Samoa reinstated as a primary hotspot trail
Koppers AA, Russel JA, Jackson MG, Konter J, Staudigel H, Hart SR. 2008. Samoa reinstated as a primary hotspot trail. The Geological Society of America
The classical model for the generation of hotspot tracks maintains that stationary and deep-seated mantle plumes impinge on overriding tectonic plates, thereby generating age- progressive trails of volcanic islands and seamounts. Samoa has played a key role in discredit- ing this model and the very existence of mantle plumes, because early geochronological work failed to demonstrate a linear age progression along this chain of islands. Specifi cally on Savai’i Island, the bulk of the subaerial volcanics is younger than 0.39 Ma, much younger than the 5.1 Ma age predicted from the classical hotspot model and a constant 7.1 cm/yr Pacifi c plate motion. This discrepancy led to alternative magma-producing mechanisms that involve the cracking of the lithosphere beneath the Samoan islands, as a result of the extensional regime generated by the nearby Tonga Trench. Here we report 40Ar/39Ar ages from the submarine fl anks of Savai’i Island showing that its volcanic construction began as early as 5.0 Ma and in a true intraplate setting. This reinstates Samoa as a primary hotspot trail associated with a deep mantle plume and a linear age progression.
- Type
- Published Report
- Authors
- Koppers, Anthony; Russel, Jamie; Jackson, Matthew; Konter, Jasper; Staudigel, Hubert; Hart, Stanley
- Date of Issue
- 2008
- Units
- NPSA
- Keywords
- National Park of American Samoa, NPSA, Pacific plate, plate extension, Primary hotspots, Samoa, seamounts