Using geochemistry to map mantle flow beneath the Lau Basin

Research Article| November 01, 1998 Using geochemistry to map mantle flow beneath the Lau Basin Simon Turner; Simon Turner 1Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, United Kingdom Search for other works by this author on: GSW Google Scholar Chris Hawkesworth Chris Hawkesworth 1Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, United Kingdom Search for other works by this author on: GSW Google Scholar Author and Article Information Simon Turner 1Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, United Kingdom Chris Hawkesworth 1Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, United Kingdom Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1998) 26 (11): 1019–1022. https://doi.org/10.1130/0091-7613(1998)026<1019:UGTMMF>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Simon Turner, Chris Hawkesworth; Using geochemistry to map mantle flow beneath the Lau Basin. Geology 1998;; 26 (11): 1019–1022. doi: https://doi.org/10.1130/0091-7613(1998)026<1019:UGTMMF>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Geochemical tracers can be used to map mantle flow beneath the Lau Basin– Tonga region over the past 6 m.y. and constrain the extent and means by which different components contribute to the magmas erupted there. Helium isotope data track the Samoan plume to show that it infiltrated into the northwestern part of the Lau Basin, at ∼40 mmṁyr−1, through an opening tear in the Pacific plate. In contrast to other recent studies, our analysis indicates that this plume does not contribute to the arc lavas. A Louisville plume component is present in the northern Tonga arc lavas, but this was added from volcaniclastic sediments transported into the arc on the subducting slab and does not require the presence of plume material within the mantle wedge. The Louisville tracer has been used to infer that the mantle wedge beneath the island-arc is downwelling at the rate of 20–40 mmṁyr−1, owing to viscous drag against the downgoing Pacific plate. A third geochemical tracer, provided by the distinction between Indian and Pacific mantle, indicates that Indian mantle has migrated eastward at rates of 45–65 mmṁyr−1. The inferred rates of migration indicate that the translation of geochemical signatures occurs by mantle flow rather than by the order-of-magnitude-faster movement of partial melts. Except for the flow in the mantle wedge, the directions of mantle flow in this region are unrelated to the overlying plate motions. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.