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Parental magma composition of the syntectonic Dawros Peridotite chromitites, NW Connemara, Ireland

Published online by Cambridge University Press:  14 October 2011

E. HUNT ,
B. O'DRISCOLL  and
J. S. DALY
E. HUNT*
Affiliation:
School of Physical and Geographical Sciences, Keele University, Keele, UK
B. O'DRISCOLL
Affiliation:
School of Physical and Geographical Sciences, Keele University, Keele, UK
J. S. DALY
Affiliation:
UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4, Ireland
*
†Author for correspondence: [email protected]
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Abstract

Chromium-spinels have been widely used as petrogenetic indicators to infer parent melt compositions and the tectonic setting of their formation. This study integrates petrographic, quantitative textural and geochemical analyses of Cr-spinel seams within the Dawros Peridotite, NW Connemara, Ireland to determine the composition of their parental magmas. Calculation of Cr no. (Cr/(Cr + Al)) (0.50–0.77) values and TiO2 (0.18–0.36 wt%) contents of the Cr-spinel seams, coupled with an estimation of the Al2O3 and TiO2 contents (~11.86 wt% and ~0.39 wt%, respectively) of their parental melts, indicates that they probably formed from boninitic melts sourced from a highly depleted mantle. This implies that the Cr-spinel seams formed in a supra-subduction zone undergoing high degrees of partial melting. The Cr-spinel data support tectonic models for the formation of the Dawros Peridotite (and Connemara Metagabbro-Gneiss Complex) during island arc collision, immediately prior to Grampian orogenesis at ~470 Ma. The occurrence of the Dawros chromitite seams at the approximate transition between the lower harzburgite sequence and the upper lherzolite sequence bears marked similarities to the positions of such seams in larger anorogenic layered mafic-ultramafic intrusions, and implies that the Dawros Peridotite behaved as an open-system magma chamber.

Keywords

Cr-spinelDawros Peridotiteisland arcboninitemelt–rock interaction
Type
Original Articles
Information
Geological Magazine , Volume 149 , Issue 4 , July 2012 , pp. 590 - 605
Copyright
Copyright © Cambridge University Press 2011

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References

Ahmed, A. H., Arai, S., Adbel-Aziz, Y. M., Ikenne, M. & Rahimi, A. 2009. Platinum-group elements distribution and spinel composition in podiform chromitites and associated rocks from the upper mantle section of the Neoproterozoic Bou Azzer ophiolite, Anti-Atlas, Morocco. Journal of African Earth Sciences 55, 92–104.CrossRefGoogle Scholar
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. Contributions to Mineralogy and Petrology 101, 27–40.CrossRefGoogle Scholar
Ballhaus, C. 1998. Origin of podiform chromite deposits by magma mingling. Earth and Planetary Science Letters 156, 185–93.CrossRefGoogle Scholar
Barnes, S. J. 1998. Chromite in komatiites, 1. Magmatic controls on crystallisation and composition. Journal of Petrology 39, 1689–720.CrossRefGoogle Scholar
Barnes, S. J. & Roeder, P. L. 2001. The range of spinel compositions in terrestrial mafic and ultramafic rocks. Journal of Petrology 42, 2279–302.CrossRefGoogle Scholar
Bennett, M. C. & Gibb, F. G. F. 1983. Younging directions in the Dawros peridotite, Connemara. Journal of the Geological Society, London 140, 63–73.CrossRefGoogle Scholar
Bonavia, F. F., Diella, V. & Ferrario, A. 1993. Precambrian podiform chromites from Kenticha Hill, Southern Ethiopia. Economic Geology 88, 108–202.CrossRefGoogle Scholar
Boorman, S., Boudreau, A. & Kruger, F. J. 2004. The Lower Zone–Critical Zone transition of the Bushveld Complex: a quantitative textural study. Journal of Petrology 45, 1209–35.CrossRefGoogle Scholar
Büchl, A., Brügmann, G. & Batanova, V. G. 2004. Formation of podiform chromitite deposits: implications from PGE abundances and Os isotopic compositions of chromites from the Troodos complex, Cyprus. Chemical Geology 208, 217–32.CrossRefGoogle Scholar
Bremner, D. L. & Leake, B. E. 1980. The geology of the Roundstone Ultrabasic Complex, Connemara. Proceedings of the Royal Irish Academy 80B, 395–433.Google Scholar
Dewey, J. F. & Shackleton, R. M. 1984. A model for the evolution of the Grampian tract in the early Caledonides and Appalachians. Nature 312, 115–21.CrossRefGoogle Scholar
Droop, G. T. R. 1987. A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria. Mineralogical Magazine 51, 431–5.CrossRefGoogle Scholar
Friedrich, A. M., Bowring, S. A., Martin, M. W. & Hodges, K. V. 1999. Short-lived continental magmatic arc at Connemara, western Irish Caledonides: implications for the age of the Grampian orogeny. Geology 27, 27–30.2.3.CO;2>CrossRefGoogle Scholar
Higgins, M. D. 2000. Measurement of crystal size distributions. American Mineralogist 85, 1105–16.CrossRefGoogle Scholar
Higgins, M. D. 2006. Quantitative Textural Measurements in Igneous and Metamorphic Petrology. Cambridge: Cambridge University Press, 265 pp.CrossRefGoogle Scholar
Higgins, M. D. 2009. CSD Corrections version 1.3.9.1 [Digital Download]. http://depcom.uqac.ca/~mhiggins/csdcorrections.html.Google Scholar
Higgins, M. D. 2010. Textural coarsening in igneous rocks. International Geology Review 1, 1–23.Google Scholar
Hulbert, L. J. & Von Gruenewaldt, G. 1985. Textural and compositional features of chromite in the Lower and Critical Zones of the Bushveld Complex, South of Potgietersrus. Economic Geology 80, 872–95.CrossRefGoogle Scholar
Ingold, L. M. 1937. The geology of the Currywongaun-Doughruagh area, Co. Galway. Proceedings of the Royal Irish Academy B43, 135–59.Google Scholar
Irvine, T. N. 1965. Chromian spinel as a petrogenetic indicator: part 1. Theory. Canadian Journal of Earth Sciences 2, 648–72.CrossRefGoogle Scholar
Irvine, T. N. 1967. Chromian spinel as a petrogenetic indicator: part 2. Petrologic applications. Canadian Journal of Earth Sciences 4, 71–103.CrossRefGoogle Scholar
Irvine, T. N. 1977. Origin of chromite layers in the Muskox intrusion and other intrusion: a new interpretation. Geology 5, 273–7.2.0.CO;2>CrossRefGoogle Scholar
Kamenetsky, V. S., Crawford, A. J. & Meffre, S. 2001. Factors controlling chemistry of magmatic spinel: an empirical study of associated olivine. Journal of Petrology 42, 655–71.CrossRefGoogle Scholar
Kanaris-Sotiriou, R. & Angus, N. S. 1976. The Currywongaun-Doughruah syntectonic intrusion, Connemara, Ireland. Journal of the Geological Society, London 132, 485–508.CrossRefGoogle Scholar
Kelemen, P. B., Whitehead, J. A., Aharonov, E. & Jordahl, K. A. 1995. Experiments on flow focusing in soluble porous media, with applications to melt extraction from the mantle. Journal of Geophysical Research 100, 475–96.CrossRefGoogle Scholar
Kelemen, P. B., Hirth, G., Shimizu, N., Spiegelman, M. & Dick, H. J. B. 1997. A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges. Philosophical Transactions of the Royal Society of London A355, 283–318.CrossRefGoogle Scholar
Leake, B. E. 1958. The Cashel-Lough Wheelaun Intrusion, Co. Galway. Proceedings of the Royal Irish Academy 59B, 155–203.Google Scholar
Leake, B. E. 1964. New light on the Dawros peridotite, Connemara, Ireland. Geological Magazine 101, 63–75.CrossRefGoogle Scholar
Leake, B. E. 1970. The fragmentation of the Connemara basic and ultrabasic intrusions. In Mechanism of Igneous Intrusion (eds Newall, G. & Rast, N.), pp 103–22. Liverpool: Seel House Press.Google Scholar
Leake, B. E. 1989. The metagabbros, orthogneisses and paragneisses of the Connemara complex, western Ireland. Journal of the Geological Society, London 146, 575–96.CrossRefGoogle Scholar
Leake, B. E. & Tanner, P. W. G. 1994. The Geology of the Dalradian and Associated Rocks of the Connemara, Western Ireland: A report to accompany the 1:63360 geological map and cross-sections. Dublin: Royal Irish Academy.Google Scholar
Lord, R. A., Prichard, H. M., Sá, J. H. S. & Neary, C. R. 2004. Chromite geochemistry and PGE fractionation in the Campo Formoso Complex and Ipueira-Medrado Sill, Bahia State, Brazil. Economic Geology 99, 339–63.CrossRefGoogle Scholar
Marchesi, C., González-Jiménez, J. M, Gervilla, F., Garrido, C. J., Griffin, W. L., O'Reilly, S. Y., Proenza, J. A. & Pearson, N. J. 2011. In situ Re–Os isotopic analysis of platinum-group minerals from the Mayarí-Cristal ophiolitic massif (Mayarí-Baracoa Ophiolitic Belt, eastern Cuba): implications for the origin of Os-isotope heterogeneities in podiform chromitites. Contributions to Mineralogy and Petrology 161, 977–90.CrossRefGoogle Scholar
Marsh, B. D. 1998. On the interpretation of crystal size distributions in magmatic systems. Journal of Petrology 39, 553–99.CrossRefGoogle Scholar
Maurel, C. & Maurel, P. 1982. Etude experimentale de la distribution de l'aluminium entre bain silicate basique et spinelle chromifere: implications petrogenetiques, teneur en chrome des spinelles. Bulletin of Mineralogy 105, 97–202.Google Scholar
Melcher, F., Grum, W., Simon, G., Thalhammer, T. V. & Stumpel, E. F. 1997. Petrogenesis of the ophiolitic giant chromite deposits of Kempirsai, Kazakhstan: a study of solid and fluid inclusions in chromite. Journal of Petrology 38, 1419–58.CrossRefGoogle Scholar
Mondal, S. K. & Mathez, E. A. 2007. Origin of the UG2 chromitite layer, Bushveld Complex. Journal of Petrology 48, 495–519.CrossRefGoogle Scholar
Naldrett, A. J., Kinnaird, J., Wilson, A., Yudoskaya, M., McQuade, S., Chunnett, G. & Stanley, C. 2009. Chromitite composition and PGE content of the Bushveld chromitites: Part 1 – the Lower and Middle Groups. Applied Earth Sciences (Transactions of the Institution of Mining and Metallurgy, Section B) 118, 131–61.CrossRefGoogle Scholar
O'Driscoll, B. 2005. Textural equilibrium in magmatic layers of the Lough Fee ultramafic intrusion, NW Connemara, Ireland: implications for adcumulus mineral growth. Irish Journal of Earth Sciences 23, 39–45.CrossRefGoogle Scholar
O'Driscoll, B., Donaldson, C. H., Daly, J. S. & Emeleus, C. H. 2009. The roles of melt infiltration and cumulate assimilation in the formation of anorthosite and a Cr-spinel seam in the Rum Eastern Layered Intrusion, NW Scotland. Lithos 111, 6–20.CrossRefGoogle Scholar
O'Driscoll, B., Emeleus, C. H., Donaldson, C. H. & Daly, J. S. 2010. Cr-spinel seam petrogenesis in the Rum Layered Suite, NW Scotland: cumulate assimilation and in situ crystallization in a deforming crystal mush. Journal of Petrology 51, 1171–201.CrossRefGoogle Scholar
O'Driscoll, B. & Petronis, M. S. 2009. Oxide mineral formation during the serpentinization of a Cr-spinel seam: insights from rock magnetic experiments. Geochemistry, Geophysics, Geosystems 10, Q01008, doi:10.1029/2008GC002274.CrossRefGoogle Scholar
O'Driscoll, B., Powell, D. G. R. & Reavy, R. J. 2005. Constraints on the development of magmatic layering in a syntectonic mafic-ultramafic suite, NW Connemara, Ireland. Scottish Journal of Geology 41, 119–28.CrossRefGoogle Scholar
Page, P. & Barnes, S. J. 2009. Using trace elements in chromites to constrain the origin of podiform chromitites in the Thetford Mines Ophiolite, Québec, Canada. Economic Geology 104, 997–1018.CrossRefGoogle Scholar
Pearce, J. A., Lippard, S. J. & Roberts, S. 1984. Characteristics and tectonic significance of supra-subduction zone ophiolites. In Marginal Basin Geology: Volcanic and associated sedimentary and tectonic processes in modern and ancient marginal basins (eds Kokelaar, B. P. & Howells, M. F.), pp. 77–94. Geological Society of London, Special Publication no. 16.Google Scholar
Quintiliani, M., Andreozzi, G. B. & Graziani, G. 2006. Fe2+ and Fe3+ quantification by different approaches and f O2 estimation for Albanian Cr-spinels. American Mineralogist 91, 907–16.CrossRefGoogle Scholar
Rollinson, H. 2008. The geochemistry of mantle chromitites from the northern part of the Oman ophiolite: inferred parental melt compositions. Contributions to Mineralogy and Petrology 156, 273–88.CrossRefGoogle Scholar
Rollinson, H., Appel, P. W. U. & Frei, R. 2002. A metamorphosed Early Archean chromitite from West Greenland: implications for the genesis of Archean anorthositic chromitites. Journal of Petrology 43, 2143–70.CrossRefGoogle Scholar
Rothstein, A. T. V. 1957. The Dawros peridotite, Connemara, Eire. Quarterly Journal of the Geological Society of London 113, 599–602.CrossRefGoogle Scholar
Rothstein, A. T. V. 1972. Spinels from the Dawros Peridotite, Connemara, Ireland. Mineralogical Magazine 38, 957–60.CrossRefGoogle Scholar
Sobolev, A. V. & Danyushevsky, L. V. 1994. Petrology and geochemistry of boninites from the north termination of the Tonga Trench: constraints on the generation conditions of primary high-Ca boninite magmas. Journal of Petrology 35, 1183–211.CrossRefGoogle Scholar
Tanner, P. W. G. & Shackleton, R. M. 1979. Structure and stratigraphy of the Dalradian rocks of the Beannabeola area, Connemara, Eire. In The Caledonides of the British Isles Reviewed (eds Harris, A. L., Holland, C. H. & Leake, B. E.), pp 243–56. Geological Society of London, Special Publication no. 8.Google Scholar
Uysal, I., Tarkian, M., Sadiklar, M. B., Zaccarini, F., Meisel, T., Garuti, G. & Heidrich, S. 2009. Petrology of Al- and Cr-rich ophiolitic chromitites from the Muğla, SW Turkey: implications from composition of chromite, solid inclusions of platinum-group mineral, silicate, and base-metal mineral, and Os-isotope geochemistry. Contributions to Mineralogy and Petrology 158, 659–74.CrossRefGoogle Scholar
Waters, C. & Boudreau, A. E. 1996. A re-evaluation of crystal-size distributions in chromite cumulates. American Mineralogist 81, 1452–9.CrossRefGoogle Scholar
Wellings, S. A. 1997. Emplacement of mafic intrusions, north-west Connemara: constraints from petrology and structures. Irish Journal of Earth Sciences 16, 71–84.Google Scholar
Wellings, S. A. 1998. Timing of deformation associated with the syn-tectonic Dawros-Currywongaun-Doughruah Complex, NW Connemara, western Ireland. Journal of the Geological Society, London 155, 25–37.CrossRefGoogle Scholar
Wilson, M. 1989. Igneous Petrogenesis: A global tectonic approach, 1st ed. London: Chapman & Hall, 466 pp.CrossRefGoogle Scholar
Yardley, B. F. & Senior, A. 1982. Basic magmatism in Connemara, Ireland: evidence for a volcanic arc? Journal of the Geological Society, London 139, 67–70.CrossRefGoogle Scholar
Zhou, M.-F., Reid, M. S., Keays, R. R. & Kerrich, R. W. 1998. Controls on platinum-group elemental distributions of podiform chromitites: a case study of high-Cr and high-Al chromitites from Chinese orogenic belts. Geochimica et Cosmochimica Acta 62, 677–88.CrossRefGoogle Scholar
Zhou, M.-F. & Robinson, P. T. 1997. Origin and tectonic environment of podiform chromite deposits. Economic Geology 92, 259–62.CrossRefGoogle Scholar
Zhou, M.-F., Robinson, P. T., Malpas, J., Aitchison, J., Sun, M., Bai, W.-J., Hu, X.-F. & Yang, J.-S. 2001. Melt/mantle interaction and melt evolution in the Sartohay high-Al chromite deposits of the Dalabute ophiolite, NW China. Journal of Asian Earth Sciences 19, 517–34.CrossRefGoogle Scholar
Zhou, M.-F., Robinson, P. T., Malpas, J. & Li, Z. 1996. Podiform chromitites in the Luobusa Ophiolite (Southern Tibet): implications for melt-rock interaction and chromite segregation in the upper mantle. Journal of Petrology 37, 3–21.CrossRefGoogle Scholar
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