FN Archimer Export Format
PT J
TI Temporal source evolution and crustal contamination at Lopevi Volcano, Vanuatu Island Arc
BT 
AF BEAUMAIS, Aurelien
   CHAZOT, Gilles
   DOSSO, Laure
   BERTRAND, Herve
AS 1:1;2:1;3:2;4:3;
FF 1:;2:;3:;4:;
C1 Univ Brest UBO, UMR Domaines Ocean 6538, Inst Univ Europeen Mer, F-29280 Plouzane, France.
   CNRS, IFREMER, UMR6538, Dept Geosci Marines, F-29280 Plouzane, France.
   Univ Lyon 1, Ecole Normale Super Lyon, Lab Geol Lyon, UMR CNRS 5570, F-69364 Lyon, France.
C2 UBO, FRANCE
   CNRS, FRANCE
   UNIV LYON, FRANCE
SI BREST
IF 2.515
TC 8
UR https://archimer.ifremer.fr/doc/00167/27801/26223.pdf
LA English
DT Article
DE ;Lopevi;Vanuatu;Geochemistry;Isotopes;Subduction;Mantle source
AB Here we present a new geochemical study of Lopevi volcano, one the most active volcanoes in the Vanuatu island arc. We focus on the temporally well-defined sequence of lava flows emitted since 1960, and for the first time, on pre-1960 volcanic products, including high-MgO basalts and felsic andesites, the most evolved lavas sampled so far on this island. This work reports the first Pb and Hf isotopic study of lavas from Lopevi island. These lavas display correlations between differentiation indexes such as SiO2 content and isotopic ratios. The felsic andesites extend the known correlations with both the least (Sr-Pb) and the most (Nd-Hf) radiogenic isotopic compositions on the island. Our results confirm that the rising magma interacted with the sub-arc crust. Assimilation-Fractional Crystallization (AFC) quantitative modeling of trace element ratios and isotopic compositions requires 1% and 10% of assimilated partial melts of a mafic oceanic crust to account for the pre- and post-1960 lavas, respectively. The post-1960 lavas differ from the former lavas emitted similar to 20 years earlier by enrichments in fluid mobile elements (K, Ba, Rb ... ), Th, and Light Rare Earth Elements (LREE). We ascribe these features to slight variations in the metasomatic agent added to the sub-arc mantle and ultimately derived from the subducted lithosphere. However, the contrasting time scales involved in subducted lithosphere dehydration and magma genesis, relative to the time elapsed between eruptions of the two lava series, suggest that two different portions of mantle which have undergone slightly different metasomatism, gave birth to the Lopevi lavas. These distinct magmas are still present beneath the volcano.
PY 2013
PD AUG
SO Journal Of Volcanology And Geothermal Research
SN 0377-0273
PU Elsevier Science Bv
VL 264
UT 000326558800007
BP 72
EP 84
DI 10.1016/j.jvolgeores.2013.07.005
ID 27801
ER

EF