Personal profile

About

The geoscience research I do is very strongly instrument-based: I examine unusual and sometimes difficult-to-measure tracers in rocks as a means of understanding large-scale dynamic and chemical processes in the Earth. Toward these ends I am involved as both a user and manager of the USF Center for Geochemical Analysis, which houses our ICP-MS and IC plasma emission spectrometry instruments; and I'm an original co-PI and core user of the electron microprobe/SEM facilities of the Florida Center for Analytical Electron Microscopy (FCAEM).

I'm interested in the chemical and petrologic manifestations of the phenomenon of plate convergence, which has had me investigating a variety of questions in subduction zone and orogenic belt settings. Most recently this has involved the examination of shallow forearc metamorphic rocks, and arc lavas in subduction settings where the parameters of subduction (convergence rate, slab dip, slab age, inferred slab surface temperatures) show along-strike variation. Making use of "fluid-mobile" elemental and isotopic tracers (B, Cs, As; B isotopes) we can identify and quantify the role of shallowly released, H2O-dominated slab outfluxes in the petrogenesis of arc lavas, and the relationships between this outflux and other recognized slab-derived releases related to the melting of subducted sediments and the dehydration and/or melting of subducted ocean crust.  In my role as a Shipboard Inorganic Geochemist on IODP Expedition 366 to the forearc of the Mariana subduction system, my student Ray Johnston and I have begun an in-depth examination of shallow subduction related fluid-rock exchange phenomena associated with the serpentinite seamounts and mud volcanoes that are found there.  My student Antonio Luna is seeking to contrast the mantle-wedge/subduction channel derived geochemical signatures from the Mariana forearc and related land-based localities with those encountered in slow-spreading ocean crust, in which serpentinites and altered gabbroic rocks can be significant constituents, working both from new samples he obtains from his participation in the joint IODP Expeditions 367-368 effort in the South China Sea, and other recognized slow-spreading ridge localities in the IODP collections.

Related documents

Education/Academic qualification

M.A., M. Phil., Ph.D., Columbia University

19831989

B.S., Western Carolina University

19781983

Disciplines

  • Geochemistry
  • Geology