I am both a petrologist and a geochemist. I study modern and ancient environments. My current research focus is on:

- The Archean and Paleoproterozoic Earth: the evolution of early prokaryotic life and environmental conditions on the early Earth.

- Develoment of stable isotope tracers in geomicrobiology and astrobiology (Fe, Se and multiple S isotopes)

- Archean and Paleoproterozic greenstone belt geology (Barberton Greenstone Belt, S Africa; Marowijne Greenstone Belt, Suriname)

- Origin of banded iron formations

I have also worked over many years to develop microanalytical techniques for isotopic and trace element analysis. Since my early career I have had a continued interest in the investigation of melt generation processes and crust-mantle interactions in subduction zones, especially related to Mio-Pliocene volcanism in Eastern Europe.