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B1 subdivisions in thin komatiites at Kambalda, Western Australia

Published online by Cambridge University Press:  01 May 2009

B. Thomson
Affiliation:
Upper Kennerty Mills Cottage, Kennerty Mills Road, Peterculter, Aberdeen AB1 OLR, Scotland, U.K.

Abstract

B1 subdivisions are narrow foliated zones of stubby, skeletal olivine blades, situated at the top of the granular olivine cumulates (B2) in ponded komatiite lavas. They developed at a late stage in pond crystallization as a result of compaction-related circulation of intercumulus liquids through and along the top of the cumulates. The total thickness of a B1 and its degree of blade parallelism are related to lateral position within ponded lavas. The deeper, hotter and longer-lived core regions generated a thick B1 with a high degree of blade parallelism (ordered B1), whereas the shallower, peripheral regions produced a narrow B1 with a poor degree of blade parallelism (disordered B1), or failed to develop one at all.

Type
Articles
Copyright
Copyright © Cambridge University Press 1989

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