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Widespread volcanism has been known in the Sicilian Channel for a long time, even if some submarine volcanoes have only recently been discovered. Most of this volcanism formed along the NNE-trending transfer zone known as the Capo Granitola–Sciacca Fault Zone, while others, such as the islands of Pantelleria and Linosa, are associated with the continental rift zone that has developed since the early Pliocene in the central part of the Sicilian Channel through the formation of three deep tectonic troughs (Pantelleria, Linosa and Malta). However, the origin of a group of five volcanoes (here called "Tetide volcanic cluster") that form a NW-SE alignment on the eastern edge of the Adventure Plateau is not yet known. In this work, we hypothesize that this volcanic alignment may represent the remnants of a failed rift attempt that was unable to generate another tectonic trough in the Sicilian Channel. Based on seismic sections and gravimetric data, three phases in the formation of this volcanic alignment can be identified: (i) a major magmatic intrusion in the early Pliocene associated with a NW-SE normal fault that formed during the opening of the Pantelleria graben, leading to the uplift and deformation of the host sedimentary rocks; (ii) a late Pliocene-Quaternary tectono-magmatic quiescent phase; and (iii) a renewed magma intrusion through fissures or cracks that led to the formation of the volcanoes in the late Quaternary. This process was not able to cause significant extension and only limited volcanism, which is why the "Tetide volcanic cluster" is interpreted as the morphological expression of a failed rift. [ABSTRACT FROM AUTHOR]

Widespread volcanism has been known in the Sicilian Channel for a long time, even if some submarine volcanoes have only recently been discovered. Most of this volcanism formed along the NNE-trending transfer zone known as the Capo Granitola–Sciacca Fault Zone, while others, such as the islands of Pantelleria and Linosa, are associated with the continental rift zone that has developed since the early Pliocene in the central part of the Sicilian Channel through the formation of three deep tectonic troughs (Pantelleria, Linosa and Malta). However, the origin of a group of five volcanoes (here called “Tetide volcanic cluster”) that form a NW-SE alignment on the eastern edge of the Adventure Plateau is not yet known. In this work, we hypothesize that this volcanic alignment may represent the remnants of a failed rift attempt that was unable to generate another tectonic trough in the Sicilian Channel. Based on seismic sections and gravimetric data, three phases in the formation of this volcanic alignment can be identified: (i) a major magmatic intrusion in the early Pliocene associated with a NW-SE normal fault that formed during the opening of the Pantelleria graben, leading to the uplift and deformation of the host sedimentary rocks; (ii) a late Pliocene-Quaternary tectono-magmatic quiescent phase; and (iii) a renewed magma intrusion through fissures or cracks that led to the formation of the volcanoes in the late Quaternary. This process was not able to cause significant extension and only limited volcanism, which is why the “Tetide volcanic cluster“ is interpreted as the morphological expression of a failed rift.

The Nieve monogenetic volcanic cluster is located in the central–eastern region of the Michoacán–Guanajuato volcanic field, along the Huiramba fault zone, a relay ramp in the Morelia–Acambay fault system produced by oblique north-northwest transtension. This volcanic cluster includes at least 17 middle Pliocene to late Pleistocene lava domes, two small shield volcanoes, and two scoria cones. Between 4 and 3.8 Ma, two effusive eruptions built two small shield volcanoes overlying one another, with a magma volume of 3.93 km3. Between 2.9 Ma and 21.4 ka, 17 lava domes and two scoria cones were emplaced on the flanks of these volcanoes. The entire cluster resulted in a total erupted volume of 17 km3, covering an area of 326 km2 and reaching a thickness of emplaced volcanic material of 1200 m, resulting in a magma eruption rate equivalent to 0.004 km3/ka. All the rocks associated with this cluster are within a relatively restricted range in composition, between 53.9 and 64.2 wt% SiO₂, from andesite enriched in silica to basaltic andesite. The presence of intrusive-rock xenoliths and xenocrysts with dissolution textures reveals that assimilation processes modified the magmas. Based on the regional geological record, we suggest that the establishment of the Nieve volcanic cluster has been controlled by tectonic structures and the basement of the region, which has allowed the chemical evolution of these magma batches that probably had sources in at least two deep reservoirs as reflected by the Nb/Th versus Ta/U ratio. • The Nieve cluster includes 21 Pliocene-Pleistocene monogenetic volcanoes in México. • 19 self-similar volcanoes share distribution, mineral assemblage and composition. • Two deep reservoirs feed the independent and spatially coalescent volcanoes. [ABSTRACT FROM AUTHOR]

In the Central Andes, large (> 500 km2) and long-lived (1–5 Ma) volcanic clusters (LVCs) are less explored and their eruptive history and magmatic regimes less understood than smaller, short-lived (<0.5 Ma), individual stratocones. The Chachani-large volcanic cluster (C-LVC) sizeable volume (c. 290 km3) consists of twelve edifices forming the 1.06–0.64 Ma group of stratovolcanoes and the 0.46–0.05 Ma group of domes coulees and block-lava flow fields. Both groups overlie pre-Chachani lavas and tuffs 1.02–1.27 Ma, and together they have buried large nested craters or a caldera associated with the c. 1.62–1.66 Ma Arequipa Airport ignimbrite. The C-LVC evolved from: (i) homogeneous compositions of the pre-Chachani and Chachani basal eruptive units to (ii) relatively wide compositional variations (53–67 wt% SiO 2) between mafic andesite and dacite at moderate eruptive rates (0.27–0.41 km3/ka) for the 'Old Edifice' group, and finally to (iii) narrower (57–64 wt% SiO 2) andesitic compositions coinciding with extrusive activity at 2.5 times lower eruptive rates (0.12–0.15 km3/ka) for the 'Young Edifice' group. The large compositional variations in the Old Edifice group are related to strongly contrasting resident and recharge magma compositions of hybridized lavas. In contrast, the narrow compositional range and lower eruption rate during the second half of the C-LVC eruptive history represent a trend towards more homogeneous, andesitic magma composition with time. Mineral texture and compositional studies provide evidence for disequilibrium and magma mixing in the C-LVC shallow (5–20 km depth range) magma reservoirs. These temporal changes in magma composition document that the transcrustal magma systems of the C-LVC evolved and matured with time by a combination of processes: fractional crystallization, crustal contamination and magma mixing/mingling with variable rates of mafic recharge. This resulted in a shift in time to a steady state, monotonous (andesite) regime as a result of coupling between compositional parameters and thermal conditions, density constraints, and the viscosity/crystallinity of erupted magmas. • Long-lived volcanic clusters are less explored than stratocones in the Central Andes. • The Chachani LVC eruptive history shows narrowing SiO 2 compositional ranges over time. • Mineral composition changes support frequent recharge events along the C-LVC lifetime. • Eruptive rates have slowed in time at C-LVC, coinciding with magmatic compositions. • C-LVC represents post-caldera activity after the 1.66 Ma Arequipa Airport ignimbrite. [ABSTRACT FROM AUTHOR]