Photogrammetric modeling and optimization of a stromatolite bioherm from the Yacoraite Formation (Maastrichtian-Danian, Argentina): a tool to preserve and enhance the paleontological heritage

Abstract

The virtualization of the fossil record has aroused an increasing attention. Fossils, as well as outcrops, can be digitized by various techniques, e.g., laser scanner, photogrammetry and/orcomputed tomography. One of the less explored applications involving 3D models is related to digital preservation and enhancement of the paleontological heritage. Here we present a 3D modeling experience, using high resolution digital photogrammetry and post-processing method offossil stromatolites from a Maastrichtian outcrop in Maimará (Quebrada de Humahuaca, UNESCO World Heritage Site, Jujuy, Argentina), well known for its ichnological and paleontologicalrecord. To model the outcrop, 408 photographs taken over a 18x7 m area were processed using the software Agisoft Metashape. The obtained 3D model (3.63 GB and about 41 million faces) wasoptimized to facilitate visualization and promote dissemination. Optimization consisted in simplifying the geometry of the model maintaining its original appearance and without changing theoverall topology. Retopology was conducted using the software Instant Meshes, while different textures were generated through the software Blender. The resulting 3D model has 31000 faces(4.36 MB), being externally very similar to the original. It can be viewed through any device for domestic use (e.g., laptop, tablet, smartphone) on digital repositories (e.g. Sketchfab), which allows the user to also share relevant information about the real specimens, such as their geological context or paleontological importance. 3D modeling of the fossil record and its optimization represent a very powerful and reliable tool in education, promotion of science and heritage preservation.