Microstructures of mantle xenoliths from the Mt. Melbourne, northern Victoria Land, Antarctica

Abstract

We performed microstructural analyzed on mantle xenoliths from the Mt. Melbourne, northern Victoria Land, Antarctica, using the EBSD technique. The analyzed samples defined as lherzolite, harzburgite and dunite show protogranular olivine and orthopyroxene and interstitial clinopyroxene and spinel. Ca-in-orthropyroxene thermometer estimates the equilibrium temperature as 860920 °C. Eigenvalues of [010] and Fabric-Index Angle (FIA) identify five samples as D-type and one sample as A-type olivine. Orthopyroxene and clinopyroxene exhibit dispersed multiple clusters in CPOs probably caused by poor indexation or low abundance of minerals. Seismic properties of the peridotites display concordant direction of fast S-wave polarization and a-axis of olivine. Observed fast S-wave splitting in northern Victoria Land along NESW direction can be partially explained by the studied peridotites.