Current Research
Geochronology: Ion microprobe in-situ dating of U-Pb
minerals (zircon, monazite, titanite, rutile, baddelejite) with a composite
internal structure. Dating of minerals or mineral zones formed at different
stages during the evolution of a rock unit in order to define detailed
P-T-time paths and thus determine rates of geological processes (e.g.
exhumation, subduction, cooling, melt residence and extraction). Combining
different isotopic schemes in order to unravel complex geological evolutions.
Imaging: Cathodoluminescence and back scattered electron
imaging as well as element mapping of datable minerals in order to understand
diffusion profiles and mobility of isotopes and trace elements. Relating
specific zoning patterns to crystallisation processes.
Trace element geochemistry: The composition of datable minerals such
as zircon, monazite and titanite in different geological environments
as indicator of coexisting paragenesis to relate age and metamorphism.
Modelling the distribution of trace elements between major and accessory
phases. Trace element partitioning between garnet and zircon as a tool
to detect equilibrium crystallisation. The effect of melt and fluids
on the trace element composition of datable minerals.
Metamorphic petrology: Main interests in the stability of U-bearing
minerals over a wide range of P-T-fluid conditions. Understanding the
chemical variation of such minerals with varying P-T and fluid composition
in order to link datable minerals and metamorphic conditions. Quantifying
solubility and mobility of trace and major elements in metamorphic and
hydrothermal fluids.
Petrography: The study of microstructures in order to establish crystallization
sequences and equilibrium/disequilibrium relations between major and
accessory minerals. This aims to determine a genetic link between major
and trace (mainly U-bearing) minerals, which in turns lead to the definition
of reactions responsible for the formation of datable minerals. Study
of solid and melt inclusions in datable mineral zones to constrain their
formation in P-T space.
Field work: Using the field as natural
laboratory for understanding the response of datable minerals to increase/decrease
in temperature and/or pressure over continuous metamorphic sequences
(e.g. Reynolds Range in central Australia). The study of tectonically
complex terrains in which the behaviour of different chronometers can
be investigated and compared within a variety of rock types and metamorphic
grades (the European Alps).
Experimental petrology: Experimental determination of zircon/melt and
zircon/garnet trace element distribution coefficients in a granitic composition.
Project in collaboration with Dr J. Hermann. Stability of monazite and
experimental determination of the monazite-allanite transition.