James Ross Island Volcanic Group

The James Ross Island Volcanic Group is a stratigraphic unit of Cenozoic age distributed on James Ross Island and Vega Island of the James Ross Island group, the Tabarin and Trinity peninsulas of Graham Land and surrounding islands in the Prince Gustav and Antarctic sounds.[1]

James Ross Island Volcanic Group
Stratigraphic range: Cenozoic
TypeGroup
Lithology
PrimaryAlkali basalts
OtherHawaiites, benmoreites, mugearites
Location
RegionAntarctica
Type section
Named forJames Ross Island

The volcanic group consists predominantly of alkali basalts with minor hawaiites, benmoreites and mugearites. They are interpreted to have been deposited by volcanic eruptions in an extensional back-arc setting after subduction had ceased along the western margin of the Antarctic Peninsula. K–Ar dating of these rocks suggest that they were erupted from about 7 million years ago up until about a few hundred thousand years ago.[1] However, volcanic rocks as young as only a few thousand years old may exist on James Ross Island.[2]

Rocks of the James Ross Island Volcanic Group comprise Surtseyan tuff cones and Strombolian cinder cones, as well as lava deltas and overlying subaerial lava flows.[1] The dominating feature of the James Ross Island Volcanic Group is Mount Haddington, a massive shield volcano of Miocene-to-Pliocene age on James Ross Island.[2][3]

Subdivisions

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The James Ross Island Volcanic Group includes the following geological formations:[4]

  • Cape Lachman Formation
  • Cape Well-met Formation
  • Dobson Dome Formation
  • Donnachie Cliffs Formation
  • Ekelof Point Formation
  • Forster Cliffs Formation
  • Hamilton Formation
  • Jefford Point Formation
  • Johnson Mesa Formation
  • Jonkers Mesa Formation
  • Keltie Head Formation
  • Kipling Mesa Formation
  • Lachman Crags Formation
  • Lookalike Peaks Formation
  • Palisade Nunatak Formation
  • Patalamon Mesa Formation
  • Sandwich Bluff Formation
  • Smellie Peak Formation
  • Stickle Ridge Formation
  • Sungold Hill Formation
  • Taylor Bluff Formation
  • Terrapin Hill Formation
  • Tumbledown Formation
  • Vertigo Cliffs Formation

Features

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The James Ross Island Volcanic Group includes the following volcanic features:[4]

See also

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References

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  1. ^ a b c Smellie, John L.; Edwards, Benjamin R. Glaciovolcanism on Earth and Mars: Products, Process and Palaeoenvironmental Significance. Cambridge University Press. p. 94. ISBN 978-1-107-03739-7.
  2. ^ a b "James Ross Island". Global Volcanism Program. Smithsonian Institution. Retrieved 2020-03-23.
  3. ^ Menzies, John; van der Meer, Jaap J.M. (2018). Past Glacial Environments. Elsevier. p. 357. ISBN 978-0-08-100524-8.
  4. ^ a b Smellie, J.L.; Johnson, J.S.; Nelson, A.E. (2013). Geological map of James Ross Island. I. James Ross Island Volcanic Group (Map). 1:125 000. Cambridge, United Kingdom: British Antarctic Survey.