A 3D model for the formation of turtleback surfaces: The Horzum Turtleback of western Turkey as a case study

Abstract

Turtleback surfaces are common elements of highly extended terrains all over the world. This paper presents a 3D model explaining the formation of turtleback surfaces based on field observations made on the Horzum Turtleback of the Alaşehir graben, western Turkey. Tree essential features have been determined as forming a turtleback surface. These are 1) the rolling hinge mechanism on a normal fault system, where the initial fault stays operational after forming second and third normal faults in its hanging wall; 2) relay ramps between initial fault segments; and 3) a synextensional intrusion on the shear zone of the initial normal fault at midcrustal level. Te strike-slip tectonic setting is not among the essential features as suggested recently for Death Valley turtlebacks. © TÜBİTAK.