When most people think of the Antarctic, they think of snow, ice and glaciers - but the continent and surrounding waters are littered with fiery volcanoes.

The Marie Byrd Seamounts in the Amundsen Sea are not active, like many volcanoes there are. Their summit plateaus are today at depths of 2400-1600 meters but, because they are very difficult to reach with conventional research vessels, they have hardly been explored.



Credit and link: Gondwana Research

"The latter are called intraplate volcanoes. They are often found above a so-called mantle plume. Hot material rises from the deep mantle, collects under the earth's crust, makes its way to the surface and forms a volcano," said Dr. Reinhard Werner, one of the authors of the current paper. One example are the Hawaiian Islands. But neither of the above models fits the Marie Byrd Seamounts. "There are no plate boundary in the vicinity and no plume underground," says graduate geologist Andrea Kipf from GEOMAR, first author of the study.



But that still does not explain the Marie Byrd Seamounts because they are not located on the Antarctic continent, but on the adjacent oceanic crust instead. "Continental tectonic plates are thicker than the oceanic ones. This ensures, among other things, differences in temperature in the underground," says volcanologist Werner. And just as air masses of different temperatures create winds, the temperature differences under the earth's crust generate flows and movements as well. Thus the plume material, that once lay beneath the continent, was able to shift under the oceanic plate. With disruptions due to other tectonic processes, there were cracks and crevices which allowed the hot material to rise, turn into magma and then- about 60 million years ago - allowed the Marie Byrd Seamounts to grow. "This created islands are comparable to the Canary Islands today," explains Andrea Kipf. "Some day the volcanoes became extinct again, wind and weather eroded the cone down to sea level, and other geological processes further eroded the seamounts. Finally, the summit plateaus arrived at the level that we know today," the PhD student describes the last step of the development.


Citation: A. Kipf, F. Hauff, R. Werner, K. Gohl, P. van den Bogaard, K. Hoernle, D. Maicher, A. Klügel, 'Seamounts off the West Antarctic margin: A case for non-hotspot driven intraplate volcanism', Gondwana Research, In Press, Corrected Proof, DOI: 10.1016/j.gr.2013.06.013