Temporal evolution of a post-caldera, mildly peralkaline magmatic system: Furnas volcano, São Miguel, Azores

Jeffery, Adam J.; Gertisser, Ralf; O’Driscoll, Brian; Pacheco, José; Whitley, Sean; Pimentel, Adriano; Self, Stephen

doi:10.1007/s00410-016-1235-y

Cited by 39 publications

(41 citation statements)

References 92 publications

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“…For the specific case of the Azores we consider the presence of large quantities of sediments unlikely due to the young age and limited quantity of sediments however, the igneous lithologies may act as a density barrier. Other central volcanoes in the Azores, for example, the neighboring Pico Alto volcano (Jeffery et al, 2017), Sete Cidades (Beier et al, 2006) and Furnas (Jeffery et al, 2016) on São Miguel, and the Caldeira volcano on Faial (Dias et al, 2007) also have shallow magma reservoirs in 2-to 4-km depth (3-7 km for the Caldeira volcano) and our barometric data for Santa Bárbara agree with these observations.…”

Section: Ponding Depth and The Role Of Fractional Crystallizationsupporting

confidence: 85%

Progressive Changes in Magma Transport at the Active Serreta Ridge, Azores

Romer

Beier

Haase

et al. 2019

Geochem Geophys Geosyst

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Volcanism in the Eastern Azores Plateau occurs at large central volcanoes and along subaerial and submarine fissure zones, resulting from a mantle melting anomaly combined with transtensional stresses. Volcanic structures are aligned WNW‐ESE and NW‐SE, reflecting two tectonic stress fields that control the direction of lateral melt transport. Terceira Island is influenced by both stress fields, dividing the island into an eastern and western part. Several submarine volcanic ridges with variable orientations are located west of Santa Bárbara, the youngest central volcano on Terceira. Major, trace element and Sr‐Nd‐Pb‐Hf isotope compositions from submarine lavas and glasses, in part associated with the 1998–2001 Serreta Ridge eruption, vary between different lava suites, suggesting a formation from different mantle sources. Submarine lavas are more primitive than those from Santa Bárbara volcano, indicating that they are not laterally connected with the shallow magma reservoir located in 2‐ to 5‐km depth beneath the central volcano. Mineral thermobarometric data suggest that the older Serreta magmas were laterally transported at depths >5 km from Santa Bárbara predominantly in WNW direction. We propose that lithospheric extension controls magma transport from the central volcano to Serreta Ridge. The youngest Serreta lavas differ from Santa Bárbara and other submarine ridges in having less radiogenic Pb and higher Hf isotope ratios representing a new magma pulse ascending from the mantle. We conclude that lateral magma transport and the morphology of volcanic ridges are controlled by tectonic stresses in the lithosphere, whereas vertical melt transport is initiated by processes in the mantle.

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Section: Ponding Depth and The Role Of Fractional Crystallizationsupporting

confidence: 85%

Progressive Changes in Magma Transport at the Active Serreta Ridge, Azores

Romer

Beier

Haase

et al. 2019

Geochem Geophys Geosyst

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“…Pre-eruptive temperatures for the combined dataset exhibit considerable range, extending from around 1,050 • C for magmas with peralkaline affinity (e.g., the trachytes of Faial; Pimentel et al, 2015; the phonolites of the Granadilla eruption, Tenerife; Bryan, 2006), to ∼ 700 • C for mildly to strongly peralkaline magmas (Figure 8). This range extends down to approximately 600 • C if autolithic peralkaline syenite clasts, considered to (Putirka, 2008;Mollo et al, 2015), calculated in this study using the data of Imsland et al (1977), Storey (1981), Le , Renzulli and Santi (2000), Siebel et al (2000), Troll and Schmincke (2002), Rodriguez-Losada and Martinez-Frias (2004) (Ablay et al, 1998;Troll and Schmincke, 2002;Rodriguez-Losada and Martinez-Frias, 2004;Bryan, 2006;Dávila-Harris et al, 2013;Zanon and Frezzotti, 2013;Pimentel et al, 2015;Chamberlain et al, 2016;Eisele et al, 2016;Jeffery et al, 2016bJeffery et al, , 2017.…”

Section: Temperaturementioning

confidence: 84%

“…This process not only controls the generation of peralkaline felsic magmas from basaltic progenitors, but also controls evolutionary trends within peralkaline felsic magmas, forming felsic magmas with varying degrees of peralkalinity. There exists a wide range of published studies and quantitative models which reliably recreate the compositions observed in the magmatic systems of the Atlantic, including major element, least-squares mass balance models, thermodynamic models, and trace element models (e.g., Iceland: Carmichael, 1964;Macdonald et al, 1990;Furman et al, 1992a;Sigmarsson et al, 1992;Hards et al, 2000;Prestvik et al, 2001;Martin and Sigmarsson, 2007; Azores: Widom et al, 1992;Mungall and Martin, 1995;Renzulli and Santi, 2000;Beier et al, 2006;Larrea et al, 2013Larrea et al, , 2014aZanon, 2015;Jeffery et al, 2016bJeffery et al, , 2017Canary islands: Freundt and Schmincke, 1995;Ablay et al, 1998;Neumann et al, 1999;Sliwinski et al, 2015;Tornare et al, 2016;Cape Verde: Holm et al, 2006;Kogarko, 2008;Hildner et al, 2011;Cameroon Line: Marzoli et al, 2000;Ascension Island: Harris, 1983;Kar et al, 1998;Chamberlain et al, 2016;Bouvet Island: Le Roex and Erlank, 1982;Prestvik et al, 1999; Tristan da Cunha: Le Roex et al, 1990;Harris et al, 2000;Gough Island: Le Roex, 1985;Harris et al, 2000;St. Helena: Baker, 1969; Fernan...…”

Section: Fractional Crystallizationmentioning

confidence: 99%

“…Although they are not ubiquitous, the occurrence of pre-eruptive magma mixing/mingling processes is well documented for many of the Atlantic Ocean islands (e.g., Iceland: Sparks et al, 1977;McGarvie et al, 1990;Azores: Storey, 1981;Jeffery et al, 2016bJeffery et al, , 2017D'Oriano et al, 2017;Madeira: Klügel and Klein, 2006;Canary Islands: Wolff, 1985;Araña et al, 1994;Edgar et al, 2002;Cape Verde;Holm et al, 2006;Eisele et al, 2016;Ascension: Weaver et al, 1996;Gough Island: Le Roex, 1985;Bouvet Island: Prestvik et al, 1999). These mixing processes are diverse in their end-members, and include direct mixing between mafic and felsic magmas (e.g., Araña et al, 1994;Lopes and Ulbrich, 2015), mixing between felsic magmas (e.g., Troll and Schmincke, 2002;Bryan, 2006;Pimentel et al, 2015), mingling of melt and crystalline mush (i.e., mush remobilisation) (e.g., Weaver et al, 1996;Sliwinski et al, 2015;D'Oriano et al, 2017;Jeffery et al, 2017), and small-scale mixing of partially melted contaminants and volumetrically superior melt (e.g., Turner et al, 2017).…”

Section: Magma Mixing/minglingmentioning

confidence: 99%

“…Temperature estimates derived from two-oxide and other models define considerable ranges for each volcanic island for which there are data. The data derived via alkali feldspar-melt models cluster within the broad range of 1,050-850 • C, and include data from the Azores (Jeffery et al, 2016b(Jeffery et al, , 2017, and calculated using the data of Storey, 1981;Renzulli and Santi, 2000), the Canary Islands (calculated in this study using the data of Troll and Schmincke, 2002;Rodriguez-Losada and Martinez-Frias, 2004;Bryan, 2006;Jutzeler et al, 2010;Clay et al, 2011), Bouvet Island (calculated in this study using the data of Imsland et al, 1977), Gough Island (calculated in this study using the data of Le , and Trindade (calculated in this study using the data of Siebel et al, 2000). Specifically, the estimates from Gran Canaria (Canary Islands), Trindade, and a single ignimbrite formation from Terceira, Azores (GVI, Jeffery et al, 2017), lie at lower values of around 700-850 • C. It is noteworthy that temperature estimates derived from alkali feldspar-melt models appear to record generally higher temperature values than the frequently applied two-oxide models, which likely reflects the comparatively earlier crystallization of alkali feldspar, as well as the rapid re-equilibration timescales of coexisting Fe-Ti oxides (e.g., Gardner et al, 1995;Venezky and Rutherford, 1999;Pimentel et al, 2015), meaning that the lower temperatures recorded by Fe-Ti oxide phases reflect the final pre-eruptive magma system and/or syn-eruptive conditions within the plumbing system.…”

Section: Temperaturementioning

confidence: 99%

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Peralkaline Felsic Magmatism of the Atlantic Islands

Jeffery

Gertisser

2018

Front. Earth Sci.

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The oceanic-island magmatic systems of the Atlantic Ocean exhibit significant diversity in their respective sizes, ages, and the compositional ranges of their eruptive products. Nevertheless, almost all of the Atlantic islands and island groups have produced peralkaline felsic magmas, implying that similar petrogenetic regimes may be operating throughout the Atlantic Ocean, and arguably elsewhere. The origins of peralkaline magmas are frequently linked to low-degree partial melting of enriched mantle, followed by protracted differentiation in the shallow crust. However, additional petrogenetic processes such as magma mixing, crustal melting, and contamination have been identified at numerous peralkaline centers. The onset of peralkalinity leads to magma viscosities lower than those typical for metaluminous felsic magmas, which has profound implications for processes such as crystal settling. This study represents a compilation of published and original data which demonstrates trends that suggest that the peralkaline magmas of the Atlantic Ocean islands are generated primarily via extended (up to ∼ 95%), open system fractional crystallization of mantle-derived mafic magmas. Crustal assimilation is likely to become more significant as the system matures and fusible material accumulates in the crust. Magma mixing may occur between various compositional end-members and may be recognized via hybridized intermediate magmas. The peralkaline magmas are hydrous, and frequently zoned in composition, temperature, and/or water content. They are typically stored in shallow crustal magma reservoirs (∼ 2-5 km), maintained by mafic replenishment. Low melt viscosities (1 × 10 1.77 to 1 × 10 4.77 Pa s) facilitate two-phase flow, promoting the formation of alkali-feldspar crystal mush. This mush may then contribute melt to an overlying melt lens via filter pressing or partial melting. We utilize a three-stage model to account for the establishment, development, and termination of peralkaline magmatism in the ocean island magmatic systems of the Atlantic. We suggest that the overall control on peralkaline magmatism in the Atlantic is magma flux rate, which controls the stability of upper crustal magma reservoirs. The abundance of peralkaline magmas in the Atlantic suggests that their development must be a common, but not inevitable, stage in the evolution of ocean islands.

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Magma Storage at Ocean Islands

Barker

Rydeblad

Silva

2021

Geophysical Monograph Series

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The Cape Verde archipelago is a group of Ocean Islands in the Central Atlantic that forms two chains of islands trending Northwest and Southwest. Several of the islands are considered to be volcanically active, with frequent eruptions on Fogo. We examine the mineral chemistry and thermobarometry of the southern islands; Santiago, Fogo and Brava together with the Cadamosto Seamount. Our objective is to explore the magmatic storage system and implications for volcanic eruptions and associated hazards at Cape Verde. The volcanic rocks at Cape Verde are alkaline and dominantly mafic, whereas the island of Brava and the Cadamosto Seamount are unusually felsic. Clinopyroxene compositions range from 60 to 90 Mg# at Santiago and Fogo. In contrast, at Brava and the Cadamosto Seamount the clinopyroxene compositions are 5 to 75 Mg#. Mineral chemistry and zonation records fractional crystallization, recharge, aggregation of crystals, magma mixing and variations in thermal conditions of the magma at temperatures from 925 to 1250ºC. Magma storage depths at Santiago, Fogo, Brava and the Cadamosto Seamount are between 12 and 40 km, forming deep sub-Moho magma storage zones. Transient magma storage in the crust is suggested by fluid inclusion re-equilibration and pre-eruption seismicity. A global compilation of magma storage at Ocean Islands suggests deep magma storage is a common feature and volcanic eruptions are often associated with rapid magma ascent through the crust. Shallow magma storage is more variable and likely reflects local variations in crustal structure, sediment supply and tectonics. Petrological constraints on the magma plumbing system at Cape Verde and elsewhere are vital to integrate with deformation models and seismicity in order to improve understanding and mitigation of the volcanic hazards.

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Temporal evolution of a post-caldera, mildly peralkaline magmatic system: Furnas volcano, São Miguel, Azores

Cited by 39 publications

References 92 publications

Progressive Changes in Magma Transport at the Active Serreta Ridge, Azores

Progressive Changes in Magma Transport at the Active Serreta Ridge, Azores

Peralkaline Felsic Magmatism of the Atlantic Islands

Magma Storage at Ocean Islands

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