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New study of breakup of eastern Gondwana (Australia and Antarctica)



From: Ben Creisler
bcreisler@gmail.com


A new online paper that may be of interest:

L.T. White, G.M. Gibson & G.S. Lister (2013)
A reassessment of paleogeographic reconstructions of eastern Gondwana:
Bringing geology back into the equation.
Gondwana Research (advance online publication)
http://dx.doi.org/10.1016/j.gr.2013.06.009
http://www.sciencedirect.com/science/article/pii/S1342937X1300213X

In recent years several tectonic reconstructions have been presented
for Australia-Antarctica break-up, with each putting the Australian
plate in a different location with respect to Antarctica. These
differences reflect the different datasets and techniques employed to
create a particular reconstruction. Here we show that some of the more
recent reconstructions proposed for Australia-Antarctica break-up are
inconsistent with both our current knowledge of margin evolution as
well as the inferred match in basement terranes on the two opposing
conjugate margins. We also show how these incorrect reconstructions
influence the fit of the Indian plate against Antarctica if its
movement is tied to the Australian plate. Such errors can have a major
influence on the tectonic models of other parts of the world. In this
case, we show how the position of the Australia plate can predetermine
the extent of Greater India, which is (rightly or wrongly) used by
many as a constraint in determining the timing of India-Asia, or
India-Island Arc collisions during the closure of Tethys. We also
discuss the timing of Australia-Antarctica break-up, and which linear
magnetic features are a product of symmetric sea-floor spreading
versus those linear magnetic features that result from rifting of a
margin. The 46 Ma to 84 Ma rotational poles previously proposed for
Australia-Antarctica break-up, and confined to transitional crust and
the continent-ocean transition zone, more likely formed during earlier
stages of rifting rather than during symmetric sea-floor spreading of
oceanic crust. So rotation poles that have been derived from magnetic
anomalies in such regions cannot be used as input in a plate
reconstruction. A new reconstruction of the Australia-Antarctica
margin is therefore proposed that remains faithful to the best
available geological and geophysical data.


News release and video:

http://www.rhul.ac.uk/aboutus/newsandevents/news/newsarticles/studyrevealsancientjigsawpuzzleofpastsupercontinent.aspx

A video demonstrating the ancient jigsaw puzzle can be viewed here:

https://vimeo.com/68311221