Quote:
Originally Posted by andyc
Fossils from polar regions demonstrate plate tectonics and continental drift (with a bit of geological scale climate & greenhouse gas change thrown in), *not* that Earth tilted wildly on its axis any more than we very well understand from orbital mechanics (e.g. Milankovitch cycles).
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Hi Andy,
And one of course doesn't have to go far here in Sydney to see wonderful examples of continental drift.
Large swaths of Sydney are built upon Haweksbury River sandstone.
Some of it is most dramatically seen through the cuttings of the M1
(previously F3) Freeway between Sydney and the Central Coast.
Very close to where I am right now.
Douglas Mawson I recollect was one of the first to recognize the
sandstones he saw in Antarctica were "Hawkesbury River" sandstone.
All when Australia and Antarctica were all part of Gondwanaland and
"Sydney" was much closer to the south pole.
Quote:
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Originally Posted by http://www.adderley.net.au/geology/exhibition/
The Hawkesbury Sandstone is a Triassic sedimentary quartzose sandstone
(mainly quartz) with a smaller proportion of feldspar, clay,
and iron compounds such as siderite (FeCO3).
It was formed from the sands which came from Antarctica
about 200 million years ago, carried by a vast river system.
Over millions of years these sands were consolidated into sandstone
up to 50 metres thick on the peninsula.
Hawkesbury Sandstone contains minor shale beds rich in fossils.
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http://www.adderley.net.au/geology/e.../04_02_12.html