Perhaps you have seen the "Whale Tails", aka "Reverence", a sculpture on the north side of I-89 as the road travels west and north towards Lake Champlain after having cut through the Green Mountains from Montpelier? The tails are solitary and curious. Why would they be so honored so far from the ocean and, at about 180 feet, so far above today's sea level? The artist wanted to make a statement about the "fragility" of the planet. Perhaps. There's a more expansive message here.
As Brio motored west from our first stop on the St. Lawrence River, she was greeted by pastoral scenes along the River.
She was also treated to a welcoming party of a humpback. The whale was seemingly waving its fins and splashing them in the water. As all good-mannered whales do, this humpback bid us adieu with a wave of its tale.
And ...
And the good-bye:
Here is a drawing of what the humpback looks like "in a book." You can see just how long the flippers are. Was the whale saying, "Hello?" Or warning others of our presence? After we learn French, we need to learn "whale talk."
But this brings us to a larger connection, linked back to the sculpture. The River is full of whales, perhaps lured by the incredible feeding of nutrients draining down from the Great Lakes and the middle of the continent. Think of all that feeds into this River.
Now, let's go back to immediate post-glacial times, just after the last glacial maximum. The ice had retreated from Long Island and Cape Cod. It was about 12,000 years before present. Humans were not too far away, perhaps still south of Long Island.
Here, from Four Billion Years and Counting, you can see how the ice cap shrank from 21,400 years ago to 15,000 years ago to 12,700 years ago to 11,500 years ago to 9,000 years ago to 7,800 years ago. The graphic also presents the sea level at these times. Remember that as the ice melted, it would cause sea level to rise. But complicating the picture is that the land was depressed by the tremendous weight of the glaciers. The land did not rebound immediately. So, the meltwater flooded the depressed land and caused large parts of the terrain to be underwater.
You can see this in the following set of drawings, covering the post-glacial times around Quebec City from 12,000 years ago to 11,000 years ago to 9,000 years ago to present. Look at how much of the Quebec province around the St. Lawrence River was in fact flooded. This post-glacial body of water was directly connected to the Atlantic Ocean. It was salty most of the time and existed as the Champlain Sea.
Between 15,000 years ago and 11,500 years ago, the ice cap would advance and retreat episodically, allowing for the Atlantic (and salt water and whales) to move into the flooded highlands as far as Lake Champlain (remember, it was depressed) and then be cut off. There are whale fossils in the area around the highlands above the current Lake Champlain shoreline and they date from this dynamic time.
Other fossils, small bivalve animals from the 15,000 years ago to 11,000 years ago timeframe, exist as salinity indicators. These specific fossils are very sensitive to hypo- and hyper-salinity in the environments in the Champlain Sea where Lake Champlain exists today. Some species thrive in low salinity conditions while other species thrive in high salinity conditions. So, we know that the connection to the Atlantic Ocean was "alive" and served as a conduit for whales and salt water over these few thousands of years.
These four diagrams show how the connection would have existed, but only for a short time geologically speaking. The 12,000 years ago picture would have certainly have also covered the Champlain Valley in sea water. But that connection would have been lost due to the land rising faster than the sea level rose AND the ice cap retreating well north of the St. Lawrence River by 9,000 years ago.
So, today, the St. Lawrence River is rich in marine life, as our humpback whale friend suggests. But the geographic extent is limited due to the passing of the immediate post-glacial time. By 9,000 years ago, humans were roaming the area that had been underwater and, before that, under ice.
Cheers,
Brio
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