The impact of microbial mats in promoting record of Maastrichtian crocodylomorph tracks from Yacoraite Formation, Argentina

• Autores: Martín, Alfredo Alejandro; de Valais, Silvina; Díaz Martínez, Ignacio; Villafane, Patricio Guillermo; López Isla, Gabriel Ricardo; Citton, Paolo
• Año de publicación: 2025
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Exactas y Naturales; Overtracks; Palaeoenvironment; Palaeoecology; Swimming behaviour; Late Cretaceous; Ciencias Exactas y Naturales
• Institución: Universidad Nacional de Río Negro

Fil: Martín, Alfredo Alejandro. Instituto Superior de Correlación Geológica (INSUGEO, CONICET-UNT), Avenida Presidente Perón S/N, Tucumán, Tucumán Province 4107, Argentina
Fil: de Valais, Silvina. Instituto de Investigación en Paleobiología y Geología (IIPG, CONICET-UNRN), Avenida Roca 1242, General Roca, Río Negro Province 8332, Argentina
Fil: Díaz Martínez, Ignacio. Department of Earth Sciences and Condensed Matter Physics, Faculty of Sciences, University of Cantabria, Santander, Cantabria 39005, Spain
Fil: Villafane, Patricio Guillermo. Department of Botany and Geology, University of Valencia, C/Doctor Moliner 50, Burjassot, Valencia 46100, Spain
Fil: Citton, Paolo. Instituto de Investigación en Paleobiología y Geología (IIPG, CONICET-UNRN), Avenida Roca 1242, General Roca, Río Negro Province 8332, Argentina
Fil: López Isla, Gabriel Ricardo. Instituto Superior de Correlación Geológica (INSUGEO, CONICET-UNT), Avenida Presidente Perón S/N, Tucumán, Tucumán Province 4107, Argentina
Here we report tetrapod tracks from a stratigraphic level of Maastrichtian age in the Yacoraite Formation (Maimar a ichnosite, Jujuy Province, Argentina). The ichnological material consists of convex hyporeliefs whose formation was induced by growth of microbial mats in an upper subtidal-lower intertidal setting. Ichnological features that are recognized in tracks and traces allowed to include them into the categories of ‘punting tracks’ and ‘buoyancy tracks’. These categories suggest swim behaviours of the producers, which are tentatively interpreted as crocodylomorphs. Reconstruction of the filling process leading to tracks preservation and inclusion into the geological record enabled reconstructing at least two different phases of mats development, one dominated by chemical precipitation and the other by trapping and binding of coated grains and other particles. These two phases of mat growth are related to slightly changing energetic conditions of the palaeoenvironment and further support a marine origin for the unit. Finally, it is suggested that biologically induced, in-situ mineral precipitation promotes fast formation of overtracks through early lithification achieving preservation of tetrapod tracks well before their complete filling.
Here we report tetrapod tracks from a stratigraphic level of Maastrichtian age in the Yacoraite Formation (Maimar a ichnosite, Jujuy Province, Argentina). The ichnological material consists of convex hyporeliefs whose formation was induced by growth of microbial mats in an upper subtidal-lower intertidal setting. Ichnological features that are recognized in tracks and traces allowed to include them into the categories of ‘punting tracks’ and ‘buoyancy tracks’. These categories suggest swim behaviours of the producers, which are tentatively interpreted as crocodylomorphs. Reconstruction of the filling process leading to tracks preservation and inclusion into the geological record enabled reconstructing at least two different phases of mats development, one dominated by chemical precipitation and the other by trapping and binding of coated grains and other particles. These two phases of mat growth are related to slightly changing energetic conditions of the palaeoenvironment and further support a marine origin for the unit. Finally, it is suggested that biologically induced, in-situ mineral precipitation promotes fast formation of overtracks through early lithification achieving preservation of tetrapod tracks well before their complete filling.