Or conversely, if it was always assumed that there was land under large masses of solid ice, when did we know that there was no land underneath the Arctic ice?
I know that modern machinery can scan below the very thick ice to determine the extent of the rock underneath, but how early on did we know conclusively that there was land under the southern ice mass, and none under the northern ice mass? And how exactly was the conclusion reached by those earliest folks?
This is pretty much a guess, but in January 1841 Sir James Clark Ross discovered Mt. Erebus while erupting which pretty much is definitively land. I think there is ice free land in the vicinity.
Also a guess, but submarines might have made the discovery. I’ve heard that the Ruskies used to trash their old subs under the North Pole.
We knew whether there was land or sea underneath the ice pretty much as soon as we saw the ice. Even to casual inspection, the difference between land and sea ice is fairly obvious. Sea ice is low and flat and dark; land ice is high and irregular and bright. Even in ancient times, it was understood that icebergs were formed on land, because seawater just doesn’t freeze that way.
Understood by those who have firsthand experience with seawater freezing?
(Just because I imagine that there were seaside areas where the water never froze over, but an iceberg drifting by under certain conditions wasn’t exactly impossible.
James Clark Ross and Charles Wilkes were both early explorers in Antarctica. Both explored the area in the late 1830s and early 1840s. Charles Wilkes was the first to claim that it was a continent. James Clark Ross may have found Mt. Erebus but he thought that the south pole was mostly water. He proved himself wrong when he tried to sail to the south pole, and couldn’t. So, while both were aware that there was land around the south pole, I think Charles gets the first credit for realizing that the whole south pole area had land underneath.
For the north pole, people generally believed (correctly) that it was sea all the way to the top even back in the 1600s when the area hadn’t been fully explored. Expeditions in the 1800s got closer and closer to the pole and didn’t find land. Later expeditions in the early 1900s finally reached the pole and confirmed it was all sea.
Yes . . . I suppose a Mediterranean sailor out in the north Atlantic might be baffled by an iceberg.
True, but many incorrectly believed that there was open sea at the North Pole that could be reached by penetrating a ring of sea-ice.
About the South Pole, in 20,000 Leagues Under the Sea, published in 1870, the Nautilus sails under the Antarctic ice to surface at the pole. So it was at least considered possible at that time that there was sea at the South Pole, and that much of the Antarctic was sea, even though as you note it was known that there must also be significant land mass to generate the icebergs of the southern ocean.
Yes. Or even if he got as far as “Hey, maybe it froze someplace it was very cold and then floated this far,” I don’t think he would have been able to guess that cold place was land and not open sea.
Wilkes went on to even greater notoriety, almost bringing in Great Britain against the U.S. in the Civil War: Trent Affair - Wikipedia
Is that to say that all the icebergs in the North Atlantic come from Greenland, Iceland, or Canada, for instance? Could be; I’m no expert, but that’s news to me. Glad to have my ignorance lessened.
The vast majority come from Greenland, and western Greenland at that. The rest mostly from Ellesmere Island in Canada. Cite.
I’m pretty sure no Atlantic icebergs of any size come from Iceland, because the glaciers don’t reach the sea there. (Well, tiny ones emerge from the Jökulsárlón lake, and pass under the road bridge into the sea, but they won’t go far!)
The Piri Reis Map from 1513 shows the ice free coast of Antartica. It’s supposed to date from ancient times. Google for more information.
How would that work, exactly?
Perhaps you should have Googled it first yourself:
:smack::smack::smack: Ouch, I was at work and barely remembered the map. Wiki at work is banned.
The scuttling? I assume they’d punch a hole in the ice, set some charges, then get everyone off and over to another ship that would take them back.
Thanks, **Colophon. **I guess that means there aren’t icebergs in the southern ocean, huh? Didn’t realize that, either.
The Piri Reis map needs a bit more explanation than a “disclaimer” from Wikipedia.
Wikipedia is most certainly not an absolutely reliable source -a good fount of information - yes; a definitive source of current knowledge - ho hum; sometimes, maybe, depends on the contributer.
I am always a bit suspicious of any so-called authority from Wikipedia as anyone with an agenda (and an in with the editors) can slant entries in any way they choose.
Google a little further and read a few more citations.
Seismic mapping beneath ice sheets is quite similar to seismic mapping routinely done in other areas.
What
