A critical examination of the Emperor and Hawaiian volcanic chains

M. Nathenson1, G.R. Foulger1,2, D.L. Anderson3, B.R. Julian1 & J.H. Natland4

1U.S. Geological Survey, 345 Middlefield Rd., Menlo Park, CA 94025, U.S.A.
2Dept. Geological Sciences, Science Laboratories, University of Durham, Durham DH1 3LE, U.K., g.r.foulger@durham.ac.uk
3Caltech, MS 252-21, Pasadena, CA 91125 U.S.A.
4RSMAS/MGG University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149

The Emperor and Hawaiian volcanic chains are usually assumed to represent a single entity, and to be an exemplary fit to the plume model. However, many features do not conform to this hypothesis. These include: 1) the great “bend” does not result from a change in direction of motion of the Pacific plate, since no such change occurred, 2) southerly motion of ~ 800 km of the melt locus occurred during formation of the Emperor chain, and stopped at the time of the great bend, 3) the chain apparently commenced near a ridge, 4) there is no Hawaiian “plume head”, 5) the melt volume flux varies greatly along the chains and has increased by an order of magnitude during the last 5 Myr, 6) there is no significant heatflow anomaly around the bathymetric swell, 7) there is no measurable thermal rejuvenation near Hawaii, 8) low temperatures relative to those required for a plume are estimated from geothermometry, 9) there is no petrological or geochemical evidence that requires a deep melt source, and 10) seismic evidence indicates relatively normal wave speeds throughout the mantle beneath Hawaii. A large number of seamounts unaffiliated with volcanic chains have similar geochemistry to Hawaii. A fully quantified hypothesis for Hawaii that can explain these features is long overdue.