antarctic peninsula path since breakup: review and implications for james ross basin development...
TRANSCRIPT
Antarctic Peninsula path since breakup: review and
implications for James Ross Basin development
Marta E. Ghidella
Instituto Antártico Argentino
Introduction
Examine of the Antactic Peninsula path for four tectonic models:
1. Ghidella et al (2002)
2. Lawver et al (1999)
3. Livermore – Nankivell – Eagles (1996, 1997, 2000)
4. Jokat et al (2003)
Examine the relationship of the AP path with James Ross Basin development
James Ross
Basin
Reconstructions
• We are going to show reconstructions for the SAM movement, ANT kept fixed
• We are not including the reconstruction of the Scotia plate
• The plots include synthetic isochrons, calculated from rotated C34 picks.
• The path of one point of the tip of the Antarctic Peninsula will be displayed for each epoch
Ghidella et al
Reconstructions begin ...
Next:
Ghi - 160 - SAM
fixedGhi – 160 - SAM
fixed
Ghi-147-SAM
fixed
Ghi –131 - SAM
fixed
Ghi – 118 - SAM
fixed
Ghi – 90 - SAM
fixed
Ghi – 83 - SAM
fixed
Ghi – 66 - SAM
fixed
Ghi – 33 - SAM
fixed
Ghi - 26 - SAM
fixed
back Ghi – 0 – SAM
fixed
Lawver et al
Reconstructions continue ...
Next:
Law – 160 – SAM
fixed
Law – 147 – SAM
fixed
Law – 131 – SAM
fixed
Law – 118 – SAM fixed
Law – 90 – SAM
fixed
Law – 83 – SAM fixed
Law – 66 – SAM fixed
Law – 33 – SAM fixed
Law – 26 – SAM fixed
Law – 0 – SAM fixedback
Jokat et al
Reconstructions continue ...
Next:
Jo – 159 – SAM fixed
Jo – 147 – SAM fixed
Jo – 131 – SAM fixed
Jo – 118 – SAM fixed
Jo – 90 – SAM fixed
Jo – 83 – SAM fixed
Jo – 66 – SAM fixed
Jo – 33 – SAM fixed
Jo – 26 – SAM fixed
Jo – 0 – SAM fixedback
Livermore – Nankivell - Eagles
Reconstructions continue ...
Next:
Liv – 165 – SAM fixed
Liv – 150 – SAM fixed
Liv – 132 – SAM fixed
Liv – 119 – SAM fixed
Liv – 93 – SAM fixed
Liv – 83 – SAM fixed
Liv – 66 – SAM fixed
Liv – 33 – SAM fixed
Liv – 26 – SAM fixed
Liv – 0 – SAM fixedback
End of reconstructions
LawverGhidella
Jokat Livermore
All paths at present
Reconstruction of the magnetic anomaly field in the Scotia Sea at 66.6 Ma by Graeme Eagles
Our plot of 66.5 Ma with ANT fixed
• Some features of James Ross Basin evolution from del Valle et al (1995)
• Inferences from common features of the AP path in the four reconstructions
Comparison
del Valle, R.A., Lirio, J.M., Rinaldi, C.A., 1993: Sedimentación y tectónica en la cuenca de Larsen, Antártida. Proc. of the XII Congreso Geológico Argentino, vol. III, 135-143.
AP velocity
Rotation near AP
tipAP overrides oceanic crust
Pow
ell B
asin
op
en
s
James Ross Basin subsidence and tectonic episodes
Sou
th A
tlan
tic
op
en
s
The four models differ before the opening of the South Atlantic (~132 Ma)
Common features afterwards:
1) Rotation near AP tip ~ 120 – 90 Ma ... (30 Ma !!!!)
JRB: slow rate of sedimentation episodes of compressive wrench
tectonics2) AP overriding SAM-ANT oceanic crust -> ~ 80 – 34 Ma
JRB: increased sedimentation rate during 15 Ma
episodes of compressive wrench tectonics
Perhaps the compressive tectonics is more important in 2 ?
Summary
Thank you for your attention ...
end