Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-24T17:29:29.307Z Has data issue: false hasContentIssue false
  • English
  • Français

The parental magma on Rhum: evidence from alkaline segregations and veins in the peridotites from Salisbury's Dam

Published online by Cambridge University Press:  01 May 2009

D. E. Kitchen
D. E. Kitchen
Affiliation:
University of Ulsterat Jordanstown, Shore Road, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland
Get access Rights & Permissions [Opens in a new window]

Abstract

Feldspathic peridotites on Rhum contain teschenite segregations and veins. Bulk rock and mineral compositional trends define a path of alkali and iron enrichment related to discontinuous isolation of evolving intercumulus melts. Compositionally zoned and skeletal crystals of actinolite, zircon, apatite, sphene, epidote and chlorite are enclosed by clear analcime, and appear to have grown directly from a water-rich fluid at some undercooling, and below dry equilibrium solidus temperatures. The occurrence of late stage residua with undersaturated alkalirich characteristics in the Rhum ultrabasic complex suggests that the patental magma was alkaline rather than tholeiitic, and had similarities to the Plateau Magmas on Skye.

Type
Articles
Information
Geological Magazine , Volume 122 , Issue 5 , September 1985 , pp. 529 - 537
Copyright
Copyright © Cambridge University Press 1985

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

Brown, G. M. 1956. The layered ultrabasic rocks of Rhum, Inner Hebrides. Philosophical Transactions of the Royal Society of London, B 240, 1–53.Google Scholar
Donaldson, C. H. 1975. Ultrabasic breccias in layered intrusions – the Rhum complex. Journal of Geology 83, 33–45.CrossRefGoogle Scholar
Drever, H. I. & Johnston, R. 1959. The lower margin of the Shiant Isles sill. Quarterly Journal of the Geological Society of London 114, 343–65.CrossRefGoogle Scholar
Esson, T., Dunham, A. C., Thompson, R. N. 1975. Low alkali, high calcium tholeiite lavas from the Isle of Skye, Scotland. Journal of Petrology 16, 488–97.CrossRefGoogle Scholar
Gibb, F. G. F. 1973. The zoned clinopyroxenes of the Shiant Isles Sill, Scotland. Journal of Petrology 14, 203–30.CrossRefGoogle Scholar
Gibb, F. G. F. 1976. Ultrabasic rocks of Rhum and Skye: the nature of the parent magma. Journal of the Geological Society of London 132, 209–22.CrossRefGoogle Scholar
Gibb, F. G. F. & Henderson, C. B. M. 1978. The petrology of the Dippin sill, Isle of Arran. Scottish Journal of Geology 14, 1–27.CrossRefGoogle Scholar
Henderson, P. & Gijbels, R. 1976. Trace element indicators of the genesis of the Rhum layered intrusion, Inner Hebrides. Scottish Journal of Geology 12, 325–33.CrossRefGoogle Scholar
Henderson, C. B. M. & Gibb, F. G. F. 1977. Formation of analcime in the Dippin Sill, Isle of Arran. Mineralogical Magazine 41, 534–7.CrossRefGoogle Scholar
Henderson, C. B. M. & Gibb, F. G. F. 1983. Felsic mineral crystallization trends in differentiating alkaline basic magmas. Contributions to Mineralogy and Petrology 84, 355–64.CrossRefGoogle Scholar
Thompson, R. N. 1982. Magmatism of the British Tertiary Province. Scottish Journal of Geology 18, 49–107.CrossRefGoogle Scholar
Wadsworth, W. J. 1961. The layered ultrabasic rocks of South West Rhum, Inner Hebrides. Philosophical Transactions of the Royal Society of London, B 244, 21–64.Google Scholar
Walker, F. 1930. The geology of the Shiant Isles (Hebrides). Quarterly Journal of the Geological Society of London 86, 355–98.CrossRefGoogle Scholar
Wilkinson, J. F. G. 1958. The petrology of a differentiated teschenite sill near Gunnedah, New South Wales. American Journal of Science 256, 1–39.CrossRefGoogle Scholar