Geology, mineral chemistry and formation conditions of calc-silicate minerals of Astamal Fe-LREE distal skarn deposit, Eastern Azarbaijan Province, NW Iran

Baghban, Saeid; Hosseinzadeh, Mahnaz; Moayyed, Mohsen; Mokhtari, Mir Ali Asghar; Gregory, Daniel D.

doi:10.1016/j.oregeorev.2014.12.016

Cited by 30 publications

(13 citation statements)

References 21 publications

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“…without any Ti and Cr (in a.p.f.u) indicating that the clinopyroxenes are of metamorphic origin. Figure 10e shows similarities and differences between clinopyroxenes of the Qozlou Fe skarn and clinopyroxenes from the Cananea, Yerington, Bingham, Twin Butte, Astamal, and Pahnavar skarn deposits (Harris and Einaudi 1982;Mokhtari 2012;Baghban et al 2015Baghban et al , 2016. The chemical formula for clinopyroxene varies slightly and is as follows: The Mn/Fe ratio of clinopyroxene varies according to the type of metal concentrated in the skarn deposit (Nakano et al 1991).…”

Section: Clinopyroxenementioning

confidence: 99%

“…The latter skarns are associated with alkali plutonic and volcanic rocks. Figure 7d shows similarities and differences between garnets of the Qozlou skarn and the Pahnavar, Mission, Yerington, Bingham, Twin Butte, and Astamal skarn deposits (Harris and Einaudi 1982;Mokhtari 2012;Baghban et al 2015Baghban et al , 2016.…”

Section: Garnetmentioning

confidence: 99%

“…7 a, b The BSE images from zoned (a) and without zoning (b) garnet crystals in sample Q-26 from the Qozlou Fe deposit; the EPMA-analyzed points are shown on the photos; c composition of the garnet crystals from the Qozlou Fe skarn deposit on the Ad-Gr-(Sp + Al + Pyp) ternary diagram; representative EPMA data are given in Table 1; d comparison of the Fe/(Fe + Al) mole fraction of garnet from the Qozlou skarn and some other skarn deposits. Adopted data from Einaudi (1982a), Pahnavar data from Mokhtari (2012), Yerington data from Harris and Einaudi (1982), Astamal, Bingham, Mission, and Twin Butte data from Baghban et al (2015) Fig. 8 a Compositional variations (FeO-Al 2 O 3 ) from core to the rims of the garnet crystals in the Qozlou Fe skarn deposit; b compositional variation (andradite and grossularite) from core to the rim in one of the zoned garnet crystals (Fig.…”

Section: Physico-chemical Condition Of Skarn Formationmentioning

confidence: 99%

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Mineral chemistry and formation conditions of calc-silicate minerals of Qozlou Fe skarn deposit, Zanjan Province, NW Iran

Mokhtari

Kouhestani

Gholizadeh³

2019

Arab J Geosci

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The Qozlou Fe skarn deposit is located at the Abhar-Mahneshan belt of the Central Iranian Zone. It is associated with Upper Eocene porphyritic granite that intruded into the Upper Cretaceous impure carbonaceous rocks. The Qozlou granite has high-K calc-alkaline affinity and is classified as subduction-related metaluminous I-type granitoids. Skarn aureole in the Qozlou is composed of endoskarn and exoskarn zones, with the exoskarn zone being the main skarn and mineralized zone. It includes garnet skarn, garnet-pyroxene skarn, pyroxene skarn, epidote skarn, and pyroxene-bearing marble sub-zones. The Qozlou Fe deposit is 300 m long and 5-30 m wide. Magnetite is the main ore mineral associated to pyrite, chalcopyrite, and pyrrhotite. Garnet, clinopyroxene, actinolite, epidote, calcite, and quartz occur as gangue minerals. Covellite, hematite, and goethite were formed during the supergene processes. The ore and gangue minerals have massive, banded, disseminated, brecciated, veinveinlets, replacement, and relict textures. EPMA data indicate that garnets have andradite-grossularite compositions (Ad 39.97-100-Gr 0-49.62) and clinopyroxenes have diopsidic composition (En 29.43-42.5-Fs 14.31-20.99-Wo 43.08-50.17). Based on mineralogical and textural criteria, skarnification processes in the Qozlou skarn can be categorized into three discrete stages: (1) isochemical (metamorphic-bimetasomatic), (2) metasomatic prograde, and (3) metasomatic retrograde. Anhydrous calc-silicate minerals (garnet and clinopyroxene) were formed during the prograde metasomatic stage, while ore minerals and hydrous calc-silicate minerals were formed during the retrograde ore-forming sub-stage. Temperature and ƒO 2 conditions range between 430 and 550°C and 10 −26 and 10 −23 , respectively, for the metasomatic prograde stage. The retrograde metasomatizing fluids had likely ƒS 2 = 10 −6.5 and temperatures < 430°C at the beginning of the ore-forming sub-stage.

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Section: Clinopyroxenementioning

confidence: 99%

Section: Garnetmentioning

confidence: 99%

Section: Physico-chemical Condition Of Skarn Formationmentioning

confidence: 99%

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Mineral chemistry and formation conditions of calc-silicate minerals of Qozlou Fe skarn deposit, Zanjan Province, NW Iran

Mokhtari

Kouhestani

Gholizadeh³

2019

Arab J Geosci

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“…Garnet/pyroxene ratios are usually used to determine the oxidationstate of hydrothermal fluids in skarn deposits (Baghban, Hosseinzadeh, Moayyed, Mokhtari, & Gregory, 2015;Meinert, 1997;Meinert, Hedenquist, Satoh, & Matsuhisa, 2003;Zhai et al, 2014;Zuo et al, 2015). The oxidized skarn would preferentially contain andradite garnet (contains Fe 3+ ) and diopside, whereas it tends to contain grossular garnet and hedenbergite clinopyroxene (contain Fe 2+ ) in reduced conditions (Einaudi & Burt, 1982;Zuo et al, 2015).…”

Section: Garnet Growth Process and Hydrothermal Fluid Evolutionmentioning

confidence: 99%

Garnet composition as an indicator of skarn formation: LA‐ICP‐MS and EPMA studies on oscillatory zoned garnets from the Haobugao skarn deposit, Inner Mongolia, China

et al. 2018

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Oscillatory zoned garnets are widespread in the Haobugao skarn‐type copper–lead–zinc–iron polymetallic deposit, and they can record garnet growing process in the early stages of metallogenesis. In order to investigate the skarn‐forming process and hydrothermal fluid evolution of the Haobugao deposit, major, trace, and rare earth element (REE) contents of oscillatory zoned garnets were analysed by electron probe microscope analysis (EPMA) and laser‐ablation inductively‐coupled plasma mass spectrometry (LA‐ICP‐MS) techniques. Three distinct generations of garnets were identified: the first generation garnets (Grt I) are Fe‐rich, euhedral, fine‐ to coarse‐grained, isotropic, show characteristic concentric oscillatory zoning, and have light rare earth element (LREE)‐enriched and heavy rare earth element (HREE)‐depleted REE patterns, with strong positive Eu anomalies and low ΣREE concentrations. The second generation garnets (Grt II) are Al‐rich, anhedral to subhedral, anisotropic, with abundant oscillatory zoning alone the growth lines, and have LREE‐depleted and HREE‐enriched REE patterns, with negligible Eu anomalies and relatively higher ΣREE concentrations. The third generation garnets (Grt III) are anhedral, anisotropic and generally occurred at the rim of pre‐existing Grt I or beside fractures that cut through the pre‐existing Grt I crystals. All these three generations garnets show oscillatory zoning under an optical microscope and have different compositions from each other, but there's limited chemical zoning (such as bell‐shaped zoning of major elements) in each individual garnet crystal. The texture and composition characteristics of the garnets indicate that the Grt I is precipitated rapidly from high temperature and oxidized magmatic fluids by advective metasomatism, in a high water/rock ratio condition; the Grt II is precipitated from low temperature residual fluids that were in equilibrium with the host rock by diffusive metasomatism, in a low water/rock ratio condition; and the Grt III is formed by retrograde hydrothermal‐metasomatic alteration of pre‐existing garnets. The incorporation of REE into garnet is controlled by its crystal chemistry and fluid composition, dominated by the YAG (yttrium aluminium garnet) ‐type substitution mechanism ()X2+−1VIIIREE3++1VIIISi4+−1IVZ3++1IV.

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“…There are many iron skarns in Iran. Some economically important well-known iron skarn deposits in Iran are as: Sangan [1] Gelali, Baba Ali, Khosro Abad and Shahrak [2] and Astamal [3] [4]. According to this, Saheb Fe-Cu skarn deposit is North-West Iran and coordinated 34˚46' to 35˚46' east longitude and 36˚16' to 36˚17' north latitude (part of Sanandaj-Sirjan zone is enclosed).…”

Section: Introductionmentioning

confidence: 99%

Mineralization, Mineralogy and Geochemistry of Saheb Fe-Cu Deposit of Saqqez (Kurdestan), NW Iran

Zandi¹,

Rad²,

Gourabjeripour³

et al. 2018

OJG

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The Saheb Fe-Cu skarn deposit is located in the Sanandaj-Sirjan metamorphic belt, SE Saqqez, western Iran and has been formed along the contact between the Oligo-Miocene aged Saheb granitoid and the Permian aged impure calcareous rocks and includes endoskarn and exoskarn. Exoskarn is widely developed and includes garnet and epidote skarn zones. The majority of mineralized zones are concentrated in garnet skarn. The relatively oxidizing mineralogical assemblage of the Saheb skarn includes garnet (andradite-grossular), pyroxene (diopside-hedenbergite), magnetite and hematite. Magnetite is the main and abundant ore mineral throughout the ore deposit. Based on field evidences and microscopic studies of skarn zone samples, two stages of prograde and retrograde alteration are distinguishable. According to the results of sample analysis of Saheb skarn intrusive body by XRF and ICP-MS techniques, the combination of this body is chiefly granite to granodiorite-diorite and belongs to the I-type granitoids, metaluminous and K-rich calc-alkaline series. The Saheb granitoid is related to the VAG (Volcanic Arc Granite) tectonic setting.

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Geology, mineral chemistry and formation conditions of calc-silicate minerals of Astamal Fe-LREE distal skarn deposit, Eastern Azarbaijan Province, NW Iran

Cited by 30 publications

References 21 publications

Mineral chemistry and formation conditions of calc-silicate minerals of Qozlou Fe skarn deposit, Zanjan Province, NW Iran

Mineral chemistry and formation conditions of calc-silicate minerals of Qozlou Fe skarn deposit, Zanjan Province, NW Iran

Garnet composition as an indicator of skarn formation: LA‐ICP‐MS and EPMA studies on oscillatory zoned garnets from the Haobugao skarn deposit, Inner Mongolia, China

Mineralization, Mineralogy and Geochemistry of Saheb Fe-Cu Deposit of Saqqez (Kurdestan), NW Iran

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