Admiralty Lake was a

proglacial lake In geology, a proglacial lake is a lake formed either by the damming action of a moraine during the retreat of a melting glacier, a glacial ice dam, or by meltwater trapped against an ice sheet due to isostatic depression of the crust around t ...

in the basin of what is now

Lake Ontario Lake Ontario is one of the five Great Lakes of North America. It is bounded on the north, west, and southwest by the Canadian province of Ontario, and on the south and east by the U.S. state of New York (state), New York. The Canada–United Sta ...

. The shoreline of Admiralty Lake was about lower than Lake Ontario. The shoreline of

Glacial Lake Iroquois Glacial Lake Iroquois was a prehistoric proglacial lake that existed at the end of the last ice age approximately 13,000 years ago. Description The lake was essentially an enlargement of the present Lake Ontario that formed because the St. ...

, an earlier proglacial lake, was much higher than Lake Ontario's, because a lobe of the Laurentian Glacier blocked what is now the valley of the

St Lawrence River The St. Lawrence River (, ) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawren ...

. Lake Iroquois drained over the

Niagara Escarpment The Niagara Escarpment is an approximately discontinuous, arc-shaped but generally northward-facing escarpment, or cuesta, in Canada and the United States. The escarpment begins south of Lake Ontario and circumscribes the top of the Great Lake ...

, and down the

Mohawk River The Mohawk River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed October 3, 2011 river in the U.S. state of New York (state), New York. It is the largest tributary of the Hudson R ...

. When the lobe of the glacier retreated the weight of the glacier kept the outlet of the St Lawrence River lower than the current level. As the glacier continued to retreat the region of the

Thousand Islands The Thousand Islands (, ) constitute a North American archipelago of 1,864 islands that straddles the Canada–US border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. They stretch for about downstream fr ...

rebounded, and the lake filled to its current level.

References

Bibliography

*"Nearshore Geology". Aquatichabitat.ca. Archived from the original on 2012-01-27. *J Terasmae, E Mirynech (1964). "Postglacial chronology and the origin of deep lake basins in Prince Edward County, Ontario". Conference on Great Lakes Research, 1964 - International Association for Great Lakes Research. {{DEFAULTSORT:Admiralty Lake Proglacial lakes Geology of New York (state) Glacial lakes of Canada