Rochester/NY Finger Lakes region

[deemery]

Pretty much any round pond in New England is likely a kettle.  Moraines here range in size from Cape Cod to the series of 2' tall moraines in a field in NH, which a grad student wrote about.  Drumlins are pretty common.  Another feature in my part of NH (and maybe James', too) are features formed as the glaciers receded and sea levels rose.  A couple of the small hills are deltas that formed from glacial run-off into sea levels that were 100' higher than they are now.

The paper I wrote for my first geology course looked at sea levels during glacial retreat.  It's a fascinating story.  You have to consider not just the water rising in the ocean, but the movement of ground.  The ground starts being pushed down by the massive weight of the glaciers.  As the glaciers retreat, the land rebounds, as well as ocean levels rise because of glacial melt.  Thus you get this "up, down, then flat" (Land rises, oceans rise, land sinks a bit, ocean levels stabilize) graph of the sea level relative to the terrain:

A grad student picked up on this and did a thesis looking in detail at the local maximum sea level.  She found a couple places in coastal NH that were above sea level even during that peak.  

I dunno if anyone else is interested, but I was fascinated by this.  And I suspect there are similar stories around the Great Lakes, with those huge glacial lakes formed as the glaciers melted, AND the movement of the land as the glacial load was removed.

dave

[Dave Buchholz]

I always wondered about the claim of roding sea levels due to glacial melting.So my curiosity was about the opposite point.

So how low were the sea levels when glaciers were at peak formation?
Some studies indicate they were likely 400 ft lower than today.

So how many civilizations were wiped out as the rose. Is that what happened to Atlantis?
Was Noah's flood about that water cresting over a certain range of hills formations, flooding the valley below?

It makes me wonder what existed that is now gone below the ocean waves.

[deemery]

Well, the global sea level low point at the glacial maximum, based on the paper that looked across a lot of data, is probably about -125m to -150m at roughly the glacial maximum of 20k years ago.  As I said earlier, calculating sea level is surprisingly complex because the continents got pushed down, as well as the sea levels reducing due to water removed from the oceans (and sitting as ice on the land.)  And of course, in the northern regions where the continents were pushed down by larger ice loads (North America, Scandinavia, northern Eurasia), the coasts there will show a different coastline than around the equator. 

But starting about 10k years ago, and particularly 6k years ago (4000 BC), sea levels have been pretty stable.  So I don't think the concept of 'global floods' per Noah or Atlantis are born out by the current evidence.   (Ice core data is one of the newer measures of sea levels and global temperatures, based on ratios of oxygen isotopes.  Fascinating stuff!) 

In short, the graph above for the Maine coast is pretty much the same pattern across the globe, with that oscillation (the pop and dip) that then levels out.

dave

[jbvb]

...
I dunno if anyone else is interested, but I was fascinated by this.  And I suspect there are similar stories around the Great Lakes, with those huge glacial lakes formed as the glaciers melted, AND the movement of the land as the glacial load was removed.

In fact, last week I looked up the history of Great Lakes water levels and found a fascinating page on how the Indiana Dunes came to be.  Didn't anticipate your question, or I'd have bookmarked it