The Unit 12 allivalite, Eastern Layered Intrusion, Isle of Rum: a textural and geochemical study of an open-system magma chamber

Holness, M. B. and Winpenny, B. (2009) The Unit 12 allivalite, Eastern Layered Intrusion, Isle of Rum: a textural and geochemical study of an open-system magma chamber. Geological Magazine, 146 (3). pp. 437-450. ISSN ISSN: 0016-7568 EISSN: 1469-5081 DOI 10.1017/S0016756808005797

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Abstract

The Eastern Layered Intrusion of the Rum Central Complex, NW Scotland, comprises 16 macro-units broadly defined by a basal peridotite body overlain by gabbros and troctolites. The local term for the upper plagioclase-bearing cumulates is ‘allivalite’. The Unit 12 allivalite contains five subsidiary peridotite horizons, each continuous on the kilometre scale. Field, textural and geochemical evidence points to the Unit 12 allivalite forming by progressive accumulation of crystals from up to seven separate magma batches, varying from picrite to basalt. The thickness of the magma lens in the sill-like chamber was as low as 30 m during a significant part of the development of the Unit 12 allivalite, and evidence supports one eruption from the chamber during its accumulation.

Item Type:	Article
Uncontrolled Keywords:	08AREP IA56 2008 P, Part III
Subjects:	05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Divisions:	05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Journal or Publication Title:	Geological Magazine
Volume:	146
Page Range:	pp. 437-450
Identification Number:	10.1017/S0016756808005797
Depositing User:	Sarah Humbert
Date Deposited:	16 Feb 2009 13:02
Last Modified:	23 Jul 2013 10:07
URI:	http://eprints.esc.cam.ac.uk/id/eprint/404

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