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U.S. Department of Energy
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Calcareous nannofossil biostratigraphy of Chititu Formation, Wrangellia terrane, Alaska

Conference ·
OSTI ID:6082366

The tectonostratigraphic terrane (suspect terrane) concept has been a major catalyst in attempts to unravel the complex tectonic history of Alaska. Paleomagnetic work has suggested that the Wrangellia terrane in south-central Alaska had a paleolatitude of 32/sup 0/N +- 9/sup 0/ in the Late Cretaceous, but was accreted to North America prior to the Eocene. A plate velocity of at least 24 cm/yr is implied by this latitude and time framework. If confirmed, this velocity is one of the fastest plate velocities yet established. Calcareous nannofossils from the Chititu Formation, Wrangellia terrane, have been investigated in order to provide a refined biostratigraphic framework for establishing the age of paleolatitudes determined for the Chititu. Thirty-one species of nannofossils were identified in a section of the Chititu measured on MacColl Ridge. These species allow assignment of the section to the internationally recognized Reinhardtites anthophorus (CC 15: late early to late Santonian) and Lucianorhabdus cayeuxii (CC 16: late Santonian to earliest Campanian) biozones. Calcareous nannofossils clearly have potential for use in age determinations in Wrangellia and other Alaskan tectonostratigraphic terranes with suitable marine sedimentary sections.

OSTI ID:
6082366
Report Number(s):
CONF-880301-
Country of Publication:
United States
Language:
English