3D geological modelling of igneous intrusions in LoopStructural v1.4.4

Abstract. Over the last two decades, there have been significant advances to improve the 3D modelling of geological structures by incorporating geological knowledge into the model algorithms. These methods take advantage of different structural data types and do not require manual processing, making them robust and objective. Igneous intrusions have received little attention in 3D modelling workflows, and there is no current method that ensures the reproduction of realistic intrusion shapes. Existing techniques are strongly dependent on the availability of data and manual processing to refine models. Intrusions are usually partly or totally covered, making the generation of realistic 3D models challenging without the modeller’s intervention. In this contribution, we present a method to stochastically model intrusions based on the Object-Distance Simulation Method. We adapted this method considering typical datasets and rules of intrusion emplacement mechanisms. Using the geometric elements of intrusions (inflation direction, propagation direction) and stochastic simulations of intrusion thickness, we can generate realistic intrusions shapes while honouring observations and accounting for the spatial variability in thickness. The method is tested in synthetic and real-world case studies and the results indicate that the method can reproduce expected geometries without manual processing. A comparison with Radial Basis Function (RBF) interpolation shows that our method can better reproduce intrusion shapes, particularly when considering scenarios with sparse datasets.