The Ketavik Formation: A new stratigraphic unit and its implications for the Paleogene paleogeography and paleoclimate of southwestern Alaska

A new formation, the Ketavik Formation, is proposed for Paleogene rocks of Katmai National Park near Brooks Camp. The type section is in an area previously mapped as the Jurassic Talkeetna Formation. The proposed formation was deposited in a fluvial environment. It is distinct from the coeval Copper Lake Formation on the southeast side of the Alaska Peninsula volcanic arc and was deposited in a different river system. The Ketavik Formation may include previously mapped, undifferentiated Tertiary rocks, at least some of which are similar in age, that are scattered along a belt parallel to and northwest of the present magmatic arc. The Ketavik Formation contains dicot and coniferous leaf and wood fossils that indicate a warm temperate climate.