期刊
EARTH AND PLANETARY SCIENCE LETTERS
卷 275, 期 3-4, 页码 285-295出版社
ELSEVIER
DOI: 10.1016/j.epsl.2008.08.023
关键词
Pacific; seamount; Tokelau; Gilbert; hotspot; intraplate; plume; isotope; color coding
资金
- National Science Foundation [CCE 9102183, OCE 9730394, MRI-0079943, OCE-0453138, OCE-0241546, NSF-0549641]
- French Institut National des Sciences de I'Univers
Linear chains of intraplate volcanoes and their geochemistry provide a record of mantle melting through geological time. The isotopic compositions of their lavas characterize their mantle sources, and their ages help backtrack these volcanoes to their original, eruptive source regions. Such data may shed light on a much-debated issue in Earth Sciences: the origin of intraplate volcanism and its underlying mantle and lithosphere dynamics. We show here that three major Western Pacific Seamount groups, similar to 50-100 million years in age, display distinct Sr, Nd, Hf, and Pb isotopic signatures that can be traced back in time, both geographically and geochemically, to three separate, recently-active intraplate volcanoes in the South Pacific Cook-Austral Islands. Their unique 100 million year history, which shows a persistent geochemical fingerprint, suggests formation from large volumes of laterally fixed, long-lived source regions. Such longevity is unlikely to be attained in the relatively dynamic upper mantle. Therefore, these sources are likely anchored deep in the mantle, isolated from homogenization by mantle convection, and imply a primary origin from deep mantle plumes rather than resulting from lithosphere extension. (c) 2008 Elsevier B.V. All rights reserved.
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