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On the petrology of the ultrabasic and basic plutonic rocks of the Isle of Rum

Published online by Cambridge University Press:  14 March 2018

S. I. Tomkeieff*
Affiliation:
King's College, University of Durham, Newcastle-upon-Tyne

Extract

The Isle of Rum contains one of the most interesting assemblages of plutonic rocks of Tertiary age in the British Isles. The pioneer work of Macculloch and the later exploratory efforts of Judd and Geikie were followed by an admirable account of the rocks by Harker, given with his usual lucidity and precision. In 1938 I spent a fortnight on this island, and this paper—the outcome of my visit—aims merely at supplementing Harker's petrographical description by certain quantitative data in respect of the ultrabasic and basic rocks found there and of recording certain observations relating to the igneous tectonics.

The earliest phase of igneous activity on Rum was the eruption of doleritic and mugearitic lavas. As shown by Bailey the eruptive phase of igneous activity was followed or accompanied by the formation of a ring-fault and two subordinate vents iufilted with explosive breccia and intruded by felsite. The space inside the ring-fault was then intruded by a banded peridotite-allivalite complex and later by eucrite in the form of a semicircular ring-dike and associated sheets. Finally, a granophyre boss was intruded along the western side of the ultrabasic-basic complex.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1945

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References

List of works to which reference is made

1. Andersen, (O.). The system anorthite-forsterite-silica. Amer. Journ. Sci., 1915, ser. 4, vol. 39, pp. 407454. [M.A. 2–20.]CrossRefGoogle Scholar
2. Bailey, (E. B.). Tertiary igneous tectonics of Rhum (Inner Hebrides). Quart. Journ. Geol. Soc. London, 1945, vol. 100 (for 1944), pp. 165188.Google Scholar
3. Bowen, (N. L.). The evolution of the igneous rocks. Princeton. 1928. [M.A. 4–123.]Google Scholar
4. Du Rietz, (T.). Studies on the rocks of Rådmansö. Geol. För. Förh. Stockholm, 1929, vol. 51, pp. 473532.Google Scholar
5. Geikie, (A.) and Teall, (J. J. H.). On the banded structure of some Tertiary gabbros in the Isle of Skye. Quart. Journ. Geol. Soc. London, 1894, vol. 50, pp. 645659.Google Scholar
6. Harker, (A.). The Tertiary igneous rocks of Skye. Mem. Geol. Surv. Scotland, 1904.Google Scholar
7. Harker, (A.). The geology of the Small Isles of Inverness-shire (Rum, Canna, Eigg, Muck, etc.). Mem. Geol. Surv. Scotland, 1908.Google Scholar
8. Lundegådh, (P. H.). The Grovstanäs region. An ultra-basic gabbro massif and its immediate vicinity. Bull. Geol. Inst. Univ. Upsata, 1943, vol. 29, pp. 305388. [M.A. 9–177.]Google Scholar
9. Phillips, (F. C.). Mineral orientation in some olivine-rich rocks from Rum and Skye. Geol. mag., 1938, vol. 75, pp. 130135.CrossRefGoogle Scholar
10. Tomkeieff, (S. I.). The Tertiary lavas of Rum. Geol. Mag., 1942, vol. 79, pp. 113.[M.A. 8–316.]Google Scholar
11. Vogt, (J. H. L.). The physical chemistry of the crystallization and magmatic differentiation of igneous rocks. Journ. Geol. Chicago, 1921, vol. 29, pp. 318350, 426–443, 515–539, 627–649.Google Scholar
12. Wager, (L. R.) and Deer, (W. A.). Geological investigations in east Greenland, Part III. The petrology of the Skaergaard intrusion, Kangerdlugssuaq, east Greenland. Meddel. om Grønland, 1939, vol. 105, no. 4, 352 pp. [M.A. 8–27.]Google Scholar