HR: 09:45h
AN: V31F-08    [Abstracts]
TI: Triple-Junction Magmatism: Arc-Affinity Lavas on the Woodlark Spreading Center
AU: * Chadwick, J
EM: djchadwi@uncc.edu
AF: University of North Carolina at Charlotte, Dept. of Geog. and Earth Sciences, Charlotte, NC 28223, United States
AU: Perfit, M
EM: perfit@geology.ufl.edu
AF: University of Florida, Dept. of Geological Sciences, Gainesville, FL 32611, United States
AU: Chadwick, C
EM: siliciclaire@yahoo.com
AF: University of North Carolina at Charlotte, Dept. of Geog. and Earth Sciences, Charlotte, NC 28223, United States
AB: The Woodlark spreading center exhibits unusual, arc-affinity lavas near its triple-junction intersection with New Britain trench, at the New Georgia Group of the Solomon Islands. These lavas have major element, trace element, and isotopic compositions that are generally intermediate between the N-MORB erupted on the mid- ocean ridge further from the trench and enriched arc laves from the New Georgia Group. These unusual lavas may be the result of mixing between MORB and arc magmas that have been channeled across the trench boundary within the conduit of a slab window. Near-trench volcanism at Kavachi Seamount in the forearc region about 30 km from the trench is postulated to be a result of melts produced by the ‘blowtorch effect' above the slab window. Similar forearc volcanism and arc-affinity lavas are found at the triple junction formed by the Chile Rise and trench, suggesting that these magmatic effects may be common consequences of ridge subduction.
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
DE: 8185 Volcanic arcs
DE: 8413 Subduction zone processes (1031, 3060, 3613, 8170)
DE: 8416 Mid-oceanic ridge processes (1032, 3614)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting