Reply to comment on “dynamic topography in South America” by Hechenleitnera, Fiorelli, Larrovere, Grellet-Tinnera, and Carignano

Abstract

This is a Reply to Hechenleitner and collaborators Comment, who proposed a Cretaceous age for the whole Llanos Formation (central Argentina, Sierras Pampeanas Province), based on neosauropod fossils, instead of Miocene as originally proposed by Ezpeleta et al. (2006) and Dávila et al. (2007). However, redbeds that underlay the thick paleosoils of the Llanos Formation provided nine detrital U-Pb Paleogene (62 Ma, earliest Cenozoic) ages on zircon grains (Astini et al., 2009; Ezpeleta 2009). On the base of this evidence, and other mammal remnant within the Sierras Pampeanas (where the Llanos Formation develops), we proposed this is a condensed unit with Mesozoic ages at the bottom and Mio-Pliocene (likely younger) to the top.