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.

Christian M. Ø. Rasmussen is a postdoctoral researcher at the Natural History Museum of Denmark. His main research focus on what governs fluctuations in biodiversity through time. He has particularly specialised in Middle Ordovician through Lower Silurian brachiopod faunas, and notably their response to the Great Ordovician Biodiversification Event, as well as the End Ordovician mass extinctions. Recently, however, his research has focused on causes to Neogene biodiversity fluctuations, with a special interest in the development of biodiversity hotspots.

David Harper is a leading expert on fossil brachiopods and numerical methods in palaeontology. He is Professor of Palaeontology in Durham University, Principal of Van Mildert College and Deputy Head of College Faculty (Research). He was previously Head of Geology in the Natural History Museum of Denmark. He has published over 10 books and monographs, including a couple of influential textbooks, as well as over 250 scientific articles and, together with Øyvind Hammer, the widely–used software package PAST.

Robert B. Blodgett is a geologist/paleontologist whose research is focused on Paleozoic and Mesozoic faunas of western North America, especially Alaska. His primary specializations are with gastropods and brachiopods, but his work in the Mesozoic also includes bivalves and foraminifera. He was formerly with the Branch of Paleontology & Stratigraphy of the U.S. Geological Survey, until the untimely demise of that unit in 1995, and he now works as independent consultant.