Rapid, large-scale Neogene rotations and remagnetizations recorded by sediments on the Hikurangi Margin, New Zealand
Abstract
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.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMGP43C1497R
- Keywords:
-
- 1525 Paleomagnetism applied to tectonics: regional;
- global;
- 1527 Paleomagnetism applied to geologic processes;
- 1533 Remagnetization