Structural Evolution of a Crustal-Scale Seismogenic Fault in a Magmatic Arc: The Bolfin Fault Zone (Atacama Fault System)

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dc.contributor.authorMasoch, Simone
dc.contributor.authorGomila, Rodrigo
dc.contributor.authorFondriest, Michele
dc.contributor.authorJensen, Erik
dc.contributor.authorMitchell, Thomas
dc.contributor.authorPennacchioni, Giorgio
dc.contributor.authorCembrano, Jose
dc.contributor.authorDi Toro, Giulio
dc.date.accessioned2025-01-20T22:09:33Z
dc.date.available2025-01-20T22:09:33Z
dc.date.issued2021
dc.description.abstractHow 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.
dc.fuente.origenWOS
dc.identifier.doi10.1029/2021TC006818
dc.identifier.eissn1944-9194
dc.identifier.issn0278-7407
dc.identifier.urihttps://doi.org/10.1029/2021TC006818
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/94336
dc.identifier.wosidWOS:000691011200009
dc.issue.numero8
dc.language.isoen
dc.revistaTectonics
dc.rightsacceso restringido
dc.subject.ods13 Climate Action
dc.subject.odspa13 Acción por el clima
dc.titleStructural Evolution of a Crustal-Scale Seismogenic Fault in a Magmatic Arc: The Bolfin Fault Zone (Atacama Fault System)
dc.typeartículo
dc.volumen40
sipa.indexWOS
sipa.trazabilidadWOS;2025-01-12
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