Age and origin of magmatism at the Marie Byrd Seamounts (Amundsen Sea)

The Marie Byrd Seamounts (MBS) form a large intraplate volcanic province aligned sub-parallel to the northern shelf of Marie Byrd Land (West Antarctica). This seamount cluster extends over ~ 800 km in E-W direction and consists of 8 large volcanoes und several minor volcanic structures. The seamounts are located in 3.5-4 km water depth and have an areal coverage of up to 75x50 km at their base and reach a height of 3 km above the surrounding seafloor. Knowledge about age and origin of this seamount province has been very limited and its existence is difficult to explain by classical hotspot models. R/V Polarstern cruise ANT-XXIII/4 not only collected new bathymetric and geophysical data, it also retrieved the first igneous rock samples of the MBS. The data and the samples are used to acquire formation ages and to decipher petrogenesis and magma sources in order to obtain a spatiotemporal evolution of the MBS. In connection with geophysical data and plate reconstruction models, these investigations contribute to the reconstruction of the tectonic evolution of the SW-Pacific and to the ongoing discussion about the origin of intraplate volcanism.







Fig.1: Marie Byrd Seamount Province, marked Seamounts have been studied on RV Polarstern cruise ANTXXIII/4, Map based on etopo data set (Smith WHF, Sandwell DT 1997, Science 277).

First results of bathymetry show large seamounts with a guyot-like morphology, indicating that they once formed island volcanoes that were eroded at sea level and subsequently subsided. 40Ar/39Ar-dating places the formation of the seamount province into the Cenozoic time span. Therefore it is unlikely that the MBS were directly connected with the formation of the Pacific-Antarctic ridge and the break up of Gondwana. Geochemically, the MBS samples are relatively evolved; they range from alkalibasalt to trachybasalt. The source characteristics display a two component mixing array, one of a depleted and one of an enriched source.

Scientists

Andrea Kipf
Reinhard Werner
Folkmar Hauff
Karsten Gohl
Paul. van den Bogaard
Andreas Klügel
Kaj Hoernle

Research areas

Marie Byrd Seamounts

Publications

Kipf A, Werner R, Gohl K, Hauff F, van den Bogaard P, Hoernle K, 2008. Age and origin of magmatism at the Marie Byrd Seamounts (Amundsen Sea). Vortrag: EGU General Assembly, Vienna, Austria, 13.04.-18.04.2008

Kipf A, Werner R, Gohl K, Hauff F, Viereck-Götte L, van den Bogaard P, Veit A, Hoernle K, 2008. Erste Ergebnisse von Untersuchungen zu Ursachen und Auswirkungen des Magmatismus im Bereich der Marie Byrd Seamounts (Amundsenmeer) .Vortrag: 23. Internationale Polartagung der Deutschen Gesellschaft für Polarforschung, Münster, 10.03.-14.03.2008.

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Research funding organisation

German Research Foundation

Project number: HO 1833/15
Funding period: 2007 - 2010