Hot spot activity and tectonic settings near Amsterdam-St. Paul plateau (Indian Ocean)

• Published in: Journal of Geophysical Research
• Main Authors: Janin, Myriam, Hémond, Christophe, Guillou, Hervé, Maia, Marcia, Johnson, M. K. T., Bollinger, Claire, Liorzou, Céline, Mudholkar, A.
• Other Authors: Domaines Océaniques (LDO), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Observatoire des Sciences de l'Univers-Institut d'écologie et environnement-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), School of ocean and earth science and technology, University of Hawai‘i Mānoa (UHM), CSIR National Institute of Oceanography India (NIO), programmes SEDIT et EXTRAPLAC
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: SEIR; hot spot; K‐Ar geochronology; ridge-hot spot interaction; Indian Ocean; Capricorn plate; geo; envir; Antarctic; Indian; Southeast Indian Ridge; The Antarctic; Antarc*
• Online Access: https://doi.org/10.1029/2010JB007800; https://hal-insu.archives-ouvertes.fr/insu-00609477/file/JGR-Janin-2011.pdf; https://hal-insu.archives-ouvertes.fr/insu-00609477

International audience The Amsterdam-St. Paul (ASP) plateau is located in the central part of the Indian Ocean and results from the interaction between the ASP hot spot and the Southeast Indian Ridge (SEIR). It is located near the diffuse boundary between the Capricorn and Australian plates. The seamount chain of the Dead Poets (CDP) is northeast of the ASP plateau and may represent older volcanism related to the ASP hot spot; this chain consists of two groups of seamounts: (1) large flat‐topped seamounts formed 8-10 Ma and (2) smaller conical seamounts formed during the last 2 Myr. The ASP hot spot has produced two pulses of magmatism that have been ponded under the ASP plateau and erupted along the divergent boundary between the Capricorn and Australian plates. The N65° orientation of the CDP as well as the seamount's elongated shapes support an opening motion between the Capricorn and Australian plates along a suture oriented in the N155° direction. This motion compared to the Antarctic plate amounts to an apparent velocity of 7.7 cm/yr northeastward for the Capricorn‐Australian block. This motion does not fit with a fixed plume model. We suggest, therefore, that the ASP plume experienced a motion of about 1-2 cm/yr to the SW, which is opposite to the asthenospheric flow in this region and suggests a deep‐seated plume.