| Abstract: | 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. |
| Genre: | Article |
| ProdID: | 70020477 |
| Citation Author: | Farley, K. A.; Montanari, A.; Shoemaker, E. M.; Shoemaker, C. S. |
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| Citation End Page: | 1253 |
| Citation Issue: | 5367 |
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| Citation Language: | English |
| Citation Larger Work Title: | Science |
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| Citation Number Of Pages: | 4 |
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| Citation Search Results Text: | Geochemical evidence for a comet shower in the late Eocene; 1998; Article; Journal; Science; Farley, K. A.; Montanari, A.; Shoemaker, E. M.; Shoemaker, C. S. |
| Citation Start Page: | 1250 |
| Citation Volume: | 280 |
| Citation Year: | 1998 |
| Type: | citation/reference |
| Text: | Geochemical evidence for a comet shower in the late Eocene; 1998; Article; Journal; Science; Farley, K. A.; Montanari, A.; Shoemaker, E. M.; Shoemaker, C. S. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1126/science.280.5367.1250 |
| Date Other: | Thu, 1 Jan 1998 00:00 -0600 |
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