HR: 09:00h
AN: T41G-05 INVITED     [Abstracts]
TI: Numerical Modelling of Vein Microstructures
AU: * Bons, P D
EM: paul.bons@uni-tuebingen.de
AF: Institut fuer Geowissenschaften, Eberhard Karls Universitaet Tuebingen, Sigwartstr. 10, Tuebingen, 72072 Germany
AB: Mineral veins occur in a variety of forms (syntaxial, antitaxial, etc.), and with various microstructures (fibrous, stretched crystals, vuggy, etc.). These structures can, if correctly interpreted, provide useful insight into the geological and tectonic conditions at which the veins formed (Oliver and Bons 2001). Durney and Ramsay (1973) defined the base for the modern classification and interpretation of vein (micro-) structures. Numerical modelling, not available then, has since been added as a tool to better understand the formation of vein (micro-) structures, focussing on three aspects in particular: 1) What determines the habit of growing vein crystals? In particular, what determines the formation of a fibrous habit? (Bons 2001, Hilgers et al. 2001) 2) The formation of fibrous pressure fringes. The complex internal structures of the fringes appear mostly the result of the relative rotation of object and fringes (Koehn et al. 2001). 3) Competition between growing crystals, which for example explains the development of a conical c-axes CPO in zeolite films (Bons and Bons 2003). References: Bons, P.D. 2001. Development of crystal morphology during unitaxial growth in a progressively widening vein: I. The numerical model. Journal of Structural Geology 23, 865-872. Bons, A.J., Bons, P.D. 2003. The development of oblique preferred orientations in zeolite films and membranes. Microporous and Mesoporous Materials 62, 9-16. Durney DW, Ramsay JG (1973) Incremental strains measured by syntectonic crystal growths. In: Gravity and Tectonics (eds De Jong KA, Scholten K), John Wiley and Sons, New York, pp. 67-96. Hilgers, C., Koehn, D., Bons, P.D., Urai, J.L. 2001. Development of crystal morphology during unitaxial growth in a progressively widening vein: II. Numerical simulations of the evolution of antitaxial fibrous veins. Journal of Structural Geology 23, 873-885. Koehn, D., Aerden, D.G.A.M., Bons, P.D., Passchier, C.W. 2001. Computer experiments to investigate complex fibre patterns in natural antitaxial strain fringes. Journal of Metamorphic Geology 19, 217-232. Oliver, N.H.S., Bons, P.D. 2001. Mechanisms of fluid flow and fluid-rock interaction in fossil metamorphic-hydrothermal systems inferred from vein-wallrock patterns, geometry, and microstructure. Geofluids 1, 137-163.
DE: 8000 STRUCTURAL GEOLOGY
DE: 8030 Microstructures
DE: 8100 TECTONOPHYSICS
SC: Tectonophysics [T]
MN: Fall Meeting 2005