The Physical and Mechanical Properties of Natural Fault Zones in Basaltic Rocks ...

• Main Author: Bamberg, Bob
• Format: Text
• Language: unknown
• Published: University of Leicester 2024
• Subjects: Uncategorized; Faroe Islands
• Online Access: https://dx.doi.org/10.25392/leicester.data.25020761; https://figshare.le.ac.uk/articles/thesis/The_Physical_and_Mechanical_Properties_of_Natural_Fault_Zones_in_Basaltic_Rocks/25020761

Faults represent a critical heterogeneity in basaltic sequences, which are gaining importance as potential sites for geothermal heat extraction and carbon storage. The processes controlling the behaviour of such faults at depth remain poorly constrained. The purpose of this research is to develop an integrated model for upper-crustal fault evolution in basalts, based on detailed structural, petrological, and hydromechanical characterisation of passively exhumed fault zones in the Faroe Islands. Faults record strain localisation from incipient decametre-wide zones comprising networks of Riedel shears, into high strain, metre-wide fault cores. These contain multiple cataclastic shear bands enclosing low-strain lenses of hydrothermal breccias and/or tabular veins, indicating significant late-stage dilatation. Abundant overprinting fault rock assemblages record episodic fault zone reorganisation and reworking of fault rocks. Fluid-mediated alteration leads to replacement of the tholeiitic basalt protolith, ...