Speaker: Associate Professor Elisabeth Nadin

Department of Geosciences, University of Alaska Fairbanks

Alaska is a collage of accreted terranes whose origins are still largely unknown. The margin of southern Alaska grew substantially in Mesozoic time, with three major phases of magmatism and deposition of sediments in marine environments. In this talk, I will present the different models of accreting the Jurassic Talkeetna arc, introduce the mélange and flysch deposits of the accretionary prism to the arc, and discuss the relationships amongst them. I will introduce the terrane-bounding Border Ranges fault and discuss ongoing research into rock deformation within a recently mapped fault within the accretionary prism. I will also discuss the idea of a spreading ridge migrating along the southern Alaska coast in Eocene time. The field relations bear on recent ideas of how the rocks of Alaska were shuffled into place over time.