This Faculty Early Career Development (CAREER) award by the Divisions of Chemistry and Earth Sciences supports interdisciplinary research and education on mantle dynamics and plume-ridge interactions by Dr. Karen S. Harpp, Department of Chemistry, Lawrence University. The investigation will focus on the Galapagos hotspot, located south of the Galapagos Spreading Center (GSC), off the west coast of South America. The magmas produced here are controlled by both hotspots and mid-ocean ridges, thus serving as tracers of mantle flow patterns, extent of mixing between the two sources, and detailed lithospheric structure and dynamics. The relationship of regional volcanic features, specifically the Wolf-Darwin Lineament (WDL) as well as Pinta, Marchena, and Genovesa islands, to the ridge and hotspot are not well understood. Three mechanisms for understanding the region have been proposed: WDL pipes plume material to the ridge; lithospheric weakness at the lineament; ridge upwelling, with increased melt production because of the adjacent hotspot. Each mechanism results in different predictions for geochemical variation. Sample lavas will be collected from Wolf, Darwin, and Genovesa and their chemical compositions determined. The data will be fit to models to determine which mechanism best describes geologic activity in the area. The project will be carried out by undergraduates. In addition, inquiry-based methods and team approaches will be introduced into chemistry laboratories, including a new environmental laboratory course, at Lawrence University and undergraduate students will be involved in outreach with local school and community groups. The origin of volcanic islands in the Galapagos archipelago is not well understood because of the complex interaction between ocean ridges and local hotspots or plumes. The geological mechanism will be determined by studying the chemical composition of the lava flows at various islands. The research is integrated with education of undergraduate students who will be prepared in discovery-based laboratories prior to experience in field work in the Galapagos.
