium isotopic ratio measured in marine sediments and the presence of two almost coeval large (100 km) impact craters: Popigai in Siberia and Chesapeake bay offshore Maryland. Several layers of impact debris are known in Late Eocene sediments. One of them, the North American tektite layer most likely originates from the Chesapeake bay crater. The origin of the other layer(s) is still a matter of debate.
In the Summer of 1997, I participated in an international expedition which revisited the Popigai crater for the first time in 27 years, we were the first non-russian scientists to see this crater. The work carried out here is a follow up of this expedition. The petrography and geochemistry of a suite of impact melt rock collected during this expedition has been studied by my student Roald Tagle for his Masters Degree at the Museum fuer Naturkunde in Berlin. We are building up on this work and carrying on a detailed trace and platinum group element (PGE) analyses on the Popigai sample to characterize the type of impactor and learn about the distribution of PGE in the melt-rock. We are also comparing the Popigai impactites with the ejecta debris found in Late Eocene sediments to test if Popigai could be the source of the Ir-rich microtektite layer.
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Event stratigraphic in the Late Eocene, type section is at Massignano in Italy |
Impact breccia from the Popigai crater |
Impact melt rock from the Popigai crater |