Reply to post: Re: Sadly not the case,

ALIENS are surely AMONG US: Average star has TWO potentially Earth-like worlds

Simon Brown

Re: Sadly not the case,

dunno where you got your geology degree mate but I think you're mixing up two different concepts.

The first is the MAGNETIC poles flipping which they do every half million years or so. You can see that from the identical but mirrored stripes of reversed polarity of iron deposited in oceanic crust at spread zones. It was initially discovered in the Atlantic - searching for submarines they inadvertently discovered evidence of plate tectonics.

The second is another part of the plate tectonic "picture" which is the presence of fossilized sea shells on top of mountains and evidence of fossilised tropical forests in the rock record near Antarctica. Using the current theory that the processes existing today have existed as far back as we can tell, that means that the rocks that make up Antarctica were at one point at the or near the equator, which is 10,00km away (give or take).

Continental plates move at between 2cm & 5cm per year which isn't that fast until you think - "but it's an entire continent moving" at which point you realise that 2-5 cm / year is plenty fast for something that big and solid to be moving relative to everything around it...

So in 10,000 years it will have moved between 20 and 50 metres which is substantial but not quite at the equator. In fact it would take between 200 million and 500 million years - and as I recall the radio isotope dating and other ageing techniques (matching certain global markers like periods of major vulcanicity with specific chemical signatures across multiple rock deposits and types across continents) put the time at around 335 million years ago, from memory.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2019