Lake Erie, the great body of fresh water forming Ohio's
north coast, is the fourth largest of the five Great Lakes;
nevertheless, Lake Erie should not be considered an also-ran, as it
is the 12th largest freshwater lake in the world. Lake Erie
provides a nearly unlimited water supply to communities along its
shore, is an unmatched recreational and sport-fishing mecca, and
provides significant quantities of sand and gravel for
construction."
"Geologists, however, view Lake Erie in its present form as a
very recent feature---less than 4,000 years old---"
"Erie owes its fundamental existence to the presence of a basin
or lowland that originated long before the Pleistocene Ice Age
began about 2 million years ago. This lowland was the valley of an
east-flowing river, known as the Erigan River, that some geologists
speculate was the downstream portion of the preglacial Teays
River."
"The first of the major glacial advances obliterated this
drainage system and deepened and enlarged the basin. Succeeding
glaciations further deepened and enlarged it. Lake Erie, the
southernmost of the Great Lakes, is also the shallowest because the
ice was relatively thin (therefore lacking significant erosive
power) when it reached so far south."
"The Lake Erie basin is underlain by Silurian and Devonian
carbonates (limestone and dolomite) on the west and by Devonian
shales on the east. The carbonate rocks are generally more
resistant to erosion than are the shales; therefore, the western
basin is comparatively shallow, averaging less than 25 feet in
depth. Glacial ice was able to scoop out to a greater extent the
less resistant shales underlying the central and eastern basins.
The deepest point in Lake Erie is 210 feet in the eastern basin.
(http://www.dnr.state.oh.us/geosurvey/lakeerie/lefact1.htm)
To log this Earth Cache, have a
photo taken of yourself overlooking the end of Lake
Erie and also measure the length from the bottom of
the breakwall to the edge of the water to show what the depth was
for that day. During the winter time you may include a picture of
yourself with the ice boom taking place.
Be sure to find
ERIE’S END (GC5FFF) while in the area.