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Titel |
Seismic structure of the lithosphere and upper mantle beneath the ocean islands near mid-oceanic ridges |
VerfasserIn |
C. Haldar, P. Kumar, M. Ravi Kumar |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1869-9510
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Digitales Dokument |
URL |
Erschienen |
In: Solid Earth ; 5, no. 1 ; Nr. 5, no. 1 (2014-05-19), S.327-337 |
Datensatznummer |
250115271
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Publikation (Nr.) |
copernicus.org/se-5-327-2014.pdf |
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Zusammenfassung |
Deciphering the seismic character of the young
lithosphere near mid-oceanic ridges (MORs) is a challenging endeavor. In
this study, we determine the seismic structure of the oceanic plate near the
MORs using the P-to-S conversions isolated from quality data recorded
at five broadband seismological stations situated on ocean islands in their
vicinity. Estimates of the crustal and lithospheric thickness values from waveform inversion of the P-receiver function stacks at individual stations
reveal that the Moho depth varies between ~ 10 ± 1 km and
~ 20 ± 1 km with the depths of the
lithosphere–asthenosphere boundary (LAB) varying between ~ 40 ± 4 and ~ 65 ± 7 km. We found evidence for an
additional low-velocity layer below the expected LAB depths at stations on
Ascension, São Jorge and Easter islands. The layer probably relates to the
presence of a hot spot corresponding to a magma chamber. Further, thinning of
the upper mantle transition zone suggests a hotter mantle transition zone
due to the possible presence of plumes in the mantle beneath the stations. |
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