Geodynamic implications for zonal and meridional isotopic patterns across the northern Lau and North Fiji Basins
Price, Allison A.
Jackson, Matthew G.
Kurz, Mark D.
Gill, James B.
Blusztajn, Jerzy S.
Arculus, Richard J.
MetadataShow full item record
We present new Sr-Nd-Pb-Hf-He isotopic data for 65 volcanic samples from the northern Lau and North Fiji Basins. This includes 47 lavas obtained from 40 dredge sites spanning an east-west transect across the Lau and North Fiji basins, 10 ocean island basalt (OIB)-type lavas collected from seven Fijian islands, and eight OIB lavas sampled on Rotuma. For the first time, we are able to map clear north-south and east-west geochemical gradients in 87Sr/86Sr across the northern Lau and North Fiji Basins: lavas with the most geochemically enriched radiogenic isotopic signatures are located in the northeast Lau Basin, while signatures of geochemical enrichment are diminished to the south and west away from the Samoan hot spot. Based on these geochemical patterns and plate reconstructions of the region, these observations are best explained by the addition of Samoa, Rurutu, and Rarotonga hot spot material over the past 4 Ma. We suggest that underplated Samoan material has been advected into the Lau Basin over the past ∼4 Ma. As the slab migrated west (and toward the Samoan plume) via rollback over time, younger and hotter (and therefore less viscous) underplated Samoan plume material was entrained. Thus, entrainment efficiency of underplated plume material was enhanced, and Samoan plume signatures in the Lau Basin became stronger as the trench approached the Samoan hot spot. The addition of subducted volcanoes from the Cook-Austral Volcanic Lineament first from the Rarotonga hot spot, then followed by the Rurutu hot spot, contributes to the extreme geochemical signatures observed in the northeast Lau Basin.
Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of [publisher] for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 18 (2017): 1013–1042, doi:10.1002/2016GC006651.
The publisher requires that this item be embargoed until 2017-09-17. Please check back after 2017-09-17.
Showing items related by title, author, creator and subject.
Wang, Tingting; Lin, Jian; Tucholke, Brian E.; Chen, Yongshun J. (American Geophysical Union and the Geochemical Society, 2011-03-31)Gravity-derived crustal thickness models were calculated for the North Atlantic Ocean between 76°N and the Chain Fracture Zone and calibrated using seismically determined crustal thickness. About 7% of the ocean crust is ...
A test of basin-scale acoustic thermometry using a large-aperture vertical array at 3250-km range in the eastern North Pacific Ocean Worcester, Peter F.; Cornuelle, Bruce D.; Dzieciuch, Matthew A.; Munk, Walter H.; Howe, Bruce M.; Mercer, James A.; Spindel, Robert C.; Colosi, John A.; Metzger, Kurt; Birdsall, Theodore G.; Baggeroer, Arthur B. (Acoustical Society of America, 1999-06)Broadband acoustic signals were transmitted during November 1994 from a 75-Hz source suspended near the depth of the sound-channel axis to a 700-m long vertical receiving array approximately 3250 km distant in the eastern ...
Seiwell, Harry Richard (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1937-05)Because of general interest in the subject of vertical oscillations in the sea and because such information is scanty for the ocean basins, an investigation of the question in the western North Atlantic was initiated by ...