TITLE:
Mineral Chemistry and Geothermometry of Amphibole and Plagioclase in the Metabasites, Located at the Tanbour Metamorphic Complex in Southern Iran
AUTHORS:
Kasra Safei, Mohammad-Ali Arian, Seyed Hesam-Aldin Moien Zadeh Mirhosseini
KEYWORDS:
Metabasite, Amphibole, Plagioclase, Mineral Chemistry, Tanbor Metamorphic Complex, Sanandaj-Sirjan Metamorphic Belt
JOURNAL NAME:
Open Journal of Geology,
Vol.5 No.11,
November
30,
2015
ABSTRACT: Metabasite refers to metamorphosed
basalts and other mafic igneous rocks (rich in iron and magnesium). When a
mafic igneous rock is subjected to new pressure and temperature conditions
during metamorphism, these chemical components will rearrange themselves to
form new minerals. Metabasites can be found in many metamorphic belts including
Sanandaj-Sirjan metamorphic belt of Iran. The study area is a Tanbour
metamorphic complex in Eastern of Sirjan city, which is geologically located at
the Sanandaj-Sirjan metamorphic belt in Southern Iran. Metabasite in this
complex consists of greenschist, epidote amphibolite and amphibolite. Amphibole
and plagioclase are the main minerals in the greenschist and amphibolite, and
the a secondary mineral in some micaschist seen in the study area. The electron
microprobe analysis was done on this mineralization in greenschist, epidote
amphibolite and amphibolite, which showed that the amphiboles in greenschist
was a member of the calcic group and Actinolite type, and the amphiboles in
epidote amphibolite was a member of the calcic group and these amphiboles were
tschermakite up to Ferro-Tschermakite + Ferro-Hornblende type. The amphibole in
amphibolite is a member of the calcic group and this amphibole is
Magnesio-Hornblende type. The plagioclases in the greenschist is pure albite
(An 3.29 - 3.6), and in the epidote amphibolite is oligoclase (An 19.5 - 24.2),
while in the amphibolites is oligoclase (An 16.9 - 26.6). The estimated P–T
conditions are in favor of their metamorphism under epidote amphibolite (550°C
and 8 kbar) and amphibolite (611°C -
652° Cand 10.5 kbar) facies.