Mechanical stratigraphy and fault zone deformation of the Austin chalk in ten-mile creek, Desoto, Texas

Abstract

The Austin Chalk is a rhythmically bedded sequence of chalk and marl that represents carbonate deposition in the ancestral Gulf of Mexico during the Upper Cretaceous. The Austin Chalk differs from other chalk deposits due to its relatively high abundance of clay and volcanic ash. Outcrops of the formation stretch from north-central Texas to west Texas. This study presents a structural analysis from two sections along Ten-Mile Creek in DeSoto, Texas, where deformation of the Austin Chalk is characteristic of normal faulting in platform carbonate sequences. Outcrop studies provide the most complete view of a lithological unit. Analysis of fracture networks in outcrop provide a key insight into deformation of rock formations in the subsurface that cannot be gathered from subsurface data. Results show that fracture parameters correlate with mechanical properties and lithology, and that deformation in Ten-Mile Creek is consistent with that related to the Balcones Fault Zone.