Carbonated peridotite xenoliths from Spitsbergen: implications for trace element signature of mantle carbonate metasomatism

Ionov, Dmitri A.; Dupuy, C.; O’Reilly, Suzanne Y.; Kopylova, Maya G.; Genshaft, Yury S.

doi:10.1016/0012-821x(93)90139-z

Cited by 349 publications

(102 citation statements)

References 29 publications

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“…documented that such a process may result in depletions of Zr and reduction of Zr/Y ratios [83][84][85] similar to the studied websterite, which shows lower Zr and Zr/Y ratio than the Ol-orthopyroxenite (see Table 5). However, no primary carbonates have been observed that would further support this hypothesis.…”

Section: Origin Of Ol-orthopyroxenite and Websteritesupporting

confidence: 64%

New Occurrence of Pyroxenites in the Veria-Naousa Ophiolite (North Greece): Implications on Their Origin and Petrogenetic Evolution

et al. 2017

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Abstract:The Veria-Naousa ophiolite represents a dismembered unit in north Greece, which includes variably serpentinised lherzolite and harzburgite, locally intruded by a sparse network of dykes or thin layers of websterite and olivine-orthopyroxenite composition. The websterite and the olivine-orthopyroxenite show abundant petrographic and geochemical evidence (relic olivines with mantle affinities, Cr-rich spinels, low Al 2 O 3 , depletions in incompatible elements, and concave upwards rare earth element patterns) that they comprise replacive bodies from refractory subarc mantle precursors. The occurrence of these pyroxenites in dykes implies that channelled percolation of melts account for their replacive character. High CaO/Al 2 O 3 , low Zr and crystallisation of diopside suggest that a melt of ankaramitic/carbonatitic composition percolated in lherzolite replacing porphyroclastic olivine and forming the pyroxenes in the websterite. At a shallower level, harburgites were impregnated by boninitic melts (inferred by U-shape rare earth element patterns and very rich in Cr spinels) triggering the replacement of porphyroclastic olivine by orthopyroxene for the formation of olivine-orthopyroxenite. These peritectic replacements of olivine commonly occur in a mantle wedge regime. The peculiar characteristics of the Veria-Naousa pyroxenites with LREE and compatible elements enrichments resemble the subarc pyroxenites of Cabo Ortegal implying a similar environment of formation. Whole-rock and mineralogical (spinel and clinopyroxene) compositions are also in favour of a backarc to arc environment. It is recommended that the evolution of the Veria-Naousa pyroxenites record the evolution of the subarc region and the opening of a backarc basin in a broad SSZ setting in the Axios Zone of eastern Greece.

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Section: Origin Of Ol-orthopyroxenite and Websteritesupporting

confidence: 64%

New Occurrence of Pyroxenites in the Veria-Naousa Ophiolite (North Greece): Implications on Their Origin and Petrogenetic Evolution

et al. 2017

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“…These anomalies, as well as the Th-U ones, are deep (Fig. 10b), which, together with high mg# and low Al content, suggests that the most likely metasomatising agent was carbonatitic melt (Yaxley et al 1991;Rudnick et al 1993;Ionov et al 1993 andColtorti et al 1999). If this is the case, a strong negative Ti anomaly should occur in clinopyroxene, but the Ti/Ti* is only 0.6-2.3.…”

Section: Discussion Evolution Of Group a Harzburgitesmentioning

confidence: 96%

Depleted subcontinental lithospheric mantle and its tholeiitic melt metasomatism beneath NE termination of the Eger Rift (Europe): the case study of the Steinberg (Upper Lusatia, SE Germany) xenoliths

et al. 2015

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The ca. 30 Ma Steinberg basanite occurs at the NE termination of the Eger (Ohře) Rift in the NW Bohemian Massif, Central Europe, and belongs to the Cenozoic alkaline Central European Volcanic Province. The basanite hosts a suite of mantle xenoliths, most of which are harzburgites containing relatively magnesian olivine (Fo 90.5-91.6) and Alpoor (0.04-0.13 a pfu) orthopyroxene (mg# 0.90-0.92). Some of these harzburgites also contain volumetrically minor clinopyroxene (mg# 0.92-0.95, Al 0.03-0.13 a pfu) and have U-shaped LREE-enriched REE patterns. The Steinberg harzburgites are typical for the Lower Silesian -Upper Lusatian domain of the European subcontinental lithospheric mantle. They represent residual mantle that has undergone extensive partial melting and was subsequently affected by mantle metasomatism by mixed carbonatite-silicate melts. The Steinberg xenolith suite comprises also dunitic xenoliths affected by metasomatism by melt similar to the host basanite, which lowered the Fo content in olivine to 87.6 %. This metasomatism happened shortly before xenolith entrainment in the erupting lava. One of the xenoliths is a wehrlite (olivine Fo 73 %, clinopyroxene mg# 0.83-0.85, subordinate orthopyroxene mg# 0.76-0.77). Its clinopyroxene REE pattern is flat and slightly LREE-depleted. This wehrlite is considered to be a tholeiitic cumulate. One of the studied harzburgites contains clinopyroxene with similar trace element contents to those in wehrlite. This type of clinopyroxene records percolation of tholeiitic melt through harzburgite. The tholeiitic melt might be similar to Cenozoic continental tholeiites occurring in the Central European Volcanic Province (e.g., Vogelsberg, Germany).

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“…However, in comparison with the typical high Ba-Sr granites with Sr contents over 500 ppm (Tarney and Jones, 1994;Fowler et al, 2008), the TSGT potassic rocks possess relatively lower Sr abundances (b 400 ppm), but with some having higher Ba contents (up to 2000 ppm; Table 3), and this is inconsistent with an origin related to carbonate metasomatism (LaFlèche et al, 1998). Furthermore, the low-P 2 O 5 characteristics of all high Ba-Sr granites are in disagreement with carbonatitic melt metasomatism as described by Green and Wallace (1988), Ionov et al (1993) and Rudnick et al (1993). Thus possible melt-related metasomatism from pelagic sediments that commonly have enhanced Ba (thousands of ppm), and are invariably enriched in LREE (La/Yb ca.…”

Section: Nature Of the Magma Sourcementioning

confidence: 91%

Late Neoarchean potassic high Ba–Sr granites in the Taishan granite–greenstone terrane: Petrogenesis and implications for continental crustal evolution

Peng

Wilde

et al. 2013

Chemical Geology

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Carbonated peridotite xenoliths from Spitsbergen: implications for trace element signature of mantle carbonate metasomatism

Cited by 349 publications

References 29 publications

New Occurrence of Pyroxenites in the Veria-Naousa Ophiolite (North Greece): Implications on Their Origin and Petrogenetic Evolution

New Occurrence of Pyroxenites in the Veria-Naousa Ophiolite (North Greece): Implications on Their Origin and Petrogenetic Evolution

Depleted subcontinental lithospheric mantle and its tholeiitic melt metasomatism beneath NE termination of the Eger Rift (Europe): the case study of the Steinberg (Upper Lusatia, SE Germany) xenoliths

Late Neoarchean potassic high Ba–Sr granites in the Taishan granite–greenstone terrane: Petrogenesis and implications for continental crustal evolution

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