| Abstract: | Palynologically defined Cretaceous-Tertiary boundary sites in nonmarine rocks in western North America exhibit similar characteristics. All are marked by abrupt disappearance of the regional uppermost Cretaceous palynoflora at the level of an iridium anomaly; most also yeild shock-metamorphosed minerals. All are in coal-bearing, fluvial or paludal depositional settings, although the boundary horizon may be below, within, above, or at some stratigraphic distance from coal seams. At many sites the lowermost Tertiary beds contain assemblages overwhelmed by fern spores that, together with extinctions of some groups of angiosperms, are taken as evidence of regional devastation of terrestrial plant communities and subsequent recolonization by pioneer species. ?? 1990. |
| Genre: | Article |
| ProdID: | 70016048 |
| Citation Author: | Nichols, D. J. |
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| Citation End Page: | 84 |
| Citation Issue: | 1-4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Review of Palaeobotany and Palynology |
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| Citation Number Of Pages: | 10 |
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| Citation Search Results Text: | Geologic and biostratigraphic framework of the non-marine Cretaceous-Tertiary boundary interval in western North America; 1990; Article; Journal; Review of Palaeobotany and Palynology; Nichols, D. J. |
| Citation Start Page: | 75 |
| Citation Volume: | 65 |
| Citation Year: | 1990 |
| Type: | citation/reference |
| Text: | Geologic and biostratigraphic framework of the non-marine Cretaceous-Tertiary boundary interval in western North America; 1990; Article; Journal; Review of Palaeobotany and Palynology; Nichols, D. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/0034-6667(90)90058-Q |
| Date Other: | Mon, 1 Jan 1990 00:00 -0600 |
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