Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
Géochimie isotopique du lithium dans les basaltes-Géochimie des ...
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tel-00344949, version 1 - 7 Dec 2008<br />
VOL. 14, 2005 INTERNATIONAL RESEARCH<br />
Figure 4<br />
3-D bathymetric image of the South Menard volcanic structure with caldera-type I and younger-type II volcanoes.<br />
by the coa<strong>les</strong>cence of indivi<strong>du</strong>al volcanoes. Fresh pillows<br />
with basaltic glass were dredged .<br />
b) Near 41°15’S, between 112°10’W and 113°55’W<br />
Two successful dredges sampled altered pillows from the<br />
western and vesicular basalts from the eastern part of the<br />
ridge.<br />
Further work will test 1) the existence of two sub-Pacifi c<br />
mantle domains south and north of the Easter microplate<br />
(Vlastelic et al., 1999); 2) the relationship between the<br />
geochemical and morphological variations <strong>des</strong>cribed<br />
along the ridge and the thermal structure of the underlying<br />
mantle (Vlastelic et al., 2000, Ondréas et al., 2001) and 3)<br />
the relationship between off-axis and ridge volcanism and<br />
kinematics.<br />
Acknowledgments<br />
We would like to thank Captain M. Houmard and the crew<br />
of the N/O L’Atalante L’Atalante L’Atalante for their kindness and their very<br />
effi cient work at sea in the well-named roaring forties<br />
and fi fties!<br />
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