Orthopyroxene-enrichment in the lherzolite-websterite xenolith suite from Paleogene alkali basalts of the Poiana Ruscă Mountains (Romania)

Abstract

In this paper we present the petrography and geochemistry of a recently collected lherzolite-websterite xenolith series and of clinopyroxene xenocrysts, hosted in Upper Cretaceous–Paleogene basanites of Poiana Ruscă (Romania), whose xenoliths show notable orthopyroxene-enrichment. In the series a slightly deformed porphyroclastic-equigranular textured series could represent the early mantle characteristics, and in many cases notable orthopyroxene growth and poikilitic texture formation was observed. The most abundant mantle lithology, Type A xenoliths have high Al and Na-contents but low mg# of the pyroxenes and low cr# of spinel suggesting a low degree (< 10 %) of mafic melt removal. They are also generally poor in overall REE-s (rare earth elements) and have flat REY (rare earth elements+ Y) patterns with slight LREE-depletion. The geochemistry of the Type A xenoliths and calculated melt composition in equilibrium with the xenolith clinopyroxenes suggests that the percolating melt causing the poikilitization can be linked to a mafic, Al-Na-rich, volatile-poor melt and show similarity with the Late Cretaceous–Paleogene (66–72 Ma) subduction-related andesitic magmatism of Poiana Ruscă. Type B xenoliths, with their slightly different chemistry, suggest that, after the ancient depletion, the mantle went through a slight metasomatic event. A subsequent passage of mafic melts in the mantle, with similar compositions to the older andesitic magmatism of Poiana Ruscă, is recorded in the pyroxenites (Fe-rich xenoliths), whereas the megacrysts seem to be cogenetic with the host basanite. The Poiana Ruscă xenoliths differ from the orthopyroxene-enriched mantle xenoliths described previously from the Carpathian-Pannonian Region and from the Dacia block.

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  • Agranier A. & Lee C.-T.A. 2007: Quantifying trace element disequilibria in mantle xenoliths and abyssal peridotites. Earth Planet. Sci. Lett. 257, 290–298.

  • Arai S. 1994: Characterization of spinel peridotites by olivine–spinel compositional relationships: Review and interpretation. Chem. Geol. 113, 191–204.

  • Arai S., Ishimaru S. & Okrugin V. 2003: Metasomatized harzburgite xenoliths from Avacha volcano as fragments of mantle wedge of the Kamchatka arc: implication for the metasomatic agent. Island Arc 12, 233–246.

  • Arai S., Takada S., Michibayashi M. & Kida M. 2004: Petrology of peridotite xenoliths from Iraya volcano, Philippines, and its implication for dynamic mantle-wedge processes. J. Petrology 45, 369–389.

  • Arai S., Shimizu Y., Morishita T. & Ishida Y. 2006: A new type of orthopyroxenite xenolith from Takashima, Southwest Japan: silica enrichment of the mantle by evolved alkali basalt. Contr. Mineral. Petrology 152, 387–398.

  • Bali E., Falus Gy., Szabó Cs., Peate D.W., Hidas K., Török K. & Ntaflos T. 2007: Remnants of boninitic melts in the upper mantle beneath the central Pannonian Basin? Miner. Petrology 90, 51–72.

  • Bali E., Zajacz Z., Kovács I., Szabó Cs., Halter W., Vaselli O., Török K. & Bodnar R.J. 2008: A quartz-bearing orthopyroxene-rich websterite xenolith from the Pannonian Basin, Western Hungary: Evidence for release of quartz-saturated melt from a subducted slab. J. Petrology 49, 421–439.

  • Ballhaus C., Berry R.F. & Green D.H. 1991: High pressure experimental calibration of the olivine–orthopyroxene–spinel oxygen geobarometer: implications for the oxidation state of the upper mantle. Contr. Mineral. Petrology 107, 27–40.

  • Berkesi M., Guzmics T., Szabó Cs., Dubessy J., Bodnar R.J., Hidas K. & Ratter K. 2012: The role of CO2-rich fluids in trace element transport and metasomatism in the lithospheric mantle beneath the Central Pannonian Basin, Hungary, based on fluid inclusions in mantle xenoliths. Earth Planet. Sci. Lett. 331–332, 8–20.

  • Berza T., Constantinescu E. & Vlad S.N. 1998: Upper Cretaceous magmatic series and associated mineralisation in the Carpathian–Balkan Orogen. Resour. Geol. 48, 4, 281–306.

  • Binns R.A., Duggan M.B. & Wilkinson J.F.G. 1970: High pressure megacrysts in alkaline lavas from north–eastern New South Wales. Amer. J. Sci. 269, 132–168.

  • Brey G.P. & Köhler T.P. 1990: Geothermobarometry in four phase lherzolites. II. New thermobarometers and practical assessment of existing thermobarometers. J. Petrology 31, 1353–1378.

  • Ciobanu C., Cook N.J. & Stein H. 2002: Regional setting and geochronology of the Late Cretaceous Banatitic magmatic and metallogenetic belt. Mineralium Depos. 37, 541–567.

  • Cvetković V., Downes H., Prelević D. & Jovanović M. 2004: Characteristics of the lithospheric mantle beneath East Serbia inferred from ultramafic xenoliths in Palaeogene basanites. Contr. Mineral. Petrology 148, 335–357.

  • Cvetković V., Lazarov M., Downes H. & Prelević D. 2007: Modification of the subcontinental mantle beneath East Serbia: Evidence from orthopyroxene-rich xenoliths. Lithos 94, 90–110.

  • Cvetković V., Downes H., Hock V., Prelević D. & Lazarov M. 2010: Mafic alkaline metasomatism in the lithosphere underneath East Serbia: evidence from the study of xenoliths and the host alkali basalts. Geol. Soc. London, Spec. Publ. 337, 213–239.

  • Cvetković V., Šarić K., Prelević D., Genser J., Neubauer F., Höck V. & von Quadt A. 2013: An anorogenic pulse in a typical orogenic setting: The geochemical and geochronological record in the East Serbian latest Cretaceous to Palaeocene alkaline rocks. Lithos 180–181, 181–199.

  • Dantas C., Grégoire M., Koester E., Conceição R.V. & Rieck Jr. N. 2009: The lherzolite–websterite xenolith suite from Northern Patagonia (Argentina): Evidence of mantle-melt reaction processes. Lithos 107, 107–120.

  • Dobosi G. & Jenner G.J. 1999: Petrologic implications of trace element variation in clinopyroxene megacrysts from the Nógrád volcanic province, north Hungary: a study by laser ablation microprobe-inductively coupled plasma-mass spectrometry. Lithos 46, 731–749.

  • Downes H. 2001: Formation and modification of the shallow subcontinental lithospheric mantle: a review of geochemical evidence from ultramafic xenolith suites and tectonically emplaced ultramafic massifs of Western and Central Europe. J. Petrology 42, 233–250.

  • Downes H., Vaselli O., Seghedi I., Ingram G., Rex D., Coradossi N., Pécskay Z. & Pinarelli L. 1995: Geochemistry of late Cretaceous–early Tertiary magmatism in Poiana Ruscă (Romania). Acta Vulcanol. 7, 209–217.

  • Embey-Isztin A. & Dobosi G. 2011: The origin and significance of poikilitic and mosaic peridotite xenoliths in the western Pannonian Basin. Bull. Hung. Geol. Soc. 141, 267–281 (in Hungarian).

  • Embey-Isztin A., Scharbert H.G., Dietrich H. & Poulditis H. 1989: Petrology and geochemistry of peridotite xenoliths in alkali basalts from the Transdanubian Volcanic Region. J. Petrology 34, 317–343.

  • Embey-Isztin A., Dobosi G., Altherr R. & Meyer H.P. 2001: Thermal evolution of the lithosphere beneath the western Pannonian Basin: evidence from deep-seated xenoliths. Tectonophysics 331, 285–306.

  • Frey F.A. & Prinz M. 1978: Ultramafic inclusions from San Carlos, Arizona: petrologic and geochemical data bearing on their petrogenesis. Earth Planet. Sci. Lett. 38, 129–176.

  • Green T., Blundy J., Adam J. & Yaxley G. 2000: SIMS determination of trace element partition coefficients between garnet, clinopyroxene and hydrous basaltic liquids at 2–7.5 GPa and 1080–1200 °C. Lithos 53, 165–187.

  • Hart S.R. & Dunn T. 1993: Experimental cpx/melt partitioning of 24 trace elements. Contr. Mineral. Petrology 113, 1–8.

  • Hellebrand E., Snow J.E., Dick H.J.B. & Hofmann A.W. 2001: Coupled major and trace elements as indicators of the extent of melting in mid-ocean-ridge peridotites. Nature 410, 677–681.

  • Iancu V., Berza T., Seghedi A., Gheuca I. & Hann H.-P. 2005: Alpine polyphase tectono-metamorphic evolution of the South Carpathians: A new overview. Tectonophysics 410, 337–365.

  • Ianovici V., Vlad S., Borcos M. & Bostinescu S. 1977: Alpine porphyry copper mineralization of West Romania. Mineralium Depos. 12, 307–317.

  • Janković S. 1997: The Carpatho–Balkanides and adjacent area: a sector of the Tethyan Eurasian metallogenetic belt. Mineralium Depos. 32, 426–433.

  • Jovanović M., Downes H., Vaselli O., Cvetković V., Prelević D. & Pécskay Z. 2001: Paleogene mafic alkaline volcanic rocks of East Serbia. Acta Vulcanol. 13, 159–173.

  • Karamata S., Knezević V., Pécskay Z. & Djordjević M. 1997: Magmatism and metallogeny of the Ridanj–Krepoljin belt (eastern Serbia) and their correlation with northern and eastern analogues. Mineralium Depos. 32, 452–458.

  • Kelemen P.B., Dick H.J.B. & Quick J.E. 1992: Formation of harzburgite by pervasive melt-rock reaction in the upper mantle. Nature 358, 635–644.

  • Kelemen P.B., Hart S.R. & Bernstein S. 1998: Silica enrichment in the continental upper mantle via melt/rock reaction. Earth Planet. Sci. Lett. 164, 387–406.

  • Kräutner F. 1969: Magmatites finales alcalines quaternaires dans la partie NE du massif de Poiana Rusca. Rev. Roum. Géol. Géophys. Géogr., Sér. Géol. 13, 47–67.

  • Kräutner H.G. 1997: Alpine and pre-Alpine terranes in the Romanian Carpathians and Apuseni Mountains. IGCP Project No. 276. Ann. Geol. Pays. Hellén. 37, 331–400.

  • Manning C.E. 2004: The chemistry of subduction-zone fluids. Earth Planet. Sci. Lett. 223, 1–16.

  • Marchev P., Arai S., & Vaselli O. 2006: Cumulate xenoliths in Oligocene alkaline basaltic and lamprophyric dikes from the eastern Rhodopes, Bulgaria: Evidence for the existence of layered plutons under the metamorphic core complexes. Geol. Soc. Amer., Spec. Pap. 409, 237–258.

  • Marchev P., Arai S., Ishida Y., Shirasaka M. & Downes H. 2008: Trace element and isotopic composition of mafic and ultra-mafic cumulate xenoliths in alkaline basalts from the Eastern Rhodopes, Bulgaria: Inferences on deep processes under the metamorphic core complexes. IOP Conf. Series: Earth and Environmental Science 2, 012015.

  • McDonough W.F. & Sun S.S. 1995: The composition of the Earth. Chem. Geol. 120, 223–253.

  • McInnes B.I.A., Gregoire M., Binns R.A., Herzig P.M. & Hannington M.D. 2001: Hydrous metasomatism of the sub-arc mantle, Lihir, Papua New Guinea: petrology and geochemistry of fluid metasomatised mantle wedge. Earth Planet. Sci. Lett. 188, 169–183.

  • McKenzie D. & O’Nions R.K. 1991: Partial melt distributions from inversion of rare earth element concentrations. J. Petrology 32, 1021–1091.

  • Norman M.D. 1998: Melting and metasomatism in the continental lithosphere: laser ablation ICPMS analysis of minerals in spinel lherzolites from eastern Australia. Contr. Mineral. Petrology 130, 240–255.

  • Pearce N.J.G., Perkins W.T., Westgate J.A., Gorton M.P., Jackson S.E., Neal C.R. & Chenery S.P. 1997: A compilation of new major and trace element data for NIST SRM 610 and NIST SRM 612 glass reference materials. J. Geostand. Geoanalysis 21, 115–144.

  • Rădulescu D. & Săndulescu M. 1973: The plate-tectonics concept and geological structure of the Carpathians. Tectonophysics 16, 155–161.

  • Rehfeldt T., Foley S.F., Jacob D.E., Carlson R.W. & Lowry D. 2008: Contrasting types of metasomatism in dunite, wehrlite and websterite xenoliths from Kimberley, South Africa. Geochim. Cosmochim. Acta 72, 5722–5756.

  • Ringwood A.E. 1958: Constitution of the mantle. Geochim. Cosmochim. Acta 15, 195–212.

  • Russo-Săndulescu D. & Berza T. 1979: Banatites from the western part of the Southern Carpathians (Banat). Rev. Roum. Géol. Géophys. Géogr., Sér. Géol. 23, 149–158.

  • Russo-Săndulescu D., Berza T., Bratosin I. & Ianc R. 1978: Petrological study of the Bocsa Banatitic massif (Banat). Dări de Seăma ale Institutului de Geologie si Geofizica 64, 1, 105–172.

  • Santos J.F., Scharer U., Gil Ibarguchi J.I. & Girardeau J. 2002: Genesis of pyroxenite-rich peridotite at Cabo Ortegal (NW Spain): Geochemical and Pb–Sr–Nd isotope data. J. Petrology 43, 17–43.

  • Schmid S.M., Bernoulli D., Fügenschuh B., Matenco L., Schefer S., Schuster R., Tischler M. & Ustaszewski K. 2008: The Alpine–Carpathian–Dinaridic orogenic system: correlation and evolution of tectonic units. Swiss J. Geosci. 101, 139–183.

  • Smith D., Riter J.C.A. & Mertzman S.A. 1999: Water–rock interactions, orthopyroxene growth, and Si-enrichment in the mantle: evidence in xenoliths from the Colorado Plateau, southwestern United States. Earth Planet. Sci. Lett. 165, 45–54.

  • Stosch H.G. 1982: Rare earth element partitioning between minerals from spinel peridotite xenoliths. Contr. Mineral. Petrology 78, 166–174.

  • Sun S.S. & McDonough W.F. 1989: Chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes. In: Saunders A.D. & Norry M.J. (Eds.): Magmatism in the ocean basins. Geol. Soc. London, Spec. Publ. 42, 313–345.

  • Tschegg C., Ntaflos T., Seghedi I., Harangi S., Kosler J. & Coltorti M. 2010: Paleogene alkaline magmatism in the South Carpathians (Poiana Ruscă, Romania): Asthenospheric melts with geodynamic and lithospheric information. Lithos 120, 393–406.

  • von Cotta B. 1864: Erzlagerstatten im Banat und in Serbien. W. Braumuller, Wien, 1–105.

  • Wilshire H.G. & Shervais J.W. 1975: Al-augite and Cr-diopside ultramafic xenoliths in basaltic rocks from western United States. Phys. Chem. Earth 9, 257–272.

  • Wulff-Pedersen E.N., Neumann E.-R. & Jensen B.B. 1996: The upper mantle under La Palma, Canary Islands: formation of Si–K–Na-rich melt and its importance as a metasomatic agent. Contr. Mineral. Petrology 125, 113–139.

  • Wulff-Pedersen E.N., Neumann E.-R., Vannucci R., Bottazzi P. & Ottolini L. 1999: Silicic melts produced by reaction between peridotite and infiltrating basaltic melts: ion probe data on glasses and minerals in veined xenoliths from La Palma, Canary Islands. Contr. Mineral. Petrology 137, 59–82.

  • Xu Y.G., Menzies M.A., Vroon P., Mercier J.-C. & Lin C.Y. 1998: Melt percolation-reaction atop the plume: evidence from poikiloblastic spinel harzburgite xenoliths from Boree (Massif Central, France). Contr. Mineral. Petrology 132, 65–84.

  • Zindler A. & Jagoutz E. 1988: Mantle cryptology. Geochim. Cosmochim. Acta 52, 319–333.

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