Dear Noah and all:
I faced a similar problem concerning a shear zone that shows, in
different locations, two different stretching lineation orientation. Both
are consistent with a sinistral strike-slip displacement, but one of the
orientations indicates an inverse component, whilst the other indicates a
normal component. In this case, I applied the model proposed by Lin et al.
(1998) for transpressional zones. Probably, it won't explain your problem,
but it may help. Anyway, this paper is part of a book that I'm sure you'll
be interested in.
The book reference is: Holdsworth, R.E.; Strachan, R.A.; Dewey,
J.F.(Eds) 1998. "Continental transpressional and transtensional tectonics"
Geological Society of London Special Publications.
The article by Lin et al is: "Transpression (or transtension) zones of
triclinic symmetry: natural example and theoretical modelling" pages 41-57.
You can also take a look to:
Lin, S.; Williams, P.F. (1992) "The geometrical relationship between the
stretching lineation and the movement direction of shear zones" J. Struct.
Geol. 14: 491-497.
Good luck
Manuel
--
Manuel Díaz Azpiroz
Dpto. Geología, Universidad de Huelva
Campus de La Rábida. Crtra. Palos de la Frontera s/n
21087 Huelva
Tf: 959-351000/351012
Fax: 959-530175
E-mail: [log in to unmask]
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