Late Ordovician Brachiopods from West-Central Alaska: Systematics, Ecology and Palaeobiogeography

A Late Ordovician silicified brachiopod fauna from the White Mountain area, west-central Alaska is described and interpreted in a palaeoecological and biogeographical context. This area is situated within the Nixon Fork Subterrane of the Farewell Terrane, which origin and timing of final docking with Laurentia has been much debated. The current study adds new faunal data to the debate with nearly 100 species described, of these at least nine are new. The fauna is predominantly a deep-water autochthonous fauna that was mixed with an allochthonous fauna as a result of down-slope movement of turbidity currents. Biogeographically this study demonstrates close faunal affinities with Siberia.