AGE AND PETROGENESIS OF ACID VOLCANITES OF THE ALGANSKY MOUNTAINS OF THE KORYAK HIGHLANDS (NORTHEASTERN OF RUSSIA)

The isotopic dating of U-Pb by the zircon method of volcanic acid zircons of the Konachan complex (Algansky mountains, northwestern part of the Koryak highlands) confirmed their Late Eocene age (34.6 ± 0.5-38.8 ± 0.4 Ma, Priabon). It has been shown that silicic rocks are represented by moderately potassium, peraluminous (ASI = 1.23–1.30), moderately and high magnesian differences, often with a high content of Cr and Ni. The contents of Sr, Y and Yb are adakite. High ratios of 143Nd/144Nd and low 87Sr/86Sr in the rocks of the complex, the distribution pattern of rare and rare-earth elements suggest that the source of salite melt, to some extent contaminated by sedimentary material, was metabasites. The formation of the Konachan complex is caused by magmatism during accretion of terranes of the Olyutor-East Kamchatka island-arc system [27]; compression processes led to the blocking of the upwelling front of the continental asthenosphere, initiating intense crustal anatexis and silicate magmatism.

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Petrogenesis and regional tectonic significance of Late Devonian mafic intrusions in the Meguma Zone, Nova Scotia

Canadian Journal of Earth Sciences ◽

10.1139/e95-145 ◽

1995 ◽

Vol 32 (11) ◽

pp. 1883-1898 ◽

Cited By ~ 22

Author(s):

Marcus C. Tate ◽

D. Barrie Clarke

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Island Arc ◽

Late Devonian ◽

Calc Alkaline ◽

Mafic Intrusions ◽

Heavy Rare Earth Elements ◽

Regional Tectonic ◽

Spider Diagrams ◽

Ocean Lithosphere

Late Devonian (377–368 Ma, 40Ar/39Ar; 376 Ma, U–Pb) mafic intrusions in the Meguma Zone crop out as dykes, plugs, and synplutonic bodies of gabbro, diorite, or lamprophyre. All of the intrusions have similar lithologie characteristics and hydrous ferromagnesian mineral assemblages, and they appear to represent a genetically related series of mafic bodies with similar petrogenetic histories in the crust of the Meguma Zone. The intrusions show wide chemical variation of SiO2 (45.7–65.7 wt.%), Al2O3 (8.9–26.5 wt.%), MgO (2.8–26.5 wt.%), CaO (1.2–11.2 wt.%), and K2O (0.1–4.4 wt.%), and they have calc-alkaline, high-K calc-alkaline, and shoshonitic characteristics. Large-ion lithophile elements (LILE) are present at variable but high concentrations (e.g., Ba = 62–1920 ppm, Sr = 176–2567 ppm) relative to most high field strength element (HFSE) abundances (e.g., Y = 10–37 ppm, Zr = 8–421 ppm), and light rare-earth elements (LREE) have much higher concentrations than heavy rare-earth elements (HREE) (La/Lu = 24–330). Initial Sr isotopic ratios (0.7044–0.7079) and εNd values (−4.36 to 3.69) are highly variable. Scatter on major oxide variation diagrams probably results from the fractionation of all the major modal phases in the intrusions (olivine, augite, hornblende, and (or) plagioclase), and the cumulate characteristics of some bodies support this suggestion. Nevertheless, parallel patterns for the intrusions on mid-ocean ridge basalt (MORB) normalized spider diagrams support the notion of similar mafic parent melts, and Sr–Nd isotopic data identify contamination by continental crust in only one of the intrusions. The most primitive picrite contains approximately basaltic HFSE in conjunction with HREE at 5–11CN, perhaps suggesting that the magmas emanated from depleted peridotite or pyroxenite, but high alkalies, LILE (<60MN), and LREE (10–100CN), and elevated initial Sr ratios in all of the intrusions, also require the existence of an enriched source component. Troughs in the spider diagrams at Ta, Nb, and Ti, and Sr–Nd isotopic values comparable with modern island-arc basalts, suggest that fluids derived from subducted ocean lithosphère metasomatized the mantle. Tectono-magmatic discriminators imply a continental margin arc environment rather than an island arc, and the intrusions record either Early Devonian subduction of Iapetus Ocean lithosphère beneath the Avalon terrane, Middle Devonian subduction of Theic Ocean lithosphère beneath the Meguma terrane, or an inherited subduction signature formed during a much older event.

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Petrography and geochemical characteristics of Chang 7 sandstone in Yanhe profile, Ordos Basin: Implication for paleoenvironment and tectonic background

Interpretation ◽

10.1190/int-2019-0158.1 ◽

2020 ◽

Vol 8 (4) ◽

pp. T981-T990

Author(s):

Haijun Gao ◽

Delu Li ◽

Dingming Dong ◽

Hongjun Jing ◽

Hao Tang

Keyword(s):

Grain Size ◽

Rare Earth ◽

Rare Earth Elements ◽

Ordos Basin ◽

Island Arc ◽

Geochemical Characteristics ◽

Hydrocarbon Exploration ◽

Source Rocks ◽

Grain Size Analysis ◽

Alkaline Basalt

The Chang 7 oil layer from the upper Triassic Yanchang Formation is an important layer for hydrocarbon exploration. Most studies on the Chang 7 oil layer have focused on the source rocks, while research on the sandstone is still inadequate, especially on the petrography and geochemical characteristics. Using seven sandstone samples of the Chang 7 oil layer in the Yanhe profile, the grain-size analysis, major elements, trace elements, and rare earth elements were tested. The results find that the sandstone of fine-grained sediments of the Chang 7 oil layer is dominated by arkose with a minor number of lithic arkose. The range of grain size (Mz) is from 2.72 to 3.92 Φ, and the C value and M value of the sandstone samples suggest characteristics of turbidity deposition. The Al/Si ratios of all of the samples imply high clay mineral content. The results of trace and rare earth elements demonstrate the reducing condition, freshwater, and cold and dry weather. The provenance of the sandstone samples is mainly from island arc acidic volcanic rock, and the type of provenance is mixed with sedimentary rock, granite, and alkaline basalt. The tectonic background is continental island arc. This study provides a systematic geologic foundation for the formation of sandstone of Chang 7 oil layer in Ordos Basin.

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Distribution pattern of rare earth elements in fern

Biological Trace Element Research ◽

10.1007/bf02783321 ◽

1998 ◽

Vol 64 (1-3) ◽

pp. 13-26 ◽

Cited By ~ 27

Author(s):

Femgfu Fu ◽

Tasuku Akagi ◽

Kazunori Shinotsuka

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Distribution Pattern

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Rare earth elements and the island arc tholeiitic series

Earth and Planetary Science Letters ◽

10.1016/0012-821x(70)90018-x ◽

1970 ◽

Vol 9 (1) ◽

pp. 17-28 ◽

Cited By ~ 342

Author(s):

P. Jakesˇ ◽

J. Gill

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Island Arc

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Early Carboniferous Paleo-Asian oceanic plate subduction: Implications from geochronology and geochemistry of early Carboniferous magmatism in southern West Junggar, NW China

10.5194/egusphere-egu21-11906 ◽

2021 ◽

Author(s):

Pengde Liu ◽

Xijun Liu ◽

Zhiguo Zhang ◽

Yujia Song ◽

Yao Xiao ◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Partial Melting ◽

Early Carboniferous ◽

Orogenic Belt ◽

Island Arc ◽

Spinel Lherzolite ◽

Oceanic Plate ◽

Island Arcs ◽

West Junggar

&#160; &#160; The subduction and closure of the Paleo-Asia Ocean generated the Central Asian Orogenic Belt (CAOB), which extends from the Urals in the west through Kazakhstan, northwestern China, Mongolia, and northeastern China to the Russian Far East. It is generally accepted that the CAOB comprises a complicated and varied collage of terranes, including island arcs, ophiolites, accretionary prisms, seamounts, and microcontinents. The CAOB is the world&#8217;s largest accretionary orogen and is also considered a type area for studying Phanerozoic continental growth. The accretionary processes of the orogen might have resulted from either the progressive duplication of a single and long-lived island-arc system or the collision of several island arcs and micro-continents, similar to the complex archipelago systems in the modern southwestern Pacific. West Junggar is located in a key area of the CAOB, has been a focus of studies of the tectonic evolution and crustal growth of the orogenic belt. West Junggar has been considered by some geologists as a paleo-Asian intra-oceanic subduction system, whereas others have variously argued that West Junggar was formed by single subduction, arc&#8211;arc collision, or ridge subduction, or by post-collisional processes after the early Carboniferous. An understanding of the Carboniferous tec-tonic setting is critical for determining the evolution of West Junggar. A series of early Carboniferous volcanic and intrusive rocks occur in the southern West Junggar. Our new zircon U&#8211;Pb geochronological data reveal that diorite intruded at 334.1 &#177; 1.1 Ma, and that basaltic andesite was erupted at 334.3 &#177; 3.7 Ma. These intrusive and volcanic rocks are calc-alkaline, display moderate MgO (1.62&#8211;4.18 wt.%) contents and Mg# values (40&#8211;59), low Cr (14.5&#8211;47.2 ppm) and Ni (7.5&#8211;34.6 ppm) contents, and are characterized by enrichment in light rare-earth elements and large-ion lithophile elements and depletion in heavy rare-earth elements and high-field-strength elements, meaning that they belong to typical subduction-zone island-arc magma. The rocks show low initial 87Sr/86Sr ratios (0.703649 to 0.705008), positive &#400;Nd(t) values (+4.8 to +6.2, mean +5.4), and young TDM Nd model ages ranging from 1016 to 616 Ma, indicating a magmatic origin from depleted mantle involving partial melting of 10%&#8211;25% garnet and spinel lherzolite. Combining our results with those of previous studies, we suggest that these rocks formed as a result of northwestward subduction of the Paleo-Asian Junggar oceanic plate, which caused partial melting of sub-arc mantle. We conclude that intra-oceanic arc magmatism was extensive in southern Paleo-Asian Ocean during the early Carboniferous.This study was financially supported by the National Natural Science Foundation of China (41772059) and the CAS &#8220;Light of West China&#8221; Program (2018-XBYJRC-003).

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The distribution pattern of Rare Earth Elements (REE) in Vitis vinifera L. discriminates the substrate of growth ?

10.5194/egusphere-egu2020-5770 ◽

2020 ◽

Author(s):

Marcella Barbera ◽

Pierpaolo Zuddas ◽

Filippo Saiano

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Vitis Vinifera ◽

Distribution Pattern ◽

Vitis Vinifera L ◽

Experimental Conditions ◽

Plant Parts ◽

Aerial Parts ◽

Order Of Magnitude ◽

Leaves And Roots

Rare Earth Elements (REE) have been employed to stimulate the plant growth in national and international strategies while their role still remains controversial as the process involved in soil-plant system is not completely understood yet. &#160;In this study we have investigated the effect of REE amount in the substrate during the Vitis vinifera L growth analysing the REE distribution in the different part of the plants. Experiments were carried out over 1 year using two different substrates: one with a "natural" substrate (blank experiments) and another using the same substrate artificially enriched by an equimolar solution of REE (spiked experiments).We found that both plant mass and amount of REE in leaves are both not influenced by the substrate enrichment. However, roots are by 1 order of magnitude enriched in REE for the 3 orders of magnitude enriched substrate of growth. This indicates that Vitis vinifera L. does not significantly transfer REE into the aerial parts during growth while identify roots as the plant critical parts responsible for the filtering of the environmental stress.&#160; Plotting the REE normalized distribution for every element, the different experimental conditions can be significantly discriminated: under spiked substrate conditions, REE normalised distribution shows a &#8216;zig zag&#8217; pattern in both leaves and roots. We propose that the REE normalised distribution pattern measured in the different plant parts (leaves and roots) can be used to discriminates the conditions of substrate characteristics during the vitis vinifera growth. Acting as natural tracers, the REE normalised distribution could be potentially used as tool tracing the substrate origin of the Vitis vinifera plant.&#160;

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Rare earth elements in the bimodal Mount Peyton batholith: Evidence of crustal anatexis by mantle-derived magma

Canadian Journal of Earth Sciences ◽

10.1139/e82-022 ◽

1982 ◽

Vol 19 (2) ◽

pp. 308-315 ◽

Cited By ~ 5

Author(s):

D. F. Strong ◽

C. Dupuy

Keyword(s):

Trace Elements ◽

Rare Earth ◽

Rare Earth Elements ◽

Mafic Magma ◽

Crustal Melting ◽

Crustal Anatexis ◽

Fractionation Process ◽

Rock Types ◽

Liquid Fractionation ◽

Representative Samples

The Mount Peyton batholith of central Newfoundland is one of many Siluro-Devonian ("Acadian") plutons of the Appalachians with contrasting mafic and silicic compositions. The distributions of rare earth and other trace elements in 18 representative samples indicate that the contrasting rock types are not genetically related by any crystal–liquid fractionation process. Rather they support earlier suggestions that the granitic melt was generated by crustal melting due to intrusion of the mantle-derived mafic magma, and the two evolved independently through processes involving some crystal fractionation and contamination with country rocks during ascent.

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Rare-earth elements in Cu-Ni ores of the Norilsk region

Arctic Ecology and Economy ◽

10.25283/2223-4594-2021-1-76-89 ◽

2021 ◽

Vol 11 (1) ◽

pp. 76-89

Author(s):

A.V. Grigoryeva ◽

◽

A.V. Volkov ◽

K.Y. Murashov ◽

◽

...

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Total Content ◽

Negative Slope ◽

Primitive Mantle ◽

High Tech ◽

Northwestern Part ◽

Rare Elements ◽

High Enrichment ◽

Host Rocks

The deposits of the Norilsk region are confined to the marginal northwestern part of the Siberian platform and are associated with the manifestation of the Early Mesozoic trap volcanism. Sulfide mineralization is concentrated in the intrusive facies of the volcano-intrusive complex. Four main types of Cu-Ni ores are distinguished according to textural features: massive, vein-disseminated, brecciated, and disseminated. The main types of Cu-Ni ores differ significantly from each other in the chemical composition and content of rock- and ore-forming components. The enrichment ratios of ore trace elements in the Oktyabrskaya and Talnakhskaya vein-disseminated ore mainly reach hundreds (S, Pt, Au, Se,Te, Pb, As, Sn, Mo) and thousands (Ni, Cu, Ag, Pd) times. A rather high enrichment of all types of Bi, Re and Cd ores has been revealed, which are potentially industrially significant as high-tech metals, and can be promising for associated mining. The amount of rare-earth elements (REE) in ores is several times less than in the upper crust and more than in the primitive mantle. The concentration of rare earths in the main types of ores, with the exception of massive ones, exceeds the level of the chondrite standard, and REE fractionation is weak. The distribution spectra of chondrite-normalized REEs have a slight negative slope: the total content of light REEs is higher than that of heavy ones. The similarity of the geometry of the REE spectra of massive, vein-disseminated, brecciated and disseminated types of ores containing a significant admixture of host rocks indicates the inheritance of the REE composition in ores from the host rocks. In the disseminated ores of common taxite gabbro-dolerites, the Eu anomaly is present in the Kharaelakhsky (Oktyabrskoye Deposit) and Talnakhsky (Talnakhskoye Deposit) intrusions, it is positive, and in the Norilsk I Intrusive (in the same rocks), it is negative. Higher concentrations of REEs and significant fractionation of light and heavy rare elements are typical for host contact-metamorphic and metasomatic rocks with vein-disseminated (exocontact) ores. For olivine-free hornfels and skarns in brecciated ores, as well as for vein-disseminated ores, significant fractionation of light REEs with relatively heavy ones and a pronounced Eu minimum are characteristic. In massive ores, the distribution of REEs is determined by the composition of xenoliths.

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