antarctic peninsula path since breakup: review and implications for james ross basin development...

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