Bushveld oikocryst pyroxene show peritectic reactions – [publication]

This study investigates a widespread but enigmatic type of pyroxenite within the Upper Critical Zone of the Bushveld Complex. These orthopyroxenite cumulates contain euhedral oikocrysts of bottle-green augite, typically around 1 cm in size and surrounded by “haloes” of nearly pure plagioclase. These oikocrysts evidently formed by peritectic reaction between orthopyroxene and melt, with the former margins of the now-dissolved opx being marked by chains of chromite crystals. This texture represents a circumstance whereby oikocrysts in the same rock develop at different overlapping stages: plagioclase oikocrysts forming early in diffusive connection with the magma column, and clinopyroxene forming peritectic poikilitic textures within residual liquid pockets chemically isolated from the overlying magma body.

Read more about these interesting textures in the full article:

Barnes, S.J., Latypov, R., Chistyakova, S. et al. Idiomorphic oikocrysts of clinopyroxene produced by a peritectic reaction within a solidification front of the Bushveld Complex. Contrib Mineral Petrol 176, 5 (2021). https://doi.org/10.1007/s00410-020-01747-4