Genesis of the Western Samoa seamount province: age, geochemical fingerprint and tectonics

Hart, Stanley R.; Coetzee, Minette; Workman, R. K.; Blusztajn, Jerzy; Johnson, K. T. M.; Sinton, John M.; Steinberger, Bernhard; Hawkins, James W.

doi:10.1016/j.epsl.2004.08.005

Cited by 101 publications

(191 citation statements)

References 38 publications

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“…The tectonic setting of Samoa is complicated by having the northern termination of the Tonga Trench only 100 km to the south of the island chain. Hart et al (2004a) have given a synthesis of the regional tectonic history and how plume-trench interaction has influenced the distribution of Samoan volcanism, specifically the en-echelon topographic ridges seen in Figure 1. Hart et al (2004a) also established, from KAr dating and isotope geochemistry of seamounts extending to the west of Savaii, that the Samoan plume has been active for at least 25 million years, producing a 1700 km long volcanic chain.…”

Section: Geological and Geochemical Settingmentioning

confidence: 99%

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

157

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%

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

157

146

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“…The Samoa hot spot seems to have existed for at least 23 million years and was responsible for the five major islands of Samoa as well as a lineament of submarine seamounts and banks extending 1300 km west from Savai'i (Natland 1980;Clouard & Bonneville 2001;Hart et al 2004). An active submarine volcano, Vailulu'u Seamount, approximately 30 km east of Ta'u, appears to mark the current location of the Samoa hot spot.…”

Section: The Pacific Linear Volcanic Chainsmentioning

confidence: 99%

“…An active submarine volcano, Vailulu'u Seamount, approximately 30 km east of Ta'u, appears to mark the current location of the Samoa hot spot. Ta'u has a youthful uneroded shield morphology, while the islands to the west (Savai'i dated at up to 5.21 Ma, Koppers et al 2006; Upolu dated at 3.2-1.4 Ma; and Tutuila dated at 1.53-1.0 Ma, Natland 2003) demonstrate various stages of advanced erosion ( Hart et al 2004). An isolated volcano (Machias Seamount), south of Upolu and adjacent to the Tonga Trench, has been dated at 0.97 Ma (Hawkins & Natland 1975).…”

Section: The Pacific Linear Volcanic Chainsmentioning

confidence: 99%

The age and origin of the Pacific islands: a geological overview

Neall

Trewick

2008

Phil. Trans. R. Soc. B

295

237

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The Pacific Ocean evolved from the Panthalassic Ocean that was first formed ca 750 Ma with the rifting apart of Rodinia. By 160 Ma, the first ocean floor ascribed to the current Pacific plate was produced to the west of a spreading centre in the central Pacific, ultimately growing to become the largest oceanic plate on the Earth. The current Nazca, Cocos and Juan de Fuca (Gorda) plates were initially one plate, produced to the east of the original spreading centre before becoming split into three. The islands of the Pacific have originated as: linear chains of volcanic islands on the above plates either by mantle plume or propagating fracture origin, atolls, uplifted coralline reefs, fragments of continental crust, obducted portions of adjoining lithospheric plates and islands resulting from subduction along convergent plate margins. Out of the 11 linear volcanic chains identified, each is briefly described and its history summarized. The geology of 10 exemplar archipelagos ( Japan, Izu-Bonin, Palau, Solomons, Fiji, New Caledonia, New Zealand, Society, Galápagos and Hawaii) is then discussed in detail.

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“…Also, the Samoan hotspot has recorded increased magmatic activity during the last few million years (myr) [23][24][25] . The most active hotspot in the Indian Ocean, the La Réunion hotspot, shows an increase in magmatism since 3 Ma (refs 26, 27).…”

Section: Magmatic Events For the Studied Hotspots Since 5 Mamentioning

confidence: 99%

Late Cenozoic Global Pulsations in Hotspot Magmatism and their Possible Interplay with Plate Tectonics, Earth's Core and Climate

Mjelde

2016

Current Science

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A study of the Earth's main hotspots indicates an increase in magmatism during the last 1.5 myr, supporting a previous hypothesis on global magmatic copulsation on c. 10 myr scale through the Cenozoic. A similar pattern is found for magmatism dominantly related to plate tectonics since 15 Ma. It is suggested that the inferred syncronicity in magmatism is related to two large areas under Africa and the central Pacific expressing anomalously slow S-wave velocities in the lower mantle. Heterogeneous heat flux in the fluid outer core related to the lower mantle anomalies may cause spatially related aspherical inner core growth and rotation of the inner core with respect to the lower mantle. It is speculated that the heterogeneous heat flux in the outer core can be modulated by inner core processes of aspherical growth and rotation on 10 myr scale, subsequently leading to syncronized plume pulses from the rim of the hot lower mantle anomalies. Some of the magmatic pulses appear to coincide with abrupt drops in eustatic sea level, and it is suggested that these were caused by glaciations triggered by the volcanism.

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Genesis of the Western Samoa seamount province: age, geochemical fingerprint and tectonics

Cited by 101 publications

References 38 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

The age and origin of the Pacific islands: a geological overview

Late Cenozoic Global Pulsations in Hotspot Magmatism and their Possible Interplay with Plate Tectonics, Earth's Core and Climate

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