Many of the geological features on the surface of this planet has been shaped by ancient glaciers. These gigantic sheets of ice of immense weight moving across the earth have carved gorges, grinded rocks into fine gravel, raised sea level and left boulders at unexpected places when they melted away. But it’s another thing to hear a geologist say “the sand in this desert was created by glaciers” or “this gorge was carved by glaciers” and quite another to actually see scratches and grooves on the bedrock left behind by glaciers as it dragged over the surface. These abrasions are called Glacial Grooves and the most outstanding example of this feature can be found at Kelleys Island, in Ohio, in the United States.
Glacial grooves, also called glacial striations, were first recognized as the result of a moving glacier in the late 1700s by Swiss alpinists. They were also one of the first to realise that if they were visible today, then the glaciers must also be receding.
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