Abstract
Accretionary complexes record the histories of changes in physical properties of sediments from unlithified sediments to lithified rocks through the deformation processes along subduction interface. The trench sediment suffered various deformation of particulate flow, pressure solution deformation and cataclastic faultings from ductile to brittle regime during accretion in subduction zone. Tectonic mélange is a characteristic rock in on-land accretionary complexes. The dominant deformation mechanism of tectonic mélange formation is pressure solution on the basis of microscopic observation. However, brittle slickenlines are also commonly observed on mélange foliations at the outcrop scale. Although the slickenlines as a brittle failure is common on the surface of the pressure solution foliation, the relationship of their kinetic are still uncertain. Detailed observations of slickenlines suggest that they are formed by reactivation of the mélange foliations, which indicates that the slickenlines are developed after formation of block in matrix texture characterized in mélange. In addition, mélange foliations are cut by faults related to underplating of oceanic materials. Therefore, formation of slickenlines occur before underplating in a relatively deep portion along subduction interface. On the basis of P-T conditions reported from other parts of the Cretaceous Shimanto Belt, the mélange formation and underplating is inferred to have occurred around the seismic front or within the seismogenic zone. The change in deformation mechanisms from pressure solution to brittle failure may be the first change in physical properties from plastic to brittle around seismic front.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.