HR: 1340h
AN: GP43C-1497 [Abstracts]
TI: Rapid, large-scale Neogene rotations and remagnetizations recorded by sediments on the Hikurangi Margin, New Zealand
AU: * Rowan, C J
EM: c.j.rowan@gmail.com
AF: National Oceanography Centre, University of Southampton, European Way, Southampton,
SO14 3ZH, United Kingdom
AU: * Rowan, C J
EM: c.j.rowan@gmail.com
AF: University of Johannesburg, Department of Geology, P.O. Box 524, Auckland Park,
Johannesburg, 2006, South Africa
AU: Roberts, A P
EM: arob@noc.soton.ac.uk
AF: National Oceanography Centre, University of Southampton, European Way, Southampton,
SO14 3ZH, United Kingdom
AB:
New paleomagnetic results from the Hikurangi margin, New Zealand, demonstrate that late diagenetic growth of
the iron sulfide greigite has occurred at up to 65% of sampling localities. When these remagnetizations are
accounted for, coherent vertical axis rotation of the entire Hikurangi margin over the last 7-10 Ma can be inferred
south of the Raukumara Peninsula, at a much faster rate (8-14°/Myr) than the presently observed rate of 3-
4°/Myr, which is only likely to characterize the tectonic regime established since 1-2 Ma. These new results
are consistent with both long- and short-term deformation on the Hikurangi margin being driven by realignment of
the subducting Pacific plate, with collision of the Hikurangi Plateau in the Late Miocene potentially being key to
both the initiation of tectonic rotations and the widespread remagnetization of Neogene sediments. Boundaries
between the rotating and non-rotating ends of the Hikurangi margin can be linked to long-term discontinuities in
intra-plate coupling resulting from structural changes along the plate boundary zone. However, accommodating
faster, more coherent rotation of the Hikurangi margin in Neogene reconstructions of the New Zealand plate
boundary region, particularly in the Late Miocene, remains a challenge.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1527 Paleomagnetism applied to geologic processes
DE: 1533 Remagnetization
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting