Digitate columnar stromatolites from Neoproterozoic dolostones of Gibraltar Formation, Mina Verdún Group, Uruguay

POIRÉ, DANIEL; CANESSA, NÉSTOR; GARCÍA REPETO, FLAVIO; CANALICCHIO, JOSÉ

Uruguay

Simposio; Southamerican Symposio of Isotope Geology; 2006

Sociedad Uruguaya de Geología

The Mina Verdún Group (Poiré et al., 2003, 2005) in the Mina Verdún Quarry include a sedimentary succession composed from base to top of (Fig. 1): Don Mario Formation (black shales and metapelites), La Toma Formation (dark green marls), El Calabozo Formation (grey massive, laminated, and stromatolite limestones) and Gibraltar Formation (black marls and shales, pink limestones and light yellow, green, reddish, black and grey dolomites). To the south, this unit has been also reported in the Burgeño Quarry by Gaucher et al. (2004). Columnar stromatolites assigned almost exclusively to Conophyton from El Calabozo Formation have been reported by Poiré et al (2003a, 2003b, 2005). Furthermore, Conophyton has also been found in limestones of the El Calabozo Formation in the Burgeño Quarry (Gaucher et al., 2004). The aim of this contribution is to introduce the occurrence of a different assemblage of columnar stromatolites in the dolostones of the Gibraltar Formation, in the Verdún Quarry.