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How Pleistocene Geology Continues to Affect New York Geology Today
The landforms and deposits in New York State created during the Pleistocene, between 1.8 million and 10 thousand years before present, have been recognized worldwide as an exemplary legacy of the most recent glaciation (sometimes referred to as an Ice Age.) Evidence from nearby ice cores in Greenland and deep sea cores suggest that New York has likely experienced at least 20 major glaciations. Significant examples of geologic features associated with the last Ice Age include Niagara Falls, the Finger Lakes of Central New York as well as in its entirety, Long Island. Glacial deposits are wide spread in New York. While in some locations, deposits are absent and bedrock is exposed at the surface, other locations have deposits greater than 1000 feet in thickness.
Since the first settlers arrived in New York, citizens have benefited by the abundance of natural resources left behind by the glaciers. As an example, the soils in New York are all the by product of the most recent glaciation. The soils provided the opportunity for early economic development that fostered the empire state as a premier center for agriculture. Today, agriculture still remains vital to NY economy and, in 2010, production returned almost $4.7 billion to the farm economy. About 23 percent of the state’s land area, nearly 7 million acres, is used by over 36,300 farms. (Source NY Dept. of Agriculture & Markets).
Sand and gravel deposits are equally crucial for repairing our aging infrastructure and providing base components for new construction. Presently, 6,742 acres in the state are actively mined for these resources. In 2008, sand and gravel added $251 million dollars to New York’s economy. Similarly clay deposits were mined to yield $28 million dollars (source USGS Mineral Yearbook). In addition, the vast quantities of sand and gravel deposited by the glaciers form aquifers that provide pure and abundant groundwater resources for both individual homes and municipalities throughout the state. These same water resources provide a crucial resource that fuels major manufacturing operations and further serves to stimulate economic development throughout New York.
Yet these same glacial deposits that provide raw materials for our daily lives and our economy also create a dynamic and responsive geologic veneer that is subject to the whims of current geologic and meteorological events.
Landslides often develop in lake clays due to the fact that these soft clays pose little friction between the clay particles (low shear strength). The clay particles are able to “slip” past one another thus sliding down the slope. Coincidentally, earthquakes often serve as the “trigger” to induce or initiate landslides as the shaking sets the clay particles in motion and allowing them to slip.