Hostname: page-component-5c6d5d7d68-wbk2r Total loading time: 0 Render date: 2024-08-16T22:20:20.108Z Has data issue: false hasContentIssue false

Possible higher pressure relics within titaniferous augites in a basic sill

Published online by Cambridge University Press:  01 May 2009

F. G. F. Gibb
Affiliation:
Department of Geology, University of Sheffield, Sheffield, S1 3JD.
C. M. B. Henderson
Affiliation:
Department of Geology, University of Manchester, Manchester, M13 9PL.

Summary

An unusual type of mottled area is described from titaniferous augites in the Dippin sill, Isle of Arran. These are characterized by abundant magnetite inclusions, irregular embayed outlines and distinctive chemical compositions. The possibility that these are due to zoning, especially sector zoning, is examined and discarded. They probably represent partly resorbed relics of pyroxene which crystallized at depth prior to the emplacement of the sill. As such they could have considerable petrogenetic implications both with regard to the sill itself and to alkaline basic magmas in general.

Type
Articles
Copyright
Copyright © Cambridge University Press 1978

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

Downes, M. J. 1974. Sector and oscillatory zoning in calcic augites from M. Etna, Sicily. Contr. Miner. Petrol. 47, 187–96.CrossRefGoogle Scholar
Ferguson, A. K. 1973. On hour-glass sector zoning in clinopyroxene. Mineralogy. Mag. 39, 321–5.CrossRefGoogle Scholar
Gibb, F. G. F. 1973. The zoned clinopyroxenes of the Shiant Isles sill, Scotland. J. Petrology 14, 203–30.CrossRefGoogle Scholar
Gibb, F. G. F. & Henderson, C. M. B. 1978. The petrology of the Dippin Sill, Isle of Arran. Scot. Jl Geol. 14, (in the press).Google Scholar
Hollister, L. S & Gancarz, A. J. 1971. Compositional sector zoning in clinopyroxene from the Narce area, Italy. Am. Miner. 56, 959–79.Google Scholar
Leung, I. S. 1974. Sector-zoned titanaugites: morphology, crystal chemistry and growth. Am. Miner. 59, 127–38.Google Scholar