مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

The Naqadeh, Pasveh and Delkeh plutons of North Sanandaj-Sirjan Zone, W Iran, are medium to high potassium calc-alkaline intrusive rocks composed of mafic and felsic rocks. Six samples were selected as representative of different units of these plutons for estimation of pressure and temperature of magmatic crystallisation. Al-in-hornblende barometry and crosstie contents of amphiboles suggest <4.5 kbar (1.6-4.5 kbar) pressure for emplacement depth of intrusives. Different thermometer methods indicate various stages of magmatic evolution from near liquidus to sub-solidus temperatures. The highest temperature resulted from orthopyroxene-clinopyroxene solvus thermometry which is more than 1100°C, reflecting initial crystallisation of pyroxene from dioritic magma. Hornblende-clinopyroxene thermometry show another hyper-solidus crystallisation phase during magmatic cooling. The temperature come from hornblende-plagioclase thermometer (695-760°C) probably refer to late stage crystallisation of the magma near solidus condition. Calculated temperature of feldspar thermometry show scatter results (281-1086°C) implies sub-solidus re-equilibration of the feldspar during magmatic and post-magmatic evolution.