Monday, January 15, 2018

Were the Great Lakes Ever Open to the Atlantic? – Part III

Continued from the previous post regarding possible bays and inlets to the Great Lakes from the Atlantic Ocean in antiquity. 
    According to Dr. Joerg Schaefer, a researcher at the Lamont-Doherty Earth Observatory at Columbia University, the rocks of New York City are a climate archive, and most New Yorkers are unaware that they are living in the middle of a glacial event park." On Long Island, in Manhattan and at locations up the Hudson River toward Albany, Dr. Schaefers three-scientist team are measuring the retreat velocity of the last glacier. What makes this possible for the first time is a new age-measuring technique that has one simple, but seemingly unreasonable, requirement: the testing of relatively clean surfaces that have been undisturbed for 18,000 years.
    According to Dr. Schaefer, evidence has been found of the glacier retreat in Marcus Garvey Park in Harlem; Inwood and Morningside Parks on the West Side of Manhattan; a pristine glacial expanse in Harriman State Park; and even a truck-size glacial boulder in Port Jefferson, N.Y. (a parking lot was built around it, given its size). "It's spectacular that in such an urban setting, there are these completely ancient features."
Two glacial erratics that were transported by moving ice at the height of the Wisconsin glaciations when the Laurentide ice sheet coveted what is now New York City to a depth of about 1000 feet (Bruce Gervais and Jackie Phillips, Universities Space Research Association)
In Central Park, Dr. Schaefer has employed a new scientific tool called "cosmogenic dating," a pioneering way of measuring the age of landforms, finding much of the visible bedrock was shaped by ice, and unmodified glacial features abound include striations (abrasion grooves that show the flow direction from northwest to southeast), glacial polish (caused when rock was buffed by sediment), chatter marks (gouges in bedrock made by glacier-dragged stones), and erratics (boulders stranded on bedrock by the glacier, such as Umpire Rock south of Heckscher Ballfields to the east of West 62nd Street, by the pétanque court).
    "As you see the deep grooves, you can almost imagine these big boulders gouging out the bedrock," said Neil Calvanese, vice president for operations of the Central Park Conservancy, which manages the park under a contract with the city. Through the years, the park has attracted research endeavors from astronomy to environmental science, and the United States Geological Survey has monitored ground water in the park, and Lamont has also maintained a seismograph in the North Meadow.
An elongated asymmetrical landform called a roche moutonnee, showing the direction of flow of the ice (Bruce Gervais and Jackie Phillips, Universities Space Research Association)

The key to showing that this area east of the Great Lakes was landform following the retreat of the last ice age glaciers, is in the identifying of beryllium-10, an unstable isotope, or radionuclide, which forms in locations that have been struck by cosmic rays, including rock surfaces. As glacial ice retreated, "it opened up the rock to cosmic rays," Dr. Schaefer said. "An isotope is created at the moment the cosmic rays strike the rock, and when the surface is exposed, the clock begins ticking."
    The unstable isotope formed in the rock has a half-life of 1.5 million years, a rate of radioactive decay that can be measured. Beryllium-10 accumulates in quartz, which has veined much of New York City's bedrock, including the Manhattan schist that underlies Central Park. Precision in identifying glacially exposed quartz "is crucial in taking the samples," Dr. Schaefer said, not only to get the right data, but also because, at $500 to $2,000 per test, the geological team cannot afford to choose too many wrong outcrops.
    Therefore, an unconventional but decidedly low-tech research tool was a 1782 British Headquarters map from the occupation of New York in the Revolutionary War. The team referenced its depiction of Manhattan's streams, lakes and landforms while roaming Central Park to identify undisturbed glacial outcrops. Dr. Schaefer and his team chiseled out small pieces of quartz, numbered them with red marker, digitally photographed them and fixed their latitude and longitude with a global positioning unit. In the lab, the rock was pulverized and, in a complex process, beryllium-10 was isolated from contaminants, then measured with a mass spectrometer to determine how long ago it had been exposed to cosmic rays.
    "We can date the retreat of the glacier to within 500 years with prime samples," said Dr. Schaefer, who is a geochemist. He hopes to reconcile his glacial-dating techniques with the ages of Hudson River marine sediments and marsh sediments. And his team hopes that study of the British Headquarters map may yield clues about subglacial water channels and patterns of ice-sheet melting, which tended to dump erratics in north-south alignments. So far, the worldwide evidence indicates that "wherever we look, the glacier seems to have decided to retreat at the same time.
    Evidently, though it has been long believed that ice sheets took a long time to melt, glacial systems, according to Dr. Schaefer, their melt "may be much more quickly moving than we thought before, and they may react on pretty small climate changes in a very dramatic way. The indications are that the rate of collapse is faster than previously believed." Some scientists have theorized that the rapid melting of prehistoric glaciers could have triggered powerful climatic change. Eventually, as the last ice sheet melted, the planet entered the relatively warm, unusually stable interglacial era it currently enjoys.
    The obvious point in all this is to show that ideas of the landforms to the east of the Great Lakes region, between the lakes and the Atlantic coast, were never huge bays, open to the lakes after the last Ice Age around 10,000 B.C. Any discussion or historical factors submitted in defense of such a landform concept is against all scientific data that has been found and measured. Therefore, the argument that there was access from the sea to the Great Lakes other than the St. Lawrence River in any time frame involving either the Jaredites or Nephites is completely without merit and has no place in a serious discussion of how Lehi could have reached Lake Erie by ship in 600 B.C.
    In light of all this, and our recent series on the inland water systems of the eastern and southern United States areas, it seems well beyond time to discard the idea of a Heartland Model or Great Lakes Model as the location for the Land of Promisesince Nephis ship or any other vessel larger than a canoe, as has been thoroughly shown by experts, could not have reached either location from the Gulf of Mexico or the Atlantic coast.
    While all these articles may seem like extensive overkill on the subject, it should be noted despite all the various ways modern science and continued new discoveries of the impossibility of Lehi or anyone else in history sailing up the St. Lawrence River past Montreal, or up the Mississippi River past Baton Rouge, has been shown time and again to have been impossible for most any vessel, especially one with the deep draft necessary to cross oceans, dogged insistence by some theorists of such happening in order to prove their theories is completely ill-founded. It is time for such theorists to face this reality and stop burying their heads in the sands and believing something could have occurred that has been proven to have not been possible.

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