I consider myself an earth scientist, extremely curious about how the earth ‘works’ and how it has evolved to its present state. I had two complementary introductions to earth science as an undergraduate; First the opportunity to work as a summer programmer for Dick Hey (Hawaii Inst. of Geophysics, now part of SOEST) to develop a program to model the patterns of marine magnetic anomalies produced by along-strike propagation of a mid-ocean ridge; and the following summer to work with Marc Parmentier (Brown Univ.) on exploring aspects of non-Newtonian mantle convection. These two experiences set me off on a wobbly career path that has included a fair amount of marine seagoing expeditions, a few highly rewarding trips to examine ophiolites, and on-shore work exploring the physics and chemistry of flow, deformation, and melting. My initial Ph.D. work focused on the dynamics of mid-ocean ridges.
Subsequently I became interested in hotspot volcanism, and the potential links between marine hotspot volcanism and the formation of hotspot swells. This work also included the attempt to convince others of the important roles that melt extraction may play in strengthening the mantle residue to melt extraction — potentially causing both the formation of hotspot swells and the creation of strong ‘compositional lithosphere’ by melt extraction at a mid-ocean ridge.
My work on hotspot volcanism also led me to explore the role(s) of a suboceanic asthenosphere in mantle convection, and to teach myself enough geochemistry to be able to explore the geochemical consequences of progressive melt extraction from a plum-pudding mantle. Upon moving to GEOMAR-University of Kiel in Germany in 1999, I became involved in the study of subduction zone dynamics, initially focusing on the effects of the partial hydration and water release from down-going slabs. I also learned about the evidence from continental rifting and kimberlites that (in my opinion!) strongly favors the plume-fed asthenosphere paradigm for mantle convection.
As a side project, I became interested in the causes of mass-extinctions, in particular worrying about the ‘too-many-coincidences’ problem that these periods appear to be associated (if we believe what’s published in the mainstream literature) with BOTH extremely rare continental flood basalts and continental rifting, and even rarer ‘impact signals’ commonly presumed to come from large extraterrestrial bolide impacts. Our recently published Verneshot hypothesis is our best guess on how to explain these coincidences in a self-consistent causal manner.
Of course, the addition of each of these new research areas has only meant that I can spend significant time on even fewer problems that interest me. My current research mostly focuses on melting, the strength of continental lithosphere, the origin of kimberlites, and effects of serpentinization on subducting slabs.
In addition, I am continuing my career-long interest in mantle convection, by pursuing simple lab and computational experiments that help teach mantle dynamics while simultaneously exploring the physics of asthenosphere entrainment by subducting slabs.