Partial melting in the Kalybar thermal aureoleNW Iran

Category Petrology
Group GSI.IR
Location 20th symposium on geosciences
Holding Date 16 April 2008

     Saygrom-Dagh plutonic complex is located in NW Iran and west of Kalyhar. This intrusion is a part olAlhorz-Azarbaijan magmatic belt which is intruded into the Azarhaijan crust in Upper EocencOligocene, during Pyrenean orogeny. The intrusion has produced a thermal aureole up to Km wide in the country rocks. The contact
between igneous and country rocks is sharp. Pelitic hornfels, metacaic-silicates, marbles and metabasites are resulted from contact metamorphism. The highest temperature within the aureole was
850°C and the presure of introsion was lower than 4 Kbar according
to petrogenetic grid for pelitic rocks. The pelitic and semi pelitic rocks are partialy melted at high temperatures and have produced small-scale migmatites. Considiring the petroghraphical and mineralogical characteristics, leucosomes are loucogranitic and have formed from solidification of a silicate melt. Texturally, loucosomes are coarse-grain and are easily distinguishable from flnc mesosomes. The main minerals in leucosome part are quartz, K-feldspar, biotite, orthopyroxene and
opaque minerals. The size difference along with granophyric texture and interstitial texture between quartz and K-feldspar are some evidence for partial melting of pelitic and semipeltic rocks within the aureole.