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| December 13, 2007 Post 2 |
| It's A Curious World |
Did a comet kill the schooner Annandale?
The schooner Annandale probably loaded coal at one of these trestles on the east side of Oswego Harbor in 1905 |
As the human race continues its massive experiment with fossil fuel induced climate change, the notion that climate can shift suddenly and catastrophically has gained traction within the scientific community. Studies of tree rings, fossil pollen, ice cores, and even written records from ancient villages have documented several such rapid changes like the 'little ice age' which is thought to have driven the Vikings from their colonies in Greenland as well as other older but no less abrupt shifts.
A few decades ago a cooling event called the Younger Dryas was recognized.. This one happened around 12,900 years ago and ironically the theory went, the melting of the glaciers in North America caused a sudden release of water from the interior of the continent through the Great Lakes basin which in turn shut down the gulf stream and caused Europe to go into the deep freeze. The same event might have also impacted the early human inhabitants of North America and some of the animals they depended on for food. Some researchers have also linked cooling and global changes in climate and rain fall at this time with the rise of agriculture in the Mediterranean area, though not all the scientific community agrees with this idea.
Still, controversy remained as to the cause of the thousand year cool down, and the archaeologists had never managed a really convincing explanation of why the Clovis people of North America suddenly experienced a catastrophic population decline along with over a hundred species of land mammals ranging from camels to sabertooths. Most of the animals that died out were larger species, over a hundred pounds of so. Some of them, like the horse and camal, survived in the old world, but died out in the new. What had been the exact cause of this large scale extinction? Did highly efficient and meat hungry paleo indian hunters kill them all off? Did the fleas, dogs, lice or other fellow travelers of the humans bring some virulent new disease from the old world that transmitted to and then devasted native animal populations? While nobody knew for sure which theory or combination of causes was correct, there was increasing suspicion that the Younger Dryas cooling event had something to do with it. So there was a lot of interest in the evidence for a comet strike as the trigger for the big chill when it was presented at a scientific conference in Mexico last spring.
There is growing evidence that a large comet exploded over Canada north of the Great Lakes about 12,900 years ago and that fiery fragments rained down onto a large area of North America. The theory goes that the after affects of the comet's strike could have plunged the continent back into a mini ice age causing the extinctions of a number of large animals like the mammoth and the giant ground sloth that once roamed our area. And many of the ice age humans may also have been victims.
At that conference a Dr Kennatt told his audience that surveys of Clovis sites found that the highest concentration of extra terrestrial materials such as irridium, particular isotopes of heluim, and unique forms of carbon occurred in the great lakes area. The major part of the comet might have impacted over the glacier itself ( which is why no big meteor crater has been found north of the lakes in Canada) and might have caused a massive sudden melting and break up of a large part of the ice sheet, leading to the sudden release of water as ice dams in the St. Lawrence valley gave way. Other comet fragments appear to have hit far to the south where forested areas caught fire sending massive amounts of smoke and soot into the air causing world wide cooling. An interesting piece of the puzzle is the presence of numerous small depressions that are eliptical in shape and often now form shallow wetlands from New Jersey to Florida. They all seem oriented in a way that indicates a possible rain of fragements striking from the northwest.
Last year, while doing a beach walk with some folks, one asked me if I had heard of a meteor crater in Lake Ontario. I looked blank and said no. But more recently a chance encounter with a geologist that led me to a spectacular detailed map of the bottom of Lake Ontario courtesy of NOAA on the Internet showed me where the crater question came from. Charity Shoal, on oddly circular reef almost like a coral atol under water, lies near where the shipping lane heads up into the St Lawrence, northeast of Main Duck. And it may be of extra terrestrial origin. Could Charity Shoal have a connection with the demise of the North American Mammoth?
In 1999 the Journal of Great Lakes Research ran an article documenting the presence of a “small rimmed depression” in Lake Ontario that they proposed might have been caused by a meteorite. Supporting the theory was the long standing knowledge of a magnetic anomaly ( marked on my well used paper charts of the area) which is typical of impact events. The article went on to say several time periods for the event were possible including pleistocene or holocene. If indeed it was from those more recent times, that would match the era of the Younger Dryas cooling event.
As far as I can find from checking Google on the net, no definitive study yet of the shoal has turned up any extra terrestrial “markers” such as iridium granules, shocked quartz, or what the scientists call 'nano diamonds'. But it's not that easy to sample rocks that are 50 feet under water and filled with hard clay sediment. I wonder if any scuba divers are checking out its geology?
Charity Shoal has been the death of several unfortunate Lake Ontario vessels. One part of the raised circular rim is only a few feet below the lake's surface. A diving site lists the schooners Annandale and Maria Annette along with the Lucinda as known victims accessible to divers today. Maybe while they're down there studying the ships, they could look around at the geology as well.
Who would have thought that a comet could perhaps have been responsible for sinking several ships on Lake Ontario 12,900 years after its own demise? It's a curious world out there.
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