Structural architecture of the Jurassic western margin of the Neuquén basin, central Chile and Argentina (35°30?S)

TAPIA, F.; FARIAS, M.; MESCUA, J. F.

Viña del Mar

Congreso; GEOSUR 2013; 2013

The Neuquén Basin is a back-arc basin filled by Late Triassic-Early Cretaceous sediments unconformably overlying the pre-Mesozoic basement (Howell et al., 2005). This basin was partially inverted during both Cretaceous and Neogene times as a result of contractional building processes of the Southern Central Andes. During both contractional stages, fold-and-thrust belts developed along the eastern border of the Andes as the Malargüe fold-and-thrust belt between 34° and 37°S. During the last decade, a controversy has arisen on the mechanisms controlling the inversion of the western border of the basin. The argument is due to the relevance of the inversion of the pre-existing normal faults (Mescua and Giambiagi, 2012; and references herein) versus the development of the new thrusts involved in the Malargüe fold-and-thrust belt (Dimieri and Turienzo, 2012). Although subsurface studies would be needed to clarify this controversy, the identification of the paleogeography before contractional stages is a first approach to understand the structural architecture of the Neuquén Basin and how it influenced the basin inversion processes. In this contribution, we present new data of the stratigraphy and structure of this Andean region which will provide a background in the understanding of the architecture of the western border of the Neuquén Basin and the subsequent development of the Malargüe fold-and-thrust belt.