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The Neogene volcanic province of SE Spain (NVPS) is characterized by calc-alkaline (CA), high-K calc-alkaline (KCA), shoshonitic (SH), ultrapotassic (UP), and alkaline basaltic (AB) volcanic series. All these series, except the AB, have high LILE/LREE, LILE/HFSE and B/Be ratios and high but variable Sr, Pb and O isotope compositions. The KCA and SH lavas contain metapelitic xenoliths whose mineralogical...
Megacrysts of clinopyroxene, pargasite and phlogopite are common in the lavas of the West Eifel volcanic field of Germany. Clinopyroxene megacrysts have been found at all seven localities studied; phlogopite and pargasite megacrysts are less common. Three types of clinopyroxene megacryst have been identified. All show undulatory extinction and local recrystallisation. Type I clinopyroxene megacrysts...
The abundance of apatite in Phanerozoic mantle may be greatly underestimated. This study shows that apatite has a widespread occurrence in Phanerozoic lithospheric mantle and can be divided into two geochemically distinct types using halogen content, presence or absence of structural CO 2 , Sr and trace element (especially U, Th, and light rare earth) ratios and abundances, and association...
The genesis of several groups of pyroxenite xenoliths from Miocene picrobasalt of the Vitim volcanic field are considered on the basis of petrology and mineral chemical data, including trace element analyses of minerals by ion probe. The pyroxenites and related xenoliths can be classified into three groups consisting of 10 sets of xenoliths: Group I (Cr-diopside series) is made up by three subdivisions;...
Spinel peridotite xenoliths recovered from the Tubaf and Edison volcanoes, south of Lihir Island in the Tabar-Lihir-Tanga-Feni island arc in Papua New Guinea, are predominantly fresh, refractory harzburgites. Many of the harzburgite xenoliths have cross-cutting vein networks and show evidence of modal metasomatism. These metasomatic veins contain a secondary mineral assemblage consisting of fibrous,...
Silicate melt pockets with or without carbonate occur in 10% of upper mantle xenoliths from the alkali basalts of the Bakony-Balaton Highland Volcanic Field (BBHVF), Western Hungary. Based on the estimated bulk composition of the melt pockets, both the carbonate-free and the carbonate-bearing ones are considered to be the result of the reaction between primary mantle clinopyroxene and/or amphibole...
Textural and petrological data of mantle peridotites sampled in the central and western parts of the Romanche Fracture Zone (Equatorial Atlantic) during the oceanographic expedition PRIMAR-96 (Russian R/V Gelendzhik) are presented. The studied rocks are mantle peridotites carrying patches, pockets and veins/dikes of magmatic origin, interpreted to be the product of various extents of magma impregnation...
Three types of fluid inclusions have been identified in olivine porphyroclasts in the spinel harzburgite and lherzolite xenoliths from Tenerife: pure CO 2 (Type A); carbonate-rich CO 2 –SO 2 mixtures (Type B); and polyphase inclusions dominated by silicate glass±fluid±sp±silicate±sulfide±carbonate (Type C). Type A inclusions commonly exhibit a “coating” (a few microns thick)...
Petrological, trace element and Sr, Nd, Pb isotopic data are reported for volcanic rocks from the island of Filicudi, Aeolian Arc, Southern Tyrrhenian Sea. The volcano consists of several monogenic and polygenic centres built up through four major phases of explosive and effusive activity started before 1 Ma. Rock composition ranges from calc-alkaline basalts to high-K andesites. There is a negative...
Some mantle-derived Kerguelen harzburgite and dunite xenoliths have bulk-rock and mineral trace element compositions that provide evidence of carbonatitic metasomatism similar to that described in some continental and other oceanic settings. Rare xenoliths contain carbonates that are highly enriched in rare earth elements (REE), interpreted to be quenched, evolved carbonatitic melts. One amphibole-bearing...
Peridotite xenoliths from western Victoria, Australia, contain varying proportions of amphibole (+/-apatite). The xenoliths also exhibit varying degrees of metasomatic enrichment as indicated by the rare-earth element (REE) patterns of clinopyroxene and amphibole analysed in situ by laser-ablation microprobe ICP-MS and by whole-rock trace-element patterns. Trace-element patterns allow the samples...
Melt inclusions in clinopyroxenes from lherzolitic xenoliths from the deep lithospheric mantle beneath the Slave Craton (Lac de Gras area, Canada) reveal multiple origins for carbonatitic melts. One type of inclusions consists of a series of silicate–carbonate–silicate concentric layers, interpreted to have unmixed under disequilibrium conditions during rapid ascent to the surface. Bulk major- and...
About half the diamonds studied from the Cenozoic placer deposits along the Namibian coast belong to the peridotitic suite. The peridotitic mantle source is heterogeneous ranging from lherzolitic to strongly Ca depleted (down to 0.24 wt.% CaO in garnet) and shows large variations in Cr/Al ratio, illustrated by very low to very high Cr 2 O 3 contents in garnet (2.6-17.3 wt.%). The Cr-rich...
Mantle xenoliths and xenocrysts were retrieved from three of the 88-86 Ma Buffalo Hills kimberlites (K6, K11, K14) for a reconnaissance study of the subcontinental lithospheric mantle (SCLM) beneath the Buffalo Head Terrane (Alberta, Canada). The xenoliths include spinel lherzolites, one garnet spinel lherzolite, garnet harzburgites, one sheared garnet lherzolite and pyroxenites. Pyroxenitic and wehrlitic...
K-Ar dating, major- and trace-element and Sr-Nd isotopic analyses were carried out for early Cretaceous (122-127 Ma) lamprophyres from the Sulu orogen in eastern China. The results show strong fractionation in rare-earth elements with (LREE) >100 times chondrite, but HREE <10 times chondrite, indicating the presence of residual garnet in the melting source. These rocks are characterized by significant...
The Archaean crust in West Greenland is dominated by grey orthogneiss complexes formed in periods of crustal accretion at around 3.8, 3.6, 3.2, 3.0–2.9 and 2.8–2.7 Ga. The majority of the gneisses have tonalite–trondhjemite–granodiorite (TTG) compositions, while subordinate quartz–dioritic and dioritic gneisses have calc-alkaline compositions. The major and trace element chemistry of gneiss samples...
Temperature estimates and chemical composition of mantle xenoliths from the Cretaceous rift system of NW Argentina (26°S) constrain the rift evolution and chemical and physical properties of the lithospheric mantle at the eastern edge of the Cenozoic Andean plateau. The xenolith suite comprises mainly spinel lherzolite and subordinate pyroxenite and carbonatized lherzolite. The spinel lherzolite xenoliths...
Nd-evolutionary paths for diversified igneous suites from southern Brazil are here re-evaluated using published results. We interpret the ε Nd paths considering the secondary fractionation of 147 Sm/ 144 Nd due to major petrogenetic processes. The inclusion of Nd isotopes and geochemical data for Precambrian and Mesozoic basic rocks allow improving the discussion on the subcontinental...
Coarse-grained, granular spinel lherzolites xenoliths from the Premier kimberlite show evidence of melt extraction and metasomatic enrichment, documenting a complex history for the shallow mantle beneath the Bushveld complex. Compositions of orthopyroxene, clinopyroxene and spinel indicate equilibration within the spinel–peridotite facies of the upper mantle, at depths from 80 to 100 km and temperatures...
Aillikites (carbonated, melilite-free ultramafic lamprophyres grading to carbonatites) are minor components of the Gardar alkaline igneous province. They occur principally as minor intrusions and as clasts in diatremes, but more voluminous aillikitic intrusions crop out near the Ilímaussaq Complex, which they predate by a few million years. These larger intrusions were emplaced at 1160±5 Ma. They...
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