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ndltd-OhioLink-oai-etd.ohiolink.edu-osu1208295003
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu12082950032021-08-03T05:53:34Z Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians Manzo, David Jason <p>In the Lower Silurian (Llandoverian) sequences of the southern Appalachians there are locally several clay layers that have been determined to be altered volcanic ash beds or K-bentonites. These clayey beds, which are referred to as the Thorn Hill K-bentonite Complex, form a distinct and important component in the successions in the easternmost southern Appalachian thrust belts. Surprisingly, these K-bentonites are very poorly known, having been overlooked, if not entirely disregarded, in the past.</p><p>Several new K-bentonite localities have been discovered in Georgia and Tennessee. Absence of volcanic ashes at many study sections suggests that these deposits are restricted to the easternmost thrust belts. New biostratigraphic information combined with sequence stratigraphy analysis indicates that the Thorn Hill K-bentonite Complex is in the upper part of the <i>D. kentuckyensis</i> Conodont Zone, and is early to middle Aeronian age. Absence of K-bentonites in the western thrust belts may be due to the fact that the ash-bearing interval is missing at a prominent sequence boundary.</p><p>Although the Taconic orogeny is thought to have occurred only in the Middle to Late Ordovician, the occurrence of Llandoverian K-bentonites provides evidence of orogenic activity in subduction zones, and that this orogeny extended into the Early Silurian. The volcanic eruption(s) could have been caused by a collision between an island arc or a microcontinent and Laurentia. Middle-Late Llandoverian K-bentonites are known also from Nova Scotia and northwestern Europe but various indications suggest that they had different source volcanoes.</p> 2002 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1208295003 http://rave.ohiolink.edu/etdc/view?acc_num=osu1208295003 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
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NDLTD
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| language |
English
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| sources |
NDLTD
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| author |
Manzo, David Jason
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| spellingShingle |
Manzo, David Jason
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| author_facet |
Manzo, David Jason
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| author_sort |
Manzo, David Jason
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| title |
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| title_short |
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| title_full |
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| title_fullStr |
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| title_full_unstemmed |
Distribution, age, and significance of lower silurian K-bentonites in the Southern Appalachians
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| title_sort |
distribution, age, and significance of lower silurian k-bentonites in the southern appalachians
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| publisher |
The Ohio State University / OhioLINK
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| publishDate |
2002
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| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1208295003
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| work_keys_str_mv |
AT manzodavidjason distributionageandsignificanceoflowersiluriankbentonitesinthesouthernappalachians
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| _version_ |
1719427254747922432
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