The controversial stratigraphy of the glacial deposits in the Tandilia System, Argentina
P. J. Pazos, A. Rapalini, 2011. "The controversial stratigraphy of the glacial deposits in the Tandilia System, Argentina", The Geological Record of Neoproterozoic Glaciations, Emmanuelle Arnaud, Galen P. Halverson, Graham Shields-Zhou
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In the Ediacaran–Cambrian Tandilia System of central Argentina, the glacial origin of the thin (10 m) Sierra del Volcán Formation (Fm.) has been recognized for many years (Spalletti & del Valle 1984), being the first undisputed glacial deposits recorded in the Río de la Plata craton. It consists of three units: (i) a basal polymictic diamictite with a kaolin-rich matrix, (ii) a middle pelite with heterolithic levels, undulatory stratification, symmetric ripples, and outsized clasts previously interpreted as dropstones, and (iii) an upper polymictic diamictite with subtle normal grading. Here, this poorly age-constrained formation is reviewed from a stratigraphic and regional context and compared with other putative glaciogenic intervals at the base of the Cerro Largo Fm. and in the Punta Mogotes borehole.