Glacial Lakes Albany, Champlain, Hitchcock, Winsooski, & Merrimack

Lake Hitchcock was a

glacial lake A glacial lake is a body of water with origins from glacier activity. They are formed when a glacier erodes the land and then melts, filling the depression created by the glacier. Formation Near the end of the last glacial period, roughly 10,0 ...

that formed approximately 15,000 years ago in the late

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

epoch. After the

Laurentide Ice Sheet The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glacial epochs, from 2.58 million years a ...

retreated, glacial ice melt accumulated at the terminal

moraine A moraine is any accumulation of unconsolidated debris (regolith and rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice shee ...

and blocked up the

Connecticut River The Connecticut River is the longest river in the New England region of the United States, flowing roughly southward for through four states. It rises 300 yards (270 m) south of the U.S. border with Quebec, Canada, and discharges at Long Island ...

, creating the long, narrow lake. The lake existed for approximately 3,000 years, after which a combination of

erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...

and continuing geological changes likely caused it to drain. At its longest, Lake Hitchcock stretched from the moraine dam at present-day

Rocky Hill, Connecticut Rocky Hill is a town in Hartford County, Connecticut, United States. The population was 20,845 at the 2020 census. It was originally land of the Wangunks (a tribe of Native Americans). Europeans began to settle the area of Rocky Hill in 1650, as ...

, to St. Johnsbury, Vermont (about ). Although the

rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear dep ...

through which the river flows above Rocky Hill actually continues south to

New Haven New Haven is a city in the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound in New Haven County, Connecticut and is part of the New York City metropolitan area. With a population of 134,02 ...

, on

Long Island Sound Long Island Sound is a marine sound and tidal estuary of the Atlantic Ocean. It lies predominantly between the U.S. state of Connecticut to the north and Long Island in New York to the south. From west to east, the sound stretches from the Eas ...

, the obstructing moraine at Rocky Hill diverted the river southeast to its present mouth at

Old Saybrook Old Saybrook is a town in Middlesex County, Connecticut, United States. The population was 10,481 at the 2020 census. It contains the incorporated borough of Fenwick, as well as the census-designated places of Old Saybrook Center and Saybro ...

. Lake Hitchcock is an important part of the

geology of Connecticut As part of New England, Connecticut has undergone much geologic change shaped by plate tectonics, volcanism, and glacial activity. Appalachian Mountains During the early Triassic period, the super-continent Pangea was formed as the Iapetus Ocean c ...

. It experienced annual layering of

sediments Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand a ...

, or

varve A varve is an annual layer of sediment or sedimentary rock. The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (va ...

s: silt and sand in the summertime (due to glacial meltwater) and clay in the wintertime (as the lake froze). Analysis of varves along Canoe Brook in Vermont was conducted by John Ridge and Frederick Larsen, including radiocarbon dating of organic materials. Their research indicates that the lake formed sometime prior to around 15,600 years ago. Later, abrupt changes in sediment composition around 12,400 years ago appear to mark the initial breaching of the lake's dam. These varved lake deposits were later used by European settlers for

brick-making A brickworks, also known as a brick factory, is a factory for the manufacturing of bricks, from clay or shale. Usually a brickworks is located on a clay bedrock (the most common material from which bricks are made), often with a quarry for ...

. The lake was named after

Edward Hitchcock Edward Hitchcock (May 24, 1793 – February 27, 1864) was an American geologist and the third President of Amherst College (1845–1854). Life Born to poor parents, he attended newly founded Deerfield Academy, where he was later principal, ...

(1793–1864), a geology professor from

Amherst College Amherst College ( ) is a private liberal arts college in Amherst, Massachusetts. Founded in 1821 as an attempt to relocate Williams College by its then-president Zephaniah Swift Moore, Amherst is the third oldest institution of higher educatio ...

who had studied it.

References

{{DEFAULTSORT:Hitchcock Connecticut River Former lakes of the United States Glacial lakes of the United States Proglacial lakes

See also

References