Cretaceous Dinosaurs of Alaska:
Impact of the Origin of Beringia
Tony Fiorello, Dallas Museum of Natural History
Cretaceous dinosaur discoveries are now well documented in Alaska and offer new insight into the origin of Beringia. Previous work has suggested that during the Cretaceous Alaska was home to a modestly diverse dinosaur fauna, comprised of animals that were year-round residents of the Cretaceous high latitudes. Further, there is at least one example of adaptation within the dinosaur fauna for existence within the physical constraints of the Arctic. Also, coeval dinosaur discoveries in southwestern Alaska demonstrate that a vast ancient Arctic terrestrial ecosystem existed that supported significant numbers of large herbivores. Additional discoveries in coeval deposits in the central region of Alaska demonstrate a taxonomically diverse vertebrate terrestrial ecosystem. Fossils within accreted terranes are typically used to describe the age or origin of the exotic geologic blocks. One product of the accretionary process is to provide new pathways for faunal exchange between previously disconnected landmasses. One such landmass is Beringia, that entity encompassing northeastern Asia and northwestern North America, and the surmised land connection between the two regions. The present Quaternary concept of Beringia includes a climatic overprinting in the form of glacial advances and retreats driving changes in sea level and yielding faunal and floral exchanges between Asia and North America. Also within the Beringian ecosystem are specializations of the respective vertebrate fauna, as well as the flora.
A review of tectonic reconstructions and the striking taxon-free parallels in patterns of the fauna and flora between Cretaceous data of Alaska and Quaternary data of Beringia in general suggest the concept of Beringia can, and should be formally extended back in time to the Cretaceous, certainly to the Cenomanian and perhaps even earlier. This implies that the concept of Beringia is rooted in its accretionary history rather than in a climatic history.
Friday, November 4, 4:00 pm
UT Institute for Geophysics, Room 800
4412 Spicewood Springs Rd. #600