Evolution of the Lithospheric Mantle Beneath the Kerguelen Archipelago: Formation of Heterogeneities in a Plume Environment

Abstract

The Earth's mantle behaves as a viscous fluid over geologic timescales. The variation and amplitude of mantle geochemical heterogeneities reflect the efficiency of heat and mass transfer processes as well as the composition of entrained components. Mantle plumes, such as the Kerguelen plume in the Southern Indian Ocean, represent the main mechanism for entrainment in the mantle. The study of mantle xenoliths associated with Kerguelen hotspot volcanism can provide important constraints on melt extraction and migration processes, and sources of mantle heterogeneities. The Kerguelen plume is remarkable among mantle plumes because its voluminous volcanic activity is long lived (at least 115 myr) and occurred in diverse geotectonic environments related to the spreading of the Indian Ocean. Xenoliths outcrop exclusively in the youngest and most a lkal ine lavas of the Kerguelen Archipelago, which lies on the northern part of the oceanic Kerguelen Plateau and represents the last 38 myr of the plume's volcanic activity.