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Incompatible element

About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.


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Journal ArticleDOI
07 Jan 2007-Ofioliti
TL;DR: The Nain ophiolite is a highly dismembered ophiola complex cropping out at the north of the Nain town to the west of central Iran as discussed by the authors, which consists of both mantle and crustal suites and include serpentinized peridotites, peridotsites, harzburgites associated with dunite and lherzolite, pegmatitic and isotropic gabbros, plagiogranites, sheeted dikes and pillow lavas.
Abstract: The Nain ophiolite is a highly dismembered ophiolite complex cropping out at the north of the Nain town to the west of central Iran. The igneous rocks of this complex consist of both mantle and crustal suites and include serpentinized peridotites, peridotites, harzburgites associated with dunite and lherzolite, pegmatitic and isotropic gabbros, plagiogranites, sheeted dikes and pillow lavas. Several pyroxenite, wehrlite and rodingite dikes are present in the ultrabasic rocks. The sheeted dikes include subalkaline basalts, basaltic andesites and andesites. Their magma was of sub-alkaline (low potassium tholeiite) type and they are chemically similar to island arc tholeiitic basalts. The N-MORB-normalized incompatible elements for the sheeted dike samples indicate depletion in most of the high field strength elements (HFSE). The concentrations of the large ion lithophile elements (LILE) in these rocks are all greater than those in the N-MORB. Significant chemical characteristics of the these rocks are the positive anomaly for Th and negative anomaly of Nb that are considered to represent a subduction zone component. The chondrite-normalized rare earth element (REE) patterns of these rocks show HREE enrichment and LREE depletion [(LaN/SmN)ave = 0.63]. Their geochmistry also shows that the primary melt derived from high degrees of partial melting of a mantle source previously depleted with respect to the source of mid-ocean ridge basalts, and were subsequently enriched by aqueous fluids driven off subducted oceanic lithosphere in an arcbasin setting. We conclude that the Nain ophiolite is a supra-subduction zone type ophiolite.

19 citations

Journal ArticleDOI
TL;DR: The geochemical composition of metavolcanics (metabasalts and metaandesites) of the Tunka terrane is considered in this paper, where they are differently enriched in incompatible elements relative to N-MORB.

19 citations

Journal Article
TL;DR: The Wanganzhen complex is one of representative example of Taihang-Da Hinggan tectonomagmatic belt in eastern China, which as the largest scale adn the most rock types.
Abstract: The Wanganzhen complex is one of representative example of Taihang-Da Hinggan tectonomagmatic belt in eastern China, which as the largest scale adn the most rock types. It consists of three-stage rocks. According to the major element, trace element, REE and ND, SR, PB isotopic characteristics of the Wanganzhen complex reported in this paper, the main stage rocks (Granodiorite, adamellite, and few quartz diorite) have similar petrological and geochemical characteristics to those of adakite with SiO₂≥58%, Al₂O₃≥15%, low Y content (4.20~12.68μg/g), high SR content (518~861μg/g) and Sr/Y ratios (60.19~178.10), LREE enrichment with (La/Yb)N=34.06~76.91, HREE depletion with Yb=.044~1.00, no obviously Eu anomaly (Eu/Eu*=0.83~1.03), and relative depletion in the high field strength elements (such as Nb, Hf, Ti), I(Sr)=0.7060, negative eNd(t) value (-16.29~-14.27) and positive eSr(t) value (+23.7~+25.0), but obviously different from those of subduction-related adakites. These adakite-like rocks were most likely derived from the partial melting of basaltic lower crust in the thickened crust resulted from hot mantle material upwellins as several mushroom cloud and the thermally altered ground uplifting to the bottom of continental crust during late Jurassic period. But the early and the late stage ones belong to non-adakites. The early basic- to intermediate- instrusive rocks (hornblendite, gabbroite and diorite) are high Mg and Fe, LREE enrichment, EU positive anomaly, enriched in compatible elements and low incompatible elements, I(Sr)=0.7056, eNd(t)=-16.72~-10.92, which are the products of partial melting of subcontinental lithospheric enrich mantle and probably represent the underplating basaltic magma below the thickened continental crust during early Mesozoic era. The late alkaline intermediate to acid-intrusive rocks (alkali-granite, quartz syenite and quartz monzonite) are characteristic of high K and Na alkaline series and high ΣREE, negative Eu anomaly, low Sr content, high Y and Yb, negative Sr anomaly, I(Sr)=0.7062, eNd(t)=-16.25, suggesting that the formation of adakite-like rocks of the main stage result in the lithospheric delamination and cause asthenosphere to upwell to the bottom of thinned continental crust, so the rocks of the late stage are formed by the partial melting of the materials in the crust-mantle transformation belt even in the middle crust. In this paper the Rb-Sr isochronal age of granodiorite (145.7±5.3Ma) is reported. Based on the Rb-Sr isochronal age of granite and granidiorite, the main body of the Wanganzhen complex was probably formed in late Jurrasic period between 137.8Ma and 145.6Ma.

19 citations

Journal ArticleDOI
TL;DR: The Ordovician Laohushan ophiolite, located in the eastern part of the North Qilian Mountains, is mainly composed of meta-peridotites, gabbros and basalts alternating with sediments as mentioned in this paper.
Abstract: The Ordovician Laohushan ophiolite, located in the eastern part of the North Qilian Mountains, is mainly composed of meta-peridotites, gabbros and basalts alternating with sediments. The sediments are mainly turbidites, including sandstones, siltstones, cherts etc. Major elements show that the basalts are subalkaline tholeiites and may be analogous to ocean-floor basalts. Except a few N-MORBs, most of the basalts are E-MORBs as indicated by incompatible element ratios such as (La/Ce)N, La/Sm, Ce/Zr, Zr/Y and Zr/Nb. Negative Nb anomaly is common but negative Zr, Hf and Ti anomalies are quite rare. Based on the geochemical characteristics, it is suggested that the Laohushan basalts were formed in a back-arc basin. eNd (t) of the basalts ranges between +3.0 and +8.9 and (87Sr/86Sr), ranges between 0.7030 and 0.7060, indicating a depleted mantle source which was mixed with more or less enriched mantle components. Furthermore, the petrography of the sandstones and geochemistry of the cherts suggest that the sediments were deposited near a continental margin.

19 citations

Journal ArticleDOI
TL;DR: Two submarine volcanoes (named Friday and Domingo) have been mapped and sampled to the west of the youngest island (Alexander Selkirk) in the Juan Fernandez chain, SE Pacific as mentioned in this paper.
Abstract: Two submarine volcanoes (named Friday and Domingo) have been mapped and sampled to the west of the youngest island (Alexander Selkirk) in the Juan Fernandez chain, SE Pacific. Samples from the seamounts are fresh, highly vesicular olivine and plagioclase-phyric basanites. Their MgO contents lie between 7 and 4 wt.%. Major element variation trends, especially decreasing SiO2 with increasing MgO, cannot be explained by crystal fractionation, and suggest the influence of CO2 during partial melting. Highly incompatible element ratios in both Friday and Domingo magmas are identical, with the exception of ratios involving Th and Nb for which Domingo shows depletions. These depletions are coupled with depletions in Zr, Hf and Ca and enrichments in the heavy rare-earth elements and Al2O3. All these geochemical features can be explained if the Domingo magmas reacted with harzburgitic mantle materials during transit to the surface in a manner shown experimentally to occur during CO2-dominated kimberlite magmatism. The metasomatism results in the stabilisation of clinopyroxene, rutile and zircon which withhold the elements depleted at Domingo, and the breakdown of garnet which releases HREE and Al into the magmas. Magmas erupting from the large, more mature Friday edifice have traversed a mantle region already metasomatised during earlier stages of volcanism and so are not significantly modified during passage. The Juan Fernandez trace element patterns are similar to the low 87Sr/86Sr, high 143Nd/144Nd components in many Pacific hotspots and to the pattern suggested for recycled, altered, dehydrated oceanic crust, implying that such recycled crust is a common component in many hotspots. Isotopically, the Juan Fernandez magmas lie between the composition of prevalent mantle (PREMA) and HIMU.

19 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202216
202157
202056
201960
201851