Dodehak granitoid stock with tonalite to granodiorite compos ition
is exposed south of Dodehak vi llage, north of Ab-e-Gann (Mahalat) in
Urumieh-Dorhtar volcanic belt of Iran. Based on petrography and point
analysis (EPMA). plagioclase crystals show nonnal zoning with graph ic
tex.ture is present. Samples from SE of the intrus ion are different and
myrmekite texture is present in the rocks, while graph ic texture is absent and
plagioc lases have lost their zon ing. In samples from SE of the area.
mynnekite is rim type and plagioc lases show cross shape twinning. Based on
whole rock XRF analyses, Rb-S i~ and K20 -Na10 diagrams show nonlinear
trends and EPMA analysis indicate that plagioc lases are homogeneous
albite. Such petrographical and geochemical features are evidence for
alkaline metasomatism in SE of the Dodehak intrus ion.