An isotopic survey of Pacific oceanic plateaus; implications for their nature and origin

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doi: 10.1029/GM043p0207
Author(s): Mahoney, John J.
Author Affiliation(s): Primary:
Hawaii Inst. Geophys., Honolulu, HI, United States
Other:
Northwest. Univ., United States
NOAA, United States
Volume Title: Seamounts, islands, and atolls
Volume Author(s): Keating, Barbara H., editor; Fryer, Patricia; Batiza, Rodey; Boehlert, George W.
Source: Seamounts, islands, and atolls, edited by Barbara H. Keating, Patricia Fryer, Rodey Batiza and George W. Boehlert. Geophysical Monograph, Vol.43, p.207-220. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0065-8448. ISBN: 978-1-118-66420-9 CODEN: GPMGAD
Note: In English with English summary. Hawaii Inst. Geophys., Contrib. No. 1848. 75 refs.; illus. incl. 1 table, sketch map
Summary: Available basement samples from Pacific oceanic plateaus show oceanic island or plume-type Nd and Sr isotopic signatures, in contrast to their chemical characteristics which tend to be broadly similar to those of MORB. No clear indication of continental affinities is found in any of the plateau lavas. Other evidence suggests the plateaus could have been formed at ancient spreading ridges, possibly near triple junctions. The isotopic results argue for proximity to hotspots as well, and a near ridge hotspot origin is proposed here. Seawater alteration has disturbed Sr isotopic values in the plateau basalts, in some cases severely, though Sm-Nd systematics generally remain unaffected. A multiple step acid-leaching procedure removes nearly all the isotopic effects of alteration, however, and allows recovery of Sr isotopic ratios very close to those with which the lavas were erupted.
Year of Publication: 1987
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 05 Petrology, Igneous and Metamorphic; 18 Geophysics, Solid-Earth; Alkaline earth metals; Basalts; Bottom features; Crust; Geochemistry; Halmyrolysis; Hot spots; Igneous rocks; Isotopes; Lava; Metals; Nd-144/Nd-143; Neodymium; Ocean floors; Oceanic crust; Oceanography; Pacific Ocean; Plate tectonics; Plateaus; Rare earths; Spreading centers; Sr-87/Sr-86; Stable isotopes; Strontium; Volcanic rocks
Record ID: 1988068615
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.

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