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Microstructural Relationship between Olivine and Clinopyroxene in Ultramafic Rocks from the Red Hills Massif, Dun Mountain Ophiolite.

Authors :
Shao, Yilun
Negrini, Marianne
Liu, Cai
Gao, Rui
Source :
Minerals (2075-163X). Nov2023, Vol. 13 Issue 11, p1415. 18p.
Publication Year :
2023

Abstract

The microstructural relationship between olivine and clinopyroxene is significant in recovering the mantle evolution under clinopyroxene-saturated melting conditions. This study focuses on olivine/clinopyroxene-related ultramafic rocks (dunite, wehrlite, olivine clinopyroxenite, and clinopyroxenite) in the Ells Stream Complex of the Red Hills Massif. (Olivine) clinopyroxenites have an A/D-type olivine crystallographic preferred orientation (CPO) whereas peridotites have various olivine CPO types. B-type olivine CPO was newly discovered, which may have been generated under hydrous conditions. The discovery of B-type CPO means that all six olivine CPO types could exist in a single research area. Clinopyroxene CPOs also vary and have weaker deformation characteristics (e.g., lower M index and weaker intracrystalline deformation) than olivine; thus, they probably melted and the clinopyroxene-rich ultramafic bands existed as melt veins. Irregular clinopyroxene shapes in the peridotites and incoherent olivine and clinopyroxene CPOs ([100]OL and [001]CPX are not parallel) also indicate a melted state. The dominant orthorhombic and LS-type CPOs in olivine and clinopyroxene imply that simple shear was the main deformation mechanism. Such complicated microstructural characteristics result from the overprinted simple shear under high temperatures (>1000 °C) and hydrous melting environments until the melt-frozen period. This case study is helpful to better understand the olivine and clinopyroxene relationship. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
2075163X
Volume :
13
Issue :
11
Database :
Academic Search Index
Journal :
Minerals (2075-163X)
Publication Type :
Academic Journal
Accession number :
173864620
Full Text :
https://doi.org/10.3390/min13111415