Thermal regime of the Southeast Indian Ridge between 88°E and 140°E: Remarks on the subsidence of the ridge flanks
|Author(s)||Geli Louis1, Cochran James R.2, Lee T. C.3, Francheteau J.4, Labails C.1, Fouchet C.1, Christie D.5|
|Affiliation(s)||1 : IFREMER, Marine Geosci Dept, F-29280 Plouzane, France.
2 : Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA.
3 : Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA.
4 : Univ Bretagne Occidentale, CNRS 6538, UMR, Plouzane, France.
5 : Univ Alaska Fairbanks, W Coast & Polar Reg Undersea Res Ctr, Fairbanks, AK USA.
|Source||Journal Of Geophysical Research-solid Earth (0148-0227) (Amer Geophysical Union), 2007-10 , Vol. 112 , N. B10/B10101 , P. 1-17|
|WOS© Times Cited||6|
|Keyword(s)||Southeast Indian Ridge, seafloor subsidence, mantle temperature|
|Abstract||The flanks of the Southeast Indian Ridge are characterized by anomalously low subsidence rates for the 0-25 Ma period: less than 300 m Ma(-1/2) between 101 degrees E and 120 degrees E and less than 260 m Ma(-1/2) within the Australian-Antarctic Discordance (AAD), between 120 degrees E and 128 degrees E. The expected along-axis variation in mantle temperature (similar to 50 degrees C) is too small to explain this observation, even when the temperature dependence of the mantle physical properties is accounted for. We successively analyze the effect on subsidence of different factors, such as variations in crustal thickness; the dynamic contribution of an old, detached slab supposedly present within the mantle below the AAD; and depletion in phi(m), a parameter here defined as the "ubiquitously distributed melt fraction" within the asthenosphere. These effects may all contribute to the observed, anomalously low subsidence rate of the ridge flanks, with the most significant contribution being probably related to the depletion in phi(m). However, these effects have a deep-seated origin that cannot explain the abruptness of the transition across the fracture zones that delineate the boundaries of the AAD, near 120 degrees E and near 128 degrees E, respectively.|