Antarctica Once Abutted Death Valley 182
Science News has a story of strange bedfellows. It seems that Antarctica was once adjacent to what is now the American Southwest, some 800 million years ago. Earth's continents then formed a supercontinent called Rodinia, predating Pangaea by some 550 million years. "...the ratios of neodymium isotopes in the ancient sediments in the Transantarctic Mountains are the same as those in what was then Laurentia, says Goodge. Also, the hafnium isotope ratios in the 1.44-billion-year-old zircons found in East Antarctica match those of the zircons found in the distinctive granites now found primarily in North America. Finally, the researchers note, the ratios of various isotopes and elements in a basketball-sized chunk of granite found in East Antarctica — a chunk ripped by a glacier from bedrock now smothered by thick ice, the team speculates — match those of granite found only in what was southwestern Laurentia, which today is the American Southwest."
Comment removed (Score:3, Interesting)
Re:Millions of years is a lie (Score:3, Interesting)
Just because you confuse "theory" (argument supported by facts) and "hypothesis" (educated guess) doesn't mean that other people are wrong and that people who do science are talking out their asses.
This is exactly like the retard^W Creationist argument that "I've never seen any animal evolve into another species" totally ignoring what is actually /meant/ by the accepted definition of "species" while the retard^W Creationist uses his own private definition of "species".
You argue without and against reason, and do not deserve reasonable argument back. To attempt to do so would be trying to drain your ocean of stupidity with a pipette.
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BMO
Re:but wait... (Score:5, Interesting)
I happened to catch part of a program on the History Channel this morning that was talking about Rodinia and how the coalition of the continents into a supercontinent disrupted ocean currents, allowing the poles to become colder, expanding the continuously-frozen area until the process ran away, completely covering the Earth in ice until the eruptions that accompanied the breakup of the supercontinent threw CO2 and methane into the air that couldn't be absorbed into the oceans (covered as they were by ice), building up to the point where the greenhouse effect melted a permanent ice-free zone, which (being darker than the ice) would absorb more heat, triggering a positive feedback. The program described this happening in a single freeze-and-thaw, although some 'snowball earth' theories suggest that there were several freezovers as the CO2/methane levels rose and fell until the Cambrian Explosion. It seemed to me, though, that the arguments for Rodinia and Snowball Earth can also be explained by other theories, and that drawing conclusions about conditions that far in the past based on evidence that can accumulate in different ways is going to remain somewhat speculative.
Re:Death Valley is a bitchin place (Score:3, Interesting)
Another phrase is "douchebags who made their bikes as loud as possible kept waking up our baby and drove us out of our house".
If my wife thought she could get away with it, her phrase would be "loud pipes will meet the piano wire I've strung across the street".
brother deserts (Score:2, Interesting)
I thought I read once that Antarctica was considered a desert because its precipitation levels were so low. (the snow doesn't melt, therefore it doesn't go through the water cycle and precipitate!) Or maybe that was the Arctic. Or Siberia. Hmm.
Either way, I'm not too surprised!
Re:but wait... (Score:3, Interesting)
The coastlines on the maps are the more or less modern coastlines, superimposed on the ancient plates, purely to help orient us. I think they assume we don't take the coastlines literally.
There are lots of interesting sites with graphics of continental drift in that period.
This one: http://www.scotese.com/Rodinia3.htm [scotese.com] shows both what the coastlines might have been like, as well as having a key map of the modern shapes. And http://www.palaeo.de/edu/scotese [palaeo.de] and http://www.ucmp.berkeley.edu/geology/tectonics.html [berkeley.edu] have some animations showing the continents moving through the period. Really awe-inspiring (in the meaning, not the quality of the graphics).
Antarctic joke (Score:3, Interesting)
A few days later, the first thing the geologist sees when he reaches the area is of course this rock. He aborts his trip, comes back to the main base all excited about some revolutionary theory or other and starts writing feverishly about it. It took us a bit of courage to tell him the truth and deflate him... He was able to go back to his advanced camp, but it proves that it can be too easy to fake/mistake data in some cases.
Re:but wait... (Score:2, Interesting)
Why do all discussions of Rodinia talk about a single super-continent? How do we know that there was only ONE super-continent on one side and the rest was H2O? couldn't there have been 2 or 3 other landmasses that are now at the bottom of the ocean or even melted back into the earth core by now?