Sunday, January 14, 2018

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

Continued from the previous post regarding possible bays and inlets to the Great Lakes from the Atlantic Ocean in antiquity. 
    In 2003, according to Wayne Reeves and Christina Palassio, this deep Laurentian flowing river was discovered beneath the area of the Great Lakes, where water still flows down this old glacier-formed depressionbut underground (Toronto's Water from Lake Iroquois to Lost Rivers to Low-flow Toilets,Coach House Books, Toronto, 2007, pp284285). 
    The source of this aquifer is the Georgian Bay, approximately 120 miles away.
    Since first proposed by Spencer in 1881, the Laurentian River system has been noted and delineated by different Ontario geoscientists, with the main drainage pathway for a significant portion of the Great Lakes Basin flowing from the Wasaga Beach area at Georgian Bay southwards through Simcoe County and York Region to Toronto where it has been traced into the Lake Ontario basin.
The Laurentian River, which flowed through the Toronto area, drained this great depression. It began from Lake Superior and flowed through the Lake Huron Basin, the Georgian Bay Basin and, through a valley in bedrock, now hidden by the Oak Ridges Moraine, to the Lake Ontario Basin and thence by the St. Lawrence Valley to the Ocean 

    At this point, the bedrock under Toronto has several dips believed to have been carved by the Laurentian River, which remains measure more than 15 ½ miles wide, 62 miles long and greater than 328-feet deep, with the sediments ranging from sands and gravels near the bottom and clay silts near the top ("Quaternary Geology: Toronto and Surrounding Area,Ontario Geological Survey, 1980).
    As for the condition of the Great Lakes and surrounding land forms, Dr. Joseph William Spencer, geologist and geomorphologist and best known for his work on the geology of southern Ontario and the Great Lakes, published a book titled The Falls of Niagara: their evolution and varying relations to the Great Lakes. He was one of the geologists who made a special study of the creation of the Great Lakes, stating that the last touch in the completion of the North American continent has been the making of these lakes. Thus, it can be said that after the last glacial period around 10,000 B.C., according to geologists, the landscape and topography of the Great Lakes and subsequent terrain to the east to the sea was 1) fixed and complete, and 2) the distance was even greater than it is today.
    In describing the ancient conditions, J. W. Spencer of the Royal Society of London, also added, "the lake district formed a great plateau at a considerable altitude above the sea, with some bordering mountains or high lands." (J.W. Spencer, Niagara as a Timepiece, Appletons Popular Science Monthly, ed. William Jay Youmans, Vol49, Appleton and Company, New York, 1896, p157). This district was high enough to permit the excavation of deep valleys, many of which have long since been filled up with sand and drift and now lie beneath the lake waters. The sea was then farther distant from the present lake region than now.In fact, todays landfall measurement shows that Lake Ontario is 243-feet above sea level, and that Lake Erie is 571-feet in elevation.
    In geologic time, according to Wayne Grady in The Great Lakes, it has been estimated that the foundational geology that created the conditions shaping the present day upper Great Lakes was laid from 1.1 to 1.2 billion years ago, when two previously fused tectonic plates split apart and created the Midcontinental Rift, which crossed the Great Lakes Tectonic Zone. A valley was formed providing a basin that eventually became modern day Lake Superior. When a second fault line, the Saint Lawrence rift, formed approximately 570 million years ago, the basis for Lakes Ontario and Erie were created, along with what would become the Saint Lawrence River” (Greystone Books, Vancouver, 2007, pp42-43).
When Lake Iroquois and Lake Algonquin existed, the northern area (white) was the retreating ice shield. These lakes formed in the great depressions caused by the Ice Age glaciers and were left when they retreated northward 

The Great Lakes are estimated to have been formed by deglaciation at the end of the last glacial period (the Wisconsin glaciation ended 10,000 to 12,000 years ago), when the Laurentide Ice Sheet receded (Grahame Larson and R. Schaetzl, Origin and Evolution of the Great Lakes,Journal of Great Lakes Research Vol.27, Num.4, 2001, pp518-546). The retreat of the ice sheet left behind a large amount of meltwater (Lake Algonquin and Lake Chicago) that filled up the basins that the glaciers had carved, thus creating the Great Lakes as we know them today. Because of the uneven nature of glacier erosion, some higher hills became Great Lakes islands. The Niagara Escarpment follows the contour of the Great Lakes between New York and Wisconsin, including Glacial Lake Iroquois and the Champlain Sea.
    It should also be noted that the land below the glaciers "rebounded" as it was uncovered. Because the glaciers covered some areas longer than others, this glacial rebound occurred at different rates. Historically, the Great Lakes, in addition to their lake ecology, were surrounded by various forest ecoregions (except in a relatively small area of southeast Lake Michigan where savanna or prairie occasionally intruded). Logging, urbanization, and agriculture uses have changed that relationship. In the early 21st century, Lake Superior's shores were 91% forested, Lake Huron 68%, Lake Ontario 49%, Lake Michigan 41%, and Lake Erie, where logging and urbanization was most extensive, 21%. Some of these forests are second or third growth (i.e. they have been logged before, changing their composition) 
Off the east coast of the U.S. showing that the crustal arrangement of the land east of the Great Lakes was part of a solid shield and shelf and could not possibly have been opened to become a bay without extensive plate tectonic movement, which would, therefore, still exist 

East of the Great Lakes region, between the lakes and the Atlantic coast, the area was once covered by a vast crystalline shield of frozen water of this Laurentide ice sheet. It carved the terrain of the metropolitan area, and as it melted, dumped so much transported rock, gravel, sand and sediment that it created parts of Long Island, Connecticut and New Jersey, including the barrier islands at the coast. It also deposited such notable landforms as Battle Hill, in the Green-Wood Cemetery in Brooklyn. Northward, it formed part of the plateau and dissected southern rim of the Canadian Shield in the province of Québec, and is a western extension of the Laurentian Mountains, continuing across the Ottawa Valley into Ontario as the Opeongo Hills. Viewed from the valleys of the Ottawa and St. Lawrence Rivers, the south-facing escarpments of the Shield give the appearance of mountains 1600 to 2600 feet highthis Laurentian Region in Quebec extends over 120 miles northward from the scarps and to stretch from the Gatineau River in the west over 340 miles to the Saguenay River in the northeast, rising from a mean elevation of 1300 feet to over 3200 feet north of Quebec City in the Reserve Faunique des Laurentides.
    As for the falls themselves, according to J.W. Spencer in Appletons Popular Science Monthly (p16), the age of the falls is computed at thirty-one thousand years, with its present or last stage has been three thousand years. And according to this Science Monthly, these figures are based upon the severest analytical methods at present attainable. Thus it can be seen that the Falls, contrary to the uninformed opinions of some theorists, existed long before the time of their claim of the Nephites arrival.
    In fact, any way you look at it, the Niagara Falls, in their present condition and location date to 1000 B.C., four hundred years prior to the time Lehi is supposed to have sailed up that river from Lake Ontario and into Lake Erie, a direct vertical rise in the water flow of between 170 and 180 feet, and were actual falls somewhat like the present for thousands of years before that--there is no possible way Lehi could have reached Lake Erie in this theorist-claimed manner .
(See the net post, Were the Great Lakes Ever Open to the Atlantic? Part II, regarding whether or not the Great Lakes region was open to the Atlantic Ocean in ages past)

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