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The structure and petrogenesis of the Trallval and Ruinsival areas of the Rhum ultrabasic complex

Published online by Cambridge University Press:  03 November 2011

J. A. Volker  and
B. G. J. Upton
J. A. Volker
Affiliation:
Department of Geology and Geophysics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, Scotland, UK.
B. G. J. Upton
Affiliation:
Department of Geology and Geophysics, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, Scotland, UK.
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Abstract

Detailed mapping of the Trallval-Ruinsival area of the ultrabasic complex of Rhum has revealed the relationship between the intrusive peridotites, which form a major part of the complex, and the layered ultrabasic rocks. The layered rocks on Trallval are correlated with Units 8 to 15 of the Eastern Layered Series as seen on Hallival and Askival, and part of an additional unit, Unit 16, has also been identified. The layered rocks of Ruinsival and the western part of Trallval form part of the Central Series and have been subdivided into six cyclic units. They are associated with four sets of intrusive breccia zones which converge towards a central region. Four cylindrical plugs of intrusive peridotite occur within the area of outcrop of the Central Series. Criteria are listed for the distinction of intrusive peridotite from conformable peridotites formed in situ. Distinctive textures and structures are described; these include vertical feldspathic streamers, which are interpreted as direct evidence for the upward expulsion of interstitial fluid, and loading structures at the contact between a peridotite layer and underlying allivalite are ascribed to the intrusion of a peridotite sill. A comparison of the Eastern Layered Series and the Central Series suggests that three stages were involved in the formation of the ultrabasic rocks: (i) the accretion of rhythmically layered unconsolidated olivine cumulates; (ii) the upward expulsion of intercumulus liquid; and (iii) the formation of either allivalite (as in the Eastern Layered Series) or ultrabasic breccia zones (as in the Central Series) from the expelled intercumulus liquid, depending on whether the tectonic environment was quiescent or extensional.

Keywords

allivalitebrecciascumulateslayeringperidotitetroctolite
Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 81 , Issue 1 , 1990 , pp. 69 - 88
Copyright
Copyright © Royal Society of Edinburgh 1990

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References

Aoki, K., Ishiwaka, K. & Kanisawa, S. 1981. Fluorine geochemistry of basaltic rocks from continental and oceanic regions and petrogenetic applications. CONTRIB MINERAL PETROL 76, 53–59.CrossRefGoogle Scholar
Anketell, J. M., Cegla, J. & Duzlynski, St. 1970. On the deformational structures in systems with reversed density gradients. ANN GEOL SOC POLAND 40, 3–30.Google Scholar
Bédard, J. H., Sparks, R. S. J., Renner, R., Cheadle, M. J. & Hallworth, M. A. 1988. Peridotite sills and metasomatic gabbros in the Eastern Layered Series of the Rhum Complex. J GEOL SOC LONDON 145, 207–24.CrossRefGoogle Scholar
Brown, G. M. 1956. The layered ultrabasic rocks of Rhum, Inner Hebrides. PHILOS TRANS R SOC LONDON B240, 1–53.Google Scholar
Butcher, A. R. 1984. A study of postcumulus structures in the Rhum layered intrusion, Inner Hebrides, Scotland. Unpubl. Ph.D. thesis, University of Manchester.Google Scholar
Butcher, A. R., Young, I. M. & Faithfull, J. W. 1985. Finger structures in the Rhum complex. GEOL MAG 122, 491–502.CrossRefGoogle Scholar
Campbell, I. H. 1978. Some problems with the cumulus theory. LITHOS 11, 311–23.CrossRefGoogle Scholar
Donaldson, C. H. 1974. Olivine crystal types in harrisitic rocks of the Rhum pluton and in Archaean spinfex rocks. BULL GEOL SOC AM 85, 1721–26.2.0.CO;2>CrossRefGoogle Scholar
Donaldson, C. H. 1975. Ultrabasic breccias in layered intrusions. The Rhum complex. J GEOL 83, 33–45.CrossRefGoogle Scholar
Donaldson, C. H., Drever, H. I. & Johnston, R. 1973. Crystallisation of poikilo-macro-spherulitic feldspar in a Rhum peridotite. NATURE 243, 69–70.Google Scholar
Dowty, E. 1980. Crystal growth and nucleation theory and the numerical simulation of igneous crystallisation. In Hargraves, R. B. (ed.) Physics of Magmatic Processes, 419–85. Princeton, N.J.: Princeton University Press.CrossRefGoogle Scholar
Dunham, A. C. 1965. A new type of banding in the ultrabasic rocks from central Rhum, Inverness-shire, Scotland. AM MINERAL 50, 1410–20.Google Scholar
Dunham, A. C. & Wadsworth, W. J. 1978. Cryptic variation in the Rhum layered intrusion. MINERAL MAG 42, 347–56.CrossRefGoogle Scholar
Emeleus, C. H. 1987. The Rhum layered complex. In Parsons, I. (ed.) Origins of layering in igneous rocks, 263–86. Dordrecht: D. Reidel.CrossRefGoogle Scholar
Emeleus, C. H., Wadsworth, W. J. & Smith, N. J. 1985. The early igneous and tectonic history of the Rhum Tertiary Volcanic Centre. GEOL MAG 122, 451–57.CrossRefGoogle Scholar
Faithfull, W. J. 1985. The Lower Eastern Layered Series of Rhum. GEOL MAG 122, 459–68.CrossRefGoogle Scholar
Gibb, F. G. F. 1976. Ultrabasic rocks of Rhum and Skye: the nature of the parent magma. J GEOL SOC LONDON 132, 209–222.CrossRefGoogle Scholar
Harker, A. 1908. The Geology of the Small Isles of Inverness-shire. MEM GEOL SURV SCOTLAND.Google Scholar
Hughes, C. J. 1960. The Southern Mountains igneous complex, Isle of Rhum. Q J GEOL SOC LONDON 114, 111–38.CrossRefGoogle Scholar
Huppert, H. E. & Sparks, R. S. J. 1980. The fluid dynamics of a basaltic magma chamber replenished by influx of hot, dense ultrabasic magma. CONTRIB MINERAL PETROL 75, 279–89.CrossRefGoogle Scholar
Kullerud, G., Yund, R. A. & Moh, G. H. 1969. Phase relations in the Cu-Fe-S, Cu-Ni-S and Fe-Ni-S systems. ECON GEOL MONOGR 4, 323–43.Google Scholar
Irvine, T. N. 1975. Crystallisation sequences in the Muskox intrusion and other layered intrusions. I. Origin of chromitite deposits and similar deposits of magmatic ores. GEOCHIM COSMOCHIM ACTA 39, 991–1020.CrossRefGoogle Scholar
Irvine, T. N. 1979. Rocks whose composition is determined by crystal accumulation and sorting. In Yoder, H. S. (ed.) The Evolution of the Igneous Rocks, Fiftieth Anniversary Perspectives, 245–306. Princeton, N.J.: Princeton University Press.Google Scholar
Irvine, T. N. 1980. Magmatic infiltration metasomatism, double-diffusive fractional crystallisation and adcumulus growth in the Muskox intrusion and other layered intrusions. In Hargraves, R. B. (ed.) Physics of Magmatic Processes, 325–83. Princeton, N.J.: Princeton University Press.CrossRefGoogle Scholar
Jackson, E. D. 1961. Primary textures and mineral associations in the ultramafic zone of the Stillwater complex, Montana. US GEOL SURV PROF PAP 358.Google Scholar
MacLean, W. H. 1969. Liquidus phase relations in the FeS-FeO Fe3O4-SiO system, and their application in geology. ECON GEOL 64, 865–84.CrossRefGoogle Scholar
McBirney, 1959. Factors governing emplacement of volcanic necks. AM J SCI 257, 431–48.Google Scholar
McClurg, J. E. 1982. Geology and structure of the northern part of the Rhum ultrabasic complex. Unpublished Ph.D. Thesis, University of Edinburgh.Google Scholar
McDonald, J. A. 1965. Liquid immiscibility as one factor in chromitite seam formation in the Bushveld igneous complex. ECON GEOL 60, 1674–85.CrossRefGoogle Scholar
Moore, J. G. 1970. Water content of basalt erupted on the ocean floor. CONTRIB MINERAL PETROL 28, 272–79.CrossRefGoogle Scholar
Morse, S. A., Owens, B. E. & Butcher, A. R. 1987. Origin of finger structures in the Rhum complex: phase equilibrium and heat effects. GEOL MAG 124, 205–10.CrossRefGoogle Scholar
Propach, G. 1976. Models of filter differentiation. LITHOS 9, 203–09.CrossRefGoogle Scholar
Sparks, R. S. J., Huppert, H. E., Kerr, R. C., McKenzie, D. P. & Tait, S. R. 1985. Postcumulus processes in layered intrusions. GEOL MAG 122, 55–68.CrossRefGoogle Scholar
Stolper, E. 1982. Water in silicate glasses: an infrared spectroscopic study. CONTRIB MINERAL PETROL 81, 1–17.CrossRefGoogle Scholar
Tait, S. R. 1985. Fluid dynamic and geological evolution of cyclic unit 10, Rhum, Eastern Layered Series. GEOL MAG 122, 469–84.CrossRefGoogle Scholar
Volker, J. A. 1983. The geology of the Trallval area, Rhum, Inner Hebrides. Unpubl. Ph.D. Thesis, University of Edinburgh.Google Scholar
Wadsworth, W. J. 1961. The layered ultrabasic rocks of south-west Rhum, Inner Hebrides. PHILOS TRANS R SOC LONDON B244, 21–64.Google Scholar
Williams, H. & McBirney, A. R. 1979. Volcanology. Los Angeles: Freeman and Cooper.Google Scholar
Young, I. M. 1984. Mixing of supernatant and interstitial fluids in the Rhum layered intrusion. MINERAL MAG 48, 345–50.CrossRefGoogle Scholar
Young, I. M. & Donaldson, C. H. 1985. Formation of granular-textured layers and laminae within the Rhum crystal pile. GEOL MAG 122, 519–28.CrossRefGoogle Scholar
Young, I. M., Greenwood, R. C. & Donaldson, C. H. 1988. Formation of the Eastern Layered Series of the Rhum Complex, northwest Scotland. CAN MINERAL 26, 225–33.Google Scholar