These scientists have identified three contemporaneous levels more than 12,000 years ago, on two continents yielding siliceous scoria-like objects (SLO’s),” said H. Richard Lane, program director of National Science Foundation’s Division of Earth Sciences, which funded the research.
“SLO’s are indicative of high-energy cosmic airbursts/impacts, bolstering the contention that these events induced the beginning of the Younger Dryas. That time was a major departure in biotic, human and climate history.
The cause of the Younger Dryas cooling period has been very controversial. Some researchers have proposed an extraterrestrial impact and have produced evidence of the event, but others claim that the results have not been replicated. The new findings, reported this week in the Proceedings of the National Academy of Sciences, appear to provide that needed replication. — Thomas H. Maugh II, LA Times