C-O isotopes of the Ediacarian Loma Negra Formation in Barker area, Tandilia System, Argentina: diagenetic implications

Abstract

The Neoproterozoic sedimentary succession of the Tandilia Basin is exposed in Olavarría and Barker areas and composed of the Villa Mónica, Cerro Largo, Las Aguilas, Olavarría and Loma Negra formations (Sierras Bayas Group) and the Cerro Negro Formation. On top of the Loma Negra Formation a regional unconformity, Barker Surface, was related to an important sea level fall which could be linked to Gaskiers glaciation, however no negative C isotopes excursions were observed.