Electronic Material Properties - und Geowissenschaften ...

with observed chemical zoning in metamorphic minerals, is a valuable method for
constraining the prograde P-T path when standard methods are inapplicable.
To understand metamorphic mechanisms and to model kinetic evolution of the
maturation of organic matter, R. Le Bayon (associated with G. Brey – University of
Frankfurt am Main, D; L. Nasdala – University of Vienna, A; W.G. Ernst – University
of Stanford, USA) is carrying pressure-temperature-time experiments at the
mineralogical institute of the University of Frankfurt am Main. This modelling will
serve as a tool to better understand and constrain the pressure-temperature-time
evolution of carbonaceous-bearing metamorphic rocks.
The studies of H. Hofmann (assistant since August 2004) are based in the research
field of applied clay mineralogy, e.g. geochemical processes related to the formation
of bentonites by the low- grade alteration of volcanic ashes and tuffs. Bentonites,
namely the swelling smectites, are most important to a large number of industrial and
technical applications due to their special physico-chemical properties like sorption
capacity for water, cations and organic complexes, as well as high swelling- and
sealing capacity. Possible technical and geotechnical applications related to these
properties are located in the pharmaceutical – and oil industry, and since a couple of
years in the secure disposal of radioactive waste. Each of these applications requires
different material properties. Despite the fact that most of the properties of smectites
are quite well known physically and chemically, it is not yet clear where they originate
from and how fast material properties can change if the environmental conditions
change. To be able to predict if and how the material will change under extreme
conditions like they are present in a nuclear waste disposal site, it is essential to
know how fast the material can adapt to new environmental conditions.
Bentonites are formed by alteration of volcanic ashes and tuffs, partly millions of
years ago. However, it is not well known, when under which conditions the alteration
process initiated, and how much time is required to form the swelling clays. It is
attempted to determine the kinetics of the reaction progress and the controlling
factors of physico-chemical property changes responding to different environmental
conditions.
The main projects of D. Scheuvens, collaborating with M. Hinderer (FG Applied
Sedimentology) and E. Stein in the Odenwald mountains is based on a rock-registry
survey jointly with the IFS (Institut für Gesteinskonservierung) and the UNESCO
Geopark Bergstraße-Odenwald centre. E. Stein also investigates the interplay of
plutonism, deformation and metamorphism in the eastern part of the `zone axiale´ of
the Montagne Noire (southern France), a classical geological region to study the
burial and exhumation of rocks.
Staff Members
Head Prof. Dr. Rafael Ferreiro Mählmann
Research associates Dr. Ronan Le Bayon, PD Dr. Eckardt Stein
Dr. Heiko Hofmann, Dr. Dirk Scheuvens
- 133 -