Geochemical evidence for a comet shower in the late Eocene
Analyses of pelagic limestones indicate that the flux of extraterrestrial helium-3 to Earth was increased for a 2.5-million year (My) period in the late Eocene. The enhancement began ~1 My before and ended ~1.5 My after the major impact events that produced the large Popigai and Chesapeake Bay craters ~36 million years ago. The correlation between increased concentrations of helium-3, a tracer of fine-grained interplanetary dust, and large impacts indicates that the abundance of Earth-crossing objects and dustiness in the inner solar system were simultaneously but only briefly enhanced. These observations provide evidence for a comet shower triggered by an impulsive perturbation of the Oort cloud.
Citation Information
Publication Year | 1998 |
---|---|
Title | Geochemical evidence for a comet shower in the late Eocene |
DOI | 10.1126/science.280.5367.1250 |
Authors | K.A. Farley, A. Montanari, E.M. Shoemaker, C.S. Shoemaker |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Science |
Index ID | 70020477 |
Record Source | USGS Publications Warehouse |