Dunite nodules (Foss) and megacrysts of olivine (Fos3 s4 ) and clinopyroxene (FS13W043En44) are present as rare inclusions in the rhyodacite (~ 66wt %SiO z ) of Kauaopuu Ridge, Oahu, Hawaii. The rhyodacite is interbedded with caldera-filling tholeiitic lavas of the Waianae volcano. Results: (I) Dunite nodules (::;; I cm) consist of xenomorphic-granular olivine and minor chrome spinel and clinop...

The formation of amphibole cumulates beneath arc volcanoes is a key control on magma geochemistry, and generates a hydrous lower crust. Despite being widely inferred from trace element geochemistry as a major lower crustal phase, amphibole is neither abundant nor common as a phenocryst phase in arc lavas and erupted pyroclasts, prompting some authors to refer to it as a 'cryptic' fractionating ...

Mantle-derived xenoliths brought to the Earth’s Surface by basalts are important windows to understand composition, evolution and processes of the lithospheric mantle. The lithosphere of the southeastern China is dominated by peridotite or lherzolite [1, 2]. The spinel peridotite xenoliths studied are from Fangshan basalt, eastern China, which are composed of olivine, clinopyroxene, orthopyroxe...

Mineral chemistry, major and trace elements and Sr-Nd isotopes are presented for basalts and trachybasalts from the Quaternary alkaline Tepi shield from southwest Ethiopia. The lavas are variably porphyritic with phenocrysts of olivine (Fo67–87), clinopyroxene (Wo45–47En38–40Fs13–16), plagioclase (An57–68) and Ti-magnetite set in a microcrystalline matrix. Although there are two high-MgO lavas ...

[1] We report the influence of shear deformation on the microstructure of water-saturated olivine and clinopyroxene aggregates. Prior to deformation, the aqueous fluid was isolated in pockets along grain corners in the olivine-water aggregates, while it was interconnected by a network of grain-edge tubules in the clinopyroxene-water aggregate. During deformation of both types of aggregates, the...

clinopyroxene phenocrysts and microphenocrysts in potassic and sodic eosen alkaline volcanic rocks from the northern lahrud (nw iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. the rock series hosting the clinopyroxene phenocrysts is phonolitic tephrite and tephritic phonolite composition. theses rocks generally show porphyriti...

Li contents [Li] and isotopic composition (δLi) of mafic minerals (mainly amphibole and clinopyroxene) from the alkaline to peralkaline Ilímaussaq plutonic complex, South Greenland, track the behavior of Li and its isotopes during magmatic differentiation and final cooling of an alkaline igneous system. [Li] in amphibole increase from b10 ppm in Caamphiboles of the least differentiated unit to ...