Browsing by Author "Gomila, Rodrigo"
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- ItemAlong-strike architectural variability of an exhumed crustal-scale seismogenic fault (Bolfin Fault Zone, Atacama Fault System, Chile)(2022) Masoch, Simone; Fondriest, Michele; Gomila, Rodrigo; Jensen, Erik; Mitchell, Thomas M.; Cembrano, Jose; Pennacchioni, Giorgio; Di Toro, GiulioFault zone architecture and its internal structural variability play a pivotal role in earthquake mechanics, by controlling, for instance, the nucleation, propagation and arrest of individual seismic ruptures and the evolution in space and time of foreshock and aftershock seismic sequences. Nevertheless, the along-strike architectural variability of crustal-scale seismogenic sources over regional distances is still poorly investigated. Here, we describe the architectural variability of the >40-km-long exhumed, seismogenic Bolfin Fault Zone (BFZ) of the intra-arc Atacama Fault System (Northern Chile). The BFZ cuts through plutonic rocks of the Mesozoic Coastal Cordillera and was seismically active at 5-7 km depth and <= 300 degrees C in a fluid-rich environment. The BFZ in-cludes multiple altered fault core strands, consisting of chlorite-rich cataclasites-ultracataclasites and pseudo-tachylytes, surrounded by chlorite-rich protobreccias to protocataclasites over a zone up to 60-m-thick. These fault rocks are embedded within a low-strain damage zone, up to 150-m-thick, which includes strongly altered volumes of dilatational hydrothermal breccias and clusters of epidote-rich fault-vein networks at the linkage of the BFZ with subsidiary faults. The strong hydrothermal alteration of rocks along both the fault core and the damage zone attests to an extensive percolation of fluids across all the elements of the structural network during the activity of the entire fault zone. In particular, we interpret the epidote-rich fault-vein networks and associated breccias as an exhumed example of upper-crustal fluid-driven earthquake swarms, similar to the presently active intra-arc Liquin similar to e-Ofqui Fault System (Southern Andean Volcanic Zone, Chile).
- ItemHydrothermal alteration in an exhumed crustal fault zone : Testing geochemical mobility in the Caleta Coloso Fault, Atacama Fault System, Northern Chile(2014) Arancibia Hernández, Gloria Cecilia; Fujita, K.; Hoshino, K.; Mitchell, T.; Cembrano, José; Gomila, Rodrigo; Morata, D.; Faulkner, D.; Rempe, M.
- ItemInsights on the structural control of a Neogene forearc basin in Northern Chile: a geophysical approach(2018) García Pérez, Tiaren; Marquardt R., Carlos; Yáñez Carrizo, Gonzalo Alejandro; Cembrano, José; Gomila, Rodrigo; Santibañez, Isabel; Maringue, José
- ItemPalaeopermeability anisotropy and geometrical properties of sealed-microfractures from micro-CT analyses: An open-source implementation(2019) Gomila, Rodrigo; Arancibia Hernández, Gloria Cecilia; Mery Quiroz, Domingo; Nehler, Mathias; Bracke, Rolf; Morata, Diego
- ItemPalaeopermeability structure within fault-damage zones : a snap-shot from microfracture analyses in a strike-slip system(2016) Gomila, Rodrigo; Arancibia Hernández, Gloria Cecilia; Mitchell, T.; Cembrano, José; Faulkner, D.
- ItemStress fields recorded on large-scale strike-slip fault systems : effects on the tectonic evolution of crustal slivers during oblique subduction(2015) Veloso Espinosa, Eugenio Andrés; Gomila, Rodrigo; Cembrano, José; González, Rodrigo; Jensen, Erik; Arancibia Hernández, Gloria Cecilia
- ItemStructural Evolution of a Crustal-Scale Seismogenic Fault in a Magmatic Arc: The Bolfin Fault Zone (Atacama Fault System)(2021) Masoch, Simone; Gomila, Rodrigo; Fondriest, Michele; Jensen, Erik; Mitchell, Thomas; Pennacchioni, Giorgio; Cembrano, Jose; Di Toro, GiulioHow major crustal-scale seismogenic faults nucleate and evolve in crystalline basements represents a long-standing, but poorly understood, issue in structural geology and fault mechanics. Here, we address the spatio-temporal evolution of the Bolfin Fault Zone (BFZ), a >40-km-long exhumed seismogenic splay fault of the 1000-km-long strike-slip Atacama Fault System. The BFZ has a sinuous fault trace across the Mesozoic magmatic arc of the Coastal Cordillera (Northern Chile) and formed during the oblique subduction of the Aluk plate beneath the South American plate. Seismic faulting occurred at 5-7 km depth and <= 300 degrees C in a fluid-rich environment as recorded by extensive propylitic alteration and epidote-chlorite veining. Ancient (125-118 Ma) seismicity is attested by the widespread occurrence of pseudotachylytes. Field geologic surveys indicate nucleation of the BFZ on precursory geometrical anisotropies represented by magmatic foliation of plutons (northern and central segments) and andesitic dyke swarms (southern segment) within the heterogeneous crystalline basement. Seismic faulting exploited the segments of precursory anisotropies that were optimal to favorably oriented with respect to the long-term far-stress field associated with the oblique ancient subduction. The large-scale sinuous geometry of the BFZ resulted from the hard linkage of these anisotropy-pinned segments during fault growth.
- ItemThe geometry, kinematics, and timing of deformation along the southern segment of the Paposo fault zone, Atacama fault system, northern Chile(2020) Ruthven, R.; Singleton, J.; Seymour, N.; Gomila, Rodrigo; Arancibia Hernández, Gloria Cecilia; Stockli, D.F.; Ridley, J.; Magloughlin, J.
- ItemThe Relationship Between Magmatism and Deformation Along the Intra-arc Strike-Slip Atacama Fault System, Northern Chile(2020) Seymour, N. M.; Singleton, J. S.; Mavor, S. P.; Gomila, Rodrigo; Stockli, D. F.; Heuser Amaya, Gert Klaus; Arancibia Hernández, Gloria Cecilia
- ItemTiming, Kinematics, and Displacement of the Taltal Fault System, Northern Chile : Implications for the Cretaceous Tectonic Evolution of the Andean Margin(2020) Mavor, S. P.; Singleton, J. S.; Gomila, Rodrigo; Heuser Amaya, Gert Klaus; Seymour, N. M.; Williams, S. A.; Arancibia Hernández, Gloria Cecilia; Johnston, S. M.; Kylander Clark, A. R. C.; Stockli, D. F.