Glacial Grooves State MemorialAbout 18,000 years ago, a 1.5-kilometer thick glacier scraped along La
Glacial Grooves State MemorialAbout 18,000 years ago, a 1.5-kilometer thick glacier scraped along Lake Erie, leaving behind large glacial grooves in the limestone of Kelleys Island; located about 6.5 kilometers off of Ohio’s northern shore. The grooves were initially found, and largely destroyed, by quarry miners in the 1830s; the surviving portion is 122-meters long, 11-meters wide, and 4.5-meters deep.The grooves themselves are long striations caused by subglacial meltwater and embedded rocks in the base of the glacier cutting through the surface of the limestone due to the immense weight of the thick ice pressing down on them. The striations go in the same general direction, allowing scientists to determine which way the glacier was flowing.The grooves contain marine fossils from the Devonian Sea which dominated the area 350 million years ago. Organisms that died mixed with sediment to become part of the limestone, and some of their remains, such as shells and coral fragments, were cemented into the rock.The Ohio Historical Society carefully removed the topsoil and sediments from the grooves in 1972, making them one of the largest exposed striations in the world. The area is now protected as Glacial Grooves State Memorial.REPhoto Credit: Benny Mazurhttp://www.flickr.com/photos/benimoto/2548604147Read More: http://www.stateparks.com/glacial_grooves_state_memorial_in_ohio.htmlhttp://geosurvey.ohiodnr.gov/portals/geosurvey/PDFs/Education/el07.pdfhttp://ohioseagrant.osu.edu/_documents/publications/GS/GS-017%20Kelleys%20Island%20glacial%20grooves.pdf -- source link
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