Hostname: page-component-77c89778f8-7drxs Total loading time: 0 Render date: 2024-07-18T20:46:15.057Z Has data issue: false hasContentIssue false
  • English
  • Français

Cognate xenoliths in the Tertiary uhrabasic dykes of south-west Skye

Published online by Cambridge University Press:  05 July 2018

Fergus G. F. Gibb
Fergus G. F. Gibb*
Affiliation:
Department of Geology, University of Toronto, Toronto 5, Canada
Get access Rights & Permissions [Opens in a new window]

Summary

A group of ultrabasic dykes occurring in south-west Skye is typified by often abundant and diverse ultrabasic xenoliths composed of essentially the same minerals as the dykes. The xenoliths, which vary considerably in shape and size, are in sharp contact with the host rocks and exhibit no evidence of remelting by, or reaction with, the dykes. Although extensive axial concentration of olivine occurred in the dykes during intrusion, the xenoliths appear to be randomly distributed throughout all but the extreme margins of the dykes and often exhibit a preferred orientation. The orientation and distribution of the xenoliths are attributed to the suppression of rotation and axial migration of the xenoliths during the emplacement of the dykes because of the relatively high viscosity of the suspending medium.

The ultrabasic xenoliths, unlike many of those occurring in basalts, kimberlites, etc., are considered unlikely to represent primary upper mantle material and it is suggested that they were probably derived by the disintegration of layered ultrabasic rocks genetically related to the dykes and hence are of cognate origin.

Type
Research Article
Information
Mineralogical Magazine , Volume 37 , Issue 288 , December 1969 , pp. 504 - 514
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1969

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.)

Footnotes

†

Present address: Department of Geology, The University, Manchester 13.

References

Bowen, (N. L.), 1928. The Evolution of the Igneous Rocks. Princeton University Press.Google Scholar
Brown, (G. M.), 1956. The layered ultrabasic rocks of Rhum, Inner Hebrides. Phil. Trans. ser. B, 240, 1–53.Google Scholar
Drever, (H. I.) and Johnston, (R.), 1958. The petrology of picritic rocks in minor intrusions, a Hebridean group. Trans. Roy. Soc. Edinb. 63, 459-97.CrossRefGoogle Scholar
Drever, (H. I.) and Johnston, (R.), 1967. Picritic Minor Intrusions, in Ultramafic and Related Rocks, ed. Wyllie, (P. J.). New York (J. Wiley).Google Scholar
Forbes, (R. B.) and Kuno, (H.), 1967. Peridotite inclusions and basaltic host rocks, in Ultramafic and Related Rocks, ed. Wyllie, (P. J.). New York (J. Wiley).Google Scholar
Gibb, (F. G. F.), 1966. Ph.D. Thesis. University of St. Andrews.Google Scholar
Gibb, (F. G. F.), 1968. Flow differentiation in the xenolithic ultrabasic dykes of the Cuillins and the Strathaird Peninsula, Isle of Skye, Scotland. Journ. Petrology, 9, 411-43.CrossRefGoogle Scholar
Goldsmith, (H. L.) and Mason, (S. G.), 1967. The Microrheology of Dispersions, in Rheotogy-Theory and Applications, 4, ed. Eirich, (F. R.). New York (Academic Press).Google Scholar
Harker, (A.), 1904. The Tertiary igneous rocks of Skye. Mere. Geol. Surv. U.K. CrossRefGoogle Scholar
Hutchison, (R.), 1966. Intrusive tholeiites of the western Cuillin, Isle of Skye. Geol. Mag. 103, 352-63.CrossRefGoogle Scholar
Jeffrey, (G. B.), 1923. The motion of ellipsoidal particles immersed in a viscous fluid. Proc. Roy. Soc. ser. A, 102, 161-79.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. 59, 693-737.Google Scholar
Shaw, (D. M.) and Harrison, (W. D.), 1955. Determination of the mode of a metamorphic rock. Ibid. 40, 614-23.Google Scholar
Taylor, (G. I.), 1923. The motion of ellipsoidal particles in a viscous fluid, Proc. Roy. Soc. set. A, 103, 58-61.Google Scholar
Wadsworth, (W. J.), 1961. The layered ultrabasic rocks of south-west Rhum, Inner Hebrides. Phil. Trans. ser. B, 244, 21-64.Google Scholar
Weedon, (D. S.), 1961. Basic igneous rocks of the southern Cuillin, Isle of Skye. Trans. Geol. Soc. Glasgow, 24, 190-212.CrossRefGoogle Scholar
Weedon, (D. S.), 1965. The layered ultrabasic rocks of Sgurr Dubh, Isle of Skye. Scot. Journ. Geol. 1, 41-68.CrossRefGoogle Scholar