>Dear Arindam,
Jerry's reply is comprehensive and excellent. Another test for
pseudotachylite at or near a fault surface is veining and injection
of melt into cracks by flash melting during a slip event. Some fine
examples of this occur along the San Gabriel Fault in Southern
California. A mega-example of impact pseudotachylite is in the
Vredefort impact structure in South Africa, where there is at least
one quarry in the most spectacular impact breccia with a
pseudotachylite matrix. Thin pseudotachylite veins propagated, almost
instantaneously during the bolide strike at about 2.0 Ga, for at
least 100km.
You have a fascinating topic to study.
Best wishes,
John Dewey
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Prof. John F. Dewey FRS, M.R.I.A., FAA, Mem. Acad. Eur., Mem.
US Nat. Acad. Sci., Distinguished Emeritus Professor University of
California, Emeritus Professor and Supernumerary Fellow, University
College Oxford.
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