The 21–25-km-thick crust of the southern Kerguelen Plateau consists of three units: (1) a ≤ 2.3-km-thick sedimentary cover; (2) a 3–6-km-thick basaltic layer with velocities ranging from 4.5 to 6.2 km/s; and (3) a 15–17-km-thick lower crust with velocities from 6.6 to 6.9 km/s, including a 3–6-km-thick transition zone located at the base of the crust. The low-velocity transition zone has an average velocity of 6.7 km/s and exhibits several internal wide-angle reflections. The velocity-depth structure of the crust differs significantly from that of other hotspot-related oceanic plateaus and suggests that the southern Kerguelen Plateau may be a fragment of a volcanic passive margin composed of a thinned continental crust overlain by basalt flows.

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