Hawai'i is the archetype of mantle plumes and characterized by a series of unique features:
- it has the largest buoyancy flux and erupted volume of lavas;
- contrary to predictions from plume models, theHawai'i mantle plume (HMP) has become stronger with time, especially on the islands where the flux is ~10(20) times higher than at 49(81) Ma;
- along the archipelago, volcanoes are distributed in two sub-parallelgeographical chains that are geochemically distinct; and
- erupted lavas show systematic compositional variations through volcano growth stages and are dominated mainly by tholeiitic shield compositions.
Statistically, the volcanoes can be subdivided into six compositional groups organized in apattern parallel to the sharp edge of the Pacific large low shear velocity province (LLSVP). Moving away from the anomalous deep mantle seismic zones, these groups show a systematic decrease towards the northeast in the contribution ofLoa-enriched characteristics. The HMP periodically entrains large-scaleheterogeneities that contribute to hotspot volcanism on a smaller timescale than previously considered. The increased resolution afforded by this analysis indicates that the heterogeneity of the deep mantle is not limited to anomalous seismic zones.
The presence of compositional asymmetry in Pacific hotspots has been linked to the presence of the LLSVP at the core mantle boundary. This lecture discusses the role of mantle plume in understanding the Earth mantle, integrating geochemical and geophysical perspectives.
