Boletín de la Sociedad Geológica Mexicana Volumen 62, núm. 2, 2010, p. 221-231 http://dx.doi.org/10.18268/BSGM2010v62n2a3

Tafofacies e icnofacies de los niveles maastrichtianos-danianos correspondientes a la Formación Yacoraite, Cordillera Oriental de la provincia de Jujuy, Argentina

Carlos A. Cónsole Gonella^1,*, Florencio G. Aceñolaza¹

¹Instituto Superior de Correlación Geológica (INSUGEO – CONICET), Universidad Nacional de Tucumán. Miguel Lillo 205, San Miguel de Tucumán (4000), Argentina.

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Abstract

In this paper we present the taphofacies and ichnofacies characterization of the sedimentary horizons in the Yacoraite Formation (Maastrichtian-Danian) in the environs of Maimará, Tilcara district, Cordillera Oriental of Jujuy province in northwestern Argentina. With this purpose in mind, two detailed stratigraphic sections were analyzed in the study area. As a result we determined a G1 taphofacies, corresponding to a monotypic and polyspecific concentration of fragmented gastropods, indicating proximity to the coast and high-energy wave action, and a P1 taphofacies, corresponding to a monotypic and polyspecific reworked fish concentration, preserved in hummocky cross-stratification structures, indicating the action of proximal tempestites. The analysis of dominant Skolithos isp., Arenicolites isp., Diplocraterion isp. and Thalassinoides isp. ichnogenus allowed us to define the archetypal Skolithos ichnofacies, typical of high-energy environments and good availability of nutrients. Also, we emphasize the record of tridactil footprints, which are assigned to the subclass of birds Enanthiornithes. The taphofacies and ichnofacies analysis, and its correlation with the sedimentary lithofacies, allow us to define a high-energy shallow depositional environment, mixed, with good oxygenation, and nutrient availability, dominated by waves and brief episodic sedimentation as a product of storm events.

Keywords: Taphofacies, Ichnofacies, Argentina, Yacoraite Formation, Maastrichtian-Danian.