Microstructures of spinel peridotite xenoliths from Baker Rocks in northern Victoria Land, Antarctica: evolution of lithospheric mantle around the Transantarctic Mountains

Abstract

Fabrics of five spinel peridotites collected from Baker Rocks in northern Victoria Land, Antarctica, were investigated to elucidate the evolution of the lithospheric mantle surrounding the Transantarctic Mountains. Analyses revealed the development of crystallographic preferred orientations (CPOs), a slight decrease in mean grain size and J-index across varying proportions of clinopyroxene, and interlobate to amoeboid textures. These findings indicate that dislocation creep is the dominant deformation mechanism for the analyzed samples. Olivine CPOs were examined using eigenvalues, fabric-index angle, and rotation axes due to the limited size of hand specimens, resulting in the identification of AG-, D-, and A-type fabrics. to melt-rich environments, supported by low fabric indices and the highest proportion of clinopyroxene, implying temperature and high-stress conditions, as evidenced by examining the relationship between microstructures and of deformation processes over geologic timescales.