HR: 14:40h
AN: MR13B-05 INVITED     [Abstracts]
TI: In Situ Optical Observation of High-Temperature Geological Processes With the Moissanite Cell
AU: * Walte, N
EM: nico.walte@uni-bayreuth.de
AF: Bayerisches Geoinstitut, Universitaet Bayreuth, Bayreuth, 95440 Germany
AU: Keppler, H
EM: hans.keppler@uni-bayreuth.de
AF: Bayerisches Geoinstitut, Universitaet Bayreuth, Bayreuth, 95440 Germany
AB: A major drawback of existing techniques in experimental earth and material sciences is the inability to observe ongoing high-temperature processes in situ during an experiment. Examples for important time-dependent processes include the textural development of rocks and oxide systems during melting and crystallization, solid-state and melt-present recrystallization and Ostwald ripening, and bubble nucleation and growth during degassing of glasses and melts. The investigation of these processes by post-mortem analysis of a quenched microstructure is time consuming and often unsatisfactory. Here, we introduce the moissanite cell that allows optical in situ observation of long-term experiments at high temperatures. Moissanite is a transparent gem-quality type of SiC that is characterized by its hardness and superior chemical and thermal resistance. Two moissanite windows with a thickness and diameter of several millimeters are placed into sockets of fired pyrophyllite and fixed onto two opposite metal plates. The sockets are wrapped with heating wire and each window is connected to a thermocouple for temperature control. The sample is placed directly between the moissanite windows and the cell is assembled similarly to a large diamond anvil cell. In situ observation of the sample is done with a microscope through observation windows and movies are recorded with an attached digital camera. Our experiments with the new cell show that temperatures above 1200°C can be maintained and observed in a sample for several days without damaging the cell nor the windows. Time-lapse movies of melting and crystallizing natural and synthetic rocks and of degassing glasses and melts will be presented to show the potential of the new technique for experimental earth and material science.
DE: 3600 MINERALOGY AND PETROLOGY
DE: 3619 Magma genesis and partial melting (1037)
DE: 3625 Petrography, microstructures, and textures
DE: 3630 Experimental mineralogy and petrology
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005