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Systematic Variation of Sr-, Nd- and Pb-Isotopes with Time in Lavas of Mauritius, Reunion Hotspot |
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| Authors: | NOHDA SUSUMU; KANEOKA ICHIRO; HANYU TAKESHI; XU SHENG; UTO KOZO |
| Institution: | 1 DEPARTMENT OF ENVIRONMENTAL SCIENCES, KUMAMOTO UNIVERSITY, KUMAMOTO 860-8555, JAPAN 2 EARTHQUAKE RESEARCH INSTITUTE, UNIVERSITY OF TOKYO, BUNKYO-KU, TOKYO 113-0032, JAPAN 3 INSTITUTE OF GEOSCIENCE, AIST, TSUKUBA 305-8567, JAPAN |
| Abstract: | We report Sr-, Nd- and Pb-isotopic compositions for the lavasof Mauritius, the second youngest volcanic island in the Réunionhotspot. The lavas of the Older Series (7·8–5·5Ma) have identical isotopic compositions (87Sr/86Sr = 0·70411to 0·70422,143Nd/144Nd = 0·512865 to 0·512854,and 206Pb/204Pb = 19·016 to 19·041) to those ofRéunion, where the center of volcanic activity is currentlylocated. The lavas of the Intermediate Series (3·5–1·9Ma) and Younger Series (0·70–0·17 Ma) areshifted to lower Sr-isotopic compositions (0·70364–0·70394,with 143Nd/144Nd = 0·512813 to 0·512948 and 206Pb/204Pb= 18·794 to 18·984). The Intermediate Series lavashave similar trace-element characteristics (e.g. Zr–Nb,Ba–Y) to those of Rodrigues, in both cases requiring theinvolvement of an enriched mantle-like component in the mantlesource. During the volcanic history of Mauritius, the magmaslost the principal isotopic characteristics of the Réunionhotspot with time, and became gradually imprinted with the isotopicsignature of a shallower mantle source that produced the CentralIndian Ridge basalts. KEY WORDS: hotspot; isotopes; Mauritius; Réunion; trace element |
| Keywords: | : hotspot isotopes Mauritius Ré union trace element |
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