| Abstract: | The Fire Clay tonstein is a kaolinized, airfall volcanic ash bed that was deposited in a widespread late Carboniferous peat-forming mire. Eleven samples from Kentucky and West Virginia, spanning a distance of 200km, and two samples from Tennessee and Virginia indicate a characteristic mineralogical signature. A high-silica alkalic rhyolitic source is suggested by the geochemistry of immobile elements and by electron-probe analyses of glass inclusions. 40Ar/39Ar sanidine plateau dating indicates an age of 312??1 Ma for the Fire Clay tonstein, which is consistent with previous 40Ar/39Ar dates for this tonstein. A new isopachous map of the Fire Clay ash-fall deposit indicates an area of 37 000km2 and a probable source to the present-day southwest. -from Authors |
| Genre: | Article |
| ProdID: | 70016921 |
| Citation Author: | Lyons, P. C. |
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| Citation End Page: | 1527 |
| Citation Issue: | 11 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geological Society of America Bulletin |
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| Citation Number Of Pages: | 13 |
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| Citation Search Results Text: | An Appalachian isochron: a kaolinized Carboniferous air-fall volcanic-ash deposit (tonstein); 1992; Article; Journal; Geological Society of America Bulletin; Lyons, P. C. |
| Citation Start Page: | 1515 |
| Citation Volume: | 104 |
| Citation Year: | 1992 |
| Type: | citation/reference |
| Text: | An Appalachian isochron: a kaolinized Carboniferous air-fall volcanic-ash deposit (tonstein); 1992; Article; Journal; Geological Society of America Bulletin; Lyons, P. C. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Wed, 1 Jan 1992 00:00 -0600 |
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