Fluvial architecture and paleoenvironmental evolution of the Los Colorados Formation (Norian): Postrift stage of the Ischigualasto–Villa Unión Basin, NW Argentina

A shift from axial to transverse drainage systems played a central role in the postrift basin filling of the Ischigualasto–Villa Unión Basin during the Norian stage. This finding challenges the traditional view that axial systems are the primary sediment feeders in such basins. Researchers analyzed fluvial architecture and paleoenvironmental evolution using facies analysis, architectural-element evaluation, and vertical stacking patterns across 11 stratigraphic intervals of the Los Colorados Formation. The study revealed changes in channel facies concentration, paleocurrents, and sediment provenance, indicating a transition from an axial to a transverse drainage system. This radial pattern in paleocurrent data suggests that transverse systems can significantly influence postrift basin evolution, as evidenced by modern examples.

Santi Malnis, P., Colombi, C. E., Rothis, L. M., & Alcober, O. (2020). Fluvial architecture and paleoenvironmental evolution of the Los Colorados Formation (Norian): Postrift stage of the Ischigualasto–Villa Unión Basin, NW Argentina. Journal of Sedimentary Research, 90(10), 1436–1462. https://doi.org/10.2110/jsr.2020.65