10.6084/m9.figshare.3453887.v1 Rocco Novellino Rocco Novellino Giacomo Prosser Giacomo Prosser Richard Spiess Richard Spiess Cecilia Viti Cecilia Viti Fabrizio Agosta Fabrizio Agosta Enrico Tavarnelli Enrico Tavarnelli Francesco Bucci Francesco Bucci Dynamic weakening along incipient low-angle normal faults in pelagic limestones (Southern Apennines, Italy) Geological Society of London 2016 mechanism decomposition powder lubrication processes pore fluid pressures Southern Apennines fault Geology 2016-06-21 11:44:46 Journal contribution https://geolsoc.figshare.com/articles/journal_contribution/Dynamic_weakening_along_incipient_low-angle_normal_faults_in_pelagic_limestones_Southern_Apennines_Italy_/3453887 <p>Slip along low-angle normal faults is a mechanical paradox requiring activation of strain weakening mechanisms. Microstructures present in the slip zones of incipient low-angle normal faults cutting carbonates in the Southern Apennines of Italy show that slip was promoted by two weakening mechanisms producing a reduction of the friction coefficient: (1) high pore fluid pressures; (2) dynamic weakening related to thermal decomposition indicated by decarbonation microstructures and concomitant localized dynamic calcite recrystallization. Furthermore, as a consequence of thermal decomposition, nanoparticles occur as infilling of injection veins, suggesting that powder lubrication processes are active along the slip surface during seismic slip. </p>