Symplectitic augite; evidence for discontinuous precipitation as an exsolution mechanism in Ca-rich clinopyroxene

Saved in:
Authors:Boland, J. N.; Otten, M. T.
Author Affiliations:Primary:
Rijksuniv. Utrecht, Inst. Earth Sci., Utrecht, Netherlands
Volume Title:Journal of Metamorphic Geology
Source:Journal of Metamorphic Geology, 3(1), p.13-20. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929
Publication Date:1985
Note:In English. 29 refs.; illus. incl. 1 table
Summary:Part of the augite in the Artfjallet gabbro of the central Swedish Caledonides consists of symplectitic intergrowths of augite with blebs or lamellae of orthopyroxene. Mineral compositions are consistent with formation of these symplectites by exsolution of orthopyroxene from magmatic augite at approx 900-1000°C. The microstructures indicate that the mechanism was discontinuous precipitation, whereby the boundary of an augite grain sweeps through a neighbouring augite leaving symplectite. Symplectite formation is catalysed by the presence of an intergranular water-rich fluid phase, which promotes grain boundary mobility. [R.A.H.]
Subjects:Augite; Chain silicates; Clinopyroxene; Exsolution; Gabbros; Geochemistry; Igneous rocks; Intergrowths; Petrology; Plutonic rocks; Precipitation; Processes; Pyroxene group; Silicates; Symplectite; Caledonides; Europe; Scandinavia; Sweden; Western Europe; Artfjallet Gabbro; Discontinuous precipitation; Symplectite intergrowths
Abstract Numbers:85M/4493
Record ID:1985069845
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Tags: Add Tag
No Tags, Be the first to tag this record!
Be the first to leave a comment!
You must be logged in first