Topic
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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01 Jan 2011
TL;DR: Based on petrochemical analyses and zircon U-Pb LA-ICP-MS dating combined with field investigation, the present authors propose that these dykes represent a crustal extension event of the Bangong lake arc zone after the closure of Bangeng lake middle-Tethys oceanic basin this paper.
Abstract: A series of NS-and EW-striking dykes occur in Bangong lake region,western segment of the Bangong lake-Nujiang suture in Tibetan plateau,including both granite porphyry and diorite porphyriteBased on petrochemical analyses and zircon U-Pb LA-ICP-MS dating combined with field investigation,the present authors propose that these dykes represent a crustal extension event of the Bangong lake arc zone after the closure of Bangeng lake middle-Tethys oceanic basinThe granite porphyries occuring only in NS-strike and the diorite porphyrites occuring both in NS-and EW-strike respectively yield a weighted mean age of 7959±032Ma(MSWD=108) with 13 zircons and(769±12)Ma(MSWD=28) with 6These results indicate that the crustal extensional process of the Bangong lake arc zone occurring in Late Cretaceous epoch was initialed only in EW-trending and slightly later also in NS-trendingPetrochemically,the two types of the dykes appear arc magmatic features characterized by enrichment of large iron incompatible elements(Rb,U,Th,K,Pb) and depletion of high field strength elements(Nb and Ti) which were attributed to metasomatism of Indian-MORB mantle by subducted sediment meltFurthermore,by analyzing geochemical characteristics of the dyke,we come to the conclusion that the granite porphyries were generated at a shallower depth under amphibolite facies conditions,and the diorite porphyrites were probably under eclogite facies or garnet amphibolite conditionsAnd the amount of sediment melt involved in the mantle metasomatism related to diorite porphyrites varies largely from 1% to 10% with a source partial melting degree ranging from 8% to 15%Whereas in the granite porphyries,the amount varies from 10% to 15% and their source partial melting degree is up to 15%
8 citations
TL;DR: In this article, the authors identified two groups of mafic dykes in the Bundelkhand Craton of the Indian shield manifest Palaeoproterozoic igneous activity.
8 citations
31 Aug 2012
TL;DR: In this paper, the authors deal with mineralization and spectrometric study as well as geology and geochemistry of the late Pan African cataclastic rocks (mylonites) of Wadi Sikait area.
Abstract: This article deals with mineralizations and spectrometric study as well as geology and geochemistry of the late Pan-African cataclastic rocks (mylonites) of Wadi Sikait area. The area is composed of metagabbros, ophiolitic melange, metasediments, mylonitic rocks, porphyritic biotite granites, leucogranites and lamprophyre dykes. The mineralogical study of the mylonitic samples revealed the presence of uranothorite, thorite, boltwoodite and niobium minerals (ferroclombite, ishikawaite), REEs bearing minerals (monazite, xenotime) and accessory minerals (zircon, pyrite, galena, fluorite, apatite). Geochemically, the mylonitic rocks are enriched in incompatible elements and HFS elements (Nb, Zr and Y) and emplaced in greisen field. The melt of mylonitic rocks were originated from pelites (clay-rich sources). The present study shows that the geochemical characteristics of the mylonitic rocks could be used as exploration guides for U, Th, Nb, Zr and Ga rich sites in similar occurrences in the northern part of the Pan- African belt of Egypt. The mylonitization process led to changes in shape and size of minerals and accompanied with change in chemical compositions of the original rock. It could be related to role of the fluid, heating and metasomatic processes. Detailed spectrometric study reveals the eU/eTh ratio varies directly with eU concentration and randomly with eTh, indicating that the radioelement concentration is governed by post magmatic redistribution. The origin of these secondary minerals is mainly related to alteration of primary minerals by the action of oxidizing fluids, mobilization of uranium and then redeposition in other forms. Redistribution by circulating meteoric water might have taken place.
Key words: Mineralizations, spectrometric study, mylonites, boltwoodite, niobium.
8 citations
Journal Article•
TL;DR: In the field setting, petrography and chemical composition of feldspars of these rocks illustrate that they have been derived from a single magmatic source formed by crustal anatexis as discussed by the authors.
Abstract: Vertically and sub-vertically intruded syenite and granitic pegmatites, which carry many industrial minerals are found in the Owala-Kaikawala area in the central parts of Sri Lanka. The field setting, petrography and chemical composition of feldspars of these rocks illustrate that they have been derived from a single magmatic source formed by crustal anatexis. The enrichment of compatible elements in feldspars of the fluorite-bearing syenitic pegmatite and incompatible elements in granitic pegmatites can best be explained the chemical evolutions of the extremely fractionated melt. The initial fractionation of a volatile enriched, silica-undersaturated melt from the parental magma resulted into the fluorite-bearing syenitic pegmatite. The remaining melt that is rich in silica, fractionated again slightly and was emplaced into eastern parts of the area as granitic pegmatite. The fractionations of the fluid rich melt took place frequently until the crystallization of minerals.
8 citations
TL;DR: In this article, the late Eocene igneous rocks are characterized by high potassium, enrichment in large ion lithophile elements (LILE, e.g., Rb, Ba, Th, U), depleted in high field strength elements (HFSE), negligible Eu anomalies, with a wide range of highly incompatible element ratios.
8 citations