A Late Devonian (Frasnian) Microbiota from the Farewell-Lyman Hills Area, West-central Alaska: Issue 1216, Part 1

Bernard L. Mamet · George Plafker

Jan 1982 · U.S. Government Printing Office

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A limestone sequence near Farewell in the Alaska Range foothills of west-central Alaska contains a microbiota that includes a large diverse assemblage of foraminifers of Frasnian (early Late Devonian) age not previously reported from Alaska. The fossil assemblages and lithology suggest that the limestone sequence was deposited on a very shallow open marine bank containing patch reefs of corals, stromatoporoids, and algae. The Frasnian limestone appears to overlie pillow basalt and is probably unconformably overlain by Permian limestone and clastic rocks. The only comparable microfauna reported from the North American Cordillera is from the Southesk Formation in Jasper National Park, Alberta, Canada, which represents a somewhat more restricted facies than the coeval Alaskan carbonates. Frasnian rocks containing complex and diversified microfaunas have been widely reported in the U.S.S.R., but little information is available on their microfacies. The excellent preservation of foraminifers in the Alaskan rocks permits emendation of descriptions originally made by Russian paleontologists for the genera Frondilina Bykova 1952 and Multiseptida Bykova 1952 and description of a new species of Multiseptida, M. farewelli Mamet.