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Reference
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| Title: |
New occurrences of Late Paleozoic and Triassic fossils from the Seventymile and Yukon-Tanana terranes, east-central Alaska, with comments on previously published occurrences in the same area
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2003
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Abstract - The discovery of several new fossil occurrences of late Paleozoic conodonts and radiolarians in the Seventymile and Yukon-Tanana terranes, and of Late Triassic conodonts in the Seventymile terrane in east-central Alaska, has prompted a reevaluation of other late Paleozoic and Triassic fossils reported in the same areas. The report, in 1995, of giant parafusulinids in the Seventymile terrane within the same stratigraphic interval that more than 20 years before produced poorly preserved Permian brachiopods helped place these beds in the middle Guadalupian and to position the terrane at tropical to subtropical latitudes near ancestral North America during the Middle Permian. ..... |
| Report by: |
Cynthia Dusel-Bacon
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Anita G. Harris
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| | Age: | Carnian-Norian (latest Carnian - earliest Norian) |
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| Comment: | Another late Carnian or early Norian conodont locality lies 11 km southeast of the Lead Creek site (loc. 2, fig. 3; table 1; Foster and others, p. 1994, p. 231) and within the greenstone unit of the Seventymile terrane. This locality yielded Metpolygnathus primitius (T.R. Carr, written commun. to H.L. Foster, U.S. Geological Survey, 1985), a latest Carnian and earliest Norian species that is only slightly older than the youngest conodont Epigondolella quadrata) from the Lead Creek core (fig. 4). (from p. 11) Terrane assignment, map unit, and sample lithology: Seventymile terrane. Unit Pzq of Foster (1976); mainly greenstone but includes chert, phyllite, and quartzite. Conodonts are from carbonate within unit. (from p. 12) Age: M. primitius Zone (latest Carnian and earliest Norian); see figure 4 for conodont zonation age range of M. primitius. (from p. 12) Shown as fossil locality 2 on Figure 3. |
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