Shape-preferred orientation induced by melt-rock reaction controls orthopyroxene CPO
article
The peritectic reaction whereby olivine reacts with silica-rich melt to crystallize orthopyroxene occurs in various settings such as mid-ocean ridges, mantle plumes, and subduction zones, thereby modifying upper mantle properties. While many studies have investigated how olivine crystallographic (CPO) and shape-preferred ori entations (SPO) evolve during deformation in presence of melt, pyroxene CPO has received less attention, despite orthopyroxene being the second most abundant mantle mineral. Natural examples of synkinematic melt–rock reactions in peridotites often display CPO in reaction products without clear evidence of intracrystalline deformation. Here, we investigate the evolution of orthopyroxene (enstatite) SPO and CPO in high-pressure, high-tem perature olivine + melt deformation experiments. Olivine shows abundant evidence for dislocation creep, with CPO patterns evolving from axial-[010] at shear strains.
Topics
TNO Identifier
1019871
Source
Tectonophysics, 918, pp. 1-11.
Pages
1-11
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