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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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TL;DR: In this paper, the late Archaean volcanic rocks of the Iramba-Sekenke greenstone belt consist of tholeiitic basalts and basaltic andesites that are associated with a subordinate amount of intermediate to felsic volcanic rocks.
19 citations
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TL;DR: According to general models for subduction-related volcanic arcs, magma cornpositions become progressively richer in K₂0 and incompatible elements with increasing distance from the trench and volcanic front and with increasing depth to the Benioff zone.
Abstract: According to general models for subduction-related volcanic arcs, magma cornpositions become progressively richer in K₂0 and incompatible elements with increasing distance from the trench and volcanic front and with increasing depth to the Benioff zone. Arc-type magmas are typically hypersthene- and quartz-normative. Nepheline-normative alkali basalts are expected to erupt, if at ah, only at great distances from the trench. Along the volcanic front of the Mexican Volcanic Belt, however, hydrous, nepheline-normative, basic alkalic magmas have erupted at two different locations during the late-Quaternary Period: in the southern Colima graben and in the southern Michoacan-Guanajuato Volcanic Field. In both places, hypersthene- and quartz-nor-mative calc-alkaline magmas with typical `volcanic front' characteristics were erupting contem-poraneously. These contrasting magma suites can not be related by any simple mechanism; they appear to record distinct melting events within the upper mantle.
19 citations
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TL;DR: The basaltic subvolcanics from the Lazi-Jiama area in the eastern Gangdese as discussed by the authors define a ~(40)Ar/~(39)Ar age range from 38.07Ma to 42.7298Ma.
Abstract: The major models,including convective removal of sub-continetal lithospheric mantle,slab break-off and intracontinental subduction,for the geodynamic evolution of the Tibetan plateau,inferred that upwelling asthenosphere was involved in the Tibetan post- collisional volcanism.In these models,however,Proposed petrologic and geochemical evidences in the Tibetan post-collisional volcanism focused on the sub-continental lithospheric mantle,but were not directly associated with the asthnospheric convection. The basaltic subvolcanics from the Lazi-Jiama area in the eastern Gangdese define a ~(40)Ar/~(39)Ar age range from 38.07Ma to 42Ma. The basaltic sub-volcanics have high Mg~# values and compatible trace element abundances(such as Cr,Ni,V and Sc),low LILE contents and TREE contents.Their extremely low LREE contents and low LREE/HREE ratios have a flat primitive mantle normalized rare earth element diagram,similar to that of ocean island basalts.The primitive samples of these rocks have extremely low incompatible element abundances(Ba,Th and U),resulting in obvious depletions of these elements relative to high field strongth element(Nb)on their primitive mantle-normalized trace element pattern.These rocks have low radiogenic ~(87)Sr/~(86)Sr(0.7048~0.7064) and unradiogenic ~(144)Nd/~(143)Nd(0.5126~0.51286),primitive Pb isotopic compositions(~(206)Pb/~(204)Pb=18.3722~18.5288; ~(207)pb/~(204)pb=15.5686~15.6214;~(208)Pb/~(204)pb=38.5203~38.7298).Their Sr,Nd and Pb isotopic compositions are plotted in the range of typical OIBs from Hawaii islands and Somoa island.Combinated with previous data of post-collisional volcanic rocks from the Lahas block,our new isotopic data define a good array for the post-collisional volcanism from a depletion end-member of basaltic subvolcanics to an enrichment end-member of potassic rocks.Our data indicate that the baslatic subvolcanis have similar geocemical and isotopic characteritics with ocean island basalts(OIB),suggesting asthenospheric mantle as a vital magmatic source of Eocene volcanism in the southern Tibetan block.The identification of the basaltic volcanic rocks with a clear OIB affinity and the delineation of their source provides new evidences for the slab break-off model,underplating of basaltic melts,and temporal contraints on thickening of the Tibetan crust.
18 citations
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TL;DR: A careful review of petrological and geochemical data on the Parana-Etendeka igneous province is reported, with particular attention being devoted to the relationships between high-MgO CFB (tholeiitic basalts-picrites) and nearly coeval alkaline-carbonatite complexes linked to the same extensional tectonics on a regional scale as mentioned in this paper.
18 citations
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TL;DR: In this article, the authors investigated the compositional features of the ultramafic volcanic rocks at the time of melt entrapment and found a good correlation between the major element compositions of the melt inclusions and their host spinels, with picritic melts being found in high-Ti spinels and komatiitic melts in low-Ti spinsels.
18 citations