Espenberg volcanic field

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Coordinates: 66°21′N 164°20′W / 66.35°N 164.33°W / 66.35; -164.33
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Espenberg volcanic field
Whitefish Maar
Highest point
PeakDevil Mountain[1]
Elevation797 ft (243 m)[1]
Coordinates66°21′N 164°20′W / 66.35°N 164.33°W / 66.35; -164.33[1]
Geography
Espenberg volcanic field is located in Alaska
Espenberg volcanic field
Espenberg volcanic field
Geology
Last eruptionPleistocene[1]

Espenberg is a

BP, when a large eruption formed the 8 by 6 kilometres (5.0 mi × 3.7 mi) wide Devil Mountain Maar and deposited tephra over 2,500 square kilometres (970 sq mi), burying vegetation and forming the largest maar on Earth. Other maars in the field are the North and South Killeak Maars and Whitefish Maar, and Devil Mountain is a shield volcano
.

The large size of these maars has been attributed to the interaction between permafrost and ascending magma, which favoured intense explosive eruptions. Soils buried underneath the Devil Mountain Maar tephra have been used to reconstruct the regional climate during the last glacial maximum. The maars are part of the Bering Land Bridge National Preserve.

Toponyms

"Killeak" means "East" in the

Inupiaq language.[2] Devil Mountain Maar is also known as "Qitiqliik" or "Kitakhleek" ("Double Lakes") and Whitefish Maar as "Narvaaruaq" or "Navaruk" ("Big Lake").[3][2] This volcanic field is also known as the Cape Espenberg-Devil Mountain volcanic field.[4]

Geography and geomorphology

The Espenberg volcanoes lie on the northern

bush aircraft.[6]

Espenberg is located on a peninsula between the

back-arc region.[11] Volcanic rocks from the field have basaltic compositions.[12]

Devil Mountain Maar

Devil Mountain Maar is 8 by 6 kilometres (5.0 mi × 3.7 mi) wide and 200 metres (660 ft) deep, while North Killeak Maar, South Killeak Maar and Whitefish Maar are 4 kilometres (2.5 mi), 5 kilometres (3.1 mi) and 4.3 kilometres (2.7 mi) wide

sand spit into the northern 5.1 kilometres (3.2 mi) wide North Devil Mountain Maar and the 3.4 kilometres (2.1 mi) wide South Devil Mountain Maar;[5] formerly they were considered to be two separate maars.[16]

The water surface of the maars lies between 60–80 metres (200–260 ft) below their rim.

gullies around the other maars.[8]

The maars are emplaced in over 300 metres (980 ft) thick lavas and sediments of Pleistocene age.

thermokarst lakes, dry lakes and yedoma hills dot the landscape.[20]

Climate, biota and human use

At

Caribou used to be frequent in the area, and there are numerous fish in the maars.[7]

sediment cores were obtained from North Killeak Maar[25] and Whitefish Maar;[2] the former has been used to reconstruct the past climate of the region during the Holocene, including the occurrence of cold periods.[25] The Espenberg volcanoes are part of the Bering Land Bridge National Preserve.[26]

Eruption history

The non-maar vents at Espenberg appear to be over 500,000 years old, given that they are covered with vegetation and the lavas shattered by frost,[27] and are probably older than the maars.[28] The Espenberg maars were originally considered to be of Holocene age, but research has shown that the latest eruptions occurred during the Pleistocene.[1] Various dating methods have been used to determine the ages of the Espenberg maars:[5]

North and South Killeak Maar
  • Whitefish Maar might be 100,000 – 200,000 years old,[5] perhaps 160,000 years ago.[29] Sedimentation since the eruption has partly filled in Whitefish Maar[8] and reduced its depth.[13]
  • North Killeak Maar is over 125,000 years old,[7] older than South Killeak Maar.[5]
  • South Killeak Maar formed over 40,000 years ago.[5]
  • Devil Mountain Maar is the youngest vent, it formed 17,500 years
    BP[5] and is the most recent volcanic event of the area.[30] Formerly it was believed that its northern half was 7,100 years old.[7]

All maars formed in one complex eruption sequence

base surges and Strombolian deposits,[32] while frozen blocks of sediment were ejected from the vents.[15] Devil Mountain Maar appears to have formed from the coalescence of several vents during the course of the eruption.[33] Individual explosive events formed the depressions on the floor of the maars.[13]

Devil Mountain Maar deposited a

last glacial maximum in the region;[36] vegetation at that time was apparently different from today[37] and there was no widespread ice cover.[38] The tephra is used as a tephrostratigraphic marker for the late Pleistocene.[34] The eruption of the Killeak Maars also produced tephra deposits, which are also found in lakes and have similar compositions to the tephra of the Devil Mountain Maar.[39] Their deposition disrupted local wetlands and altered the topography.[40]

Mechanism of formation

Maars are after cinder cones the second-most common type of volcano. They form when magma interacts explosively with surrounding rocks, excavating broad but shallow craters on the surface. The Espenberg maars are the first known maars to have formed within permafrost;[5] other large maars in permafrost have been found in the Pali-Aike volcanic field of Argentina.[41] Interactions between magma and ice are different than these between lava and ice, as ice conducts heat only slowly and a large amount of energy is consumed during its sublimation; thus its melting and explosive evaporation occurs only slowly.[42]

The maars lie in c. 100 metres (330 ft) thick permafrost,

glacial climate, while interglacial (including Holocene) eruptions on the Seward Peninsula have yielded lava flows; this implies that the glacial climate influenced the types of eruption that took place.[29]

The Espenberg maars have been used as analogues for certain craters on the planet Mars.[44]

References

  1. ^ a b c d e "Espenberg". Global Volcanism Program. Smithsonian Institution.
  2. ^ a b c Schaaf 1988, p. 268.
  3. ^ a b Schaaf 1988, pp. 40–41.
  4. ^ a b c Kuzmina et al. 2008, p. 245.
  5. ^ a b c d e f g h i j Begét, Hopkins & Charron 1996, p. 62.
  6. ^
    OCLC 27910629
    .
  7. ^ a b c d Schaaf 1988, p. 39.
  8. ^ a b c d e f Begét, Hopkins & Charron 1996, p. 63.
  9. ^ a b "Espenberg". Global Volcanism Program. Smithsonian Institution., Synonyms & Subfeatures
  10. ^ Schaaf 1988, p. 275.
  11. ^ Graettinger 2018, p. 10.
  12. ^ Schaaf 1988, p. 14.
  13. ^ a b c d e Begét, Hopkins & Charron 1996, p. 64.
  14. S2CID 202877143
    .
  15. ^ a b Begét, Hopkins & Charron 1996, p. 67.
  16. ^ Schaaf 1988, p. 278.
  17. ^ Schaaf 1988, p. 277.
  18. ^ Begét, Hopkins & Charron 1996, pp. 62–63.
  19. ^ Schaaf 1988, p. 135.
  20. ^ a b c Goetcheus & Birks 2001, p. 136.
  21. ^ a b Goetcheus & Birks 2001, p. 137.
  22. ^ a b Lenz et al. 2016b, p. 585.
  23. ^ Schaaf 1988, p. 10.
  24. ^ Kuzmina et al. 2008, p. 246.
  25. ^
    ISSN 0004-0851
    .
  26. ^ Schaaf 1988, p. 263.
  27. ^ Schaaf 1988, pp. 275–276.
  28. ^ Lenz et al. 2016, p. 58.
  29. ^ a b Beget, J.; Layer, P.; Keskinen, M. (2003). Interactions between volcanism, permafrost, Milankovitch cycles and climate change on the Seward Peninsula. Geol. Soc. Am. Abstr. Programs. Vol. 35. p. 546.
  30. ^ Lenz et al. 2016b, p. 597.
  31. ^ Kuzmina et al. 2008, p. 247.
  32. ^ a b Begét, Hopkins & Charron 1996, p. 66.
  33. doi:10.1029/98JE02494
    .
  34. ^
    ISSN 0277-3791
    .
  35. ISSN 0016-7061
    .
  36. ^ Goetcheus & Birks 2001, p. 142.
  37. ^ Goetcheus & Birks 2001, p. 144.
  38. ISSN 0033-5894
    .
  39. ^ Lenz et al. 2016b, p. 594.
  40. ^ Lenz et al. 2016, p. 68.
  41. ^ Graettinger 2018, p. 9.
  42. ^ a b Begét, Hopkins & Charron 1996, p. 65.
  43. ^ Begét, Hopkins & Charron 1996, p. 68.
  44. ISBN 978-0-12-813018-6
    , retrieved 24 January 2020

Sources

External links
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