Hostname: page-component-76fb5796d-wq484 Total loading time: 0 Render date: 2024-04-26T02:36:09.465Z Has data issue: false hasContentIssue false
  • English
  • Français

Time-evolution of magma sources in a continental back-arc setting: the Cenozoic basalts from Sierra de San Bernardo (Patagonia, Chubut, Argentina)

Published online by Cambridge University Press:  09 May 2008

SANDRO BRUNI ,
MASSIMO D'ORAZIO ,
MIGUEL J. HALLER ,
FABRIZIO INNOCENTI ,
PIERO MANETTI ,
ZOLTÁN PÉCSKAY  and
SONIA TONARINI
SANDRO BRUNI
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56126 Pisa, Italy Istituto di Geoscienze e Georisorse, C.N.R., Via Moruzzi 1, I-56124 Pisa, Italy
MASSIMO D'ORAZIO*
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56126 Pisa, Italy Istituto di Geoscienze e Georisorse, C.N.R., Via Moruzzi 1, I-56124 Pisa, Italy
MIGUEL J. HALLER
Affiliation:
Universidad Nacional de la Patagonia San Juan Bosco, CENPAT-CONICET, Puerto Madryn, Argentina
FABRIZIO INNOCENTI
Affiliation:
Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria 53, I-56126 Pisa, Italy Istituto di Geoscienze e Georisorse, C.N.R., Via Moruzzi 1, I-56124 Pisa, Italy
PIERO MANETTI
Affiliation:
Istituto di Geoscienze e Georisorse, C.N.R., Via Moruzzi 1, I-56124 Pisa, Italy Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira 4, I-50121 Florence, Italy
ZOLTÁN PÉCSKAY
Affiliation:
Institute of Nuclear Research, Hungarian Academy of Sciences, H-4026 Debrecen, Hungary
SONIA TONARINI
Affiliation:
Istituto di Geoscienze e Georisorse, C.N.R., Via Moruzzi 1, I-56124 Pisa, Italy
*
‡Author for correspondence: dorazio@dst.unipi.it
Get access Rights & Permissions [Opens in a new window]

Abstract

East of the Patagonian Andes, mafic volcanic rocks (mainly lava flows and scoriae) are exposed in the Sierra de San Bernardo fold belt and neighbouring areas (central Patagonia; 44.5–46° S, 69–71° W). They were erupted over a wide interval of time (late Eocene–Pleistocene; 14 new K–Ar ages), and show systematic chemical and Sr–Nd–Pb isotopic variations in time. The alkaline lavas (Mg number 57–66) erupted during the late Eocene and early Miocene, have an intraplate geochemical affinity, and have the highest 143Nd/144Nd and 206Pb/204Pb and the lowest 87Sr/86Sr ratios of the dataset. Their compositions indicate that their depth of equilibration in the mantle was greater than that of subsequent lavas. In contrast, the Plio-Pleistocene alkaline lavas (Mg number 58–71) are the most enriched in incompatible elements, still showing an intra-plate signature, and have the lowest 143Nd/144Nd and 206Pb/204Pb and the highest 87Sr/86Sr ratios. A distinctive group of early Miocene subalkaline lavas is characterized by slightly more evolved compositions (Mg number 56–59), coupled with very low incompatible element contents, flat LREE and fractionated HREE patterns (‘kinked’ pattern), and intermediate Sr–Nd–Pb isotope compositions. The Pleistocene basanites (Mg number 71–72) from the Cerro Ante monogenetic cone, on the easternmost slopes of the Patagonian Andes, have a marked orogenic geochemical signature and Sr–Nd–Pb isotope ratios that overlap with those of volcanic rocks from the adjacent active Andean arc. They originated in a mantle source extensively modified by the addition of materials from the subducting Pacific oceanic plates. We suggest that the wide chemical and isotopic variability of the Sierra de San Bernardo lavas reflects the upwelling of asthenospheric mantle beneath the study area, which induced lithospheric erosion and progressive involvement of enriched mantle domains in the genesis of magmas. In this context, late Eocene and early Miocene alkaline magmatism was dominantly sourced from the asthenospheric mantle, whereas Plio-Pleistocene alkaline magmas contain the largest proportion of an enriched lithospheric component. The peculiar compositional features of the early Miocene subalkaline lavas are interpreted in terms of high-degree mantle melting followed by melt–lithospheric mantle reaction processes. Based on current knowledge about the relative movement and decoupling between lithosphere and asthenosphere, we propose that the asthenosphere below the study area rose up to compensate for the westward drift of the mantle wedge coupled with the South American lithosphere.

Keywords

Patagoniabasaltic rocksCenozoicpetrogenesisgeodynamicsisotope geochemistry
Type
Original Article
Information
Geological Magazine , Volume 145 , Issue 5 , September 2008 , pp. 714 - 732
Copyright
Copyright © Cambridge University Press 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Albarede, F. 1992. How deep do common basaltic magmas form and differentiate? Journal of Geophysical Research 97, 10997–11009.CrossRefGoogle Scholar
Baker, P. E., Rea, W. J., Skarmeta, J., Caminos, R. & Rex, D. C. 1981. Igneous history of the Andean cordillera and Patagonian plateau around latitude 46°S. Philosophical Transactions of the Royal Society of London A303, 105–49.Google Scholar
Balogh, K. 1985. K–Ar dating of Neogene volcanic activity in Hungary. Experimental technique, experiences and methods of chronological studies. ATOMKI Rep. D/1, pp. 277–88.Google Scholar
Cande, S. C. & Leslie, R. B. 1986. Late Cenozoic tectonics of the Southern Chile Trench. Journal of Geophysical Research 91, 471–96.CrossRefGoogle Scholar
Cembrano, J., Hervé, F. & Lavenu, A. 1996. The Liquiñe-Ofqui fault zone: a long-lived intra-arc fault system in southern Chile. Tectonophysics 259, 55–66.CrossRefGoogle Scholar
Chelotti, L. A. 1997. Evolución tectónica de la Cuenca del Golfo San Jorge en el Cretácico y Terciario; algunas observaciones desde la interpretación sísmica. Boletín de Informaciones Petroleras 49, 62–82.Google Scholar
Conceição, R. V., Mallmann, G., Koester, E., Schilling, M., Bertotto, G. W. & Rodriguez-Vargas, A. 2005. Andean subduction-related mantle xenoliths: isotopic evidence of Sr–Nd decoupling during metasomatism. Lithos 82, 273–87.CrossRefGoogle Scholar
de Ignacio, C., López, I., Oyarzun, R. & Márquez, A. 2001. The northern Patagonia Somuncura plateau basalts: a product of slab-induced, shallow asthenospheric upwelling? Terra Nova 13, 117–21.CrossRefGoogle Scholar
D'Orazio, M., Agostini, S., Innocenti, F., Haller, M. J., Manetti, P. & Mazzarini, F. 2001. Slab window-related magmatism from southernmost South America: the late Miocene mafic volcanics from the Estancia Glencross area (~52°S, Argentina–Chile). Lithos 57, 67–89.CrossRefGoogle Scholar
D'Orazio, M., Agostini, S., Mazzarini, F., Innocenti, F., Manetti, P., Haller, M. J. & Lahsen, A. 2000. The Pali Aike Volcanic Field, Patagonia: slab-window magmatism near the tip of South America. Tectonophysics 321, 407–27.CrossRefGoogle Scholar
D'Orazio, M., Gonzalez-Ferrán, O., Innocenti, F., Mazzarini, F., Mazzuoli, R., Tonarini, S. & Adorni-Braccesi, A. 1999. Alkaline basaltic volcanism in the Weddell Sea side of the northernmost Antarctic Peninsula: Sr–Nd isotope and trace-element characteristics. 8th International Symposium on Antarctic Earth Sciences, Wellington, Abstract volume, p. 92.Google Scholar
D'Orazio, M., Innocenti, F., Manetti, P. & Haller, M. J. 2004. The Cenozoic back-arc magmatism of the southern extra-Andean Patagonia (44.5–52°S): A review of geochemical data and geodynamic interpretations. Revista de la Asociación Geológica Argentina 59, 525–38.Google Scholar
D'Orazio, M., Innocenti, F., Manetti, P., Haller, M. J., Di Vincenzo, G. & Tonarini, S. 2005. The Late Pliocene mafic lavas from the Camusú Aike Volcanic Field (~50°S, Argentina): evidences for geochemical variability in slab window magmatism. Journal of South American Earth Sciences 18, 107–24.CrossRefGoogle Scholar
D'Orazio, M., Innocenti, F., Manetti, P., Tamponi, M., Tonarini, S., González-Ferrán, O., Lahsen, A. & Omarini, R. 2003. The Quaternary calc-alkaline volcanism of the Patagonian Andes close to the Chile Triple Junction: geochemistry and petrogenesis of volcanic rocks from the Cay and Maca volcanoes (~ 45°S, Chile). Journal of South American Earth Sciences 16, 219–42.CrossRefGoogle Scholar
Espinoza, F., Morata, D., Pelleter, E., Maury, R. C., Suárez, M., Lagabrielle, Y., Polvé, M., Bellon, H., Cotten, J., De la Cruz, R. & Guivel, C. 2005. Petrogenesis of the Eocene and Mio-Pliocene alkaline basaltic magmatism in Meseta Chile Chico, southern Patagonia, Chile: evidence for the participation of two slab windows. Lithos 82, 315–43.CrossRefGoogle Scholar
Fitzgerald, M. G., Mitchum, R. M., Uliana, M. A. & Biddle, K. T. 1990. Evolution of the San Jorge Basin, Argentina. American Association of Petroleum Geologists Bulletin 74, 879–920.Google Scholar
Foley, S. F., Venturelli, G., Green, D. H. & Toscani, L. 1987. The ultrapotassic rocks: characteristics, classification, and constraints for petrogenetic models. Earth Science Reviews 24, 81–134.CrossRefGoogle Scholar
Futa, K. & Stern, C. R. 1988. Sr and Nd isotopic and trace element composition of Quaternary volcanic centers of southern Andes. Earth and Planetary Science Letters 88, 253–63.CrossRefGoogle Scholar
Gerlach, D. C., Frey, F. A., Moreno-Roa, H. & López-Escobar, L. 1988. Recent volcanism in the Puyehue–Cordon Caulle region, Southern Andes, Chile (40.5°S): petrogenesis of evolved lavas. Journal of Petrology 29, 333–82.CrossRefGoogle Scholar
Gorring, M. L. & Kay, S. M. 2000. Carbonatite metasomatized peridotite xenoliths from southern Patagonia: implications for lithospheric processes and Neogene plateau magmatism. Contributions to Mineralogy and Petrology 140, 55–72.CrossRefGoogle Scholar
Gorring, M. L. & Kay, S. M. 2001. Mantle processes and sources of Neogene slab window magmas from southern Patagonia, Argentina. Journal of Petrology 42, 1067–94.CrossRefGoogle Scholar
Gorring, M. L., Kay, S. M., Zeitler, P. K., Ramos, V. A., Rubiolo, D., Fernandez, M. I. & Panza, J. L. 1997. Neogene Patagonian plateau lavas: Continental magmas associated with ridge collision at the Chile Triple Junction. Tectonics 16, 1–17.CrossRefGoogle Scholar
Gorring, M. L., Singer, B., Gowers, J. & Kay, S. M. 2003. Plio-Pleistocene basalts from the Meseta del Lago Buenos Aires, Argentina: evidence for asthenosphere–lithosphere interactions during slab window magmatism. Chemical Geology 193, 215–35.CrossRefGoogle Scholar
Gripp, A. E. & Gordon, R. G. 2002. Young tracks of hotspots and current plate velocities. Geophysical Journal International 150, 321–61.CrossRefGoogle Scholar
Guivel, C., Morata, D., Pelleter, E., Espinoza, F., Maury, R. C., Lagabrielle, Y., Polvé, M., Bellon, H., Cotten, J., Benoit, M., Suárez, M. & de la Cruz, R. 2006. Miocene to Late Quaternary Patagonian basalts (46–47°S): geochronometric and geochemical evidence for slab tearing due to active spreading ridge subduction. Journal of Volcanology and Geothermal Research 149, 346–70.CrossRefGoogle Scholar
Hart, S. R. 1984. The DUPAL anomaly: a large-scale isotopic anomaly in the southern hemisphere. Nature 309, 753–6.CrossRefGoogle Scholar
Hart, S. R., Hauri, E. H., Oschmann, L. A. & Whitehead, J. A. 1992. Mantle plumes and entrainment: isotopic evidence. Science 256, 517–20.CrossRefGoogle ScholarPubMed
Hechem, J. J. & Strelkov, E. 2002. Secuencia sedimentaria mesozoica del Golfo San Jorge. In Geología y Recursos Naturales de Santa Cruz (ed. Haller, M. J.), pp. 129–47. Relatorio del XV Congreso Geológico Argentino, Buenos Aires, Argentina.Google Scholar
Hervé, F., Davidson, J., Mpodozis, E. & Covacevich, E. V. 1981. The late Palaezoic in Chile: stratigraphy, structure and possible tectonic framework. Anais da Academia Brasileira de Ciências 53, 361–73.Google Scholar
Hickey, R., Frey, F. A. & Gerlach, D. 1986. Multiple sources for basaltic arc rocks from the Southern Volcanic Zone of the Andes (34°–41°S): trace element and isotopic evidence for contributions from subducted oceanic crust, mantle, and continental crust. Journal of Geophysical Research 91, 5963–83.CrossRefGoogle Scholar
Hickey-Vargas, R., Moreno-Roa, H., López-Escobar, L. & Frey, F. A. 1989. Geochemical variations in Andean basaltic and silicic lavas from the Villarrica–Lanin volcanic chain (39.5° S): an evaluation of source heterogeneity, fractional crystallization and crustal assimilation. Contributions to Mineralogy and Petrology 103, 361–86.CrossRefGoogle Scholar
Hirose, K. & Kushiro, I. 1993. Partial melting of dry peridotite at high pressures: determination of compositions of melts segregated from peridotite using aggregates of diamond. Earth and Planetary Science Letters 114, 477–89.CrossRefGoogle Scholar
Hole, M. J., Kempton, P. D. & Millar, I. L. 1993. Trace-element and isotopic characteristics of small-degree melts of the asthenosphere: evidence from the alkalic basalts of the Antarctic Peninsula. Chemical Geology 109, 51–68.CrossRefGoogle Scholar
Hole, M. J., Saunders, A. D., Rogers, G. & Sykes, M. A. 1995. The relationship between alkaline magmatism, lithospheric extension and slab window formation along continental destructive plate margins. In Volcanism associated with extension at consuming plate margins (ed. Smellie, J. L.), pp. 265–85. Geological Society of London, Special Publication no. 81.Google Scholar
Homovc, J. F., Conforto, G. A., Lafourcade, P. A. & Chelotti, L. A. 1995. Fold beld in the San Jorge Basin, Argentina: an example of tectonic inversion. In Basin Inversion (eds Buchanan, J. G. & Buchanan, P. G.), pp. 235–48. Geological Society of London, Special Publication no. 88.Google Scholar
Kay, S. M., Ardolino, A. A., Gorring, M. L. & Ramos, V. A. 2007. The Somuncura large igneous province in Patagonia: interaction of a transient mantle thermal anomaly with a subducting slab. Journal of Petrology 48, 43–77.CrossRefGoogle Scholar
Kay, S. M. & Copeland, P. 2006. Early to middle Miocene backarc magmas of the Neuquén Basin: Geochemical consequences of slab shallowing and the westward drift of South America. In Evolution of an Andean margin: a tectonic and magmatic view from the Andes to the Neuquén Basin (35°–39° S lat) (eds Kay, S. M. & Ramos, V. A.), pp. 185–213. Geological Society of America, Special Paper no. 407.Google Scholar
Kempton, P. D., Hawkesworth, C. J., Lopez-Escobar, L., Pearson, D. G. & Ware, A. J. 1999. Spinel ± garnet lherzolite xenoliths from Pali Aike: Part 2, Trace element and isotopic evidence bearing on the evolution of lithospheric mantle beneath southern Patagonia. In The J. B. Dawson volume (eds Gurney, J. J., Gurney, J. L., Pascoe, M. D. & Richardson, S. H.), pp. 415–28. Proceedings of the 7th International Kimberlite Conference, Red Rood Design, Cape Town, South Africa.Google Scholar
Klemme, S. & O'Neill, H. St. C. 2000. The near-solidus transition from garnet lherzolite to spinel lherzolite. Contributions to Mineralogy and Petrology 138, 237–48.CrossRefGoogle Scholar
Kogiso, T., Tatsumi, Y. & Nakano, S. 1997. Trace element transport during dehydration processes in the subducted oceanic crust: 1. Experiments and implications for the origin of ocean island basalts. Earth and Planetary Science Letters 148, 193–205.CrossRefGoogle Scholar
Kushiro, I. 2001. Partial melting experiments on peridotite and origin of mid-ocean ridge basalt. Annual Review of Earth and Planetary Science 29, 71–107.CrossRefGoogle Scholar
Lizuain, A., Ragona, D. & Folguera, A. 1995. Mapa Geológico de la Provincia del Chubut, República Argentina. Secretaría de Minería, Dirección Nacional del Servicio Geológico, Scale 1:750.000. Buenos Aires, Argentina.Google Scholar
López-Escobar, L., Kilian, R., Kempton, P. & Tagiri, M. 1993. Petrography and geochemistry of Quaternary rocks from the Southern Volcanic Zone of the Andes between 41°30′ and 46°00′S, Chile. Revista Geológica de Chile 20, 33–55.Google Scholar
López-Escobar, L., Parada, M. A., Hickey-Vargas, R., Frey, F. A., Kempton, P. D. & Moreno, H. 1995. Calbuco Volcano and minor eruptive centers distributed along the Liquiñe–Ofqui Fault Zone, Chile (41°–42° S): contrasting origin of andesitic and basaltic magma in the Southern Volcanic Zone of the Andes. Contribution to Mineralogy and Petrology 119, 345–61.CrossRefGoogle Scholar
Marshall, L. G., Cifelli, R. L., Drake, R. E. & Curtis, G. H. 1986. Vertebrate paleontology, geology and geochronology of the Tapera de López and Scarritt Pocket, Chubut Province, Argentina. Journal of Paleontology 60, 920–51.CrossRefGoogle Scholar
Massaferro, G. I., Haller, M. J., D'Orazio, M. & Alric, V. I. 2006. Sub-recent volcanism in Northern Patagonia: a tectonomagmatic approach. Journal of Volcanology and Geothermal Research 155, 227–43.CrossRefGoogle Scholar
McDonough, W. F. & Sun, S. S. 1995. The composition of the Earth. Chemical Geology 120, 223–53.CrossRefGoogle Scholar
Ntaflos, Th., Bjerg, E. A., Labudia, C. H. & Kurat, G. 2007. Depleted lithosphere from the mantle wedge beneath Tres Lagos, southern Patagonia, Argentina. Lithos 94, 46–65.CrossRefGoogle Scholar
Pankhurst, R. J. & Rapela, C. R. 1995. Production of Jurassic rhyolite by anatexis of the lower crust of Patagonia. Earth and Planetary Science Letters 134, 23–36.CrossRefGoogle Scholar
Pankhurst, R. J., Rapela, C. W., Fanning, C. M. & Márquez, M. 2006. Gondwanide continental collision and origin of Patagonia. Earth Science Reviews 76, 235–56.CrossRefGoogle Scholar
Pearce, T. H. 1978. Olivine fractionation equations for basaltic and ultrabasic liquids. Nature 276, 771–4.CrossRefGoogle Scholar
Plá Cid, J., Nardi, L. V. S., Gisbert, P. E., Merlet, C. & Boyer, B. 2005. SIMS analyses on trace and rare earth elements in coexisting clinopyroxene and mica from minette mafic enclaves. Contributions to Mineralogy and Petrology 148, 675–88.CrossRefGoogle Scholar
Quartino, B. J. 1958. El basalto olivínico del Cerro El Pedrero, Chubut. Revista de la Asociación Geológica Argentina 12, 233–64.Google Scholar
Ramos, V. A. & Kay, S. M. 1992. Southern Patagonian plateau basalts and deformation: backarc testimony of ridge collisions. Tectonophysics 205, 261–82.CrossRefGoogle Scholar
Rivalenti, G., Mazzucchelli, M., Laurora, A., Ciuffi, S. I. A., Zanetti, A., Vannucci, R. & Cingolani, C. A. 2004. The backarc mantle lithosphere in Patagonia, South America. Journal of South American Earth Sciences 17, 121–52.CrossRefGoogle Scholar
Rivalenti, G., Mazzucchelli, M., Zanetti, A., Vannucci, R., Bollinger, C., Hémond, C. & Bertotto, G. W. 2007. Xenoliths from Cerro de los Chenques (Patagonia): An example of slab-related metasomatism in the backarc lithospheric mantle. Lithos 99, 45–67.CrossRefGoogle Scholar
Schilling, M., Conceição, R. V., Mallmann, G., Koester, E., Kawashita, K., Hervé, F., Morata, D. & Motoki, A. 2005. Spinel-facies mantle xenoliths from Cerro Redondo, Argentine Patagonia: petrographic, geochemical, and isotopic evidence of interaction between xenoliths and host basalt. Lithos 82, 485–502.CrossRefGoogle Scholar
Scoppola, B., Boccaletti, D., Bevis, M., Carminati, E. & Doglioni, C. 2006. The westward drift of the lithosphere; a rotational drag? Geological Society of America Bulletin 118, 199–209.CrossRefGoogle Scholar
Shervais, J. W. 1982. Ti–V plots and the petrogenesis of modern and ophiolitic lavas. Earth and Planetary Science Letters 59, 101–18.CrossRefGoogle Scholar
Spera, F. J. & Bohrson, W. A. 2001. Energy-constrained open-system magma processes I: general model and energy-constrained assimilation fractional-crystallization (EC-AFC) formulation. Journal of Petrology 42, 999–1018.CrossRefGoogle Scholar
Steiger, K. H. & Jäger, E. 1977. Subcommission on geochronology: Convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters 36, 359–62.CrossRefGoogle Scholar
Stern, C. R., Frey, F. A., Futa, K., Zartman, R. E., Peng, Z. & Kyser, T. K. 1990. Trace-element and Sr, Nd, Pb and O isotopic composition of Pliocene and Quaternary alkali basalt of the Patagonian Plateau lavas of southernmost South America. Contributions to Mineralogy and Petrology 104, 294–308.CrossRefGoogle Scholar
Stern, C. R. & Kilian, R. 1996. Role of the subducted slab, mantle wedge and continental crust in the generation of adakites from the Andean Austral Volcanic Zone. Contributions to Mineralogy and Petrology 123, 263–81.CrossRefGoogle Scholar
Stern, C. R., Kilian, R., Olker, B., Hauri, E. H. & Kyser, T. K. 1999. Evidence from mantle xenoliths for relatively thin (< 100 km) continental lithosphere below the Phanerozoic crust of southernmost South America. Lithos 48, 217–35.CrossRefGoogle Scholar
Sturm, M. E., Klein, E. M., Graham, D. W. & Karsten, J. 1999. Age constraints on crustal recycling to the mantle beneath the southern Chile Ridge: He–Pb–Sr–Nd isotope systematics. Journal of Geophysical Research 104, B3, 5097–114.CrossRefGoogle Scholar
Sudo, A. & Tatsumi, Y. 1990. Phlogopite and K-amphibole in the upper mantle: implication for magma genesis in subduction zones. Geophysical Research Letters 17, 29–32.CrossRefGoogle Scholar
Sun, S. S. & McDonough, W. F. 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In Magmatism in the Ocean Basins (eds Saunders, A. D. & Norry, M. J.), pp. 313–45. Geological Society of London, Special Publication no. 42.Google Scholar
Sylwan, C. A. 2001. Geology of the Golfo San Jorge Basin, Argentina. Journal of Iberian Geology 27, 123–57.Google Scholar
Taylor, S. R. & McLennan, S. M. 1995. The geochemical evolution of the continental crust. Reviews in Geophysics 33, 241–65.CrossRefGoogle Scholar
Thybo, H. 2006. The heterogeneous upper mantle low velocity zone. Tectonophysics 416, 53–79.CrossRefGoogle Scholar
Tiepolo, M., Zanetti, A., Oberti, R., Brumm, R., Foley, S. & Vannucci, R. 2003. Trace-element partitioning between synthetic potassic richterites and silicate melts, and contrasts with the partitioning behaviour of pargasites and kaersutites. European Journal of Mineralogy 15, 329–40.CrossRefGoogle Scholar
Todt, W., Cliff, R. A., Hanser, A. & Hofmann, A. W. 1996. Evaluation of a 202Pb–205Pb double spike for high-precision lead isotope analysis. In Earth processes: reading the isotopic code (eds Hart, S. R. & Basu, A.), pp. 429–37. American Geophysical Union, Geophysical Monograph vol. 95. Washington, DC, USA.Google Scholar
Vernieres, J., Godard, M. & Bodinier, J.-L. 1997. A plate model for the simulation of trace element fractionation during partial melting and magmas transport in the Earth's upper mantle. Journal of Geophysical Research 102, 24771–84.CrossRefGoogle Scholar
Wagner, T. P. & Grove, T. L. 1998. Melt/harzburgite reaction in the petrogenesis of tholeiitic magma from Kilauea volcano, Hawaii. Contributions to Mineralogy and Petrology 131, 1–12.CrossRefGoogle Scholar
Xu, Y. G., Ma, J. L., Frey, F. A., Feigenson, M. D. & Liu, J. F. 2005. Role of lithosphere–asthenosphere interaction in the genesis of Quaternary alkali and tholeiitic basalts from Datong, western North China Craton. Chemical Geology 224, 247–71.CrossRefGoogle Scholar