Chemical composition of basalts from ODP holes at the Kerguelen Plateau

Composition of basalts does not directly depend on their age. Specific features of plateau magmatism are commonly explained in terms of a long-living deep magma plume, which variously interacted with a depleted upper mantle source at different stages of plateau formation. However, taking into account block morphology and deep structure of the plateau, one can suggest that plateau volcanism was initiated by a large fault.

As the volcanism prograded to the northwest, depth of fault penetration into the mantle changed. Composition of basalts in the plateau basement was also governed by formation depth of primary melts.