The tetrad effect in REE distribution patterns: A quantitative approach to genetic issues of argillic and propylitic alteration zones of epithermal Cu-Pb-Fe deposits related to andesitic magmatism (Khan Kandi District, NW Iran)

Abedini, Ali; Azizi, Mansour Rezaei; Dill, Harald G.

doi:10.1016/j.gexplo.2020.106516

Cited by 10 publications

(7 citation statements)

References 74 publications

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“…The overall compositions of the diopsides from Russia remained relatively uniform, indicating their crystallization in a similar magma system. They had higher Cr, Sc, Zr, Sr, and REE, which were close to the composition of volcanic clinopyroxene in basalt magma [52,53]. Clinopyroxene is commonly present in igneous rocks and exhibits large compositional variations.…”

Section: Origin Of Different Diopsides: Elemental Constraintsmentioning

confidence: 62%

Gemology, Mineralogy, and Spectroscopy of Gem-Quality Diopside from Pakistan and Russia: New Insights for the Chromogenic Mechanism and Possible Origin

Wang

He²,

et al. 2023

Crystals

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Green diopside is currently popular in the jewelry market due to its attractive color and excellent transparency. Gem-quality diopsides are mainly sourced from Pakistan, Italy, Russia, and other places. The color, geographic origin, and formation mechanism are the main factors affecting the value of gemstones, which can be determined by examining their gemology and composition characteristics. This study systematically characterizes the standard gemology of green diopsides from Pakistan and Russia and compares them with the blue diopsides produced within the skarn process and the diopsides from the nearby region in Russia from previous studies by gemological microscopy, spectral testing (infrared, Raman and ultraviolet-visible spectroscopy), and chemical analyses (electron probe and laser ablation inductively coupled plasma mass spectrometry). The results show that the spectral characteristics and phase composition of the green diopside samples from Pakistan and Russia have excellent uniformity and similarity. The high Cr, Fe, V, and Ni contents are the reasons why they appear as green. Meanwhile, the elemental characteristics of the diopside are effective tools for distinguishing different origins of different diopsides. The Russian green diopsides have higher contents of Sr, Sc, Zr, and rare earth elements (REE), indicating that they are related to alkaline ultrabasic rocks, and the source of the diopside sample from Pakistan is metamorphic rock.

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Section: Origin Of Different Diopsides: Elemental Constraintsmentioning

confidence: 62%

Gemology, Mineralogy, and Spectroscopy of Gem-Quality Diopside from Pakistan and Russia: New Insights for the Chromogenic Mechanism and Possible Origin

Wang

He²,

et al. 2023

Crystals

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“…During the interaction of acidic solutions with the host rock, ligands such as SO 4 2– and Cl – are consumed because of the increase in the pH of the solution. Hence, highly acidic hydrothermal fluids are considered to generate large tetrad effect values (Abedini et al , 2020). Such solutions probably produced the intermediate argillic alterations observed in the Hashtjin area, as is supported by the formation of kaolinite and goethite-bearing assemblages (Dill et al , 2015).…”

Section: Discussionmentioning

confidence: 99%

Rare earth element geochemistry of altered pyroclastic rocks in the Hashtjin area of north-west Iran

et al. 2020

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This study evaluates the rare earth element (REE) geochemistry in altered trachyandesitic ignimbrites, tuff and lava flows in the Hashtjin area by assessing chondrite-normalized REE patterns and Y/Ho geochemical ratios. Modifications in the REE patterns took place along altered fault zones that were affected by hypogene and supergene alterations. The precursor volcanic and pyroclastic rocks contain phenocrysts of plagioclase accompanied by augite, zircon, apatite and pyrite. Based on X-ray diffraction analysis, the main mineral assemblages of the altered units consist of kaolinite as the main clay mineral, SiO 2 polymorphs (quartz and cristobalite) and anatase as a minor constituent. The chondrite-normalized REE patterns of argillic samples reveal fractionation of light REEs (LREEs) compared to heavy REEs (HREEs), together with a marked Eu anomaly and a weak W-type tetrad effect related to the weak non-charge radius control (CHARAC) behaviour of REEs and slightly higher Y/Ho and Zr/Hf ratios. The relationship between the Y/Ho and Zr/Hf ratios and recognizable T 3 and T 4 effects (tetrad effect) suggests that an increasing degree of water-rock interaction occurred during hypogene alteration processes by acidic hydrothermal fluids that were overprinted by supergene alteration. Water-rock interaction and adsorption by Mn-oxides and clay minerals are considered to have played important roles in determining the close to non-CHARAC behaviour of REEs during the argillic alteration of the pyroclastic rocks in the Hashtjin area.

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“…Geochemical and mineralogical characteristics are usually used to indicate the genesis and crystallization sequence of minerals (Pirajno and Smithies, 1992;Siahcheshm et al, 2014;Rezaei Azizi et al, 2018a;Rezaei Azizi et al, 2018b;Rajabpour et al, 2018;Zhao et al, 2019;Abedini et al, 2020;Harlaux et al, 2020). In the Mg-Fe/(Fe + Mg) diagram, the Fe/(Fe + Mg) values of tourmaline indicate their distance from the granitic source in a granite-related hydrothermal Sn-W deposit (Pirajno and Smithies, 1992).…”

Section: Origin Of Tourmalines In the Hydrothermal Vein And Skarnmentioning

confidence: 99%

Hydrothermal fluid evolution in the Cuonadong Sn–W–Be polymetallic deposit, southern Tibet: indicated by the in–situ element and boron isotope compositions of tourmaline

Xie

Yan²,

Zhang³

et al. 2023

Front. Earth Sci.

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The Cuonadong Sn–W–Be polymetallic deposit in the Himalayan leucogranite belt is a representative hydrothermal deposit. The role of fluid exsolution directly from magma and the fluid reaction with surrounding rocks for ore-forming element enrichment is still controversial. Tourmaline is a significant B-bearing mineral in the hydrothermal deposit, and its geochemical and B isotopic signatures can record the source and evolution of the ore-forming fluid. Two types of hydrothermal tourmaline in the hydrothermal quartz vein (Tur-1) and skarn (Tur-2) were used in this study. Both Tur-1 and Tur-2 have low X-site occupancy and mainly belong to the alkali group. Tur-1 plots in the schorl field, whereas Tur-2 is largely Mg-rich dravite. The B isotope analyses of Tur-1 have δ11B values of −13.7 to −13.2‰, whereas Tur-2 has higher δ11B values of −11.1 to −9.3‰. The distinct contact relationship and geochemical compositions suggest that Tur-1 in the hydrothermal vein was formed from a magmatic-hydrothermal fluid with little influence from surrounding rocks and had a genetic relationship with the Cuonadong leucogranite, whereas Tur-2 in the skarn involved more fluid from surrounding rocks with high δ11B values and strong metasomatic texture. The higher ore-forming element contents in Tur-2 than those in Tur-1 indicate that the reaction between the magmatic exsolution fluid and the surrounding rock is essential for the enrichment and precipitation of ore-forming elements.

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The tetrad effect in REE distribution patterns: A quantitative approach to genetic issues of argillic and propylitic alteration zones of epithermal Cu-Pb-Fe deposits related to andesitic magmatism (Khan Kandi District, NW Iran)

Cited by 10 publications

References 74 publications

Gemology, Mineralogy, and Spectroscopy of Gem-Quality Diopside from Pakistan and Russia: New Insights for the Chromogenic Mechanism and Possible Origin

Gemology, Mineralogy, and Spectroscopy of Gem-Quality Diopside from Pakistan and Russia: New Insights for the Chromogenic Mechanism and Possible Origin

Rare earth element geochemistry of altered pyroclastic rocks in the Hashtjin area of north-west Iran

Hydrothermal fluid evolution in the Cuonadong Sn–W–Be polymetallic deposit, southern Tibet: indicated by the in–situ element and boron isotope compositions of tourmaline

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