HR: 0800h
AN: T11B-0368    [Abstracts]
TI: A Mesozoic crustal suture in the New Zealand region recorded on seismic reflection data.
AU: * Davey, F J
EM: F.Davey@gns.cri.nz
AF: GNS Science, PO Box 30368, Lower Hutt, 6040 New Zealand
AB: The geology of the South Island, New Zealand, records the accretion of terranes to Gondwana during the Paleozoic and Mesozoic. Lower crustal and upper mantle seismic reflectivity, recorded along two profiles off western and southeastern South Island, New Zealand, are interpreted in terms of a northeast-dipping paleo-subduction zone. The inferred suture off south-eastern Stewart Island, south of South Island,lies approximately under the southern margin of the Median Batholith. Its relationship to this feature and the other terranes is uncertain, but the preferred interpretation is that the suture is related to the docking of the Brook Street oceanic island arc terrane to the Gondwana margin in the Triassic, the junction of which is now largely covered by the Median Batholith. The second inferred northeast-dipping paleo-subduction zone, imaged in the lower crustal-upper mantle off the central West Coast of western South Island, underlies Paleozoic terranes. Both inferred sutures dip away from Gondwana, have similar strikes and are approximately collinear after restoration of the region for Cenozoic horizontal deformation, suggesting that they are parts of the same paleo-suture that was oriented sub-parallel to the former Gondwana margin and to the present Paleozoic and Mesozoic terranes forming South Island.
DE: 7218 Lithosphere (1236)
DE: 8104 Continental margins: convergent
SC: Tectonophysics [T]
MN: Fall Meeting 2005