Stark's Knob

Stark's Knob is a basaltic pillow lava formation near Schuylerville, New York, United States. It formed about 460 to 440 million years ago in relatively shallow sea water. It is often mistakenly referred to as a volcano, probably because early investigators described it as a volcano or volcanic plug.[1]

It was here during the Saratoga Campaign of the American Revolution that General John Stark of New Hampshire cut off the retreat of British General John Burgoyne's army, hence its name.

Geology

A 1912 picture of Stark's Knob. Note how the right side (northern half) is stripped bare of vegetation.

The geological history and plate tectonic significance of Stark's Knob has been reinterpreted as a result of field and laboratory research in the early 2000s. The Knob has often been considered to represent a fragment of the volcanic island arc that collided with the eastern margin of Laurentian ("ancestral North America") in the Taconian orogeny (or mountain building episode)in the Late Ordovician (ca. 465 million years ago). The age of the Stark's Knob volcanism is provided by discovery of a Late Ordovician snail fossil in a thin limestone layer deposited on the pillows. The traditional interpretation is that Stark's Knob was supposedly derived from the central Connecticut region and was pushed into eastern New York at the height of the Taconian orogeny. However, the geological setting of Stark's Knob shows that it was overrun and lies in a chaotic belt of rocks that now underlie the rocks of the Taconian overthrust belt. If pushed into eastern New York, Stark's Knob should be part of the overthrust succession, but lies under the Taconian master thrust. More importantly, geochemical analysis shows that the basaltic rocks of Stark's Knob have a so-called MORB (Mid Ocean Ridge Basalt) composition and are comparable to basalt formed in a rift environment. These data indicate that the basaltic rock of Stark's Knob is parautochthonous (essentially in place and not transported). The volcanic pillows were formed as the edge of the Laurentian plate fractured as it was pulled down the subduction zone. This tectonic process took place as the edge of Laurentia consisted of cold, dense rock and essentially sunk into the subduction zone. THus, Stark's Knob served to change the understanding of plate tectonic processes as it provided the first evidence of volcanisn on the sudducting plate. Similar and coeval volcanism took place in the Jonestown, Pennsylvania area during the Taconian orogeny. More importantly, this basaltic volcanism on the subducting plate is now recognized in very ancient rocks in the Northwest Territories of Canada, as well as on the modern sea floor east of central Japan.[1][2]

History

Revolutionary War

During the American Revolution's Saratoga Campaign, the knob provided a crucial asset for American forces led by General John Stark. Forces were stationed between the knob and the nearby Hudson River to block possible escape of British forces led by General John Burgoyne. British forces were in nearby Schuylerville at the time, just south of the knob. Accounts differ to what happened next, but either Stark's forces placed cannons on the knob or, more likely, placed them at the base of it, blocking the only avenue of escape for the surrounded British.[2][3] The knob is named for General Stark.[4]

Modern History

In 1916, the property was deeded to the state. This was partly to prevent the mining of the formation for use in road building. After many years of virtual neglect and a number of proposals to sell the property, the state finally decided to take action to prevent the site's further decay as well as curb vandalism and maintain trails.[2][5] In 2005, the site was incorporated into the mater plan of Hudson Crossing Park, a bi-county park centered on Champlain Canal Lock 5 Island.[2]

References

  1. 1 2 "Stark's Knob: Geological Origins". Office of Cultural Education, New York State Education Department. Retrieved 6 November 2010.
  2. 1 2 3 4 "Master Plan". Hudson Crossing Park. Retrieved 4 October 2014.
  3. ↑ "Stark's Knob: Historical Background". Office of Cultural Education, New York State Education Department. Retrieved 6 November 2010.
  4. ↑ Parks and Recreation, Village of Schuylerville website, accessed November 6, 2010
  5. ↑ "Stark's Knob: 1914-1999". Office of Cultural Education, New York State Education Department. Retrieved 6 November 2010.

Landing, E., G. Pe-Piper, W.S.F. Kidd, K. Azmy. 2003. Tectonic setting of outer trench slope volcanism: pillow basalt and limestone in the Ordovician Taconian orogen of eastern New York. Canadian Journal of Earth Sciences, 40:1173–1187, Figs. 1–8, Tables 1–3.

External links

Coordinates: 43°7′5.76″N 73°35′15.77″W / 43.1182667°N 73.5877139°W / 43.1182667; -73.5877139

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