WHAT'S DIFFERENT ABOUT HUALALAI, KOHALA AND LOIHI?
Hualalai and Kohala were the first subaerial volcanoes to form after a gap in volcanic activity between Maui and the Island of Hawaii. They also erupted during the largest upsurge in magmatic flux of the Hawaiian plume6,7. Higher magma flux does not necessarily translate into higher degrees of partial melting, as indicated by higher Ba/Y, Nb/Y, and La/Yb for Kohala lavas relative to other Hawaiian shields. In general, Hualalai, Kohala, and Loihi all have intermediate isotope and trace elemental compositions overlapping the Kea-Loa boundary. It is interesting to note that all Island of Hawaii volcanoes are characterized by a juxtaposition of both Kea and Loa trend characteristics in the same volcano, and the most extreme crossover volcanoes occur after a gap in volcanism between islands, i.e. Kauai, West Molokai, Waianae, Mahukona, and Kohala. Approximately 16% of Hawaiian shield samples “crossover” the Loa-Kea divide based on an analysis of radiogenic Pb (N=542).
1Xu et al. (2014) GCA, 132, 214-327. 2Marske et al. (2007) EPSL, 259, 34-50. 3Jackson et al. (2012) G3, 13(9). 4Hanano et al. (2010) G3, 11(1). 5Harrison et al. (in press) AGU Mono. 6Vidal & Bonneville (2004) JGR 109, B03104. 7Robinson & Eakins (2006) JVGR, 151, 309-317.