Toward a chronostratigraphy of the Paleocene-Eocene sedimentary record in northwestern Argentina. (January 2022)

• Record Type: Journal Article
• Authors: del Papa, Cecilia; Babot, Judith; Dahlquist, Juan; López, Daniel García; Deraco, Virginia; Herrera, Claudia; Bertelli, Sara; Rougier, Guillermo W.; Giannini, Norberto P.
• Is Part Of: Journal of South American earth sciences. Volume 113(2022)
• Publication Date: 2022-01
• Subjects: Salta group -- Non-marine sequences -- U–Pb dating -- Mammalian biostratigraphy; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2021.103677
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The Santa Bárbara Subgroup of the Salta Group in northwestern Argentina represents a key sedimentary record to understand the geological, biological, and climatological changes that occurred in South America during the Paleogene. However, the lack of absolute ages in these non-marine successions have prevented conclusive interpretations and correlations at a regional-scale. In this contribution, we present an integrative study based on sedimentological and stratigraphic approaches, a paleontological review, and, for the first time, an absolute age from a tuff level in the upper section of the Mealla Formation. We propose the following scenario: 1) Cycles of low and high accommodation stages that can be tracked at basin-scale providing a criterion to regional correlations; 2) An U–Pb zircon age of 58 Ma, which combined with previously estimated ages for Santa Bárbara Subgroup indicate that this unit is constrained between 61 and 49? Ma; 3) On view of this new age the fossil-bearing levels of the Mealla Formation fill a hiatus of more than 4 Myr in the South American vertebrate record for the middle to late Paleocene, reshaping our understanding of the early evolutionary stages of this fauna. Our results represent a robust first step to achieve reliable regional correlations and an integrative comprehension of the evolution of the Salta Basin and its fossil biota. Highlights: Cycles of low-high accommodation in fluvial-lacustrine transitional environments. New U–Pb zircon of 58 Ma for Mealla Formation reinforce the Selandian-Thanetian age. Biostratigraphy of Mealla Fm fill a gap between Carodnia zone and Itaboraian SALMA. Integrate sequence stratigraphy and Paleogene biostratigraphy for Salta Basin.