Link established between meteorite impact and massive volcanism 30 mln yrs ago

Washington, Jan 8 (ANI): In a new research, scientists have discovered the second example of a meteorite impact that occurred at the same time as massive volcanic activity 30 million years ago in Belarus.

The first time such a coincidence was observed, at the Cretaceous-Tertiary boundary, was the catastrophic event thought to be responsible for the extinction of the dinosaurs, 65 million years ago.

This new event, uncovered after the 17 km diameter Logoisk impact structure in Belarus was precisely dated, is thought to have taken place around 30 million years ago.

The crater was dated using argon isotopes, and found to have occurred at a similar time to a period of massive volcanism known as the Afro-Arabian flood volcanism, which started in NW Yemen at around 30.9 Mya (million years ago), and SW Yemen at around 29.0 Mya.

The impact also coincides broadly with a period of sudden global cooling and sea level fluctuation.

The researchers, led by Sarah Sherlock at the Open University, argue that massive volcanic eruptions and meteorite impacts are likely to have coincided much more frequently than has previously been thought, but because the preservation of impact craters on Earth is poor much of the evidence for these coincidences is lost.

Prior to the study, only one example of an impact coinciding with volcanism had been found: the Chicxulub and Boltysh impacts and the Deccan Traps flood volcanism, all of which occurred at the Cretaceous-Tertiary boundary.

Unlike the Cretaceous-Tertiary event, the combination of the Logoisk impact and the Afro-Arabain flood volcanism does not seem to have caused an extinction event.

The researchers suggest that the reason for this may be that the magnitude of the event was not sufficiently large in comparison.

While the Cretaceous-Tertiary event saw the release of around 8000 billion tons of SO2 by the volcanism and meteorite impact, the Logoisk impact and the Afro-Arabian volcanism are thought to have contributed only 30 billion tons of SO2.

Meteorite impact craters are extremely difficult to date, but an understanding of their age and frequency is crucial to attempts to control the number of future impacts, as well as understanding the links between impacts and other catastrophic events such as large volcanic eruptions and mass extinctions. (ANI)