Geology, isotope geochemistry, and fluid inclusion investigation of the Robat Zn-Pb-Ba deposit, Malayer-Esfahan metallogenic belt, southwestern Iran

Niroomand, Shojaeddin; Haghi, Ahmad; Rajabi, Abdorrahman; Shabani, Amir Ali Tabbakh; Song, Yougui

doi:10.1016/j.oregeorev.2019.103040

Cited by 10 publications

(5 citation statements)

References 59 publications

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“…Barite is an important gangue mineral, replaced by coarse-grained galena and sphalerite (e.g., Irankuh and Tiran mining districts, Robat and Kuhkolngeh deposits) and some of the barite ores are economic (e.g., Robat II deposit). However, dolomitization is common in these deposits, but silicification is the major hydrothermal alteration at the Emarat (Ehya et al, 2010), Lakan, Robat, Kuhkolangeh (Peernajmodin et al, 2018;Niroomand et al, 2019), Khanabad and Eastern Haft-Savaran deposits (Mahmoodi, 2018;Rajabi et al, 2019a). Fe-rich dolomite is also a frequently observed alteration in these deposits (Boveiri et al, 2018;Mahmoodi et al, 2019).…”

Section: Irish-type Zn-pb (±Ag±ba) Depositsmentioning

confidence: 99%

“…These include shale-hosted massive sulphide (e.g., Koushk, Chahmir, Zarigan, Hosseinabad, Ab-Bagh I), Irishtype (e.g., Kuhkolangeh, Mehdiabad, Irankuh, Ahangaran, Farahabad, Mansourabad, Robat) and Mississippi Valley-Type (e.g., Nakhlak, Khanjar-Reshm, Talkhab, Gowmar, Zenoghan, Ab-bid) deposits (Fig. 1a; Boveiri et al, 2017;Mahmoodi et al, 2018Mahmoodi et al, , 2021Niroomand et al, 2019;Peernajmodin et al, 2019;Movahednia et al, 2020;Rajabi et al, 2012bRajabi et al, , 2015aRajabi et al, , 2015bRajabi et al, , 2020Rajabi et al, , 2022 that occur in a wide variety of siliciclastic and carbonate rocks from the early Cambrian to the Tertiary. Cretaceous carbonates are the most common host rocks for the Irish-type deposits of Iran, which are largely concentrated in the Malayer-Esfahan metallogenic belt (MEMB) in southwestern Iran, and in the Yazd-Anarak metallogenic belt (YAMB) in Central Iran (Figs.…”

Section: Introductionmentioning

confidence: 99%

“…Rajabi et al (2012a) relied on tectono-sedimentary and textural evidence to describe the metallogeny and origin of the Cretaceous-hosted Zn-Pb (±Ag±Ba) deposits and proposed that most of these deposits formed as a result of SedEx-like (Irish-type) ore-forming processes, related to the early Cretaceous back-arc basins which formed southwest of the Central Iranian Microcontinent (Nain-Baft basin). Recent geological and geochemical studies in these belts (Yarmohammadi et al, 2016;Boveiri et al, 2015;Mahmoodi, 2018;Peernajmodin, 2018;Peernajmodin et al, 2018;Niroomand et al, 2019;Maghfouri et al, 2019) provided evidence of unusual Zn-Pb (±Ag±Ba) mineralizing processes, by sub-seafloor replacement in an extensional environment, akin to those of the sediment-hosted Irish-type deposits.…”

Section: Introductionmentioning

confidence: 99%

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An introduction to Irish-type Zn-Pb deposits in early Cretaceous carbonate rocks of Iran

Rajabi,

Mahmoodi,

Rastad

et al. 2023

Irish-Type Zn-Pb Deposits Around the World

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Early Cretaceous carbonates are the most common host rocks for Irish-type deposits in Iran. They are largely concentrated in the Malayer-Esfahan metallogenic belt (MEMB) in southwestern Iran, and Yazd-Anarak metallogenic belt in Central Iran. They include some world‐class ore deposits such as Mehdiabad, Irankuh, and Ahangaran. These stratabound deposits are hosted mostly in carbonates with minor siltstones and volcanic components, that formed in extensional and passive margin environments that are related to the Nain-Baft back-arc basin. The deposits are stratabound and comprise wedge-shaped to tabular sulphide-barite orebodies and occur in several different stratigraphic horizons. Dolomitization and silicification are the main wall-rock alteration styles. Replacement textures are common, and orebodies represent complex textures of sulphides and barite, such as brecciated, colloform, zebra, minor laminated, and banded replacement. Barite is an important gangue mineral in the MEMB and YAMB deposits, partly replaced by coarse-grained galena, sphalerite, and chalcopyrite. Sulphides from these Irish-type deposits have a wide spread of light δ34S values (with the majority falling between -25 to +5‰) with mostly bacterial sulphate reduction (BSR) origin. Fluid inclusion studies show that homogenization temperatures of ore minerals are typically 120 to about 280°C (majority 225-275°C), and salinities range from 2 to 24 wt.% NaCl eq, with the majority falling between 8 and 22 wt% NaCl eq. Using the criteria outlined in this study, early Cretaceous extensional sedimentary basins (e.g., Nain-Baft) are highlighted as target areas for exploration of world-class Irish-type ore deposits and correspond well with the periods of expulsions of Cretaceous CaCl2-rich brines.

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Section: Irish-type Zn-pb (±Ag±ba) Depositsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An introduction to Irish-type Zn-Pb deposits in early Cretaceous carbonate rocks of Iran

Rajabi,

Mahmoodi,

Rastad

et al. 2023

Irish-Type Zn-Pb Deposits Around the World

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“…The Emarat Zn-Pb deposit in the northwestern part of the Arak Mining District was classified as an MVT deposit by Ehya et al (2010) based on S and Pb isotopic data for hydrothermal sulphide minerals, whereas the Shams-Abad Fe-Mn-(Pb) deposit in the central part of the Arak Mining District was classified as a synsedimentary seafloor hydrothermal deposit (Ehya & Marbouti, 2021). Based on geological and textural characteristics, the Robat Zn-Pb-Ba deposit was classified as an Irish-type deposit by Niroomand et al (2019). That two deposits within the same stratigraphic host rocks and 12 kilometers apart (Fig.…”

Section: Introductionmentioning

confidence: 99%

Geological and textural characteristics as evidence for Irish-type mineralization in the Eastern Haft-Savaran deposit

Mahmoodi,

Peter,

Rajabi

et al. 2023

Irish-Type Zn-Pb Deposits Around the World

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The Eastern Haft-Savaran Zn-Pb-(Ba) deposit, located in the southeastern part of the Arak Mining District of the Malayer-Esfahan Metallogenic Belt, Iran, is hosted in the uppermost part of an early Cretaceous massive limestone unit that is capped by shale. The mineralization has a sheet-like geometry and is associated with intense dolomitization and silicification. The mineralization is mineralogically zoned: chalcopyrite-galena-pyrite-sphalerite-tetrahedrite occurs in the southern part of the deposit; sphalerite-galena-pyrite occurs in the central part of the deposit; and barite-galena-sphalerite-pyrite occurs in the northern part of the deposit. The thickest mineralization and most intense alteration are in the southern part of the deposit, associated with an aphyric rhyodacite flow containing minute euhedral barite crystals and Cu-bearing sulphides in vein/veinlets and disseminations, indicating this was the mineralizing fluid upflow site. Three hydrothermal mineralization stages are recognized. The first is mud lime sedimentation, framboidal pyrite, minute euhedral barite, sphalerite, galena and early dolomite. Minute euhedral barites are cut by microsparite formed by micrite recrystallization during diagenesis. First stage sphalerite and galena occur as inclusions in framboidal pyrite, and these were remobilized into inclusions in euhedral pyrite during recrystallization. The second (main) stage mineralization includes sphalerite, galena, chalcopyrite, tetrahedrite, pyrite and barite that with dolomite and quartz as gangue minerals replaced first stage mineralization and is associated with silicification and dolomitization. The third stage of mineralization comprises sphalerite and galena that is associated with dolomitization and calcitization. The occurrence of mineralization in an extensional back arc setting, massive limestone host rock, intense and pervasive host rock alteration, Fe-dolomite associated with main stage mineralization, the presence of mineralization load casts and minute euhedral barite, the remobilization of first stage of mineralization during diagenetic evolution of framboidal pyrite to euhedral pyrite, and timing of mineralization during early diagenesis of mud lime collectively indicate the Eastern Haft-Savaran deposit can be classified as an Irish-type deposit.

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“…For example, they allow us to distinguish between a single-stage event and multiple overprints (Yuan et al 2018; Cave et al 2020), differentiating metallogenic types (e.g. VHMS-type, skarn-type, MVT-type; Ye et al 2011; Leng et al 2018; Yuan et al 2018; Niroomand et al 2019; Xiao & Li, 2019; Zhuang et al 2019; Oyebamiji et al 2020), and constraining physicochemical conditions (e.g. T, pH, f O 2 ) of the hydrothermal fluid (Hu et al 2018; Leng et al 2018; Horn et al 2019; Maurer et al 2019; Zhuang et al 2019; Cave et al 2020; Knorsch et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Mineral textures, mineral chemistry and S isotopes of sulphides from the Tianbaoshan Pb–Zn–Cu deposit in the Sichuan–Yunnan–Guizhou triangle: implications for mineralization process

Yang

Chen²,

Qin³

et al. 2022

Geol. Mag.

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The carbonate-hosted Pb–Zn deposits in the Sichuan–Yunnan–Guizhou (SYG) triangle region are important Indosinian deposits in South China. The Tianbaoshan deposit is a typical large Pb–Zn deposit in the SYG area and occurs as pipe-like type, hosted by Sinian dolostone. It contains ∼26 Mt Zn–Pb ore (7.76–10.09 % Zn, 1.28–1.50 % Pb and 93.6 g t−1 Ag) and >0.1 Mt Cu ore (2.55 % Cu). In this study, the detailed mineral textures, mineral chemical and sulphur isotopic compositions of the various sulphides have been analysed to constrain the abnormal enrichment mechanism and mineralization relationship. Four mineralization stages have been recognized: Stage 1, minor early pyrite (Py1) with relics and infill of intergranular dolomite or quartz grains; Stage 2, Cu mineralization with coarse-grained, elliptical crystal chalcopyrite (Cp1); (3) Stage 3, Zn mineralization with dark fine-grained sphalerite (Sph1) and light coarse-grained sphalerite (Sph2); and (4) Stage 4, as represented by a quartz–calcite assemblage with galena, minor pyrite (Py2) and chalcopyrite (Cp2). The petrography of the sulphide minerals (Py1, Cp1, Sph1 and Sph2) demonstrates a mutual inclusion relationship. The nature of this relationship from core to rim and their similar sulphur isotope values (5.5–8.3 ‰) indicates a single sulphur source, suggesting that the different mineralization types are the result of different stages of a continuous hydrothermal system. Sphalerite geothermometer study suggests that sphalerite in the Tianbaoshan deposit formed in a low-temperature (<200 °C) hydrothermal system. The low concentrations of Mn and In, low In/Ge ratios and high Fe/Cd ratios in the sphalerite are consistent with those of Mississippi Valley-type (MVT) deposits, but different from those of magmatism-related deposits (e.g. epithermal, skarn and VMS deposits). The positive δ34S values for Py1 (5.1–7.9 ‰), Cp1 (5.1–7.2 ‰), Sph1 (4.7–7.4 ‰), Sph2 (3.9–8.7 ‰), Py2 (4.4–9.3 ‰) and Cp2 (5.0–6.8 ‰) indicate a sulphur source from thermochemical reduction of coeval seawater sulphate. Widely developed dissolved textures (caverns and breccias) with massive sulphide infillings and deformed host rock remnants suggest that replacement of host dolostones by ore fluids was volumetrically significant and the ore formed nearly simultaneously with the cavities. The Tianbaoshan deposit is a typical MVT deposit, which resulted from mixing of a H2S-rich fluid and a metal-rich fluid, with thermochemical sulphate reduction occurring before ore precipitation rather than during ore precipitation.

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Geology, isotope geochemistry, and fluid inclusion investigation of the Robat Zn-Pb-Ba deposit, Malayer-Esfahan metallogenic belt, southwestern Iran

Cited by 10 publications

References 59 publications

An introduction to Irish-type Zn-Pb deposits in early Cretaceous carbonate rocks of Iran

An introduction to Irish-type Zn-Pb deposits in early Cretaceous carbonate rocks of Iran

Geological and textural characteristics as evidence for Irish-type mineralization in the Eastern Haft-Savaran deposit

Mineral textures, mineral chemistry and S isotopes of sulphides from the Tianbaoshan Pb–Zn–Cu deposit in the Sichuan–Yunnan–Guizhou triangle: implications for mineralization process

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