HR: 0830h
AN: V41C-0311    [PDF]
TI: Direct Observation and Finite-Difference Modelling of the Dynamics of two Immiscible Melts
AU: * Kahle, A
EM: kahle@kristall.uni-frankfurt.de
AF: Universitaet Frankfurt, Institut fuer Mineralogie, Senckenberganlage 30, Frankfurt a.M., 60054 Germany
AU: Schmeling, H
EM: schmeling@geophysik.uni-frankfurt.de
AF: Universitaet Frankfurt, Institut fuer Geophysik, Feldbergstr. 47, Frankfurt a.M., 60323 Germany
AU: Winkler, B
EM: b.winkler@kristall.uni-frankfurt.de
AF: Universitaet Frankfurt, Institut fuer Mineralogie, Senckenberganlage 30, Frankfurt a.M., 60054 Germany
AB: The dynamics of two immiscible melts at a temperature of 1450 K was experimentally observed by time-resolved neutron radiography and compared with two-dimensional finite-difference calculations. Neutron radiography, which is the time-dependent measurement of neutron absorption, allows to observe a large melt volume in situ and real time. This feature was utilised to observe an initially layered sample which consisted of a dense brass disc overlying a silicate melt contained in a crucible. When heated a single brass drop slowly formed and fell through the silicate melt to finally cover the container bottom. The known experimental parameters (viscosity and density differences between the two melts, sample geometry) were used as input parameters in the numerical calculations. The finite-difference calculations reproduced the experimental observations. This implies that surface tension, which was not included in the model, only has a minor effect on the melt dynamics in the system we investigated. Dynamic neutron radiography has been used here for the first time to study melt dynamics, and the results obtained clearly show that this is a method which can give unique insights into the behaviour of silicate melts without having to resort to model systems.
DE: 3210 Modeling
DE: 8429 Lava rheology and morphology
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting