K−Ar ages of bentonites in the seabee formation, northern alaska: A late cretaceous (Turonian) time-scale point
1983; Elsevier BV; Volume: 4; Issue: 4 Linguagem: Inglês
10.1016/s0195-6671(83)80004-4
ISSN1095-998X
AutoresMarvin A. Lanphere, I.L. Tailleur,
Tópico(s)Geological Studies and Exploration
ResumoK−Ar ages were measured on biotite from six bentonite beds in the Upper Cretaceous (latest Cenomanian (?) and earliest Turonian) Seabee Formation of norther Alaska. The bentonite beds occur in the Shale Wall Menber of the Seabee Formation in three different coreholes in the Umiat and Simpson regions of the National Petroleum Reserve in Alaska. Fossil-bearing localities in the Shale Wall Member contain bivalves of the Inceramus labiatus (Schlotheim) group that has a worldwide distribution in rocks of mostly early Turonian age. The K−Ar ages range from 91.5±0.9 to 93.6±1.2 Ma and indicate an age of about 92 Ma for the highest occurrence of the I. labiatus group in the three coreholes.
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