UMW News BureauWilliam Sager of the Texas A&M University Department of Oceanography is the April 25, 2011 speaker for the University of Montana Western’s On the Rocks series. By Kaitlin Ens William Sager of the Texas A&M University Department of Oceanography is the April 25, 2011 speaker for the University of Montana Western’s On the Rocks series. Sager, a marine geophysicist, has participated in 38 research cruises, 17 of which he was the chief scientist, and seven Ocean Drilling Program cruises, of which he was the co-chief scientist for two. His research broadly focuses on Earth’s plate tectonics and the evolution of ocean basins. Sager’s On the Rocks presentation will center around ocean volcanism. He will discuss new views regarding hotspots, which are long-lived volcanic sources resting below the tectonic plates and capable of creating linear seamount chains such as Hawaii. “My presentation will be a personal reflection on the evolution of my thoughts, and those of the rest of geoscience, about hotspots,” Sager stated. “Research in the last decade has shifted the way we think these hotspots form and evolve. I chose the topic because I do research on plate tectonics and I have used hotspot seamount trails in the past to figure out the motions of plates. Furthermore, I have been doing research on the motion of the Pacific plate for many years and for many years the bend in the Hawaiian-Emperor seamount chain was thought to be the result of a change in plate motion, but research by me and others show that this isn't so.” Sager’s presentation will begin at 4 p.m. in Block Hall Room 311 on the Montana Western campus. On the Rocks presentations are always free and open to the public.