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Antarctica Once Abutted Death Valley
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."
Good point. My understanding about the theoretical pre-history of continents only went as far back as Gondwana, which dates back roughly 500 million years and is a very different map to the one in TFA, so I had a look at this to refresh my memory and try to resolve conflicts. If TFA is true, then the continents really do shift pretty quickly and change direction a fair bit too, considering Australia started in the northern hemisphere according to TFA, went South to join Gondwana and is now heading North again.
But back to your point about how they knew what it was called, I have a related question. How do they know that Eastern Laurentia had crinkle cut coastlines like Canada? Weren't they formed by glacial activity? How does that happen at the equator?
Also, it wasn't clear to me from TFA whether the magnetic field lines conflict with this theory or support it. If they do conflict, how do we know that the distribution of isotopes isn't due to some other phenomenon?
I don't therefore I'm not.
I thought the current theory was that Gondwana the resulting scar of whatever hit the earth forming the moon such a very long time ago. How many generations super continents where there?
But back to your point about how they knew what it was called, I have a related question. How do they know that Eastern Laurentia had crinkle cut coastlines like Canada? Weren't they formed by glacial activity? How does that happen at the equator?
Most likely, they don't know that, or even think that it did. Continental drift maps are usually drawn by moving around the outlines of the modern continents for the most part, probably because that best communicates which parts went where, rather than amorphous blobs labeled things like "p.s. this is actually Canada".
My understanding would be that the actual outline of the old continents looked nothing like that and we have no way to figure out what they actually did look like.
True, and I know lots of Harley riders, most of whom are very nice. However, anyone who rides an unmuffled motorcycle and is proud of its noise is, by definition, at least an inconsiderate jerk.
No, loud pipes make bikers think they're invincible and have the right to run red lights. At least that's what the one who drove out in front of my car thought, and I still have the scuff marks on my front bumper to prove it...
Besides, if being noticed is a problem, why is the standard-issue biker uniform an oh-so-visible black?
With the exception of the crippling heat and arsenic-laced streams, you could easily mistake the two for one another.
SJW: Someone who has run out of real oppression, and has to fake it.
Revving your goddamn engine at a stop sign to make your dick sound bigger (0 mph) is, I concede, a safe speed for neighborhood driving. It still wakes up my kid, and any driver who can't see a stationary douchebag on a motorcycle isn't going to take noise into consideration.
While there are exceptions, usually when you see people revving their engines at stop signs it isn't because they're trying to look cool. Usually what happens is people buy a bike, but don't learn anything about maintenance. They store it for long periods without running it and without draining the carburetors. Of course they gum up, especially the bottom circuit. So these clueless riders end up having to constantly rev their engines to higher RPMs to keep from stalling out. This is a problem for pretty much all bikes (not many fuel injected ones on the market) but Harleys are the ones usually bought by hobbyists and retired people.
Besides, if being noticed is a problem, why is the standard-issue biker uniform an oh-so-visible black?
Mostly for fashion, but a lot of bikers wear a lot of reflective tape specifically for visibility. I know some people who wear all bright orange. It is the sound that makes a real difference though. Regardless of color, bikers are very small compared to other vehicles and easily overlooked.