Evolución Geotectónica de las Sierras Pampeanas de Córdoba

VICTOR A. RAMOS; ROBERTO MARTINO; JUAN OTAMENDI; MÓNICA ESCAYOLA

Relatorio del XIX Congreso geológico Argentino

ALSAPEMA

Lugar: Córdoba; Año: 2014; p. 967 - 977

Geotectonic evolution of the Eastern Sierras Pampeanas. This chapter analyzes the different proposals on the Pampean orogenic evolution of the Eastern Sierras Pampeanas. These ranges were interpreted as a typical Caledonian orogen by Pastore at beginning of the XX century, and as a hercynotype orogen some years later. The advancement of knowledge, along with more accurate and numerous ages, helped to identify the different tectonic events that led to its formation. These have been grouped into three major hypotheses that attempt to reconstruct the tectonic evolution of the region: (1) collision of an oceanic ridge against an accretionary prism associated with the Río de la Plata craton; (2) collision of a ridge against Kalahari craton, dextral transform shift and juxtaposition with the Río de la Plata craton and subsequent collision with the Western Sierras Pampeanas; and (3) the Córdoba island arc terrane, collided against the Río de la Plata craton, with a westward subduction polarity, and subsequent collision of the Grenvillian Pampia terrane against the amalgamated margin with east subduction polarity. The strengths and weaknesses of each of these hypotheses are evaluated, emphasizing the inconsistencies and the necessary new data to obtain a consensus on the age and processes that led to the formation of the Eastern Sierras Pampeanas. A brief summary of the Famatinian and Andean orogenic cycles is also presented, along with taphrogenic Achalian, Gondwanian and Patagonidic cycles, in the province of Córdoba. Keywords: pampean orogeny, collision, accretionary prism, oceanic ridge, Pampia terrane.