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Eos, Transactions American Geophysical Union

Study yields surprises about seafloor spreading in back-arc basins


  • Etienne Ruellan,

    1. CNRS, Géosciences Azur, 250 Rue A. Einstein, Sophia Antipolis, 06560 Valbonne, France
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  • Yves Lagabrielle,

  • Manabu Tanahashi,

  • Shipboard Party


A study of the seafloor in the North Fiji Basin is leading to a better understanding of the geometry and evolution of spreading in back-arc basins. Two of the most important features of the area, the South Pandora Ridge and the Tripartite Ridge, belong to a presently active spreading system that began forming at least 7.2 m.y.a. The ridges spread at an average rate of about 1.6 cm/yr. By studying the segments of the ridges in greater detail, researchers found that each was either a “tectonic type,” with a more or less complex deep axial valley, or a “volcanic type,” with a high, rifted volcanic massif occupying the axial domain.

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