Abstract
Gurenko et al. (Contrib Mineral Petrol 162:349–363, 2011) report laser-assisted fluorination (LF) and secondary ionization mass spectrometry (SIMS) 18O/16O datasets for olivine grains from the Canary Islands of Gran Canaria, Tenerife, La Gomera, La Palma and El Hierro. As with prior studies of oxygen isotopes in Canary Island lavas (e.g. Thirlwall et al. Chem Geol 135:233–262, 1997; Day et al. Geology 37:555–558, 2009, Geochim Cosmochim Acta 74:6565–6589, 2010), these authors find variations in δ18Ool (~4.6–6.0 ‰) beyond that measured for mantle peridotite olivine (Mattey et al. Earth Planet Sci Lett 128:231–241, 1994) and interpret this variation to reflect contributions from pyroxenite-peridotite mantle sources. Furthermore, Gurenko et al. (Contrib Mineral Petrol 162:349–363, 2011) speculate that δ18Ool values for La Palma olivine grains measured by LF (Day et al. Geology 37:555–558, 2009, Geochim Cosmochim Acta 74:6565–6589, 2010) may be biased to low values due to the presence of altered silicate, possibly serpentine. The range in δ18Ool values for Canary Island lavas are of importance for constraining their origin. Gurenko et al. (Contrib Mineral Petrol 162:349–363, 2011) took a subset (39 SIMS analyses from 13 grains from a single El Hierro lava; EH4) of a more extensive dataset (321 SIMS analyses from 110 grains from 16 Canary Island lavas) to suggest that δ18Ool is weakly correlated (R 2 = 0.291) with the parameter used by Gurenko et al. (Earth Planet Sci Lett 277:514–524, 2009) to describe the estimated weight fraction of pyroxenite-derived melt (Xpx). With this relationship, end-member δ18O values for HIMU-peridotite (δ18O = 5.3 ± 0.3 ‰) and depleted pyroxenite (δ18O = 5.9 ± 0.3 ‰) were defined. Although the model proposed by Gurenko et al. (Contrib Mineral Petrol 162:349–363, 2011) implicates similar pyroxenite-peridotite mantle sources to those proposed by Day et al. (Geology 37:555–558, 2009, Geochim Cosmochim Acta 74:6565–6589, 2010) and Day and Hilton (Earth Planet Sci Lett 305:226–234, 2011), there are significant differences in the predicted δ18O values of end member components in the two models. In particular, Day et al. (Geochim Cosmochim Acta 74:6565–6589, 2010) proposed a mantle source for La Palma lavas with low-δ18O (<5 ‰), rather than higher-δ18O (c.f. the HIMU-peridotite composition of Gurenko et al. in Contrib Mineral Petrol 162:349–363, 2011). Here we question the approach of using weakly correlated variations in δ18Ool and the Xpx parameter to define mantle source oxygen isotope compositions, and provide examples of why this approach appears flawed. We also provide reasons why the LF datasets previously published for Canary Island lavas remain robust and discuss why LF and SIMS data may provide complementary information on oxygen isotope variations in ocean island basalts (OIB), despite unresolved small-scale uncertainties associated with both techniques.
Notes
(δ18O = ([(18O/16O)sample/(18O/16O)VSMOW] −1) × 1,000).
References
Baker JA, Macpherson CG, Menzies MA, Thirlwall MF, Al-Kadasi M, Mattey DP (2000) Resolving crustal and mantle contributions to continental flood volcanism, Yemen; constraints from mineral oxygen isotope data. J Petrol 41:1805–1820
Bindeman I, Gurenko A, Sigmarsson O, Chaussidon M (2008) Oxygen isotope heterogeneity and disequilibria of olivine crystals in large volume Holocene basalts from Iceland: evidence for magmatic digestion and erosion of Pleistocene hyaloclastites. Geochim Cosmochim Acta 72:4397–4420
Day JMD, Hilton DR (2011) Origin of 3He/4He ratios in HIMU-type basalts constrained from Canary Island lavas. Earth Planet Sci Lett 305:226–234
Day JMD, Pearson DG, Macpherson CG, Lowry D, Carracedo JC (2009) Pyroxenite-rich mantle formed by recycled oceanic lithosphere: oxygen-osmium isotope evidence from Canary Island lavas. Geology 37:555–558
Day JMD, Pearson DG, Macpherson CG, Lowry D, Carracedo JC (2010) Evidence for distinct proportions of subducted oceanic crust and lithosphere in HIMU-type mantle beneath El Hierro and La Palma, Canary Islands. Geochim Cosmochim Acta 74:6565–6589
Demény A, Cassillas R, Vennemann TW, Hegner E, Nagy G, Ahijado A, De La Nuez J, Sipos P, Pilet S, Milton J (2008) Plume-related stable isotope compositions and fluid–rock interaction processes in the Basal Complex of La Palma, Canary Islands, Spain. In: Coltorti M, Greogoire M (eds) Metasomatism in oceanic and continental lithospheric mantle. Special Publication vol 293, geological society, London, pp 155–175
Eiler JM, Stolper E, McCanta MC (2011) Intra- and intercrystalline oxygen isotope variations in minerals from basalts and peridotites. J Petrol 52:1393–1413
Goldich S (1938) A study of rock weathering. J Geol 46:17–58
Gurenko AA, Sobolev AV, Hoernle KA, Hauff F, Schmincke H-U (2009) Enriched, HIMU-type peridotite and depleted recycled pyroxenite in the Canary plume: a mixed-up mantle. Earth Planet Sci Lett 277:514–524
Gurenko AA, Bindeman IN, Chaussidon M (2011) Oxygen isotope heterogeneity of the mantle beneath the Canary Islands: insights from olivine phenocrysts. Contrib Mineral Petrol 162:349–363
Hansteen TH, Troll VR (2003) Oxygen isotope composition of xenoliths from the oceanic crust and volcanic edifice beneath Gran Canaria (Canary Islands): consequences for crustal contamination of ascending magmas. Chem Geol 193:181–193
Hausrath EM, Navarre-Sitchler AK, Sak PB, Steefel CI, Brantley SL (2008) Basalt weathering rates on Earth and the duration of liquid water on the plains of Gusev crater, Mars. Geology 36:67–70
Hoernle K (1998) Geochemistry of Jurassic oceanic crust beneath Gran Canaria (Canary Islands): implications for crustal recycling and assimilation. J Petrol 39:859–880
Hoernle K, Tilton G (1991) Sr–Nd–Pb isotope data for Fuerteventura (Canary Islands) basal complex and subaerial volcanics: application to magma genesis and evolution. Schweiz Mineral Petrogr Mitt 71:5–21
Hoernle K, Tilton G, Schmincke H-U (1991) Sr–Nd–Pb isotopic evolution of Gran Canaria: evidence for shallow enriched mantle beneath the Canary Islands. Earth Planet Sci Lett 106:44–63
Javoy M, Stillman CJ, Pineau F (1986) Oxygen and hydrogen isotope studies on the basal complexes of the Canary Islands: implications on the conditions of their genesis. Contrib Miner Petrol 92:225–235
Kita NT, Ushikubo T, Fu B, Valley JW (2009) High precision SIMS oxygen isotope analysis and the effect of sample topography. Chem Geol 264:43–57
Mattey D, Macpherson C (1993) High-precision oxygen isotope microanalysis of ferromagnesian minerals by laser-fluorination. Chem Geol 105:305–318
Mattey D, Lowry D, Macpherson C (1994) Oxygen isotope composition of mantle peridotite. Earth Planet Sci Lett 128:231–241
Pearson DG, Davies GR, Nixon PH, Greenwood PB, Mattey DP (1991) Oxygen isotope evidence for the origin of pyroxenites in the Beni Boussera peridotite massif, N. Morrocco: derivation from subducted oceanic lithosphere. Earth Planet Sci Lett 102:289–301
Rumble D, Miller MF, Franchi IA, Greenwood RC (2007) Oxygen three-isotope fractionation lines in terrestrial silicate minerals: an inter-laboratory comparison of hydrothermal quartz and eclogitic garnet. Geochim Cosmochim Acta 71:3592–3600
Sharp ZD (1990) A laser based microanalytical method for the in situ determination of oxygen isotope ratios of silicates and oxides. Geochim Cosmochim Acta 54:1353–1357
Skelton ADL, Valley JW (2000) The relative timing of serpentinisation and mantle exhumation at the ocean-continent transition, Iberia: constraints from oxygen isotopes. Earth Planet Sci Lett 178:327–338
Thirlwall MF, Jenkins C, Vroon PZ, Mattey DP (1997) Crustal interaction during construction of oceanic islands: Pb-Sr-Nd-O isotope geochemistry of the shield basalts of Gran Canaria, Canary Islands. Chem Geol 135:233–262
Valley JW, Kitchen N, Kohn MJ, Neindorf CR, Spicuzza MJ (1995) UWG-2, a garnet standard for oxygen isotope ratios: strategies for high precision and accuracy with laser heating. Geochim Cosmochim Acta 59:5223–5231
Wang Z, Eiler JM (2008) Insights into the origin of low-δ18O basaltic magmas in Hawaii revealed from in situ measurements of oxygen isotope compositions of olivines. Earth Planet Sci Lett 269:376–386
Zheng Y-F (1993) Calculation of oxygen isotope fractionation in anhydrous silicate minerals. Geochim Cosmochim Acta 57:1079–1091
Acknowledgments
This work was performed with support from the National Science Foundation (EAR-1116089) and The San Diego Foundation (C-2011-00204). We thank C. Harris, two anonymous reviewers and Editor J. Hoefs for their constructive comments.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by J. Hoefs.
This comment refers to the article available at 10.1007/s00410-010-0600-5.
An author‘s reply to this comment is available at 10.1007/s00410-012-0756-2.
Rights and permissions
About this article
Cite this article
Day, J.M.D., Macpherson, C.G., Lowry, D. et al. Oxygen isotope heterogeneity of the mantle beneath the Canary Islands: a discussion of the paper of Gurenko et al.. Contrib Mineral Petrol 164, 177–183 (2012). https://doi.org/10.1007/s00410-012-0755-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00410-012-0755-3