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My two penny'th from a laserprobe perspective - watch out for excess argon though! I think Andreas Mulch has had something more recent as well but I can't lay my hands on it right now. sarah REDDY, S.M., KELLEY, S.P. & MAGENIS, L. 1997. A microstructural and argon laserprobe study of shear zone development at the western margin of the Nanga-Parbat-Haramosh Massif, Western Himalaya. Contributions to Mineralogy and Petrology, 28, 16-29. MULCH, A., COSCA, M.A. & HANDY, M.R. 2002. In-situ UV-laser Ar/Ar geochronology of a micaceous mylonite: an example of defect-enhanced argon loss. Mineralogy and Petrology, 142, 738-752. Reddy, S.M., Kelley, S.P., Wheeler, J. 1996. A 40Ar/39Ar laser probe study of micas from the Sesia Zone, Italian Alps: Implications for metamorphic and deformation histories. J. Met. Geol. 14, 493-508. Vance, D., Ayres, M., Kelley, S.P., Harris, N.B.W. 1999. The thermal response of a metamorphic belt to extension; constraints from laser Ar data on metamorphic micas. Earth Planet. Sci. Lett. 162, 1-4, 153-164. -----Original Message----- From: Tectonics & structural geology discussion list [mailto:[log in to unmask]] On Behalf Of Rob Butler Sent: 02 February 2005 12:39 To: [log in to unmask] Subject: Radiometric dating of shear zone fabrics Eldridge and others There are some brief notes and references to the work we did here in Leeds, dating shear zones, chiefly in the Alps, using Rb-Sr ages on white mica in calc-schists. Almost all the work in the publications listed was done by Steve Freeman. Personally I quite like the method because the dates apply directly to minerals that form the deformation foliations (provided the calcite and mica are recrystallising during the deformation and this this went on significantly below closure) - so it's easier (although not with potential pitfalls) to relate the geochron to the deformation. The website is: http://earth.leeds.ac.uk/tectonics/alpine_tectonics/metamorphic/dating/ htm. Hope this rather dated dating is of interest Rob On 1 Feb 2005, at 18:06, JISCmail list wrote: > Dear Colleagues: > > I am interested in general references on the recent advances in > radiometric dating of various minerals in shear zone fabrics. Does > anyone know of any such references? I would greatly appreciate any > ideas that you might have. > > Best regards, > > Eldridge > -- > Distinguished Professor of Emeritus of Geology > Vice President, International Union of Geological Sciences Department > of Geology, University of California One Shields Avenue > Davis, CA 95616 > > Tel: 530-752-0352 > Fax: 530-752-0951 > > "Civilization exists by geologic consent, subject to change without > notice" "Civilization is an interval between ice ages" > (Will Durant) >