EAGER: A Test for the Younger Dryas Impact Hypothesis

Harvard University, Cambridge MA

Investigators

Abstract

This award provides funds, under the auspices of the EArly-concept Grants for Exploratory Research (EAGER) program, to investigate whether a bolide impact occurred at the beginning of the Younger Dryas (approximately 12,900-11,500 years ago) thereby bringing about dramatic climatic change. The research team plans to accomplish this science goal by measuring iridium concentrations in the Greenland Ice Sheet Project Two (GISP2) ice core across the Allerød-Younger Dryas boundary. The researchers argue that, as with other impact studies, anomalously high iridium concentrations are an indicator of a major bolide impact and that the ice core analyses should provides a continuous, well-documented, and well-preserved stratigraphic sequence in which to search for an anomaly. They estimate that an impact of the currently hypothesized magnitude would have produced an iridium signal between 200 and 130,000 times the background iridium level due to the continuous accumulation of terrestrial and cosmic dust. As such, the researchers postulate that their analyses will be a definitive test of the impact. The research could have broad impact on the wider science community by catalyzing new scientific thinking about the existing scientific theory that a bolide impact was a contributory cause of abrupt climatic change at the Younger Dryas boundary. The planned activities fit well into the potentially transformative, high risk, and exploratory nature of the EAGER programs.