A red-corundum-bearing vein in the Rai–Iz ultramafic rocks, Polar Urals, Russia: the product of fluid activity in a subduction zone

Meng, Fanwei; Shmelev, Vladimir R.; Куликова, К. В.; Ren, Yong’an

doi:10.1016/j.lithos.2018.09.025

Cited by 9 publications

(9 citation statements)

References 51 publications

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“…World-class sapphire deposits in desilicated pegmatites have been described from the Umba River (Solesbury, 1967) and Kalalani (Seifert and Hyršl, 1999) in Tanzania; the Sumjam deposit in Kashmir (Lydekker, 1883); the Mangare area in southern Kenya, including the well-known John Saul mine (Mercier et al, 1999;Simonet, 2000); and the Polar Urals in Russia (Meng et al, 2018).…”

Section: Geology and Genesis Of Metamorphic Corundummentioning

confidence: 99%

Geology of Corundum and Emerald Gem Deposits: A Review

Giuliani¹,

Groat²

2019

G&G

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The great challenge of geographic origin determination is to connect the properties and features of individual gems to the geology of their deposits. Similar geologic environments can produce gems with similar gemological properties, making it difficult to find unique identifiers. Over the last two decades, our knowledge of corundum and emerald deposit formation has improved significantly.The mineral deposits are classically separated into primary and secondary deposits. Primary corundum deposits are subdivided into two types based on their geological environment of formation: (1) magmatic and (2) metamorphic. Magmatic deposits include gem corundum in alkali basalts as in eastern Australia, and sapphire in lamprophyre and syenite as in Montana (United States) and Garba Tula (Kenya), respectively. Metamorphic deposits are divided into two subtypes (1) metamorphic deposits sensu stricto (in marble; mafic and ultramafic rocks, or M-UMR), and (2) metamorphicmetasomatic deposits characterized by high fluid-rock interaction and metasomatism (i.e., plumasite or desilicated pegmatites in M-UMR and marble, skarn deposits, and shear zone-related deposits in different substrata, mainly corundum-bearing Mg-Cr-biotite schist). Examples of the first subtype include the ruby deposits in marble from the Mogok Stone Tract or those in M-UMR from Montepuez (Mozambique) and Aappaluttoq (Greenland). The second subtype concerns the sapphire from Kashmir hosted by plumasites in M-UMR.Secondary corundum deposits (i.e., present-day placers) result from the erosion of primary corundum deposits. Here, corundum is found in the following types of deposits: eluvial (derived by in situ weathering or weathering plus gravitational movement), diluvial (scree or talus), colluvial (deposited at the base of slopes by rainwash, sheetwash, slow continuous downslope creep, or a combination of these processes), and alluvial (deposited by rivers). Today, most sapphires are produced from gem placers related to alkali basalts, as in eastern Australia or southern Vietnam, while placers in metamorphic environments, such as in Sri Lanka (Ratnapura, Elahera) and Madagascar (Ilakaka), produce the highest-quality sapphires. The colluvial Montepuez deposit in Mozam bique provides a huge and stable supply of clean and very highquality rubies. Primary emerald deposits are subdivided into two types based on their geological environment of formation: (1) tectonic-magmatic-related (Type I) and (2)tectonic-metamorphic-related (Type II). Several subtypes are defined and especially Type IA, hosted in M-UMR, which accounts for about 70% of worldwide production (Brazil, Zambia, Russia, and others). It is characterized by the intrusion of pegmatites or quartz veins in M-UMR accompanied by huge hydrothermal fluid circulation and metasomatism with the formation of emerald-bearing desilicated pegmatite (plumasite) and biotite schist. Type IB in sedimentary rocks (China, Canada, Norway, Kazakhstan, and Australia) and Type IC in granitic rocks (Nigeria) are of minor importance.T...

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Section: Geology and Genesis Of Metamorphic Corundummentioning

confidence: 99%

Geology of Corundum and Emerald Gem Deposits: A Review

Giuliani¹,

Groat²

2019

G&G

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“…The εHf (T) values for oligoclasites of similar age (382±2 Ma), developed in the Rai-Iz ophiolites, vary widely from -11.2 to +11.4. We suggest that these values are determined by the effect of a subduction fluid on the mantle wedge peridotites during the formation of oligoclasite veins [Meng et al, 2018].…”

Section: Hf Isotope Compositionmentioning

confidence: 91%

GRANITOID MAGMATISM IN THE NORTH OF THE URALS: U–Pb AGE, EVOLUTION, SOURCES

Удоратина

Куликова

Шуйский

et al. 2021

Geodin. tektonofiz.

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This work presents the summarization of U–Pb (SIMS, TIMS) zircon dates and petrogeochemical signatures of granitoids of the north of the Urals (Polar, Subpolar, and Northern Urals) obtained over the last decade. Granitе melts were formed from melting of different substrates, highly heterogeneous in composition and age, at all geodynamic stages distinguished in the studied area. Preuralides include island arc–accretionary (735–720 Ma, 670 Ma), collisional (650–520 Ma), and rift-related (520–480 Ma) granitoids. Uralides includes primitive island-arc granitoids (460–429 Ma), mature island-arc granitoids (412–368 Ma), early collisional (360–316 Ma) and late collisional (277–249 Ma) granitoids. As a result, the general trend of variations of oxygen (δ18OZrn, ‰), neodymium (εNd(t)wr), and hafnium (εHf(t)Zrn) isotope compositions identified in time. Mantle isotope compositions (δ18OZrn (+5.6), εNd(t)wr (+1.7), εHf(t)Zrn (+8.7...+10.6)), common for island arc granitoids (Preuralides) are changed by crustal–mantle ones (δ18OZrn (+7.2...+8.5), εNd(t)wr (–4.8...+1.8), εHf(t)Zrn (+2.1 to +13)), typical of collisional granites. According to this, the crustal matter played a significant role during the formation of the latter. The crustal-mantle isotope compositions are changed by the mantle ones, characteristic of rift-related (δ18OZrn (+4.7...+7), εNd(t)wr (+0.7...+5.6), εHf(t)Zrn (–2.04...+12.5)) and island-arc (Uralides; δ18OZrn (+4.2...+5.7), εNd(t)wr (+4.1...+7.4), εHf(t)Zrn (+12...+15.2)) granitoids.

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“…The chlorite-and amphibole-bearing harzburgites are the products of polyphase metamorphism (Meng et al 2018) and are common within and outside of the metaperidotite zone (e.g., close to the Central Chromite Deposit (CCD), where diamond has been observed; Fig. 1b) (Shmelev et al 2014;Yang et al 2015).…”

Section: Sample Descriptionsmentioning

confidence: 99%

“…The Ray-Iz (or Rai-Iz) ophiolite comprises mainly peridotites, which is considered a residual mantle formed by multistage partial melting under different tectonic settings (beneath a mid-ocean ridge and a suprasubduction zone), based on the mineral chemistry of the residual peridotites (Shmelev 2011;Shmelev et al 2018Shmelev et al , 2019. The Ray-Iz peridotite massif underwent metasomatism (via an interaction with an arc-type melt or a hydrous uid) (Glodny et al 2003;Ishimaru et al 2015;Meng et al 2018) and retrograde metamorphism during exhumation (Shmelev 2011). The Ray-Iz ophiolite has received signi cant attention, attributed to the occurrence of diamond and other unusual minerals in the podiform chromitites residing in peridotites (Yang et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Spherulitic orthopyroxene–bearing metaperidotite in Ray-Iz ophiolites (Polar Urals): high-pressure deserpentinization in a mantle wedge

Ishimaru,

Sonoda,

Miura

et al. 2024

Preprint

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The Ray-Iz (or Rai-Iz) peridotite massif, the main part of the Paleozoic Ray-Iz ophiolite in the Polar Urals, comprises harzburgite, lherzolite, and dunite lenses, which contain abundant chromitite pods. The metaperidotite zone occurs as the ENE-WSW linear zone (width: ~4 km) at the center of the Ray-Iz peridotite massif. We sampled peculiar orthopyroxene-rich peridotites from the metaperidotite zone that contain spherulitic aggregates of orthopyroxene. This investigation provided insights into the key petrologic nature of the Ray-Iz peridotite massif, particularly its P-T history. The orthopyroxene-rich rocks and their surrounding metaperidotites contain various metamorphic minerals, such as tremolite, chlorite, serpentines (lizardite and chrysotile), and talc. Furthermore, the olivine and orthopyroxene grains in these lithologies contain minute inclusions of opaque spinels (ferritchromite and Cr-rich magnetite) and metamorphic minerals (tremolite, chlorite, serpentine minerals, etc.). The spinel occurring both as discrete grains and inclusions in the orthopyroxene-rich rocks exhibits low Al and high Fe3+ concentrations, and the contents of Ca, Al, and Cr in orthopyroxene are extremely low. The presence of high-Fe3+ spinel inclusions in olivine and orthopyroxene, combined with the presence of spherulitic aggregates and the extremely low Ca and Al concentrations in orthopyroxene, indicates deserpentinization as the origin of the metaperidotites, including the orthopyroxene-rich rocks. Contact metamorphism appears to be unbefitting as the cause of the deserpentinization because of the lack of a heat source close to the Ray-Iz massif. Instead, we propose that a hydration–dehydration path resulted from the subduction and exhumation of the forearc mantle wedge peridotite.

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A red-corundum-bearing vein in the Rai–Iz ultramafic rocks, Polar Urals, Russia: the product of fluid activity in a subduction zone

Cited by 9 publications

References 51 publications

Geology of Corundum and Emerald Gem Deposits: A Review

Geology of Corundum and Emerald Gem Deposits: A Review

GRANITOID MAGMATISM IN THE NORTH OF THE URALS: U–Pb AGE, EVOLUTION, SOURCES

Spherulitic orthopyroxene–bearing metaperidotite in Ray-Iz ophiolites (Polar Urals): high-pressure deserpentinization in a mantle wedge

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