Complex geometry and kinematics of subsidiary faults within a carbonate-hosted relay ramp

Mercuri, Marco; McCaffrey, Ken J.W.; Smeraglia, Luca; Mazzanti, Paolo; Collettini, Cristiano; Carminati, Eugenio

Abstract

Minor fault geometry and kinematics within relay ramps is strongly related to the stress field perturbations that can be produced when two major fault segments overlap and interact. Here we integrate classical fieldwork and interpretation of a virtual outcrop to investigate the geometry and kinematics of subsidiary faults within a relay ramp along the Tre Monti normal fault in the Central Apennines. Although the Tre Monti fault strikes parallel to the regional extension (NE-SW) it shows predominant dip-slip kinematics, suggesting a NW-SE oriented extension acting at sub-regional scale (1–10 km). Conversely, the slickenlines collected on the front segment of the relay ramp highlight right-lateral kinematics. The subsidiary faults in the relay ramp show a complex geometry (variable attitudes) and slickenlines describe multiple kinematics (left-lateral, dip-slip, right-lateral), independently of their orientation. Our fault slip analysis indicates that a local stress field retrieved from the kinematic inversion of the slickenlines collected on the front segment, and likely promoted by the interaction between the overlapping fault segments that bound the relay zone, can explain most of the geometry and kinematics of the subsidiary faults. Further complexity is added by the temporal interaction with both the regional and sub-regional stress fields.

Citation

Mercuri, M., McCaffrey, K. J., Smeraglia, L., Mazzanti, P., Collettini, C., & Carminati, E. (2019). Complex geometry and kinematics of subsidiary faults within a carbonate-hosted relay ramp. Journal of Structural Geology, 130, Article 103915. https://doi.org/10.1016/j.jsg.2019.103915

• Journal Article Type: Article
• Acceptance Date: Oct 18, 2019
• Online Publication Date: Oct 23, 2019
• Publication Date: Jan 31, 2019
• Deposit Date: Nov 4, 2019
• Publicly Available Date: Oct 23, 2020
• Journal: Journal of Structural Geology
• Print ISSN: 0191-8141
• Electronic ISSN: 1873-1201
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 130
• Article Number: 103915
• DOI: https://doi.org/10.1016/j.jsg.2019.103915
• Public URL: https://durham-repository.worktribe.com/output/1285009