Comet strike may have triggered ancient warming event, suggests research

Representational image. Reuters[/caption]Sorting through samples of sediment from the time period, researchers discovered evidence of the strike in the form of microtektites — tiny dark glassy spheres typically formed by extraterrestrial impacts."This tells us that there was an extraterrestrial impact at the time this sediment was deposited — a space rock hit the planet," said corresponding author Morgan Schaller, Assistant Professor at Rensselaer Polytechnic Institute in New York."The coincidence of an impact with a major climate change is nothing short of remarkable," Schaller said.In recent years, PETM has become a major point of interest for scientists as it is perhaps the best past analogue to understand impacts of global climate warming today.Even so, the cause of this warming event remains a mystery. Among the suggested drivers of the observed massive injection of carbon into the atmosphere that occurred at this time are the intrusion of flood basalts into carbon-rich marine sediments, carbon degassing from volcanos, and an extraterrestrial impact on Earth.By studying sections of marine shelf on the Atlantic Coastal Plain associated with the Paleocene-Eocene boundary, the researchers reported in the journal, Science, the discovery of silicate glass spherules with distinctive morphologies and micro-craters.Based on their features, the authors said, these glass spherules are best interpreted as terrestrial debris ejected during a meteorite impact."A comet impact on its own may have contributed carbon to the atmosphere, but is too small to explain the whole event and more likely acts as a trigger for additional carbon releases from other sources," Schaller said.