Three-dimensional stromatolites from Maastrichtian–Danian Yacoraite Formation, Argentina: modelling and assessing hydrodynamic controls on growth patterns

Abstract

Stromatolites are biogenic sedimentary structures formed by the interplay of biological (microbial composition) and environmental factors (local hydrodynamic conditions, clastic input and/or water chemistry). Well-preserved, three-dimensional (3D) fossil stromatolites are key to assessing the environmental factors controlling their growth and resulting morphology in space and time. Here, we report the detailed analysis of well-exposed, highly informative stromatolite build-ups from a single stratigraphic horizon within the Maastrichtian–Danian Yacoraite Formation (Argentina). This study focuses on the analysis of depositional processes driving intertidal to shallow subtidal stromatolites. Overall depositional architecture, external morphology and internal arrangement (mega, macro, meso and microstructures) of stromatolite build-ups were analysed and combined with 3D photogrammetric models, allowing us to decipher the links between stromatolite structure and tidal dynamics. Results suggest that external morphology and architecture of elongated and parallel clusters grew under the influence of run-off channels. The internal morphology exhibits columnar structures where the space between columns is interpreted as recharge or discharge channels. This work supports the theory that stromatolites can be used as a high-resolution tool in the assessment of water dynamics, and provides a new methodological approach and data for the dynamic reconstruction of intertidal stromatolite systems through the geological record.

Microbialitic deposits of the Yacoraite Formation, NW Argentina: distribution, environments, paleoecology, and economic implications

“…In the lower part of the same section, Frías-Saba et al (2021) described a new microbialitic level composed of domical shapes up to 25 cm. The internal morphology of these domes shows a basal sector with columnar structures alternating with laminated structures and an upper sector with well-developed columns separated by the third-order channels, similar to those described by Villafañe et al (2021). The authors suggested that these microbialites developed in a subtidal/intertidal environment with moderate to high hydrodynamic energy were controlled by a shallowing upward process.…”

“…Later, Cónsole-Gonella et al (2017) presented a complete paleoenvironmental reconstruction, showing the ichnofacies implications describing the presence of five stromatolitic facies, some of them showing a remarkable degree of preservation. On the contrary, Villafañe et al (2021) studied this series and determined the relationship between hydrodynamic energy and these organo-sedimentary structures, defining seven stromatolitic beds in this locality. Finally, at the same locality, Frías-Saba et al (2021) described the influence of bacterial communities, sediment input, and CO 3 saturation of waters on the development of stromatolite microfabrics from Yacoraite Formation (for a detailed stratigraphic column with the position of microbialites, see Villafañe et al 2021).…”

“…In the same section, Villafañe et al (2021) made a high-resolution paleonvironmental study, focusing on one three-dimensionally exposed stromatolitic level (Fig. 3B).…”

“…Villafañe and Cónsole-Gonella (2019) and Villafañe et al (2021) defined different types of pores in one microbialitic level of Maimará section (MNE5): intraparticle, vug, cavern, fenestral, intercrystalline, interparticle (Fig. 7).…”

GIS-based methodology for mapping and modeling microbialite deposits in high mountain lakes and wetlands of Central Andes (Catamarca, Northwestern Argentina)

“…The use of drones would be replaced by tools such as acoustic sonar, something already used in modern environments such as Pavilion Lake (e.g., Mullins and Bird, 2007;Trembanis and Gutsche, 2019). This type of methodology could also be combined with techniques applied for the three-dimensional reconstruction of fossil microbialitic sites such as traditional photogrammetry (Villafañe et al, 2021b), Ground Penetrating Radar (de Lima et al, 2018, among others.…”