MIDDLE PERMIAN TELODIAGENETIC PROCESSES IN NEOPROTEROZOIC SEQUENCES, TANDILIA SYSTEM, ARGENTINA

ZALBA, P., MANASSERO, M., LAVERRET, E., BEAUFORT, D., MEUNIER, A., MOROSI, M., AND SEGOVIA, L.

JOURNAL OF SEDIMENTARY RESEARCH

SEPM

Lugar: USA; Año: 2006

1073-130X

In the Tandilia Basin, Buenos Aires Province, Argentina, we study the genesis of mud beds and pipes in the Loma Negra Formation (limestones), Sierras Bayas area together with the emplacement of alunite and aluminum phosphate sulfate (APS minerals) in the Las Aguilas Formation, Barker area. All these features are related to basin inversion, uplift, erosion and injection/expulsion or infiltration of fluids and oxidation reactions in the exhumed rocks during a telodiagenetic stage. On the basis of K-Ar dating of alunite in the Las Aguilas Formation (claystones) giving an age of 254 ± 7 Ma (middle Permian), these processes are considered to be linked to a major geological event which affected these Neoproterozoic lithostratigraphic units: the folding of the Ventania System, located 150 km to the SE of the study area. Key words: Neoproterozoic claystones and limestones, mud injection, alunite, aluminum phosphate sulfate minerals, Permian telodiagenesis