Mahrous,
I suggest you ignore the particulars of the granite's origins for now and
just do some careful mapping. I've made the mistake of thinking to much
about migmatitic origins before making careful observations myself. This
tends to bias the observations. So here are some field suggestions:
0. (Most important)carefully describe each granite phase that you can
readily identify as different.
1. (very important) look for cross-cutting relationships between the
"different" granites.
1.5. try to follow individual granite layers/dykes to see if they join up
to a larger mass.
2. Note the maximum and minimum layer/dyke thicknesses you see for each
type of granite.
3. Note the maximum and minimum strength of the internal fabric of each
type of "different" granites. This can be done on a qualitative scale of
unfoliated, weakly foliated, moderately foliated, strongly foliated.
4. The last and most difficult task is as much interpretation as
observation. Try to decipher the number of deformation phases each type of
granite has witnessed (what you've been doing).
I'm sure others will have plenty to add to these suggestions.
You may find that (going along the lines of what Gary suggested) these
granites may all be part of the same migmatization phase. Some may be
in-situ melts, some may have travelled less than a metre, some more than a
metre, some 100 metres, but they still may be basically the same granite.
Migmatization may have outlasted deformation of vice versa.
Good luck
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Paul M. Evins W tele# +358 8 553 1481
University of Oulu FAX# +358 8 5531484
Dept. of Geology email: [log in to unmask]
PL 3000 http://www.student.oulu.fi/~pevins/
90401 Oulu FINLAND
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