ORPHAN ARCTIC OCEAN METASEDIMENT CLASTS: LOCAL DERIVATION FROM ALPHA RIDGE OR PRE-2.6 MA ICE RAFTING?

Abstract

Phyllonite and metaquartzite clasts occur in early Pliocene or possibly Miocene sediment at the base of the University of Wisconsin Arctic Ocean core Fl-380. Single-crystal 40Ar/39Ar laserprobe ages derived from feldspars in sediment enclosing the clasts range from Middle and Late Proterozoic to Paleozoic. The clasts occur in sediment deposited 1–2 m.y. earlier than any previously reported central Arctic Ocean ice-rafted debris, and although an ice-rafted origin may be possible, a local source such as adjacent Alpha Ridge bedrock should also be considered.