Anyone who has noticed my latest Nature column will be aware that I have had to forgo the AGU Fall Meeting in San Francisco for yet another year. I suppose I can feel virtuous about not ramping up my already large carbon footprint for this year any further, but somehow I can’t help but feel a little depressed to be missing out – especially since it seems that a large proportion of the geoblogosphere will be descending on San Francisco for a little party. Just think of the Scibling shindig and add extra alcohol (if there’s any way that that is achievable, be assured that it’s geologists who will find it). This is one reason why posting has been a bit light this week – I’ve been sulking.
Anyway, a little piece of me is managing to attend, in the form of a poster about my PhD research, which will is part of the “Paleomagnetism in Orogenic Settings” session next Thursday afternoon. This isn’t something that I’ve actually blogged about too much yet (although that will change when my big New Zealand tectonics paper finally gets published, hopefully not long into the new year), so any attending readers who are curious about what I was up to before I came to South Africa, here’s your chance. Plus, an invasion of Highly Allochthonous groupies would really freak out my old supervisor, who has kindly volunteered to represent me at the poster session.
Here’s the abstract:
Thursday December 13th, 1340h
GP43C-1497: Rapid, large-scale Neogene rotations and remagnetizations recorded by sediments on the Hikurangi Margin, New Zealand
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 degrees/Myr) than the presently observed rate of 3- 4 degrees/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.
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