Geological Structures

Synonyms

Deformation structures; Tectonic structures

Definition

Geological structures are defined geometrically as features superimposed on rocks and landforms through the action of stresses arising from inherent Earth forces, gravity, and/or temperature, which distort rocks and change their original form and shape, as well as their location. Such changes referred to as deformation may occur from submicroscopic to regional scales.

Introduction

Structure is an inherent geometric attribute of igneous, sedimentary, and metamorphic rocks. Primary structures such as bedding (Fig. 1a), dykes, veins, and joints are characteristic of sedimentary and igneous rocks. Tectonic structures are superimposed geological structures on preexisting rocks by deformational processes related to tectonic plate movement forces. Preexisting rocks respond to deformation through the mechanisms of folding, shear rupture, extensional fracture, and changes to rock fabric (Twiss and Moores 2006). These structures...