| Abstract: | For many years the numerous deposits of so-called ‘Pearlette volcanic ash‘ in the Great Plains region of the United States were considered to be the remnants of the same volcanic event, and were used as a time-stratigraphic marker of probable Middle Pleistocene age. Although a few early workers had suggested that more than one air-fall event might be represented among the Pearlette occurrences, it was not until the latter half of the present century, after identification of volcanic ash beds by detailed chemical and mineralogical methods had been developed, that it could be established that the ‘Pearlette family‘ of volcanic ashes included three ash beds of subtly differing characteristics. Development of isotopic methods of age determination has established that the ages of the three are significantly different (2.09, 1.29, and 0.60 Ma). The area of distribution of the Pearlette family ash beds was found to include not only the Great Plains, but also to extend across the Rocky Mountain and the Basin and Range provinces to the Pacific Ocean. The search for the sources of these three similar appearing ash beds, facilitated greatly by information gained from concurrent mapping projects underway in areas of major Late Cenozoic volcanic activity in western United States, ultimately led to the sites of the caldera-forming eruptions in the Yellowstone National Park region. ?? 1992. |
| Genre: | Article |
| ProdID: | 70016928 |
| Citation Author: | Wilcox, R. E.; Naeser, C. W. |
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| Citation End Page: | 13 |
| Citation Issue: | C |
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| Citation Language: | English |
| Citation Larger Work Title: | Quaternary International |
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| Citation Number Of Pages: | 5 |
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| Citation Publisher: | Elsevier |
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| Citation Search Results Text: | The Pearlette family ash beds in the Great Plains: Finding their identities and their roots in the Yellowstone country; 1992; Article; Journal; Quaternary International; Wilcox, R. E.; Naeser, C. W. |
| Citation Start Page: | 9 |
| Citation Volume: | 13-14 |
| Citation Year: | 1992 |
| Type: | citation/reference |
| Text: | The Pearlette family ash beds in the Great Plains: Finding their identities and their roots in the Yellowstone country; 1992; Article; Journal; Quaternary International; Wilcox, R. E.; Naeser, C. W. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/1040-6182(92)90003-K |
| Date Other: | Wed, 1 Jan 1992 00:00 -0600 |
| Publisher: | Elsevier |
