Orthopyroxenite

Orthopyroxenite

Plutonic Rocks

Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019

Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough

For classifying ultramafic rocks, the IUGS uses the proportions of olivine, orthopyroxene, and clinopyroxene (Fig. 6.25). Peridotites, which all contain more than 50 wt% olivine, include harzburgite (orthopyroxene >> clinopyroxene), wehrlite (clinopyroxene >> orthopyroxene), and lherzolites (subequal amounts of orthopyroxene and clinopyroxene). Pyroxenites may be orthopyroxene-rich (orthopyroxenite), clinopyroxene-rich (clinopyroxenite), or in-between (websterite). The modifier olivine is put in front of a pyroxenite name if a rock contains more than 5% olivine. A different triangular diagram (not shown) is used for the rare ultramafic rocks that contain hornblende.

Petrogenesis of the Kalka, Ewarara and Gosse Pile layered intrusions, Musgrave Province, South Australia, and implications for magmatic sulfide prospectivity

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Journal Information

Published in Australian Journal of Earth Sciences, 2023

W. D. Maier, B. Wade, Sarah-Jane Barnes, R. Dutch

Gosse Pile is located north of the Hinckley fault, 10 km towards the east, and along strike, from Kalka. The body is ∼2000 m thick and has a strike length of ∼8 km (Figure 3b). It consists predominantly of steeply south-dipping (45–90°) layers of orthopyroxenite, with minor websterite, peridotite and gabbronorite (Moore, 1971a, 1971b; Wade, 2006). The rocks contain rare chromite, spinel, hornblende, biotite and sulfides; the latter found only in olivine-pyroxenites.

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Plutonic Rocks

Petrogenesis of the Kalka, Ewarara and Gosse Pile layered intrusions, Musgrave Province, South Australia, and implications for magmatic sulfide prospectivity