HR: 16:35h
AN: V54A-03    [Abstracts]
TI: The Origin of Widespread Long-lived Volcanism Across the Galapagos Volcanic Province
AU: * O'Connor, J M
EM: john.o.connor@falw.vu.nl
AF: Department of Isotope Geochemistry, Vrije University, Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV Netherlands
AU: Stoffers, P
EM: pst@gpi.uni-kiel.de
AF: Institute for Geosciences, Christian-Albrechts-University, Ludewig-Meyn-Str. 10, Kiel, D-24118 Germany
AU: Wijbrans, J R
EM: Jan.Wijbrans@falw.vu.nl
AF: Department of Isotope Geochemistry, Vrije University, Amsterdam, De Boelelaan 1085, Amsterdam, 1081 HV Netherlands
AU: Worthington, T J
EM: tw@gpi.uni-kiel.de
AF: Institute for Geosciences, Christian-Albrechts-University, Ludewig-Meyn-Str. 10, Kiel, D-24118 Germany
AB: ⁴⁰Ar/³⁹Ar ages for rocks dredged (SO144 PAGANINI expedition) and drilled (DSDP) from the Galapagos Volcanic Province (Cocos, Carnegie, Coiba and Malpelo aseismic ridges and associated seamounts) show evidence of 1) increasing age with distance from the Galapagos Archipelago, 2) long-lived episodic volcanism at many locations, and 3) broad overlapping regions of coeval volcanism. The widespread nature of synchronous volcanism across the Galapagos Volcanic Province (GVP) suggests a correspondingly large Galapagos hotspot melting anomaly (O'Connor et al., 2004). Development of the GVP via Cocos and Nazca plate migration and divergence over this broad melting anomaly would explain continued multiple phases of volcanism over millions of years following the initial onset of hotspot volcanism. The question arising from these observations is whether long-lived GVP episodic volcanism is equivalent to `rejuvenescent' or a `post-erosional' phase of volcanism that occurs hundreds of thousands or million years after the main shield-building phase documented on many mid-plate seamount chains, most notably along the Hawaiian-Emperor Seamount Chain? Thus, investigating the process responsible for long-lived episodic GVP volcanism provides the opportunity to evaluate this little understood process of rejuvenation in a physical setting very different to the Hawaiian-Emperor Chain (i.e. on/near spreading axis versus mid-plate). We consider here timing and geochemical information to test the various geodynamic models proposed to explain the origin of GVP hotspot volcanism, especially the possibility of rejuvenated phases that erupt long after initial shield-building.
DE: 3619 Magma genesis and partial melting (1037)
DE: 3621 Mantle processes (1038)
DE: 8121 Dynamics: convection currents, and mantle plumes
DE: 8137 Hotspots, large igneous provinces, and flood basalt volcanism
DE: 8415 Intra-plate processes (1033, 3615)
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005