Erebus hotspot

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The Erebus hotspot is a volcanic hotspot responsible for the high volcanic activity on Ross Island in the western Ross Sea of Antarctica. Its current eruptive zone, Mount Erebus, has erupted continuously since its discovery in 1841. Magmas of the Erebus hotspot are similar to those erupted from hotspots at the active East African Rift in eastern Africa. Mount Bird at the northernmost end of Ross Island and Mount Terror at its eastern end are large basaltic shield volcanoes that have been potassium-argon dated 3.84.8 and 0.81.8 million years old. [1]

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There is currently disagreement over the cause of volcanic activity on Ross Island. The traditional view is that the area is underlain by a mantle plume which has given rise to volcanism and, in conjunction with a second plume thought to be under Marie Byrd Land on the mainland to the east, a system of rifts known as the West Antarctic Rift System. Support for a plume origin includes petrological, geochemical, and isotopic evidence for a deep-mantle source, [2] [3] high heat flow in the area, [4] high volcanic output, [5] domal uplift, [6] [7] and seismic anomalies in the upper mantle consistent with a plume approximately 250 to 300 km (160 to 190 mi) in diameter extending 200 km (120 mi) below the surface where it changes into a narrow column that extends at least a further 400 km (250 mi) [8] [9] and according to some studies as deep as 1,000 km (620 mi). [10] [11] The area lacks the time-progressive volcanism typically associated with mantle plumes. This has been explained by the Antarctic Plate being stationary since the late Cretaceous.

Other observations appear to be inconsistent with the plume model. Uplift in the region lacks the circular symmetry typically associated with mantle plumes. Rifting occurred mainly in the late Cretaceous, whereas uplift occurred mainly in the middle Eocene, so uplift followed extension rather than preceding it as would be expected with a mantle plume. The volume of magmatism, when the long duration of volcanic activity is taken into account, appears lower than would be expected to result from a mantle plume. Seismic imaging does not show the circular symmetry expected for a mantle plume but indicates rather a linear, tectonic feature extending from Tasmania to the Ross Sea. [12] [13] [14]

Owing to these issues, some scientists have questioned the plume model and propose instead a shallow, tectonic mechanism. In this view, lithospheric extension and rifting during the late Cretaceous stretched the lithosphere, giving rise to partial melts. Though insufficient to break the surface, fertile, low-liquidus material was distributed throughout the lithospheric mantle. During the middle Eocene, tectonic changes in the Southern Ocean gave rise to further lithospheric deformation, causing strike-slip faulting which enabled decompression melting and extrusion of the fertile material emplaced during the late Cretaceous. [12] [13] [14]

Related Research Articles

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A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries.

<span class="mw-page-title-main">Gaussberg</span> Volcanic cone in Antarctica

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<span class="mw-page-title-main">Large igneous province</span> Huge regional accumulation of igneous rocks

A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive and extrusive, arising when magma travels through the crust towards the surface. The formation of LIPs is variously attributed to mantle plumes or to processes associated with divergent plate tectonics. The formation of some of the LIPs in the past 500 million years coincide in time with mass extinctions and rapid climatic changes, which has led to numerous hypotheses about causal relationships. LIPs are fundamentally different from any other currently active volcanoes or volcanic systems.

<span class="mw-page-title-main">Iceland hotspot</span> Hotspot partly responsible for volcanic activity forming the Iceland Plateau and island

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<span class="mw-page-title-main">East African Rift</span> Active continental rift zone in East Africa

The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. It was formerly considered to be part of a larger Great Rift Valley that extended north to Asia Minor.

<span class="mw-page-title-main">West Antarctic Rift System</span> Series of rift valleys between East and West Antarctica

The West Antarctic Rift System is a series of rift valleys between East and West Antarctica. It encompasses the Ross Embayment, the Ross Sea, the area under the Ross Ice Shelf and a part of Marie Byrd Land in West Antarctica, reaching to the base of the Antarctic Peninsula. It has an estimated length of 3,000 km (1,900 mi) and a width of approximately 700 km (430 mi). Its evolution is due to lithospheric thinning of an area of Antarctica that resulted in the demarcation of East and West Antarctica. The scale and evolution of the rift system has been compared to that of the Basin and Range Province of the Western United States.

<span class="mw-page-title-main">East Australia hotspot</span>

The East Australia hotspot is a volcanic province in southeast Australia which includes the Peak Range in central Queensland, the Main Range on the Queensland-New South Wales border, Tweed Volcano in New South Wales, and the Newer Volcanics Province (NVP) in Victoria and South Australia. A number of the volcanoes in the province have erupted since Aboriginal settlement. The most recent eruptions were about 5,600 years ago, and memories of them survive in Aboriginal folklore. These eruptions formed the volcanoes Mount Schank and Mount Gambier in the NVP. There have been no eruptions on the Australian mainland since European settlement.

<span class="mw-page-title-main">Kerguelen hotspot</span> Hotspot under the Indian Ocean

The Kerguelen hotspot is a volcanic hotspot at the Kerguelen Plateau in the Southern Indian Ocean. The Kerguelen hotspot has produced basaltic lava for about 130 million years and has also produced the Kerguelen Islands, Naturaliste Plateau, Heard Island, the McDonald Islands, and Rajmahal Traps. One of the associated features, the Ninety East Ridge, is distinguished by its over 5,000 km (3,100 mi) length, being the longest linear tectonic feature on Earth. The total volume of magma erupted in 130 million years with associated features has been estimated to be about 25,000,000 km3 (6,000,000 cu mi). However, as well as large igneous provinces and seamounts the hotspot has interacted with other seafloor spreading features, so this volume figure has some uncertainty.

The Anahim hotspot is a hypothesized hotspot in the Central Interior of British Columbia, Canada. It has been proposed as the candidate source for volcanism in the Anahim Volcanic Belt, a 300 kilometres long chain of volcanoes and other magmatic features that have undergone erosion. This chain extends from the community of Bella Bella in the west to near the small city of Quesnel in the east. While most volcanoes are created by geological activity at tectonic plate boundaries, the Anahim hotspot is located hundreds of kilometres away from the nearest plate boundary.

<span class="mw-page-title-main">New England hotspot</span> Volcanic hotspot in the North Atlantic Ocean

The New England hotspot, also referred to as the Great Meteor hotspot and sometimes the Monteregian hotspot, is a volcanic hotspot in the North Atlantic Ocean. It created the Monteregian Hills intrusions in Montreal and Montérégie, the White Mountains intrusions in New Hampshire, the New England and Corner Rise seamounts off the coast of North America, and the Seewarte Seamounts east of the Mid-Atlantic Ridge on the African Plate, the latter of which include its most recent eruptive center, the Great Meteor Seamount. The New England, Great Meteor, or Monteregian hotspot track has been used to estimate the movement of the North American Plate away from the African Plate from the early Cretaceous period to the present using the fixed hotspot reference frame.

<span class="mw-page-title-main">Eifel hotspot</span>

The Eifel hotspot is a volcanic hotspot in Western Germany. It is one of many recent volcanic formations in and around the Eifel mountain range and includes the volcanic field known as Volcanic Eifel. Although the last eruption occurred around 10,000 years ago, the presence of escaping volcanic gases in the region indicates that it is still weakly active.

<span class="mw-page-title-main">North Atlantic Igneous Province</span> Large igneous province in the North Atlantic, centered on Iceland

The North Atlantic Igneous Province (NAIP) is a large igneous province in the North Atlantic, centered on Iceland. In the Paleogene, the province formed the Thulean Plateau, a large basaltic lava plain, which extended over at least 1.3 million km2 (500 thousand sq mi) in area and 6.6 million km3 (1.6 million cu mi) in volume. The plateau was broken up during the opening of the North Atlantic Ocean leaving remnants preserved in north Ireland, west Scotland, the Faroe Islands, northwest Iceland, east Greenland, western Norway and many of the islands located in the north eastern portion of the North Atlantic Ocean. The igneous province is the origin of the Giant's Causeway and Fingal's Cave. The province is also known as Brito–Arctic province and the portion of the province in the British Isles is also called the British Tertiary Volcanic Province or British Tertiary Igneous Province.

<span class="mw-page-title-main">Darfur Dome</span>

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<span class="mw-page-title-main">Geology of Cape Verde</span>

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<span class="mw-page-title-main">Opening of the North Atlantic Ocean</span> Breakup of Pangea

The opening of the North Atlantic Ocean is a geological event that has occurred over millions of years, during which the supercontinent Pangea broke up. As modern-day Europe and North America separated during the final breakup of Pangea in the early Cenozoic Era, they formed the North Atlantic Ocean. Geologists believe the breakup occurred either due to primary processes of the Iceland plume or secondary processes of lithospheric extension from plate tectonics.

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<span class="mw-page-title-main">Noronha hotspot</span>

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<span class="mw-page-title-main">Plate theory (volcanism)</span>

The plate theory is a model of volcanism that attributes all volcanic activity on Earth, even that which appears superficially to be anomalous, to the operation of plate tectonics. According to the plate theory, the principal cause of volcanism is extension of the lithosphere. Extension of the lithosphere is a function of the lithospheric stress field. The global distribution of volcanic activity at a given time reflects the contemporaneous lithospheric stress field, and changes in the spatial and temporal distribution of volcanoes reflect changes in the stress field. The main factors governing the evolution of the stress field are:

  1. Changes in the configuration of plate boundaries.
  2. Vertical motions.
  3. Thermal contraction.

Intraplate volcanism is volcanism that takes place away from the margins of tectonic plates. Most volcanic activity takes place on plate margins, and there is broad consensus among geologists that this activity is explained well by the theory of plate tectonics. However, the origins of volcanic activity within plates remains controversial.

References

  1. Morgan, W.J.; Phipps Morgan, J. (2007) "Plate velocities in hotspot reference frame: electronic supplement".
  2. Hole, M.J.; LeMasurier, W.E. (1994). "Tectonic controls on the geochemical composition of Cenozoic, mafic alkaline volcanic rocks from West Antarctica". Contributions to Mineralogy and Petrology. 117 (2): 187–202. Bibcode:1994CoMP..117..187H. doi:10.1007/BF00286842. S2CID   129078098.
  3. Sims, K.W.W.; Blichert-Toft, J.; Kyle, P.R.; Pichat, S.; Gauthier, P-J.; Blusztajn, J.; Kelly, P.; Ballf, L.; Layne, G. (2008). "A Sr, Nd, Hf, and Pb isotope perspective on the genesis and long-term evolution of alkaline magmas from Erebus volcano, Antarctica". Journal of Volcanology and Geothermal Research. 177 (3): 606–618. Bibcode:2008JVGR..177..606S. doi:10.1016/j.jvolgeores.2007.08.006.
  4. Storey, B.; Leat, P.T.; Weaver, S.D.; Pankhurst, R.J.; Bradshaw, J.D.; Kelley, S. (1999). "Mantle plumes and Antarctica-New Zealand rifting: Evidence from mid-Cretaceous mafic dykes". Journal of the Geological Society, London. 156 (4): 659–671. Bibcode:1999JGSoc.156..659S. doi:10.1144/gsjgs.156.4.0659. S2CID   129513402.
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  9. Gupta, S.; Zhao, D; Raia, S.S. (2009). "Seismic imaging of the upper mantle under the Erebus hotspot in Antarctica". Gondwana Research. 16 (1): 109–118. Bibcode:2009GondR..16..109G. doi:10.1016/j.gr.2009.01.004.
  10. Sieminski, A.; Debayle, E.; Lévêque, J-J. (2003). "Seismic evidence for deep low-velocity anomalies in the transition zone beneath West Antarctica". Earth and Planetary Science Letters. 216 (4): 645–661. Bibcode:2003E&PSL.216..645S. doi:10.1016/S0012-821X(03)00518-1.
  11. Montelli, R.; Nolet, G.; Dahlen, F.A.; Masters, G. (2006). "A catalogue of deep mantle plumes: New results from finite‐frequency tomography". Geochemistry, Geophysics, Geosystems. 7 (11): n/a. Bibcode:2006GGG.....711007M. doi: 10.1029/2006GC001248 .
  12. 1 2 Rocchi, S.; Armienti, P.; D’Orazio, M.; Tonarini, S.; Wijbrans, J.R.; Di Vincenzo, G. (2002). "Cenozoic magmatism in the western Ross Embayment: Role of mantle plume versus plate dynamics in the development of the West Antarctic Rift System". Journal of Geophysical Research. 107 (B9): ECV 5-1-ECV 5-22. Bibcode:2002JGRB..107.2195R. doi: 10.1029/2001JB000515 .
  13. 1 2 Rochi, S.; Storti, F.; Di Vincenzo, G.; Rossetti, F. (2003). "Intraplate strike-slip tectonics as an alternative to mantle plume activity for the Cenozoic rift magmatism in the Ross Sea region, Antarctica". In Storti, F; Holdsworth, R.E.; Salvini, F. (eds.). Intraplate strike-slip deformation belts: Geological Society, London, Special Publications, 210. Vol. 210. Geological Society of London. pp. 145–158. doi:10.1144/GSL.SP.2003.210.01.09. S2CID   134316807.{{cite book}}: |journal= ignored (help)
  14. 1 2 Rocchi, S.; Armienti, P.; Di Vincenzo, G. (2005). "No plume, no rift magmatism in the West Antarctic Rift". In Foulger, G.R.; Natland, J.H.; Presnall, D.C.; Anderson, D.L. (eds.). Plates, plumes and paradigms: Geological Society of America Special Paper 388. Geological Society of America. pp. 435–447. doi:10.1130/0-8137-2388-4.435. ISBN   9780813723884.