Significado de las Calizas Negras de la Formación Las Tienditas (Ediacarano-Cámbrico inferior) en el Noroeste Argentino

black limestone facies cropping out at las tienditas locality (salta) have been studied by means of organic matter content. 11 samples collected along the section display that the dark color is partially due to the organic carbon content. the samples from the upper part of the section have provided high levels of organic carbon (4% toc), while the middle and lower part display values below 1% toc. data allows to identify these limestone as organic-related carbon-rich facies associated to a explained by elevate bioproductivity in marine platform. the fne lamination observed in part of the sequence has been interpreted as tidal rhythmites developed on a shallow marine environment.