The subantarctic lithospheric mantle

• Published in: Geological Society, London, Memoirs
• Main Authors: Delpech, Guillaume, Scott, James M., Grégoire, Michel, Moine, Bertrand N., Li, Dongxu, Liu, Jingao, Graham Pearson, D., van der Meer, Quinten H. A., Waight, Tod E., Michon, Gilbert, Guillaume, Damien, O’reilly, Suzanne Y., Cottin, Jean Yves, Giret, André
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2023
• Subjects: Antarctic; Indian; Kerguelen; Kerguelen Islands; Pacific; Southeast Indian Ridge; The Antarctic; Antarc*; Auckland Islands
• Online Access: https://curis.ku.dk/portal/da/publications/the-subantarctic-lithospheric-mantle(f66d6fa3-f9df-42b0-bb77-60d4ab9fbbc7).html; https://doi.org/10.1144/M56-2020-13; https://curis.ku.dk/ws/files/381638215/The_Subantarctic_lithospheric_mantle_2_48.pdf

We present a summary of peridotite in the Subantarctic (46–60° S) surrounding the Antarctic Plate. Peridotite xenoliths occur on the Kerguelen Islands and Auckland Islands. The Kerguelen Islands are underlain by a plume, whereas the Auckland Islands are part of continental Zealandia, which is a Gondwana-rifted fragment. Small amounts of serpentinized peridotite has been dredged from fracture zones on the Southeast Indian Ridge, Southwest Indian Ridge and Pacific Antarctic Ridge, and represent upwelled asthenosphere accreted to form lith-osphere. Suprasubduction-zone peridotite was collected from two locations on the Sandwich Plate. Peridotites from most subantarctic occur-rences are moderately to highly depleted, and many show signs of subsequent metasomatic enrichment. Os isotopes indicate that subantarctic continental and oceanic lithospheric mantle contains ancient fragments that underwent depletion long before formation of the overlying crust.