Shape fabric development in rigid clast populations under pure shear: The influence of no-slip versus slip boundary conditions

• Probability density functions for rigid no-slip and rigid slip are derived in the case of pure shear.
• Maximum likelihood estimation is used to estimate finite strain along with bootstrap sampling errors.
• Application to a conglomerate indicates the importance of the slip mechanism in the deformation of unconsolidated sediments.

Shape fabrics of elliptical objects in rocks are usually assumed to develop by passive behavior of inclusions with respect to the surrounding material leading to shape-based strain analysis methods belonging to the Rf/ϕ family. A probability density function is derived for the orientational characteristics of populations of rigid ellipses deforming in a pure shear 2D deformation with both no-slip and slip boundary conditions. Using maximum likelihood a numerical method is developed for estimating finite strain in natural populations deforming for both mechanisms. Application to a natural example indicates the importance of the slip mechanism in explaining clast shape fabrics in deformed sediments.