Vailulu'u undersea volcano: The New Samoa

Hart, Stanley R.; Staudigel, Hubert; Koppers, Anthony A. P.; Blusztajn, Jerzy; Baker, Edward T.; Workman, R. K.; Jackson, Michael; Hauri, E. H.; Kurz, Mark D.; Sims, Kenneth W.W.; Fornari, Daniel J.; Saal, A. E.; Lyons, Suzanne

doi:10.1029/2000gc000108

Cited by 49 publications

(84 citation statements)

References 32 publications

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Section: Geological and Geochemical Settingmentioning

confidence: 99%

“…1); it rises from a 5000 m deep seafloor to a summit depth of 590 m and rests 45 km east of its nearest neighbor, Ta'u Island (Hart et al, 2000). Vailulu'u has been shown to be both volcanically and hydrothermally very active (Hart et al, 2000;Hart et al, 2003;Staudigel et al, 2004;Konter et al, 2004). The power output from Vailuluu's summit crater is estimated to be 610-760 MW, the equivalent of 20-100 Mid-Ocean Ridge black smokers; Mn export is estimated at 240-300 kg/day, or the equivalent of about 10 black smokers Hart et al, 2003).…”

Section: Geological and Geochemical Settingmentioning

confidence: 99%

“…U-series data have been collected for lavas from each Vailulu'u and Malumalu dredge (Sims and Hart, 2004), including the following samples studied here: 63-13, 70-01, 71-02, 71-09, 72-02, 73-01, 73-03, 73-12, 76-01, 78- 210 Pb disequilibria and are interpreted to be less than 100 years old (Hart et al, 2000).…”

Section: Samples and Volcano Agesmentioning

confidence: 99%

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Volatile and trace elements in basaltic glasses from Samoa: Implications for water distribution in the mantle

Workman

Hauri

Hart

et al. 2006

Earth and Planetary Science Letters

158

146

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We report volatile (H 2 O, CO 2 , F, S, Cl) and trace element data for submarine alkalic basalt glasses from the three youngest Samoan volcanoes, Ta'u, Malumalu and Vailulu'u. Most samples are visibly sulfide saturated, so have likely lost some S during fractionation. Cl/K ratios (0.04 -0.15) extend to higher values than pristine MORBs, but are suspected to be partly due to source differences since Cl/K roughly varies as a function of 87 Sr/ 86 Sr. There are no resolvable differences in the relative enrichment of F among sources, and compatibility of F during mantle melting is established to be nearly identical to Nd. Shallow degassing has affected CO 2 in all samples, and H 2 O only in the most shallowly erupted samples from Vailulu'u. Absolute water contents are high for Samoa (0.63 -1.50 wt%), but relative enrichment of water compared to equally incompatible trace elements (Ce, La) is low and falls entirely below normal MORB values. H 2 O/Ce (58 -157) and H 2 O/La (120 -350) correlate inversely with 87 Sr/ 86 Sr compositions (0.7045 -0.7089). This leads us to believe that, because of very fast diffusion of hydrogen in mantle minerals, recycled lithospheric material with high initial water and trace element content will lose water to the drier ambient mantle during storage within the inner Earth. The net result is the counter-intuitive appearance of greater dehydration with greater mantle enrichment. We expect that subducted slabs will experience a two-stage dehydration history, first within subduction zones and then in the ambient mantle during long-term convective mixing.

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Section: Geological and Geochemical Settingmentioning

confidence: 99%

Section: Geological and Geochemical Settingmentioning

confidence: 99%

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Volatile and trace elements in basaltic glasses from Samoa: Implications for water distribution in the mantle

Workman

Hauri

Hart

et al. 2006

Earth and Planetary Science Letters

158

146

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“…Three previous expeditions in 1999-2001 showed that Vailulu'u volcano is seismically and hydrothermally active, with an average of four local earthquakes per day and hydrothermal fluxes that rival those of black smokers at midocean ridges (11)(12)(13)(14). The return to Vailulu'u in 2005 revealed a new, 300-m-high volcanic cone that had grown in the crater of Vailulu'u from 1,000-m water depth and that forms a new central summit, named Nafanua.…”

Section: Resultsmentioning

confidence: 99%

“…1). Crater waters are expelled through all breaches during ''low tides,'' as the hydrothermal dome collapses and exhales, forming a ''smokering'' around the summit of Vailulu'u (11).…”

Section: Vent Complex IImentioning

confidence: 99%

Vailulu’u Seamount, Samoa: Life and death on an active submarine volcano

Staudigel

Hart

Pile

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu'u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades. Vents fill Vailulu'u crater with a thick suspension of particulates and apparently toxic fluids that mix with seawater entering from the crater breaches. Low-temperature vents form Fe oxide chimneys in many locations and up to 1-m-thick layers of hydrothermal Fe floc on Nafanua. High-temperature (81°C) hydrothermal vents in the northern moat (945-m water depth) produce acidic fluids (pH 2.7) with rising droplets of (probably) liquid CO 2. The Nafanua summit vent area is inhabited by a thriving population of eels (Dysommina rugosa) that feed on midwater shrimp probably concentrated by anticyclonic currents at the volcano summit and rim. The moat and crater floor around the new volcano are littered with dead metazoans that apparently died from exposure to hydrothermal emissions. Acid-tolerant polychaetes (Polynoidae) live in this environment, apparently feeding on bacteria from decaying fish carcasses. Vailulu'u is an unpredictable and very active underwater volcano presenting a potential long-term volcanic hazard. Although eels thrive in hydrothermal vents at the summit of Nafanua, venting elsewhere in the crater causes mass mortality. Paradoxically, the same anticyclonic currents that deliver food to the eels may also concentrate a wide variety of nektonic animals in a death trap of toxic hydrothermal fluids.currents ͉ habitats ͉ hydrothermal ͉ vents ͉ eels S eamounts, submerged isolated mountains in the oceans, are among the most poorly understood major morphological features on Earth, offering important research targets for ocean sciences. Seamount research, which involves fields as diverse as volcanology, geology, geochemistry, geophysics, physical oceanography, and marine biology, has yielded crucial insights into the absolute motion of the tectonic plates (1), the rheology and state of stress of the underlying lithosphere (2, 3), the chemical make-up of Earth's mantle (4), and the role of hypoxia in benthic animal distributions (5). Seamounts offer unique habitats for nektonic and benthic life, including both microbes and metazoans (6, 7). The topography of seamounts can substantially enhance internal ocean tides, providing powerful ''stirring rods'' for mixing the oceans (8) and creating local currents that transport nutrients and retain larvae (9) and concentrate commercially important fishes (10).We report here the initial, integrated results from recent volcanological, biological, and oceanographic explorations of Vailulu'u Seamount (14°13ЈS; 169°04ЈW), an active submarine volcano located 45 km east of the easternmost island in the Samoan archipelago. Our data come largely from three short oceanographic cruises in March-July, 2005. A cruise on the R͞V Kilo Moana (KM) in April 2005 included 3 days of bathymetric mapping, hydrographic profiling, and geol...

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Evidence for a broadly distributed Samoan-plume signature in the northern Lau and North Fiji Basins

Price

Jackson

Blichert‐Toft

et al. 2014

Geochem. Geophys. Geosyst.

104

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Geochemical enrichment of lavas in the northern Lau Basin may reflect the influx of Samoanplume mantle into the region. We report major and trace element abundances and He-Sr-Nd-Hf-Pbisotopic measurements for 23 submarine volcanic glasses covering 10 locations in the northern Lau and North Fiji Basins, and for three samples from Wallis Island, which lies between Samoa and the Lau Basin. These data extend the western limit of geochemical observations in the Basins and improve the resolution of North-South variations in isotopic ratios. The Samoan hot spot track runs along the length of the northern trace of the Lau and North Fiji Basins. We find evidence for a Samoan-plume component in lavas as far West as South Pandora Ridge (SPR), North Fiji Basin. Isotopic signatures in SPR samples are similar to those found in Samoan Upolu shield lavas, but show a slight shift toward MORB-like compositions. We explain the origin of the enriched signatures by a model in which Samoan-plume material and ambient depleted mantle undergo decompression melting during upwelling after transiting from beneath the thick Pacific lithosphere to beneath the thin lithosphere in the northern Lau and North Fiji Basins. Other lavas found in the region with highly depleted isotopic signatures may represent isolated pockets of depleted mantle in the basins that evaded this enrichment process. We further find that mixing between the two components in our model, a variably degassed high-3 He/ 4He Samoan component and depleted MORB, can explain the diversity among geochemical data from the northern Lau Basin.

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Vailulu'u undersea volcano: The New Samoa

Cited by 49 publications

References 32 publications

Volatile and trace elements in basaltic glasses from Samoa: Implications for water distribution in the mantle

Volatile and trace elements in basaltic glasses from Samoa: Implications for water distribution in the mantle

Vailulu’u Seamount, Samoa: Life and death on an active submarine volcano

Evidence for a broadly distributed Samoan-plume signature in the northern Lau and North Fiji Basins

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