Geochemistry and Fuid-Inclusion Microthermometry of the Farsesh Barite Deposit, Iran

Abstract

The Permian carbonate-hosted Farsesh barite deposit is located southeast of the City of Aligudarz in the province of Lorestan, Iran. Structurally, this deposit lies in the Zagros metallogenic belt and the Sanandaj-Sirjan Zone. Barite mineralisations occur as open-space flling veins, and as massive and replacement ores along fractures, faults and shear zones of the Permian carbonate host rocks. In order to determine the structure, in addition to pe-trographic and fuid-inclusions studies, an ICP-MS analysis was carried out in order to measure the major as well as the trace and rare earth elements. The Farsesh barite deposit has a simple mineralogy, of which barite is the main mineral, followed by calcite, dolomite, quartz, and opaque minerals such as Fe-oxides. Replacement of bar-ite by calcite is common and is more frequent than space-flling mineralisation. Sulphide minerals are minor and mainly consist of chalcopyrite and pyrite, which are altered by weathering to covellite, malachite and azurite. Petrographic analysis and micro-thermometry were carried out on the two-phase liquid/vapour inclusions in ellipsoidal or irregularly shaped minerals ranging in size from 5–10 µm. The measurements were conducted on fuid inclusions during the heating and subsequent homogenisation in the liquid phase. The low homogenisation temperatures (200–125°C) and low to moderate salinity (4.2–20 eq wt% NaCl) indicate that the barite had precipitated from hydrothermal basinal water with low to moderate salinity. It appears from the major and trace elements that geochemical features such as Ba and Sr enrichment in the barite samples was accompanied by depletion of Pb, Zn, Hg, Cu and Sb. The geochemistry of the rare earth elements, such as low σREE concentrations, LREE-enrichment chondrite-normalised REE patterns, the negative Ce and positive Eu anomalies, the low Ce/La ratio and the positive La and Gd anomalies, suggest that the Farsesh barite was deposited from hydrothermally infuenced sea water. The Farsesh deposit contains low-temperature hydrothermal barite. The scatter plots of the barite (close to sea water) in different areas on the CeN/SmN versus CeN/YbN diagram support the possibility that the barite was formed from seawater-bearing hydrothermal fuids.

Origin and occurrence of gem-quality, skarn-hosted barite from Jebel Ouichane near Nador in Morocco

“…The temperature of barite formation has been constrained by i.e. Raman carbonaceous material geothermometry 9 , fluid inclusion data 10 , 11 , and isotopic fractionation between coexisting pyrite-barite pairs 12 . Finally, barite represents a gangue mineral associated with sedimentary-exhalative (SEDEX-type) 13 and massive sulphide (VMS) deposits 14 , as well as various stratiform and vein ore bodies 15 .…”

The role of the structures on the fluorite mineralization: Insight to fluid inclusion and alteration map of the Laal-kan fluorite deposit, NW Iran

“…Continuity of northward movement of the Arabian plate caused to increase structural deformation and permeability of host rocks (Vernant et al, 2004;Djamour et al, 2011). The magmatic activities in the UDMA acted as a thermal source of hydrothermal fluids, which usually associated with considerable ore mineralization (Hassanzadeh et al, 2008;Zarasvandi et al, 2014;Zhang et al, 2018;Behyari and Shahbazi, 2019). The host rock structures had an essential role in the emplacement of ore bodies in this region.…”

Characteristics of the Ahmadabad hematite/barite deposit, Iran – studies of mineralogy, geochemistry and fluid inclusions

“…malised to standard material have been widely used as a tool to reveal various geochemical processes (Kato, 1999). Moreover, microthermometry of fluid inclusions can potentially serve as indicator of the physico-chemical environment of barite mineralisation (Zarasvandi et al, 2014). The origin of iron and barite deposits in the Alborz Zone has always been an issue of controversy in many studies.…”