Ocean
drilling program Leg 197 to the Emperor Seamounts recovered basement
core from Detroit, Nintoku, and Koko Seamounts. The goal of this
drilling leg was to ascertain if the Hawaiian hotspot had moved over
time. Paleolatitude determinations using paleomagnetic data
showed quite a southerly shift in the hotspot during the formation of
the Emperor Seamounts and that this motion may have slowed considerably
around about the time of the "bend" and the beginning of the Hawaiian
chain. This suggests that a chnage in plate motion was not
responsible for the "dog leg" in this seamount chain. Geochemical
research currently underway is looking at the evolution of Nintoku
Seamount, possible geochemical signatures of the Earth's outer core
along the Hawaiian-Emperor chain, and using plagioclase crystal
stratigraphy to document magma evolution.Papers resulting from this research:
Shafer J., Neal C.R., Regelous M., and Gudding J. Geochemistry and petrogenesis of alkalic post-shield lavas from Nintoku Seamount, a 56 Ma Hawaiian volcano. Geochem., Geophys., Geosystems (in prep.).