Mapping deformation: the map representation of geological structure

Abstract

Faults and folds are the clearest expressions of deformation we can observe directly in the rock record. This is visualised on 2D maps through the geometry of outcrop patterns and lines or polygons with marker symbols indicating different kinematics. But the record of deformation is 4D, and faults and folds represent only the products of deformation, not the processes responsible. Understanding the evolution of the 3D structural framework through time is fundamental for all forms of subsurface exploration across the energy transition. The aim of this paper is to show how 2D geospatial databases can represent the 4D deformational record. This is by capturing the three components of deformation: the initial state of the crustal architecture to be deformed (the pre-deformational crustal facies and structural framework), the processes responsible for the deformation (geodynamics), and the products of the deformation (folds, faults, magmatism, and crustal facies). Deformation is not limited to a single tectonic cycle. Within each cycle, it is time-transgressive and highly variable spatially. By evolving these 2D geospatial databases through time using restoration and plate modelling, we can better understand the 4D complexity of deformation and how this impacts exploration.