Writers : Malekzadeh Shafaroudi, A.; Karimpour, M.H.; Mazaheri, S.A.; Hidarian Shahri, M.R.
Refference : 1st Symposium of Iranian Society of Economic Geology
Publishing Year : 1389

Abstract :

Unidirectional solidification texture quartz (UST) is reported in Iran for the first time at Khopik porphyry Cu-Au deposit, southwest of Birjand. The UST veins formed within the top of stock before the main stage of mineralization. They formed the same time as potassic alteration and show cross cutting by latter veinlets. Appearance of UST vein in the surface indicates that most of the upper part of the porphyry system is eroded. The UST veins are an indication of separation of fluid from the granitoid magma. Based on range of +5.75 to +7.44‰ δ18O VSMOW, high temperatures (Th>450°C), and high salinity 30 equivalent wt-percent NaCl) indicating that the fluid had primarily magmatic origin. Both salinity and Th of the fluid inclusion decrease from the center of quartz crystals toward the rim this is contemporaneous with lowering pressure within the magma chamber. At higher vapor pressure, UST quartz forms and as the vapor pressure decreases the granitoid rock start to crystalize. With increasing the vapor pressure UST begin to form.

Subject List : Microthermometery