HR: 08:40h
AN: V41G-03    [Abstracts]
TI: What, When, Where, and Why of Secondary Hawaiian Hotspot Volcanism
AU: * Garcia, M O
EM: mogarcia@hawaii.edu
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Ito, G
EM: gito@hawaii.edu
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Applegate, B
EM: bruce@soest.hawaii.edu
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Weis, D
EM: dweis@eos.ubc.ca
AF: Un. of British Columbia, Earth and Ocean Sciences, Vancouver, BC V6T 1Z4, Canada
AU: Swinnard, L
EM: swinnard@hawaii.edu
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Flinders, A
EM: andrealphus@gmail.com
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Hanano, D
EM: dhanano@eos.ubc.ca
AF: Un. of British Columbia, Earth and Ocean Sciences, Vancouver, BC V6T 1Z4, Canada
AU: Nobre-Silva, I
EM: inobre@eos.ubc.ca
AF: Un. of British Columbia, Earth and Ocean Sciences, Vancouver, BC V6T 1Z4, Canada
AU: Bianco, T
EM: rixctf@soest.hawaii.edu
AF: Un. of Hawaii, Geology-Geophysics, Honolulu, HI 96822, United States
AU: Naumann, T
EM: aftrn@uaa.alaska.edu
AF: Un. of Alaska, Geol. Sciences, Anchorage, AK 99508, United States
AU: Geist, D
EM: dgeist@uidaho.edu
AF: Un. of Idaho, Dept Geol. Sciences, Moscow, ID 83844, United States
AU: Blay, C
EM: teok@aloha.net
AF: TEOK Investigations, PO Box 459, Koloa, HI 96756, United States
AU: Sciaroni, L
EM: sciaronilinda@aol.com
AF: Kauai Public Schools, School Dist., Koloa, HI 96756, United States
AU: Maerschalk, C
EM: cmaersch@ulb.ac.be
AF: Un. of British Columbia, Earth and Ocean Sciences, Vancouver, BC V6T 1Z4, Canada
AU: Maerschalk, C
EM: cmaersch@ulb.ac.be
AF: Un. Libre de Bruxelles, Dept des Sci. de la Terre et de l'Env., Brussels, B-1050, Belgium
AU: Harpp, K
EM: kharpp@mail.colgate.edu
AF: Colgate Un., Geology, Hamilton, NY 13346, United States
AU: Christensen, B
AF: Colgate Un., Geology, Hamilton, NY 13346, United States
AB: Secondary hotspot volcanism occurs on most oceanic island groups (Hawaii, Canary, Society) but its origins remain enigmatic. A 28-day marine expedition used multibeam bathymetry and acoustic imagery to map the extent of submarine volcanic fields around the northern Hawaiian Islands (Kauai, Niihau and Kaula), and the JASON2 ROV to sample many volcanoes to characterize the petrology, geochemistry (major and trace elements, and isotopes) and ages of the lavas from these volcanoes. Our integrated geological, geochemical and geophysical study attempts to examine the what (compositions and source), where (distribution and volumes), when (ages), and why (mechanisms) of secondary volcanism on and around the northern Hawaiian Islands. A first-order objective was to establish how the submarine volcanism relates in space, time, volume, and composition to the nearby shield volcanoes and their associated onshore secondary volcanism. Our surveying and sampling revealed major fields of submarine volcanoes extending from the shallow slopes of these islands to more than 100 km offshore. These discoveries dramatically expand the volumetric importance, distribution and geodynamic framework for Hawaiian secondary volcanism. New maps and rock petrology on the samples collected will be used to evaluate currently proposed mechanisms for secondary volcanism and to consider new models such as small-scale mantle convection driven by thermal and melt-induced buoyancy to produce the huge volume of newly discovered lava. Our results seem to indicate substantial revisions are needed to our current perceptions of hotspot dynamics for Hawaii and possibly elsewhere.
DE: 3037 Oceanic hotspots and intraplate volcanism
DE: 3075 Submarine tectonics and volcanism
DE: 3080 Submergence instruments: ROV, AUV, submersibles
DE: 8415 Intra-plate processes (1033, 3615)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting