TITLE:
Conditions of Ore-Mineralization and Geochemical Correlation of Rare-Elements at the Robat Pb-Zn Deposit, West of Khomein, Central Iran
AUTHORS:
Golrokh Mahdavi, Ahmad Khakzad, Mohammad Lotfi
KEYWORDS:
Robat Pb-Zn Deposit, Ore-Mineralization, MVT, Fluid Inclusion
JOURNAL NAME:
Open Journal of Geology,
Vol.6 No.9,
September
14,
2016
ABSTRACT: The
Robat geological study area is located 32 Km west-northwest of Khomein town.
From the geo-structural point of view, it is in the median part of the Sanandaj-Sirjan zone [1], and from the mineralization aspect it is part of the Malayer-Esfahan Pb-Zn metallogenic belt [2]. The main hostrock of Pb-Zn ore-mineralization at
the Robat deposit is the upper parts of the orbitolina-bearing limestone at its
contact with the overlying unit of marl. Ore mineralization is characterized by
vein-veinlet, fracture-filling and replacement textures, associated with
silica, carbonate, argillic and hematitic alterations [3]. Geochemical trends of minor elements in ore
represent positive correlation of Sb, Ag, Cu, Bi, Sn, Fe, U, Th, W, V, Zr and Y
with Pb and Zn. Fluid inclusion study of samples indicates that primary fluid
inclusions mainly consist of liquid, having an average temperature of
homogeneity in the range of 160°C to 270°C, having the most frequency in the range of 180°C to 190°C at an average of 5 to 10 wt% NaCl equivalent for salinity. Based on the
graph of pressure variations versus salinity (representing paleo-depth), it is
understood that ore-mineralization at the Robat deposit is estimated to have
formed at less than 50 bars pressure representing depths shallower than 200 m. Fluid inclusion study renders that the low
salinity could be resulted from dilution by meteoric waters, also indicating
that boiling could be the major mineral precipitation process. Therefore, it is concluded, based on these studies, besides field evidence,
that the Robat Pb-Zn deposit shows strong affinity with MVT Pb-Zn
mineralization type.