Structural analysis of a blind thrust sheet in vicinity of a major fault zone: a case study in north of the Dezful Embayment (Zagros Belt, SW Iran)

Abstract

Fault-related folds with intricate geometries in foreland systems are complex structural traps. Such structures are found in the Dezful Embayment, part of the Zagros Belt's foreland basin. The study area lies south of the Balarud Fault Zone (BFZ). This study aims to understand the geometric characteristics and evolution of a subsurface thrust sheet in relation to the surrounding strata. A 3D seismic cube and well data are used to map layers and analyze the thrust sheet. The thrust zone is clearly visible in wells and seismic data, showing repeated units. Depth maps and maximum curvature attributes of the fault surface reveal NE-SW lineaments, indicating possible fault slip direction. Thickness maps of hanging and footwall blocks confirm a dominant reverse fault component with minimal strike-slip displacement. The thrust sheet's curvilinear geometry suggests folding during the latest stage of the Zagros Orogeny, in response to the thick Neogene clastics as its partial overburden. This thrust sheet should not be mistaken for the nearby BFZ