Geology Reference
In-Depth Information
Alkali granite
Gabbro
Trondhjemite
Amphibolite gneiss
Tonalite
21
°
10'
21
°
30'
Unaja
61
°
00'
024
Pyhamaa
km
60
°
50'
kalanti
Uuosikaupunki
Figure 7.21
Simplified geological map of southwest Finland showing syn-
tectonic calc-alkaline tonalite and amphibolitic gneisses in the west intruded
by a post-tectonic alkali granite in the east.
Andean batholith both contain far more tonalite and gronodioritic rocks than
granite (s.l.).
When combined with other field measurements, notably Anisotropy of Mag-
matic Susceptibility (AMS) surveys, a comprehensive picture of pluton fabric
development can be assembled that allows geologists to unravel the often com-
plex emplacement histories of granite and other magma bodies. A well studied
example is the Ardara pluton, Donegal, Ireland. Ardara is a zoned, syn-tectonic
