University of Padua

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

Masoch, Simone and Gomila, Rodrigo and Fondriest, Michele and Jensen, Erik and Mitchell, Thomas and Pennacchioni, Giorgio and Cembrano, José and Di Toro, Giulio (2023) Structural Evolution of a Crustal-Scale Seismogenic Fault in a Magmatic Arc: The Bolfin Fault Zone (Atacama Fault System). [Data Collection]

Related publications

Collection description

How 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°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.

DOI: 10.25430/
Keywords: Bolfin Fault Zone, Atacama Fault System, Precursory stuctures
Subjects: Physical:Sciences and Engineering > Earth System Science: Physical geography, geology, geophysics, atmospheric sciences, oceanography, climatology, cryology, ecology, global environmental change, biogeochemical cycles, natural resources management > Geology, tectonics, volcanology
Department: Departments > Dipartimento di Geoscienze
Depositing User: Rodrigo Alfonso Gomila Olmos de aguilera
Date Deposited: 16 May 2023 14:03
Last Modified: 16 May 2023 14:03
Cembrano, José
Di Toro,
Type of data: Text
Research funder: Marie Skłodowska-Curie Actions, Marie Skłodowska-Curie Actions, European Research Council
Research project title: FRICTION, DAMAGE, NOFEAR
Grant number: 896346
Collection period:
Resource language: English
Metadata language: English
Publisher: Research Data Unipd
Related publications:
Date: 16 May 2023
Copyright holders: The Author

Available Files


Cite As

Begin typing (e.g. Chicago or IEEE.) or use the drop down menu.

Begin typing (e.g. en-GB for English, Great Britain) or use the drop down menu.

Export As