Compositional variations in submarine volcanic ashes from the vicinity of the Vanuatu Island Arc: a response to ridge—arc collision?

Baker, P. E.; Condliffe, Eric

doi:10.1016/0377-0273(96)00010-8

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…Further work is needed to understand the causes of such elevated degassing. It is worthy of note that the central arc segment is subjected to both a westward inflow of enriched, possibly sulphur-rich Indian-type MORB mantle ( [Monzier et al, 1997] , [Peate et al, 1997] and [Turner et al, 1999] ) and to the collision with the d'Entrecasteaux ridge since 2-3 Ma ( [Collot et al, 1985] , [Collot et al, 1992] , [Burne et al, 1988] , [Greene and Collot, 1994] , [Taylor et al, 1994] and [Laporte et al, 1998] ) that has led to back-arc shortening ( [Collot et al, 1985] and [Louat and Pelletier, 1989] ) and to the development of tranverse fracture zones which may facilitate magma ascent beneath Ambae and Ambrym ( [Pontoise et al, 1994] , [Baker and Condliffe, 1996] and [Monzier et al, 1997] ).…”

Section: Discussionmentioning

confidence: 99%

First estimate of volcanic SO2 budget for Vanuatu island arc

Bani

Oppenheimer

Allard

et al. 2012

Journal of Volcanology and Geothermal Research

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International audienceThe spatial and temporal coverage of measurements of previous termvolcanicnext term gas emissions remains patchy. However, over the last decade, emissions inventories have improved thanks to new measurements of some of the lesser-known previous termvolcanicnext term areas. We report on one such region - the Vanuatu island arc, in the Southwest Pacific - for which we now have sufficient systematic observations to offer a systematic emissions inventory. Our new estimate is based on SO2 flux measurements made in the period 2004-2009 with ultraviolet spectroscopy techniques for the following volcanoes: Yasur, Lopevi, Ambrym, Ambae, Gaua and Vanua Lava (from south to north). These are the first ever measurements for Lopevi, Gaua and Vanua Lava. The results reveal the Vanuatu arc as one of Earth's prominent sources of previous termvolcanicnext term degassing with a characteristic annual emission to the atmosphere of ~ 3 Tg of SO2 (representing about 20% of hitherto published global estimates). Our new dataset highlights the sustained prodigious degassing of Ambrym volcano, whose 5 Gg d-1 mean flux of SO2 represents nearly two-thirds of the total budget for the Vanuatu arc. This confirms Ambrym as one of the largest previous termvolcanic sources worldwide comparable to Etna, often considered as the most vigorous source of previous termvolcanic emission on Earth. We also report a high degassing for Ambae of ~ 2 Gg d-1 SO2, representing more than 28 % of the Vanuatu arc budget. Thus, 90 % of the SO2 output from Vanuatu is focused in the central part of the arc (from Ambrym and Ambae) where magmas originate from enriched Indian-type mantle and where peculiar tectonic conditions could favour high magma production rates

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Section: Discussionmentioning

confidence: 99%

First estimate of volcanic SO2 budget for Vanuatu island arc

Bani

Oppenheimer

Allard

et al. 2012

Journal of Volcanology and Geothermal Research

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“…Low K arc-tholeiites erupted before 2-3 Ma, are described as "normal suites" and show a Pacific-like mantle isotopic signature. Since the onset of the subduction-collision of the D'Entrecasteaux Ridge, lavas are characterized by a strong enrichment in K 2 O, large ion lithophile elements (LILE), and LREE and by an isotopic composition shifted toward an Indian-like mantle signature with radiogenic Sr and high 207 Pb/ 204 Pb and 208 Pb/ 204 Pb isotope ratios (Dupuy et al, 1982;Briqueu et al, 1994;Baker and Condliffe, 1996;Monzier et al, 1997;Peate et al, 1997;Laporte et al, 1998). The most recent studies argue for a westward upwelling of an enriched asthenospheric mantle from the back arc in front of the D'Entrecasteaux collision zone to explain the observed chemical differences (Monzier et al, 1997;Peate et al, 1997;Pearce et al, 2007;Heyworth et al, 2011).…”

Section: Geological Setting and Previous Workmentioning

confidence: 99%

Temporal source evolution and crustal contamination at Lopevi Volcano, Vanuatu Island Arc

Beaumais

Chazot

Dosso

et al. 2013

Journal of Volcanology and Geothermal Research

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International audienceHere 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 ~ 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

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