Three-dimensional geological modelling of igneous intrusions in LoopStructural v1.5.10

Abstract. Over the last 2 decades, there have been significant advances in the 3D modelling of geological structures via the incorporation of 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 intrusion shapes comparable to those mapped in the field or in geophysical imagery. 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 model igneous intrusions in 3D considering geometric constraints consistent with emplacement mechanisms. Contact data and inflation and propagation direction are used to constrain the geometry of the intrusion. Conceptual models of the intrusion contact are fitted to the data, providing a characterisation of the intrusion thickness and width. The method is tested using synthetic and real-world case studies, and the results indicate that the method can reproduce expected geometries without manual processing and with restricted datasets. A comparison with radial basis function (RBF) interpolation shows that our method can better reproduce complex geometries, such as saucer-shaped sill complexes.