Hostname: page-component-8448b6f56d-tj2md Total loading time: 0 Render date: 2024-04-19T19:47:53.669Z Has data issue: false hasContentIssue false
  • English
  • Français

Middle Jurassic ultramafic lamprophyre dyke within the Ferrar magmatic province, Pensacola Mountains, Antarctica

Published online by Cambridge University Press:  25 June 2018

P. T. Leat ,
T. R. Riley ,
B. C. Storey ,
S. P. Kelley  and
I. L. Millar
P. T. Leat*
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
T. R. Riley
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
B. C. Storey
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
S. P. Kelley
Affiliation:
Department of Earth Sciences, The Open University, Walton Hall, Milton Keynes, MK7 6AA, UK
I. L. Millar
Affiliation:
British Antarctic Survey, c/o NERC Isotope Geoscience Laboratory, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, UK
*
*E-mail: p.leat@bas.ac.uk
Get access Rights & Permissions [Opens in a new window]

Abstract

An ultramafic lamprophyre dyke is described from the otherwise tholeiitic Ferrar magmatic province of Antarctica. We report an Ar-Ar age of 183 ± 2.2 Ma for the dyke, indistinguishable from those of the Ferrar tholeiites. However, the dyke has mineralogical and major and trace element compositions, and radiogenic isotopes ratios, very different from the Ferrar tholeiites. The sample consists of olivine and rare clinopyroxene phenocrysts with perovskite and spinel microphenocrysts in a groundmass of amphibole, nepheline and biotite. Carbonatitic globules contain calcite, dolomite, Fe-rich carbonate, nepheline, biotite, orthoclase, pyrite, clinopyroxene, apatite and silicate glass, and were formed by liquid immiscibility. The rock is mildly potassic and classifies as an ouachitite. It is strongly enriched in both moderately and highly incompatible trace elements and is the first high-Ti rock to be described from the Ferrar magmatic province. The rock has similar initial 143Nd/144Nd to OIB, notably Bouvet, Crozet and Réunion, but significantly higher initial 87Sr/86Sr. The lamprophyre magma is interpreted as having been generated by low-degree partial fusion of metasomatized lithospheric mantle as a result of heat conducted from an underlying Jurassic mantle plume. The same mantle plume was probably also responsible for generating one of the world’s largest layered gabbro bodies, the Dufek-Forrestal intrusions.

Keywords

ultramaficlamprophyredykeFerrarPensacola MountainsAntarctica
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 1 , February 2000 , pp. 95 - 111
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

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

Brewer, T.S. (1989) Mesozoic dolerites from Whichaway Nunataks. Antarct. Sci., 1, 151–5.CrossRefGoogle Scholar
Brewer, T.S., Hergt, J.M., Hawkesworth, C.J., Rex, D. and Storey, B.C. (1992) Coats Land dolerites and the generation of Antarctic continental flood basalts. Pp. 185–208 in: Magmatism and the causes of continental break-up (Storey, B.C., Alabaster, T. and Pankhurst, R.J., editors). Geological Society of London, Spec. Publ., 68.Google Scholar
Bristow, J.W. (1984) Nephelinites of the north Lebombo and south-east Zimbabwe. Spec. Publ. Geol. Soc. S. Afr., 13, 87–104.Google Scholar
Borg, S.G., DePaolo, D.J. and Smith, B.M. (1990) Isotopic structure and tectonics of the central Transantarctic Mountains. J. Geophys. Res., 95, 6647–67.CrossRefGoogle Scholar
Clarke, L.B. and Le Bas, M.J. (1990) Magma mixing and metasomatic reaction in silicate-carbonate liquids at the Kruidfontein carbonatitic complex, Transvaal. Mineral. Mag., 54, 45–56.CrossRefGoogle Scholar
Delor, C.P. and Rock, N.M.S. (1991) Alkaline-ultramafic lamprophyre dykes from the Vestfold Hills, Princess Elizabeth Land (East Antarctica): primitive magmas of deep mantle origin. Antarct. Sci., 3, 419–32.CrossRefGoogle Scholar
Duncan, R.A. and Richards, M.A. (1991) Hotspots, mantle plumes, flood basalts, and true polar wander. Rev. Geophys., 29, 31–50.CrossRefGoogle Scholar
Duncan, R.A., Hooper, P.R., Rehacek, J., Marsh, J.S. and Duncan, A.R. (1997) The timing and duration of the Karoo igneous event, southern Gondwana. J. Geophys. Res., 102, 18127–38.CrossRefGoogle Scholar
Elliot, D.H., Fleming, T.H., Kyle, P.R. and Foland, K.A. (1999) Long-distance transport of magmas in the Jurassic Ferrar Large Igneous Province, Antarctica. Earth Planet. Sci. Lett., 167, 89–104.CrossRefGoogle Scholar
Encarnación, J., Fleming, T.H., Elliot, D.H. and Eales, H.V. (1996) Synchronous emplacement of Ferrar and Karoo dolerites and the early breakup of Gondwana. Geology, 24, 535–8.2.3.CO;2>CrossRefGoogle Scholar
Ewart, A., Chappell, B.W. and Menzies, M.A. (1988) An overview of the chemical and isotopic characteristics of the eastern Australian Cainozoic volcanic provinces. J. Petrol. Special Lithosphere Issue, pp. 225–273.Google Scholar
Ferris, J., Johnson, A. and Storey, B. (1998) Form and extent of the Dufek intrusion, Antarctica, from newly compiled aeromagnetic data. Earth Planet. Sci. Lett., 154, 185–202.CrossRefGoogle Scholar
Fisk, M.R., Upton, B.G.J., Ford, C.E. and White, W.M. (1988) Geochemical and experimental study of the genesis of magmas of Reunion Island, Indian Ocean. J. Geophys. Res., 93, 4933–50.CrossRefGoogle Scholar
Fleming, T.H., Elliot, D.H., Jones, J.M., Bowman, J.R. and Siders, M.A. (1992) Chemical and isotopic variations in an iron-rich flow from the Kirkpatrick Basalt, north Victoria Land, Antarctica: implication for low-temperature alteration. Contrib. Mineral. Petrol., 111, 440–57.CrossRefGoogle Scholar
Freestone, I.C. and Hamilton, D.L. (1980) The role of liquid immiscibility in the genesis of carbonatites – an experimental study. Contrib. Mineral. Petrol., 73, 105–117.CrossRefGoogle Scholar
Ford, A.B., Schmidt, D.L. and Boyd, W.W. Jr. (1978 a) Geologic map of the Davies Valley quadrangle and part of the Cordiner Peaks quadrangle, Pensacola Mountains, Antarctica. U.S. Geol. Surv. Map A-10, 1:250 000.Google Scholar
Ford, A.B., Schmidt, D.L., Boyd, W.W. Jr. and Nelson, W.H. (1978 b) Geological map of the Saragota Table quadrangle, Pensacola Mountains, Antarctica. U.S. Geol. Surv. Map A-9, 1:250 000.Google Scholar
Gibson, S.A., Thompson, R.N., Dickin, A.P. and Leonardos, O.H. (1996) High-Ti and low-Ti mafic potassic magmas: key to plume – lithosphere interactions and flood-basalt genesis. Earth Planet. Sci. Lett., 141, 325–41.CrossRefGoogle Scholar
Gibson, S.A., Thompson, R.N., Leonardos, O.H., Dickin, A.P. and Mitchell, J.G. (1999) The limited extent of plume-lithosphere interactions during continental flood-basalt genesis: geochemical evidence from Cretaceous magmatism in southern Brazil. Contrib. Mineral. Petrol., 137, 147–69.CrossRefGoogle Scholar
Hay, R.L. and O'Neil, J.R. (1983) Carbonatite tuffs in the Laetolil Beds of Tanzania and the Kaiserstuhl in Germany. Contrib. Mineral. Petrol., 82, 403–6.CrossRefGoogle Scholar
Heimann, A., Fleming, T.H., Elliot, D.H. and Foland, K.A. (1994) A short interval of Jurassic continental flood basalt volcanism in Antarctica as demonstrated by 40Ar/39Ar geochronology. Earth Planet. Sci. Lett., 121, 19–41.CrossRefGoogle Scholar
Hergt, J.M., Chappell, B.W., Faure, G. and Mensing, T.M. (1989 a) The geochemistry of Jurassic dolerites from Portal Peak, Antarctica. Contrib. Mineral. Petrol., 102, 298–305.CrossRefGoogle Scholar
Hergt, J.M., Chappell, B.W., McCulloch, M.T., McDougall, I. and Chivas, A.R. (1989 b) Geochemical and isotopic constraints on the origin of the Jurassic dolerites of Tasmania. J. Petrol., 30, 841–83.CrossRefGoogle Scholar
Hergt, J.M., Peate, D.W. and Hawkesworth, C.J. (1991) The petrogenesis of Mesozoic Gondwana low-Ti flood basalts. Earth Planet. Sci. Lett., 105, 134–48.CrossRefGoogle Scholar
Hoernle, K.A.J. and Schmincke, H.-U. (1993) The petrology of the tholeiites through melilitite nephelinites on Gran Canaria, Canary Islands: crystal fractionation, accumulation, and depths of melting. J. Petrol., 34, 573–97.CrossRefGoogle Scholar
Hogarth, D.D. (1989) Pyrochlore, apatite and amphibole: distinctive minerals in carbonatite. Pp. 103–148 in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London.Google Scholar
Ito, E., White, W.M. and Göpel, C. (1987) The O, Sr, Nd and Pb isotope geochemistry of MORB. Chem. Geol., 62, 157–76.CrossRefGoogle Scholar
Kjarsgaard, B.A. and Hamilton, D.L. (1988) Liquid immiscibility and the origin of alkali-poor carbonatites. Mineral. Mag., 52, 43–55.CrossRefGoogle Scholar
Kjarsgaard, B. and Peterson, T. (1991) Nephelinite-carbonatite liquid immiscibility at Shombole volcano, East Africa; petrographic and experimental evidence. Mineral. Petrol., 43, 293–314.CrossRefGoogle Scholar
Leake, B.E. (1978) Nomenclature of amphiboles. Bull. Mineral., 101, 453–67.Google Scholar
le Roex, A.P. and Lanyon, R. (1998) Isotope and trace element geochemistry of Cretaceous Damaraland lamprophyres and carbonatites, northwestern Namibia: evidence for plume-lithosphere interactions. J. Petrol., 39, 1117–46.CrossRefGoogle Scholar
le Roex, A.P., Cliff, R.A. and Adair, B.J.I. (1990) Tristan da Cunha, South Atlantic: geochemistry and petrogenesis of a basanite-phonolite lava series. J. Petrol., 31, 779–812.CrossRefGoogle Scholar
Luttinen, A.V., Rämö, O.T. and Huhma, H. (1998) Neodymium and strontium isotopic and trace element composition of a Mesozoic CFB suite from Dronning Maund Land, Antarctica: implications for lithosphere and asthenosphere contributions to Karoo magmatism. Geochim. Cosmochim. Acta, 62, 2701–14.CrossRefGoogle Scholar
Macdonald, R., Kjarsgaard, B.A., Skilling, I.P., Davies, G.R., Hamilton, D.L. and Black, S. (1993) Liquid immiscibility between trachyte and carbonate in ash flow tuffs from Kenya. Contrib. Mineral. Petrol., 114, 276–87.CrossRefGoogle Scholar
Mahoney, J., le Roex, A.P., Peng, Z., Fisher, R.L. and Natland, J.H. (1992) Southwest limits of Indian Ocean ridge mantle and the origin of low 206Pb/204Pb mid-ocean ridge basalt: isotope systematics of the central Southwest Indian Ridge. J. Geophys. Res., 97, 19771–90.CrossRefGoogle Scholar
Mahoney, J.J., White, W.M., Upton, B.G.J., Neal, C.R. and Scrutton, R.A. (1996) Beyond EM-1: lavas from Afansy-Nikitin Rise and the Crozet Archipelago, Indian Ocean. Geology, 24, 615–8.2.3.CO;2>CrossRefGoogle Scholar
Minor, D.R. and Mukasa, S.B. (1997) Zircon U-Pb and hornblende 40Ar-39Ar ages for the Dufek layered mafic intrusion, Antarctica: implications for the age of the Ferrar large igneous province. Geochim. Cosmochim. Acta, 61, 2497–504.CrossRefGoogle Scholar
Mortimer, N., Parkinson, D., Raine, J.I., Adams, C.J., Oliver, P.J. and Palmer, K. (1995) Ferrar magmatic province rocks discovered in New Zealand: implications for Mesozoic Gondwana geology. Geology, 23, 185–8.2.3.CO;2>CrossRefGoogle Scholar
Molzahn, M., Reisberg, L. and Wörner, G. (1996) Os, Sr, Nd, Pb and O isotope and trace element data from the Ferrar flood basalts, Antarctica: evidence for an enriched subcontinental lithospheric source. Earth Planet. Sci. Lett., 144, 529–46.CrossRefGoogle Scholar
O'Nions, R.K. and Pankhurst, R.J. (1974) Petrogenetic significance of isotope and trace element variations in volcanic rocks from the mid-Atlantic. J. Petrol., 15, 603–34.CrossRefGoogle Scholar
O'Nions, R.K., Hamilton, P.J. and Evensen, N.M. (1977) Variations in 143Nd/144Nd and 87Sr/86Sr ratios in oceanic basalts. Earth Planet. Sci. Lett., 34, 13–22.CrossRefGoogle Scholar
Pankhurst, R.J., Marsh, P.D. and Clarkson, P.D. (1983) A geochronological investigation of the Shackleton Range. Pp. 176–82 in: Antarctic Earth Science (Oliver, R.L., James, P.R. and Jago, J.B., editors). Australian Academy of Sciences, Canberra.Google Scholar
Pankhurst, R.J., Leat, P.T., Sruoga, P., Rapela, C.W., Márquez, M., Storey, B.C. and Riley, T.R. (1998) The Chon Aike province of Patagonia and related rocks in West Antarctica: a silicic large igneous province. J. Volcanol. Geotherm. Res., 81, 113–36.CrossRefGoogle Scholar
Peate, D.W., Hawkesworth, C.J. and Mantovani, M.S.M. (1992) Chemical stratigraphy of the Paraná lavas (South America): classification of magma types and their spatial distribution. Bull. Volcanol., 55, 119–39.CrossRefGoogle Scholar
Renne, P.R., Swisher, C.C., Deino, A.L. Karner, D.B., Owens, T.L. and DePaolo, D.J. (1998) Intercalibration of standards, absolute ages and uncertainties in Ar-Ar dating. Chem. Geol., 145, 117–52.CrossRefGoogle Scholar
Rock, N.M.S. (1986) The nature and origin of ultramafic lamprophyres: alnö ites and allied rocks. J. Petrol., 27, 155–96.CrossRefGoogle Scholar
Rock, N.M.S. (1987) The nature and origin of lamprophyres: a review. Pp. 191–226 in: Alkaline igneous rocks (Fitton, J.G. and Upton, B.G.J., editors). Geological Society of London, Spec. Publ., 30.Google Scholar
Rock, N.M.S. (1991) Lamprophyres. Blackie, Glasgow.Google Scholar
Simonetti, A., Goldstein, S.L., Schmindberger, S.S. and Viladkar, S.G. (1998) Geochemical and Nd, Pb, and Sr isotope data from Deccan alkaline complexes – inferences for mantle sources and plume-lithosphere interaction. J. Petrol., 39, 1847–64.CrossRefGoogle Scholar
Storey, B.C. (1995) The role of mantle plumes in continental break-up: case histories from Gondwanaland. Nature, 377, 301–8.CrossRefGoogle Scholar
Storey, B.C. and Kyle, P.R. (1997) An active mechanism for Gondwana break-up. S. Afr. J. Geol., 100, 283–90.Google Scholar
Storey, B.C., Macdonald, D.I.M., Dalziel, I.W.D., Isbell, J.L. and Millar, I.L. (1996) Early Palaeozoic sedimentation, magmatism, and deformation in the Pensacola Mountains, Antarctica: the significance of the Ross orogeny. Geol. Soc. Am. Bull., 108, 685–707.2.3.CO;2>CrossRefGoogle Scholar
Storey, B.C., Pankhurst, R.J. and Johnson, A.C. (1994) The Grenville Province within Antarctica: a test of the SWEAT hypothesis. J. Geol. Soc., 151, 1–4.CrossRefGoogle Scholar
Sun, S.-s. and McDonough, W.F. (1989) Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Pp. 313–45 in: Magmatism in the Ocean Basins (Saunders, A.D. and Norry, M.J., editors). Geological Society of London, Spec. Publ., 42.Google Scholar
Sweeney, R.J., Duncan, R.A. and Erlank, A.J. (1994) Geochemistry and petrogenesis of central Lebombo basalts of the Karoo Igneous Province. J. Petrol., 35, 95–125.CrossRefGoogle Scholar
Thompson, R.N., Morrison, M.A., Hendry, G.L. and Parry, S.J. (1984) An assessment of the relative roles of crust and mantle in magma genesis: an elemental approach. Phil. Trans. R. Soc. Lond., A310, 549–90.Google Scholar
Veksler, I.V., Petibon, C., Jenner, G.A., Dorfman, A.M. and Dingwell, D.B. (1998) Trace element partitioning in immiscible silicate-carbonate liquid systems: an initial experimental study using a centrifuge autoclave. J. Petrol., 39, 2095–104.CrossRefGoogle Scholar
White, R. and McKenzie, D. (1989) Magmatism at rift zones: the generation of volcanic continental margins and flood basalts. J. Geophys. Res., 94, 7685–729.CrossRefGoogle Scholar
Wilson, M., Rosenbaum, J.M. and Dunworth, E.A. (1995) Melilitites: partial melts of the thermal boundary layer? Contrib. Mineral. Petrol., 119, 181–196.CrossRefGoogle Scholar
Woolley, A.R. and Kempe, D.R.C. (1989) Carbonatites: nomenclature, average chemical compositions, and element distribution. Pp. 1–14 in: Carbonatites: Genesis and Evolution (Bell, K., editor). Unwin Hyman, London.Google Scholar