摘要：Abstract
Eocene to Oligocene volcano-plutonic rocks are
widespread throughout NW Iran. The Tarom-Hashtjin
metallogenic province is one of the most promising
epithermal-porphyry ore mineralized districts in NW Iran.
The Glojeh gold deposit, located in the center of this
province, is a typical high to intermediate sulfidation epithermal
system, spatially and temporally associated with
a granite intrusion and associated high-K calc-alkaline
to shoshonitic volcano-plutonic rocks. The intrusive complexes
of the Glojeh district are characterized by: SiO2
contents of 60.9 to 70.7 wt.%, K2O+Na2O of 7.60 to 8.92
wt.%, and K2O/Na2O ratios of 0.9 to 1.8. They are enriched
in light rare earth elements (LREEs), and large ion
lithophile elements (LILEs), depleted in high field strength
elements (HFSEs), and have weak negative Eu anomalies
(Eu/Eu*= 0.5 to 0.9). 40Ar/39Ar geochronology applied
to biotite and feldspar, separated from two intrusives
(Goljin and Varmarziar), and two feldspar aliquots
separated from hydrothermal veins at North Glojeh and
South Glojeh, was carried out to constrain magmatic and
hydrothermal events. Plagioclase (± sericite), from North
Glojeh and South Glojeh produced ages (42.20±0.34 Ma,
and 42.56±1.47 Ma respectively) that overlap with the age
of the Goljin intrusion (41.87±1.58 Ma).
Geochemical data for the volcano-plutonic rocks in the
Glojeh district, that have87Sr/86Sr isotopic compositions
that range from 0.706344 to 0.708331, suggest an origin involving
partial melting of a depleted mantle source during
Neo-Tethyan subduction.
关键词：KeywordsGlojeh gold district Volcano-plutonic rocks
Tarom-Hashtjin metallogenic province Sr isotope Partial
melting Geochronology
