Hostname: page-component-848d4c4894-hfldf Total loading time: 0 Render date: 2024-05-19T05:19:03.240Z Has data issue: false hasContentIssue false
  • English
  • Français

XXII.—The Petrology of Picritic Rocks in Minor Intrusions—a Hebridean Group

Published online by Cambridge University Press:  06 July 2012

H. I. Drever  and
R. Johnston
Get access Rights & Permissions [Opens in a new window]

Synopsis

The results are presented of a detailed petrological reconnaissance of a group of picritic minor intrusions in the Hebrides. A substantial amount of new factual data is subjected to a unified treatment as a basis for reference and discussion. Olivine phenocrysts are not appreciably zoned and there is no evidence that they have a reaction relation with the liquid represented by the groundmass. Variations in the size and amount of olivine in individual intrusions are examined in detail and attributed to composite intrusion of differentiated material. A distinctive non-porphyritic facies found in several sills and in one dyke is chemically analyzed. Four analyses from widely separated localities establish this facies as a remarkably invariant, eucritic rock-type. The composition of the groundmass of the picritic rocks is variable and there is no evidence whatever of the participation of basaltic magma in their formation. Although no attempt is made to explain the new data in detail, a comprehensive working hypothesis is formulated. The origin of such picritic intrusions is believed to be due to selective fusion of pre-existing ultrabasic rock. Liquid more basic than normal basalt magmas can be formed by this process. Some re-precipitation of olivine may have preceded final emplacement of a magnesia-rich liquid which contained xenocrysts, mainly of olivine, from the source rock.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 63 , Issue 3 , 1959 , pp. 459 - 499
Copyright
Copyright © Royal Society of Edinburgh 1959

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

References to Literature

Allison, A., 1936. “The Tertiary Dykes of the Craignish Area, Argyll”, Geol. Mag., 73, 73–87.Google Scholar
Anderson, C. A., 1941. “Volcanoes of the Medicine Lake Highland, California”, Bull. Dep. Geol. Univ. Calif., 25, 347.Google Scholar
Arnold-Bemrose, H. H., 1910. “On Olivine Nodules in the Basalt of Calton Hill, Derbyshire”, Geol. Mag., 7, 1–4.Google Scholar
Bailey, E. B. Sir, et al., 1924. “Tertiary and Post-Tertiary Geology of Mull, Loch Aline and Oban”, Mem. Geol. Surv. U.K.Google Scholar
Barth, T. F. W., 1952. “The Differentiation of a Composite Aplite from the Pribilof Islands, Alaska”, Amer. J. Sci., Bowen vol., 27–36.Google Scholar
Boué, A., 1821. Essai Géologique sur l'Écosse, Paris.Google Scholar
Bowen, N. L., 1914. “The Ternary System: Diopside-Forsterite-Silica”, Amer. J. Sci., 38, 207–264.Google Scholar
Bowen, N. L., 1915 a. “Crystallization-Differentiation in Silicate Liquids”, Amer. J. Sci., 39, 175–191.Google Scholar
Bowen, N. L., 1915 b. “The Crystallization of Haplobasaltic, Haplodioritic and Related Magmas”, Amer. J. Sci., 40, 161–185.Google Scholar
Bowen, N. L., 1928. The Evolution of the Igneous Rocks. Princeton.Google Scholar
Bowen, N. L., 1947. “Magmas”, Bull. Geol. Soc. Amer., 58, 263–280.Google Scholar
Brauns, R., 1928. “Beobachten an Schmelzbasalt”, Zbl. Miner. Geol. Paläont., Abt. A, 348–351.Google Scholar
Brown, G. M., 1956. “The Layered Ultrabasic Rocks of Rhum, Inner Hebrides”, Phil. Trans., B, 240, 1–53.Google Scholar
Buddington, A. F., 1943. “Some Petrological Concepts and the Interior of the Earth”, Amer. Min., 28, 119–127.Google Scholar
Butler, J. W. Jr, 1937. “On the Time required to form the Olivine Zone in the Palisades Sill, New Jersey”, (Abs.), Amer. Min., 22, 218–219.Google Scholar
Clough, C. T. and Harker, A., 1904. “The Geology of West Central Skye with Soay”, Mem. Geol. Surv. U.K.Google Scholar
Daly, R. A., 1908. “The Origin of Augite Andesite and of Related Ultrabasic Rocks”, J. Geol, 16, 401–420.Google Scholar
Davidson, C. F., 1935. “The Tertiary Geology of Raasay, Inner Hebrides”, Trans. Rog. Soc. Edin., 58, 375–407.Google Scholar
Drever, H. I., 1952. “The Origin of some Ultramafic Rocks. A Preliminary Survey of the Evidence for and against Gravitative Accumulation of Olivine”, Medd. fra Dansk Geologish Forening, 12, 227–229.Google Scholar
Drever, H. I., 1956. “The Geology of Ubekendt Ejland, West Greenland, Part II. The Picritic Sheets and Dykes of the East Coast”, Mead. Grønland, 137, No. 4.Google Scholar
Drever, H. I., and Game, P. M., 1948. “The Geology of Ubekendt Ejland, West Greenland, Part I. A Preliminary Review”, Medd. Grønland, 134, No. 8.Google Scholar
Drever, H. I., and Johnston, R., 1957. “Crystal Growth of Forsteritic Olivine in Magmas and Melts”, Trans. Roy. Soc. Edin., 63, 289–315.Google Scholar
Drever, H. I., and Johnston, R., 1959. “The Lower Margin of the Shiant Isles Sill”, Quart. J. Geol. Soc. London (in Press).Google Scholar
Drever, H. I., and Livingstone, D. F., 1948. “Some Basaltic Rocks from West Greenland”, Proc. Roy. Soc. Edin B, 63, 97–114.Google Scholar
Ernst, T., 1936. “Der Melilith-Basalt des Westberges bei Hofgeismar, nördlich von Kassel, ein Assimilationsprodukt ultrabasischer Gesteine”, Chem. d. Erde, 10, 631–666.Google Scholar
Frankel, J. J., 1942. “Studies on Karoo Doletites, 2. Some Younger Intrusions of Olivine Basaltic Dolerite”, Trans. Geol. Soc. S. Afr., 45, 1–26.Google Scholar
Geikie, A. Sir, 1897. The Ancient Volcanoes of Great Britain, 2 vols., London. (Vol. 2.)Google Scholar
Green, J., and Poldervaart, A., 1955. “Some Basaltic Provinces”, Geochim. et Gosmoch. Ada, 7, 177–188.Google Scholar
Hamilton, J., 1957. “Banded Olivines in Some Scottish Carboniferous OHvine-Basalts”, Geol. Mag., 94, 135–139.Google Scholar
Harker, A., 1904. “The Tertiary Igneous Rocks of Skye”, Mem. Geol. Surv. U.K.Google Scholar
Harker, A., 1913. “Fractional Crystallization the Prime Factor in the Differentiation of Rock Magmas”, Int. Geol. Congr., 12, 205–208.Google Scholar
Hess, H. H., 1954. “Geological Hypotheses and the Earth's Crust under the Oceans”, Proc. Roy. Soc. Lond., A., 222, 341–348.Google Scholar
Hess, H. H., 1956. “The Magnetic Properties and Differentiation of Dolerite Sills-Discussion”, Amer. J. Sci., 2541, 446–451.Google Scholar
Hughes, C. J., 1956. “Geological Investigations in East Greenland, Pt. VI: A Differentiated Basic Sill enclosed in the Skaergaard Intrusion, East Greenland and related Sills injecting the Lavas”, Medd. Grønland, 137, No. 2.Google Scholar
Jaeger, J. C., and Joplin, G., 1955. “Rock Magnetism and the Differentiation of Dolerite Sills”, J. Geol. Soc. Aust., 2, 1–19.Google Scholar
Jaeger, J. C., and Joplin, G., 1956. “The Magnetic Properties and Differentiation of Dolerite Sills-Discussion”, Amer. J. Sci., 254, 443–446.Google Scholar
Kuno, H., 1937. “Fractional Crystallization of Basaltic Magmas”, Jap. J. Geol. Geogr., 14, 189–208.Google Scholar
Lewis, J. V., 1908. “Petrography of the Newark Igneous Rocks of New Jersey”, Rep. N.J. Geol. Surv., 1908, 99–129.Google Scholar
Macdonald, G. A., 1944. “The 1840 Eruption and Crystal Differentiation in the Kilauean Magma Column”, Amer. J. Sci., 242, 177–189.Google Scholar
Muir, I. D., Tilley, C. E., and Scoon, J. H., 1957. “Contributions to the Petrology of Hawaiian Basalts, I. The Picrite-basalts of Kilauea”, Amer. J. Sci., 255, 241–253.Google Scholar
Nockolds, S. R., 1954. “Average Chemical Compositions of some Igneous Rocks”, Bull. Geol. Soc. Amer., 65, 1007–1032.Google Scholar
Phillips, F. C., 1938. “Mineral Orientation in some Olivine-rich Rocks from Rum and Skye”, Geol. Mag., 75, 130–135.Google Scholar
Poldervaart, A., 1944. “The Petrology of the Elephant's Head Dyke and the New Amalfi Sheet (Matatiele)”, Trans. Roy. Soc. S. Afr., 30, 85–119.Google Scholar
Powers, H. A., 1955. “Composition and Origin of Basaltic Magma of the Hawaiian Islands”, Geochim. et Cosmoch. Acta., 7, 77–107.Google Scholar
Rogers, A. W., 1907. “Geological Survey of Parts of Vryberg, Kuruman, Hay and Gordonia”, Rep. Geol. Comm. C.G.H., 1907, 11–122.Google Scholar
Ross, C. S., Foster, M. D., and Myers, A. T., 1954. “Origin of Dunites and of Olivine-rich Inclusions in Basaltic Rocks”, Amer. Min., 39, 693–737.Google Scholar
Tilley, C. E., 1951. “Some Aspects of Magmatic Evolution”, Quart. J. Geol. Soc. Lond., 106, 37–61.Google Scholar
Truswell, J. F., 1955. “A Petrological Study of Dolerite Sills in the Jagersfontein Diamond Mine, Orange Free State”, Trans. Roy. Soc. S. Afr., 34, 409–416.Google Scholar
Tschermak, G., 1866. “Felsarten von ungewöhnlicher Zusammensetzung in den Umgebungen von Teschen und Neutitschein”, Sitz. Akad. Wiss. Wien, 53, 260–274.Google Scholar
Tyrrell, G. W., 1909. “The Classification of the Post-Carboniferous Igneous Intrusive Rocks of the West of Scotland”, Trans. Geol. Soc. Glasg., 13, 298–317.Google Scholar
Tyrrell, G. W., 1912. “The Late-Palæozoic Alkaline Igneous Rocks of the West of Scotland”, Geol. Mag., 9, 69–80, 120–131.Google Scholar
Wager, L. R., 1956. “A Chemical Definition of Fractionation Stages as a Basis for Comparison of Hawaiian, Hebridean, and other Basic Lavas”, Geochim. et Cosmoch. Acta., 9, 217–248.Google Scholar
Walker, F., 1940. “Differentiation of the Palisade Diabase, New Jersey”, Bull. Geol. Soc. Amer., 51, 1059–1106.Google Scholar
Walker, F., 1956. “The Magnetic Properties and Differentiation of Dolerite Sills-a Critical Discussion”, Amer. J. Sci., 254, 433–443.Google Scholar
Walker, F., and Nicolaysen, L. O., 1954. “The Petrology of Mauritius”, Colon. Geol. Min. Resour., 4, 3–43.Google Scholar
Walker, F., and Poldervaart, A., 1942. “The Karoo Dolerites of the Calvinia District”, Trans. Geol. Soc. S. Afr., 44, 127–148.Google Scholar
Walker, F., and Poldervaart, A., 1949. “Karoo Dolerites of the Union of South Africa”, Bull. Geol. Soc. Amer., 60, 591–706.Google Scholar
Weedon, D. S., 1956. “Igneous Rocks of the Southern Cuillins, Isle of Skye”, D. Phil. Thesis (unpublished), Bodleian Library, Oxford.Google Scholar