I’ve always been interested in geology. Not seriously, though. As a kid I liked to pick up all kinds of rocks, much to my mother’s dismay. When I was in my first few years at grade school in Brooklyn, Ohio, we lived right across from the steep cliffs of Big Creek. In fact, we used to play in the creek all the time and picked up quite a few small fossils in the shale there. Unfortunately for us, in 1964 when the State of Ohio decided that they were going to put I-71 right through our living room, our family had to quickly relocate. But it seems that our misfortune meant a boon for paleontologists, who also found lots of fossils in the area as the area was reconstructed for the freeway. From I-71 near Ridge Road, one can still see the remainder of the street, and the shale filled cliff of the area where Big Creek travels.
When the Cleveland Plain Dealer recently did an article about paleontologists hunting for fossils again in the Cleveland area by Big Creek, it made me want to “dig” a little more into the overall geology of the area.
The Encyclopedia of Cleveland History has a very comprehensive summary of what lies underneath the Cleveland area. An excerpt:
The major event shaping the modern local drainage systems began when ice melted northward from the Akron region, leaving a boundary ridge of drift called the Wabash End Moraine ca. 16,000 years ago, which stood for 10,000 years as a drainage divide between the southward-flowing upper Cuyahoga River and Lake Erie. An ancient Lake Cuyahoga was ponded between the Wabash Moraine and retreating Hiram-age ice. During a subsequent readvance of the Hiram ice ca. 14,800 years ago, the Defiance Moraine was deposited just north of Peninsula. When this ice began retreating ca. 14,300 years ago, short-lived Lake Independence was formed. The major fill of the Cuyahoga Valley between Cleveland and Akron consists of deposits from these two lakes. Even after the northward retreat of the ice, minor climatic fluctuations resulted in changing water levels of the Great Lakes, resulting alternately in erosion or deposition in the river valleys.
From ca. 14,000-12,500 years ago, the Lake Erie basin was occupied by a gradually falling series of large lakes, all higher than modern Lake Erie. Erosion and deposition along their southern shores formed wave-cut terraces and beach ridges which generally parallel the modern lakeshore. Lakes Maumee I-III (14,500-14,100 years ago), were from 780' to 764' above sea level; Lakes Whittlesey I and II (ca. 13,800), between 740' and 730' above sea level; Lakes Arkona I-III (13,600-13,300 years ago), 711' to 690' above sea level; and Lakes Warren I-III (13,000-12,900 years ago), 686' to 670' above sea level. Between 12,900-12,600 years ago, the opening of the Niagara Falls outlet resulted in a rapidly lowering series of lakes (Wayne, Grasmere, and Lundy). By 12,200 years ago, the inflow of water from the upper Great Lakes had been diverted northeast, and the level of early Lake Erie fell 40 meters below its modern level of 571' above sea level. There was a slow rise to 565' between ca. 4,500-2,500 B.C., when erosion to the lowered lake levels downcut the old southern divide, enabling the upper Cuyahoga to join the flow northward into Lake Erie, the last major geological event to affect this area. Beyond shaping the topography, these geological events were responsible for the materials of economic significance to Cleveland's future development.
(The entire article is quite lengthy and detailed; it can be found here if you wish to read it in its entirety.)
The video below from the Cleveland Plain Dealer speaks to how the geology of the area has made it ideal for the formation of fossils. The article that accompanied the video, which speaks a bit of the geology in the area is also interesting; it can be found here.
Some other web sites that my be of interest:
The Natural History Museum Cleveland Geological Society
Friends of Big Creek
The Ohio Geological Survey GeoFacts
Ohio Department of Natural Resources Division of Geological Survey
Ohio Seismic Network
Plain Dealer Video Hunt for Cleveland Area Fossils
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