Sedimentology of the shallow marine deposits of the Calafate Formation during the Maastrichtian transgression at Lago Argentino, Austral-Magallanes Basin, Argentina

Autor: Andrea L. Odino Barreto, Abril Cereceda, Lucía E. Gómez-Peral, Marina D. Coronel, Camila Tettamanti, Daniel G. Poiré
Jazyk: English<br />Spanish; Castilian<br />Portuguese
Rok vydání: 2021
Předmět:
Zdroj: Latin American Journal of Sedimentology and Basin Analysis, Vol 25, Iss 2 (2021)
Druh dokumentu: article
ISSN: 1669-7316
1851-4979
Popis: The Maastrichtian shallow marine deposits exposed at the south margin of the Lago Argentino within the Austral-Magallanes Basin are known as the Calafate Formation. In order to interpret the depositional systems and reconstruct the se­quence stratigraphic architecture for this unit at its type locality (Cerro Calafate), we acquire new data from seven stratigraphic sections. We recognized six facies associations (FA-1 to FA-6) corresponding to shallow marine deposits, which are organized vertically displaying a transition from shallower to deeper conditions, representing a ~90 m thick transgressive succession. The Calafate Formation de­posits are differentiated into a lower wave-dominated coast (FA1, FA2 and FA3) and an upper tide-dominated coast (FA4, FA5 and FA6), each marked by the domi­nance of wave and tidal sedimentary processes, respectively. The Calafate Forma­tion overlies the fluvial deposits of the Chorrillo Formation by a transgressive sur­face (TS), which is overlaid by a transgressive marine succession characterized by a retrogradational stacking pattern. The latter is finally covered by offshore transition marine deposits marking a progressive deepening of the depositional system that culminates with the maximum flooding surface (MFS). From here, an aggradational stacking pattern dominates the upper sandstones of the unit repre­senting the highstand systems tract (HST), which is interpreted to be the cause of short-term periods when the accommodation space rate was nearly equaled to the sediment supply rate during the Maastrichtian.
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