Hierarchical approach to define travertine depositional systems. 3D conceptual morphological model and possible applications

3D modelling represents a powerful tool to characterize the geobody architecture of depositional systems. Several examples have been proposed in literature both for marine carbonates and siliciclastics rocks. For modelling, quantitative data related to orientation, shape and dimension are fundamental. Continental carbonates, however, are not considered yet, likely because they cover a large range of deposits such as speleothems, tufas, lacustrine carbonates and travertines. The interpretation of the depositional environments of the latter is still in fact debated by the scientific community. However, the interest in continental carbonates and especially travertines increased over the last decades due to the discovery of supergiant unconventional reservoirs in the Southern Atlantic (i.e. the so-called “Pre-salt play”). Aim of this paper is to present an innovative workflow to investigate and describe continental carbonates as geobodies based on a hierarchical approach applied to three large scale travertine settings, i.e. Terme di San Giovanni (Italy), Pamukkale (Turkey) and the Lapis Tiburtinus travertines (Italy). Travertine depo-systems are divided in three different depo-zones, namely proximal, intermediate and distal, that are characterized by different depo-elements, depo-shapes and depo-facies. Finally, a 3D morphological model is created based on numerical and vector approaches and interpolation of both. The model can be applied to seismic data of Brazilian and Angolan Pre-salt, highlighting the similarities between these systems and for the first time the scale independence of these depositional system, representing an important advantage in their interpretation. The 3D model and the approach proposed facilitates seismic interpretation, allowing to define and characterize geometries of inaccessible geological contexts.