Emarat is a large-scaled Mississippi Valley-type (MVT) Lead Zinc deposit in the Sanandaj-Sirjanin zone (SSZ), Iran. This deposit is poorly studied and its mineralization features is unclear. Quartz is abundant in this deposit, which is uncommon in MVT deposits worldwide. Thus, it is worth discussing why the deposit is rich in quartz. In addition, the sources of the ore-forming fluid and materials are significant for understanding the ore genesis. The orebodies at Emarat are shown as steeply-dipping, tabular veins parallel to the stratigraphic bedding of the Early Cretaceous limestone. Mineralization was classified into two stages: (1) pre-ore stage, shown as replacement of the host limestone by fine-grained quartz and pyrite; (2) ore stage, coarse-grained quartz + sphalerite + galena + calcite as veins filling in silicified (by pre-ore stage quartz) limestone. Aqueous fluid inclusions are identified in the ore stage coarse-grained quartz. The homogenization temperatures range from 132.2 ℃ to 225.3 ℃ and the salinities vary from 18.5% to 24.2% NaCl. The fluid inclusions have high Na+ and Cl- contents with high Na+/K+ ratios (average 29) and low Ca2+, Mg2+, K+, and SO2-4 contents. These features are similar to those of basinal brine but are atypical of magmatic fluid. The δ18OV-SMOW of quartz ranges from 18.6‰ to 20.7‰, and consequently the calculated δ18OH2O values of the parent fluid are between 2.84‰ and 9.12‰. The δD values of the parent fluid are between -76.2‰ and -57.5‰. The oxygen isotopic compositions of the parent fluid are similar to those of magmatic water but can also be caused by interaction between basinal brine and the ore-hosting limestone. The latter interpretation is further supported by the fact that limestone was strongly silicified so that heavy O isotopes from the limestone were likely incorporated into the ore-forming fluid during the water/rock interaction. As such, the enrichment of the ore-related quartz at Emarat probably results from a rapid decrease of temperature during interaction between the relatively hot ore-forming basinal brine and the cold host rocks. The δ34S values of sphalerite and galena ranges from 2.6‰ to 10.3‰. This may indicate that the reduced sulfurs in the deposit were generated by thermochemical sulfate reduction. The 206Pb/204Pb , 207Pb/204Pb, 208Pb/204Pb rations of galena are 18.4112～18.4157, 15.6472～15.6497, 38.5642～38.5808, respectively. Those are similar to the lead isotopic compositions of galena from the lead zinc deposits/occurrences in SSZ. It suggests that metals in the Emarat deposit as well as in the other deposits in SSZ were derived from crustal rocks.