The submarine record of a large-scale explosive eruption in the Vanuatu Arc: ∼1 Ma Efaté Pumice Formation

Raos, Alison M; McPhie, Jocelyn

doi:10.1029/140gm18

Cited by 8 publications

(14 citation statements)

References 29 publications

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“…Geologically Efate comprises a trachydacite-dominated volcanic centre in which the predominant unit is the Efate Pumice Formation, a >0.5 km thick sequence of siliceous pyroclastic and volcaniclastic rocks forming elevated hills in the central part of Efate ( Figure 2B) that are Pleistocene (<1 Ma) in age [20]. Although Raos and McPhie [20] suggest an age of ca 1 Ma for the Efate Pumice Formation, this appears to be based on a K-Ar date on Quoin Hill basalt of 1.14 Ma [21] as the basalts are stratigraphically younger than the EPF. This must be considered a minimum age.…”

Section: Geology Of Efate and Adjacent Islandsmentioning

confidence: 99%

“…The EPF represents a major explosive pumice eruption in the Vanuatu Arc at about 1-1.5 Ma and was interpreted as predominantly deposits from submarine eruption [20]. Stratigraphically the EPF comprises a minimum of 500 m of pumiceous pyroclastic beds of up to 5 m thickness each with an estimated minimum bulk volume of 85 km 3 [20].…”

Section: Efate Pumice Formationmentioning

confidence: 99%

“…Stratigraphically the EPF comprises a minimum of 500 m of pumiceous pyroclastic beds of up to 5 m thickness each with an estimated minimum bulk volume of 85 km 3 [20]. The lower part of the EPF is formed by the Efate Pumice Breccias [27], which are described as massive to graded stratified pumice breccia locally interbedded with pumice sand and silt ( Figure 3).…”

Section: Efate Pumice Formationmentioning

confidence: 99%

“…These tuffs comprise thinly bedded to finely laminated ( Figure 7) volcanic glass shard-rich sands and silts containing calcareous microfossils (Figures 8 and 9) commonly used as indicators of a shallow marine depositional environment [28,29]. They were interpreted as a product of phreatomagmatic eruption as sea water accessed the vents because of the presence of arcuate fracture surfaces on the glass shards [20]. …”

Section: Efate Pumice Formationmentioning

confidence: 99%

“…The clast characteristics were interpreted as those generated by predominantly "dry" eruptive processes [20] but in an overall submarine environment kept dry by the force of the eruption. The generally finesdepleted nature of the deposits recognized previously was attributed to efficient elutriation during submarine transport [20].…”

Section: Eruption and Emplacement Of The Efate Pumice Breccia Unitsmentioning

confidence: 99%

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Is Efate (Vanuatu, SW Pacific) a result of subaerial or submarine eruption? An alternative model for the 1 Ma Efate Pumice Formation

2010

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Abstract:The Efate Pumice Formation (EPF) is a trachydacitic volcaniclastic succession widespread in the central part of Efate Island and also present on Hat and Lelepa islands to the north. The volcanic succession has been inferred to result from a major, entirely subaqueous explosive event north of Efate Island. The accumulated pumice-rich units were previously interpreted to be subaqueous pyroclastic density current deposits on the basis of their bedding, componentry and stratigraphic characteristics. Here we suggest an alternative eruptive scenario for this widespread succession. The major part of the EPF is distributed in central Efate, where pumiceous pyroclastic rock units several hundred meters thick are found within fault scarp cliffs elevated about 800 m above sea level. The basal 200 m of the pumiceous succession is composed of massive to weakly bedded pumiceous lapilli units, each 2-3 m thick. This succession is interbedded with wavy, undulatory and dune bedded pumiceous ash and fine lapilli units with characteristics of co-ignimbrite surges and ground surges. The presence of the surge beds implies that the intervening units comprise a subaerial ignimbritedominated succession. There are no sedimentary indicators in the basal units examined that are consistent with water-supported transportation and/or deposition. The subaerial ignimbrite sequence of the EPF is overlain by a shallow marine volcaniclastic Rentanbau Tuffs. The EPF is topped by reef limestone, which presumably preserved the underlying EPF from erosion. We here propose that the EPF was formed by a combination of initial subaerial ignimbrite-forming eruptions, followed by caldera subsidence. The upper volcaniclastic successions in our model represent intra-caldera pumiceous volcaniclastic deposits accumulated in a shallow marine environment in the resultant caldera. The present day elevated position of the succession is a result of a combination of possible caldera resurgence and ongoing arc-related uplift in the region.

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Section: Geology Of Efate and Adjacent Islandsmentioning

confidence: 99%

Section: Efate Pumice Formationmentioning

confidence: 99%

Section: Efate Pumice Formationmentioning

confidence: 99%

Section: Efate Pumice Formationmentioning

confidence: 99%

Section: Eruption and Emplacement Of The Efate Pumice Breccia Unitsmentioning

confidence: 99%

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Is Efate (Vanuatu, SW Pacific) a result of subaerial or submarine eruption? An alternative model for the 1 Ma Efate Pumice Formation

2010

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Submarine eruption-fed and resedimented pumice-rich facies: the Dogashima Formation (Izu Peninsula, Japan)

2014

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The NERC and NOC trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. of 45Submarine eruption-fed and resedimented pumice- andesite breccia restricted to the base of a submarine channel, gradationally overlain by 28 pumice breccia, which is widespread but much thinner and finer in the overbank setting. 29These two breccias share similar mineralogy and crystal composition, and are considered to 30 be co-magmatic, and derived from the destruction of a submarine dome by an explosive, clasts issued from the destruction of a hot lava dome, and pumice clasts formed by a 100 submarine explosive eruption that destroyed the lava dome. 101The Dogashima Formation is also very important because it was deposited in a submarine 102 channel and its overbank, which are well exposed in cross-section. In such island arc settings,

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Basalts from the Efate Island Group, central section of the Vanuatu arc, SW Pacific: geochemistry and petrogenesis

Raos

Crawford

2004

Journal of Volcanology and Geothermal Research

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The submarine record of a large-scale explosive eruption in the Vanuatu Arc: ∼1 Ma Efaté Pumice Formation

Cited by 8 publications

References 29 publications

Is Efate (Vanuatu, SW Pacific) a result of subaerial or submarine eruption? An alternative model for the 1 Ma Efate Pumice Formation

Is Efate (Vanuatu, SW Pacific) a result of subaerial or submarine eruption? An alternative model for the 1 Ma Efate Pumice Formation

Submarine eruption-fed and resedimented pumice-rich facies: the Dogashima Formation (Izu Peninsula, Japan)

Basalts from the Efate Island Group, central section of the Vanuatu arc, SW Pacific: geochemistry and petrogenesis

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