Samoa Hotspot - A volcanic hotspot located in the South Pacific . The hotspot model describes the rise of hot magma plumes through the earth's crust to explain the formation of volcanic islands . The idea of hot spots was proposed in 1963 by Tuzo Wilson based on studies of the Hawaiian island chain .
According to the theory, the Samoan hot spot arose as a result of the movement of the Pacific Plate on top of a magma source located deep beneath the Samoan Islands [1] .
The Samoa hotspot zone includes the Samoan Islands ( Independent State of Samoa and American Samoa ), the islands of Uvea ( Wallis and Futuna ) and Niulakita ( Tuvalu ), as well as the adjacent banks of Pasco [2] .
As the Pacific Plate moves slowly over the hot spot, thermal activity increases and magmatic plume flows through the earth's crust, forming new islands. The Samoan Islands are neatly along the line of movement of the crust above the hot spot, stretching from west to east [3] .
Classical hot spots (as in the case of Hawaii ) are characterized by a larger age of the islands farthest from the focus, while younger ones have not yet had time to move far from their place of formation (for example, Lohi , which is still at the stage of an underwater volcano ). Studies of the Loiha volcano led to the creation of a “Hawaiian” theoretical model of hot spots, based mainly on information from the Hawaiian Islands [4] .
Currently, Samoa's hot spot is a mystery to science [5] , refuting the classical model [6] . Both in the easternmost of the Samoan islands, Tau , and in the westernmost, Sawaii , volcanoes erupted in the last 150 years - the eruption of Matavanu on Sawaii (1905-1911) and the volcano on Tau (1866) [7] [8] . Moreover, the westernmost and seemingly farthest island from the plume is relatively young, which also refutes the standard model [8] . Mantle jets, as shown by studies, originate at a depth of up to 2900 km - on the border with the Earth’s core [9] .
Wailulu'u
In 1975, geoscientist Rockne Johnson discovered the submarine volcano Wailulu'u 45 km east of the island of Tau in American Samoa. Vailulu'u studied by an international team of researchers. A volcanic cone was found inside the summit crater named Nathanua [5] in honor of the goddess of war in Samoan mythology . Vailulu’s research prompted scientists to create a new hot spot formation model [4] as an alternative to the Hawaiian one.
An important difference between Vailulu and Loiha is the complete absence of tholeiitic basalts in [4] , although both are equally located in the very east of the corresponding island chains.
The northernmost of the islands of Tonga - Wawau and Niuatoputapu - move away from Fiji on the Australian plate at an average speed of 130 mm / year and 160 mm / year, respectively. At the same time, Niue and Rarotonga on the Pacific Plate approach the Australian Plate at a speed of 800 mm / year [10] . The proximity of the Samoa to the Tonga can possibly explain the relative youth of their geological rocks [8] .
See also
- Hot spot Arago
Notes
- ↑ Russell, Jamie A. Hotspot Lesson: Samoan Hotspot . Enduring Resources Earth Science Education . Date of treatment May 4, 2018.
- ↑ Samoan Hotspot Trail . Archived December 23, 2010.
- ↑ This volcano we live on . Natural History Guide to American Samoa . Date of treatment May 4, 2018.
- ↑ 1 2 3 Hart, SR; Staudigel, H .; Koppers, AA; Blusztajn, J .; Baker, ET; Workman, R .; Jackson, M .; Hauri, E .; Kurz, M .; Sims, K .; Fornari, D .; Saal, A .; Lyons, S. Vailulu'u undersea volcano: The new Samoa (neopr.) // Geochemistry, Geophysics, Geosystems. - 2000. - T. 1 , No. 12 . - DOI : 10.1029 / 2000GC000108 .
- ↑ 1 2 Lippsett, Laurence Voyage to Vailulu'u . Woods Hole Oceanographic Institution (September 3, 2009). Date of treatment May 4, 2018.
- ↑ Anthony AP Koppers Jamie A. Russell Matthew G. Jackson Jasper Konter Hubert Staudigel Stanley R. Hart. Samoa reinstated as a primary hotspot trail (Eng.) // Geology. - 2008. - No. 36 (6) . - P. 435-438 . - DOI : 10.1130 / G24630A.1 .
- ↑ Steadman, David W. Extinction & biogeography of tropical Pacific birds . - University of Chicago Press, 200. - P. 22. - ISBN 0-226-77142-3 .
- ↑ 1 2 3 Plumes of the Cook Islands (Cook), Samoa (Samoa), Tahiti (Tahiti), seamount MacDonald (Macdonald) . Earth Plumes. Date of treatment May 4, 2018.
- ↑ “Hot spots” - fifty years, not counting hundreds of millions // Knowledge is power. - 2014. - Issue. 02/2014 .
- ↑ W. Jason Morgan and Jason Phipps Morgan. Plate velocities in hotspot reference frame: electronic supplement . - P. 111.