Lower Cretaceous provenance in the northern Austral basin of Patagonia from sedimentary petrography |
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Institution: | 1. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ángel Gallardo 470 (1405), Buenos Aires, Argentina;2. Dpto. Ecología, Genética y Evolución, FCEN, Universidad de Buenos Aires, Ciudad Universitaria (1428), Buenos Aires, Argentina;3. Instituto de Investigaciones en Biodiversidad y Medioambiente, CONICET-UNCo, Av. de los Pioneros 2350 (8400), S.C. de Bariloche, Río Negro, Argentina |
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Abstract: | The northern Austral basin from Patagonia is characterized by an Early Cretaceous (Barremian–Albian) coarse-grained regressive sequence. These littoral to continental deposits conform a 150 km long basin cropping out along the Southern Patagonian Andes between 47 and 48°S. The basin fill consist of basal deltaic sandstones with interbedded shales and limestones from the Río Belgrano Formation, topped by up to 350 m of fluvial conglomerates and reworked tuffs of the Río Tarde and Kachaike formations. This continental depocenter represent a major geodynamic and paleoenviromental change from the underling marine Río Mayer Formation. In this study we analyze the tectonic setting and provenance during deposition of the coarse-grained sequence using sedimentary petrography of 37 thin sections in four stratigraphic profiles covering the northern basin. Our dataset indicates mainly a recycled orogenic sandstones provenance, in agreement with potential surrounding basement sources. |
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Keywords: | Austral basin Southern Patagonian Andes Early Cretaceous Sandstone provenance Sedimentary petrography |
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