Volcanism in Reverse and Strike-Slip Fault Settings

Abstract

Traditionally volcanism is thought to require an extensional state of stress in the crust. This review examines recent relevant data demonstrating that volcanism occurs also in compressional tectonic settings associated with reverse and strike-slip faulting. Data describing the tectonic settings, structural analysis, analogue modelling, petrology, and geochemistry, are integrated to provide a comprehensive presentation of this topic. An increasing amount of field data describes stratovolcanoes in areas of coeval reverse faulting, and shield volcanoes, stratovolcanoes, and monogenic edifices along strike-slip faults, whereas calderas are mostly associated with pull-apart structures in transcurrent regimes. Physically-scaled analogue experiments simulate the propagation of magma in these settings, and taken together with data from subvolcanic magma bodies, they provide insight into the magma paths followed from the crust to the surface. In several transcurrent tectonic plate boundary regions, volcanoes are aligned along both the strikeslip faults and along fractures normal to the local least principal stress (σ 3 ). At subduction zones, intraarc tectonics is frequently characterised by contraction or transpression. In intra-plate tectonic settings, volcanism can develop in conjunction with reverse faults or strike slip faults. In most of these cases, magma appears to reach the surface along fractures striking parallel to the local σ 1 . In some cases, there is a direct geometric control by the substrate strikeslip or reverse fault: magma is transported beneath A. Tibaldi ( ) Department of Geological Sciences and Geotechnologies, University of Milan-Bicocca, Italy e-mail: alessandro.tibaldi@unimib.it the volcano to the surface along the main faults, irrespective of the orientation of σ 3 . The petrology and geochemistry of lavas erupted in compressive stress regimes indicate longer crustal residence times, and higher degrees of lower crustal and upper crustal melts contributing to the evolving magmas when compared to lavas from extensional stress regimes. Small volumes of magma tend to rise to shallow crustal levels, and magma mixing is common in the compressional regimes. In detailed studies from the Andes and Anatolia, with geographic and temporal coverage with which to compare compressional, transcurrent and extensional episodes in the same location, there do not appear to be changes to the mantle or crustal source materials that constitute the magmas. Rather, as the stress regime becomes more compressional, the magma transport pathways become more diffuse, and the crustal residence time and crustal interaction increases.

Laboratory Modelling of Volcano Plumbing Systems: A Review

“…23d) (Galland et al 2007a). These experimental results are corroborated by geological examples of orogenic fronts curved around batholiths (e.g., Boulder Batholith, Montana, USA; Kalakay et al 2001;Lageson et al 2001) and volcanoes, such as Tromen Volcano, Northern Patagonia, Argentina (Marques and Cobbold 2006;Galland et al 2007b;Llambías et al 2011), Guagua Pichincha Volcano, Ecuador (Legrand et al 2002), and El Reventador Volcano, Ecuador (Tibaldi 2005;Tibaldi et al 2010). …”

Initiation of the Wrangell Arc: A Record of Tectonic Changes in an Arc-Transform Junction Revealed by New Geochemistry and Geochronology of the ~29–18 Ma Sonya Creek Volcanic Field, Alaska

“…These two volcanoes physically overlap one another, and show a limited areal extent with focused distribution along the Duke River fault. Evidence for Oligocene to Miocene motion on the Duke River Fault (Cobbett et al, 2017) supports the idea that transcurrent faulting can focus arc volcanism along faults (Tibaldi et al, 2010). Shifts in lava chemistry from alkaline, to transitional, to calc-alkaline, and back to transitional affinities record the relative importance of the tectonic processes of leaky transform magmatism over a slab-window (alkaline) and subduction (calc-alkaline).…”

“…Convergent margins worldwide ubiquitously contain a "transition zone" between a volcanic arc and a transform boundary (e.g., Central America, Tibaldi et al, 2010;Kamchatka, Park et al, 2002; the Philippine Sea region, Fitch, 1972). The position of the actively subducting slab and translation of the upper plate along strike-slip faults occurs as the directions and rates of plate convergence change, and these variations are recorded in the volcanic arc portion of the arc-transform transition zone (Park et al, 2002;Portnyagin et al, 2005).…”

Perpectives on Integrated Solid Earth Sciences

“…Given that such fundamental questions remain about non-volcanic tremor, slow-slip, and the region in which they occur, these authors expect that this will be a fruitful field for a long time to come. The paper by Tibaldi et al (2009) (this volume) examines recent data demonstrating that volcanism also occurs in compressional tectonic settings (reverse and strike-slip faulting), rather than the traditional view that volcanism requires an extensional state of stress in the crust. Data describing the tectonic setting, structural analysis, analogue modelling, petrology, and geochemistry are integrated to provide a comprehensive presentation.…”