Lithogeochemistry of various hydrothermal alteration types associated with precious and base metal epithermal deposits in the Tarom-Hashtjin metallogenic province, NW Iran: Implications for regional exploration

Siani, Majid Ghasemi; Lentz, David R.

doi:10.1016/j.gexplo.2021.106903

Cited by 7 publications

(16 citation statements)

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“…Additionally, there is a relative increase in Fe content due to the alteration of biotite to chlorite [44]. In Figure 11f, the (2Ca + Na + K)/Al versus K/Al plot indicates the main trends of the mass transfer processes [50,51]. The vertical tie-line at x = 1 represents the feldspar and biotite compositions.…”

Section: Discussion and Summarymentioning

confidence: 99%

Polymetallic Uranium Mineralisation in Rohil, Rajasthan, Western India: Insights from Mode of Occurrences, Structural Controls, Alteration Geochemistry and Exploration

et al. 2023

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Geological and radiometric studies of outcrops aided by extensive subsurface exploration through drill holes in an otherwise soil-covered terrain revealed the existence of low grades, medium tonnage, and metasomatite types of polymetallic uranium deposits at Rohil in India. Microscopic studies, electronprobe micro analyses, and geochemical analyses of samples from lodes indicate the polymetallic nature of mineralisation involving copper and molybdenum, in addition to uranium. Wide variations in the composition of fluid (S-, F-, P-, and O-rich) led to the formation of sulphides, fluorite, U-phosphosilicate, quartz, and magnetite, respectively, and are associated with uraninite. Litho-geochemical analyses from the Rohil deposit indicate multifarious metasomatic alterations associated with polymetallic mineralisation occurring in veins. The major mineralogical and metasomatic controls on rock compositions and the extent of material transfer processes that influenced the host rocks and mineralisati on are quantified by molar element ratio studies and alteration plots. General element ratio (GER) diagrams on chemical analyses of rock samples reveal albitisation and chloritisation as major and microclinisation, sericitisation, carbonatisation, and silicification as minor wall rock alterations associated with ore mineralisation. The alteration box plot between the chlorite–carbonate–pyrite index (CCPI) and the Ishikawa alteration index (AI) indicates the influence of hydrothermal activity and dominance of both albitisation and chloritisation. The ore zone is controlled by meso- and microstructures and the geometry of the soda- and potash-metasomatised zone around hydrothermal veins. This zone contains several anastomosing mineralised veins defined by a prominent joint that is set in quartzite that strikes subparallel to the axial surface of the F2 isoclinal folds and the pervasive schistosity S1 in the quartz–feldspar–biotite schist. Aventurisation of albite and microcline, established through electron probe micro analyses, can be considered as a pathfinder for uranium mineralisation. The close association of uranium and metallic sulphide mineralisation with microstructural, mineralogical (albitisation, chloritisation, and microclinisation), and geochemical variations can be applied as suitable exploration guides in a similar geological set-up worldwide.

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Section: Discussion and Summarymentioning

confidence: 99%

Polymetallic Uranium Mineralisation in Rohil, Rajasthan, Western India: Insights from Mode of Occurrences, Structural Controls, Alteration Geochemistry and Exploration

et al. 2023

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“…Pyrite, sericite, and chlorite-carbonate tend to be associated primarily with argillic and sericite-carbonate-clay minerals in the Siah Jangal-Sar Kahno epithermal Au vein [6]. In the Tarom-Hashtjin precious and base metal epithermal deposit, illite-smectite, illite, K-mica, and K-feldspar-biotite areas indicate argillic, sericitic, and propylitic alteration types, with the presence of K-Al gains [8].…”

Section: Introductionmentioning

confidence: 97%

“…Hydrothermal alteration is common around epithermal mineral deposits, and the alteration types are similar to those found in characteristic epithermal deposits worldwide and in Turkey [1][2][3][4][5][6][7][8][9][10][11]. One of the most crucial features of epithermal gold deposits is that they are always included within the host rock alteration.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the alteration mineral association of quartz ± calcite ± adularia ± illite in low-sulfidation deposits, including Au-Ag, or Ag-Pb-Zn ores [18,19]. Globally, the various alteration types occur at different intensities in the silicified vein [20][21][22][23], monzonite [24], diorite porphyry [5,6], granite-granodiorite porphyry [22,25,26], and metamorphic [22,27]-volcanic rocks [8,21,28].…”

Section: Introductionmentioning

confidence: 99%

“…Hydrothermal alteration has been investigated in detail concerning major-and minor oxides, trace element and rare earth element contents, mass gain and loss, molar ratio, and alteration indices for some epithermal Au deposits [5,6,8,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. Some researchers [51][52][53][54] have suggested that molar ratio plots are effective in the calculation of mass transfer related to hydrothermal alteration systems.…”

Section: Introductionmentioning

confidence: 99%

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Petrography and Geochemistry of Hydrothermal Alteration in the Low-Sulfidation Epithermal Kestanelik Au Deposit, Biga Peninsula, NW Turkey

Kiray,

Cengiz

2024

Minerals

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In this study, the facies and degrees of hydrothermal alteration related to the low-sulfidation epithermal Kestanelik Au deposit in the Biga Peninsula metallogenic province are identified through petrographic studies and analysis of geochemical characteristics, such as mass changes, molar element ratios, and alteration indices. The gold mineralization is located in silicified zones containing veins and stockwork veinlets of silica. In the Kestanelik Au deposit, common hydrothermal alteration is mainly found in the Permian-Upper Cretaceous Çamlıca basement metamorphics and the Eocene granodiorite, and less often in the Eocene Şahinli volcanic rocks of the Karabiga Massif on the Peninsula. Based on mineralogical and geochemical studies conducted on altered samples, four different alteration facies are defined as silicic, sericitic, argillic, and propylitic, which show remarkable differences in the behavior of REEs, Si, K, Al, Na, and Ca elements. The hydrothermal fluids that caused alteration in the Kestanelik Au mineralization and host rocks had low REE contents because of REE mobilization. In addition, the kaolinization of feldspars and micas, and the chloritization of biotite and feldspars, may have caused negative Eu anomalies. The characterization of rocks subjected to hydrothermal alteration that are most influenced by diverse K-metasomatism with the largest K gains and losses in Na–Ca is illustrated by molar element ratio plots. Depending on the intensity of K-metasomatism, gold mineralization increases with increasing K trends toward gold ore veins. In the Kestanelik Au field, the argillic, sericitic, and propylitic alteration types from the zones enclosing the Au ore veins are revealed using the Ishikawa alteration index and chlorite–carbonate–pyrite index. Mass changes in the altered rocks indicate that there are gains in Si, K, and Al, and losses in Na and Ca with the increasing intensity of alteration toward the ore veins. The results confirm the presence of silicic and K–metasomatic (sericite and argillic) and propylitic (Fe-rich chloride) alteration zoning extending from the inner regions to the outer regions, which characterize the epithermal ore systems.

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Geochronology and geochemistry of zircons from fertile and barren intrusions in the Sangan mining area (NE Iran): Implications for tectonic setting and mineral exploration

Siani

Mehrabi²,

Neubauer³

et al. 2022

Journal of Asian Earth Sciences

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Lithogeochemistry of various hydrothermal alteration types associated with precious and base metal epithermal deposits in the Tarom-Hashtjin metallogenic province, NW Iran: Implications for regional exploration

Cited by 7 publications

References 102 publications

Polymetallic Uranium Mineralisation in Rohil, Rajasthan, Western India: Insights from Mode of Occurrences, Structural Controls, Alteration Geochemistry and Exploration

Polymetallic Uranium Mineralisation in Rohil, Rajasthan, Western India: Insights from Mode of Occurrences, Structural Controls, Alteration Geochemistry and Exploration

Petrography and Geochemistry of Hydrothermal Alteration in the Low-Sulfidation Epithermal Kestanelik Au Deposit, Biga Peninsula, NW Turkey

Geochronology and geochemistry of zircons from fertile and barren intrusions in the Sangan mining area (NE Iran): Implications for tectonic setting and mineral exploration

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