Rifting of the oceanic Azores Plateau with episodic volcanic activity

Storch, Bettina; Haase, Karsten M.; Romer, René H.W.; Beier, Christoph; Koppers, A. A.

doi:10.1038/s41598-020-76691-1

Cited by 17 publications

(32 citation statements)

References 71 publications

(128 reference statements)

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“…The movement of the Nubian and Eurasia Plates and the opening of the Hirondelle Basin results from an extensional movement in northeastern and southwestern directions (Marques et al, 2013). This is consistent (Beier et al, 2008;Hildenbrand et al, 2014;Madureira et al, 2011;Pimentel et al, 2016;Romer et al, 2019;Self, 1976;Zanon & Pimentel, 2015), São Miguel (Beier et al, 2006;Elliott et al, 2007;Haase & Beier, 2003;Turner et al, 1997;Widom et al, 1997;Zanon, 2015), and the Northern Hirondelle Basin flank (Storch et al, 2020) with previous structural studies on this section of the Terceira Rift, that is, the SE Hirondelle Basin , the western part of São Miguel (Beier et al, 2006) at Terceira's eastern volcanoes (Madeira et al, 2015), and the offshore continuations at the NW and SE Terceira Ridges (Casalbore et al, 2015).…”

Section: The Distribution Of Tectonic and Volcanic Structures In The Northwest Hirondelle Basinsupporting

confidence: 56%

“…There is no clear evidence for ROMER ET AL. ocean seafloor spreading at the Terceira, neither geochemically (Storch et al, 2020) nor from gravity data (Luis et al, 1998) or geophysical data excluding extensive lithosphere thinning (Spieker et al, 2018). This along with the geometric similarities of magmatic segments along the Terceira Rift and the MER (Figure 9) suggests that initial oceanic rifts may be comparable to slow-diverging continental rifts rather than oceanic spreading centers.…”

Section: Geometry Of Magmatic Segments Along the Terceira Riftmentioning

confidence: 97%

“…This together with geochemical modeling at D. João de Castro indicating the presence of residual garnet in the mantle, that is, melting at >80 km (Beier et al., 2008; Robinson & Wood, 1998), shows that the lithosphere is thicker than normal oceanic lithosphere. The seamount's age is estimated to be <0.5 Ma, whereas lavas from the adjacent NW Hirondelle flank have a minimum age of 1.55 Ma (Storch et al., 2020). D. João de Castro volcano is still active as evident from seismic activity, hydrothermal venting (Cardigos et al., 2005), and the latest recorded eruption occurred 1720 CE reaching subaerial levels but was later eroded to a water depth of ∼12 m below sea level (mbsl) (Weston, 1964).…”

Section: Geological Settingmentioning

confidence: 99%

“…(b) TiO 2 , (c) FeO T , (d) CaO, (e) Na 2 O, and (f) K 2 O versus MgO contents for lavas from D. João de Castro volcano and the N and NW Castro Ridge. Literature data show lavas from the adjacent magmatic systems Terceira(Beier et al, 2008;Hildenbrand et al, 2014;Madureira et al, 2011;Pimentel et al, 2016;Romer et al, 2019;Self, 1976;Zanon & Pimentel, 2015), São Miguel(Beier et al, 2006;Elliott et al, 2007;Haase & Beier, 2003;Turner et al, 1997;Widom et al, 1997;Zanon, 2015), and the Northern Hirondelle Basin flank(Storch et al, 2020). Literature data from D. João de Castro fromBeier et al (2008).…”

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confidence: 99%

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The Evolution of Central Volcanoes in Ultraslow Rift Systems: Constraints From D. João de Castro Seamount, Azores

et al. 2021

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Volcanic activity along diverging plate boundaries in oceanic and continental settings commonly is the result of interacting magmatic and tectonic processes. Magmatism at oceanic and continental rift systems and mid-ocean ridges (MOR) plays a significant role in global plate tectonics, for example, leading to continental breakup and new oceanic crust formation (Heezen, 1960;Wilson, 1968). MORs as well as oceanic and continental rifts erupt a variety of chemically distinct lavas and have different morphological appearances depending among other processes on the extension rate. Fast-spreading MORs, for example, the East Pacific Rise (EPR), have continuous volcanically active segments and erupt large volumes of melt from the depleted

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Section: The Distribution Of Tectonic and Volcanic Structures In The Northwest Hirondelle Basinsupporting

confidence: 56%

Section: Geometry Of Magmatic Segments Along the Terceira Riftmentioning

confidence: 97%

Section: Geological Settingmentioning

confidence: 99%

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confidence: 99%

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The Evolution of Central Volcanoes in Ultraslow Rift Systems: Constraints From D. João de Castro Seamount, Azores

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“…The trace element composition of volcanic glass samples from Maka (n 4) was determined on hand-picked glass separates by a Thermo Scientific XSERIES 2 Quadrupole ICP-MS at the GeoZentrum Nordbayern (Supplementary Table S2). Details about the analytical procedure are presented in Storch et al (2020).…”

Section: Major and Trace Elementsmentioning

confidence: 99%

Trace Element and Isotope Systematics in Vent Fluids and Sulphides From Maka Volcano, North Eastern Lau Spreading Centre: Insights Into Three-Component Fluid Mixing

et al. 2021

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Back-arc spreading centres and related volcanic structures are known for their intense hydrothermal activity. The axial volcanic edifice of Maka at the North Eastern Lau Spreading Centre is such an example, where fluids of distinct composition are emitted at the Maka hydrothermal field (HF) and at Maka South in 1,525–1,543 m water depth. At Maka HF black smoker-type fluids are actively discharged at temperatures of 329°C and are characterized by low pH values (2.79–3.03) and a depletion in Mg (5.5 mmol/kg) and SO4 (0.5 mmol/L) relative to seawater. High metal (e.g., Fe up to ∼6 mmol/kg) and rare Earth element (REE) contents in the fluids, are indicative for a rock-buffered hydrothermal system at low water/rock ratios (2–3). At Maka South, venting of white smoke with temperatures up to 301°C occurs at chimneys and flanges. Measured pH values range from 4.53 to 5.42 and Mg (31.0 mmol/kg), SO4 (8.2 mmol/L), Cl (309 mmol/kg), Br (0.50 mmol/kg) and Na (230 mmol/kg) are depleted compared to seawater, whereas metals like Li and Mn are typically enriched together with H2S. We propose a three-component mixing model with respect to the fluid composition at Maka South including seawater, a boiling-induced low-Cl vapour and a black smoker-type fluid similar to that of Maka HF, which is also preserved by the trace element signature of hydrothermal pyrite. At Maka South, high As/Co (>10–100) and Sb/Pb (>0.1) in pyrite are suggested to be related to a boiling-induced element fractionation between vapour (As, Sb) and liquid (Co, Pb). By contrast, lower As/Co (<100) and a tendency to higher Co/Ni values in pyrite from Maka HF likely reflect the black smoker-type fluid. The Se/Ge ratio in pyrite provides evidence for fluid-seawater mixing, where lower values (<10) are the result of a seawater contribution at the seafloor or during fluid upflow. Sulphur and Pb isotopes in hydrothermal sulphides indicate a common metal (loid) source at the two vent sites by host rock leaching in the reaction zone, as also reflected by the REE patterns in the vent fluids.

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Plate boundary deformation at the Azores triple junction determined from continuous GPS geodetic measurements, 2002-2017

D'Araújo

Sigmundsson

Ferreira

et al. 2021

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Ground deformation in the Azores, at the triple junction between the Eurasian, Nubian, and North American plates, has been mapped with continuous GPS (Global Positioning System) geodetic measurements to improve tectonic motion estimates and for understanding volcanic unrest. We compute daily GPS positions, spanning almost 17 years (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017), from 18 continuous GPS stations. The GPS time-series are analyzed by searching for discontinuities and periodic functions. Results show that Flores and Graciosa islands have displacements close to predicted North American and Eurasian plate motions, respectively, while São Miguel, Terceira, São Jorge, Faial and Pico islands have displacements in between predicted Eurasian and Nubian plate motions. The Eurasian-Nubian plate boundary in the Azores behaves as a diffuse ultra-slow oblique spreading center with focused deformation found in the Central Group and Sao Miguel Island. The velocity field is modeled by approximating segments of the Eurasian-Nubian plate boundary with vertical dislocations with right-lateral motion and opening below a locking depth. Best fitting models have deep motion in the range of 2.4-2.7 mm yr -1 on segments directed N(76.5-78.8º)E. Such displacement accounts for more than half predicted Eurasian-Nubian relative plate motion. The modeling results suggest that the locking depth in the Central Group is about 17 km while in São Miguel is about 2 km. We found transient deformation at Fogo volcano, S\˜{a}o Miguel Island, due to unrest activity mainly during 2003-2006 and 2011-2012, and local continuous subsidence in Terceira Island, attributed to a deflation source centered on the island.

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Rifting of the oceanic Azores Plateau with episodic volcanic activity

Cited by 17 publications

References 71 publications

The Evolution of Central Volcanoes in Ultraslow Rift Systems: Constraints From D. João de Castro Seamount, Azores

The Evolution of Central Volcanoes in Ultraslow Rift Systems: Constraints From D. João de Castro Seamount, Azores

Trace Element and Isotope Systematics in Vent Fluids and Sulphides From Maka Volcano, North Eastern Lau Spreading Centre: Insights Into Three-Component Fluid Mixing

Plate boundary deformation at the Azores triple junction determined from continuous GPS geodetic measurements, 2002-2017

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