Isotopic composition Argentina 16 Isotopes 16 isotopic composition 12 Animals 6 Carbon Isotopes 6 Soils 6 animal 6 carbon 6 chemistry 6 stable isotope 6 Andes 4 Article 4 Carbon dioxide 4 Geographical origins 4 Groundwater 4 Mass Spectrometry 4 Mass spectrometers 4 Neuquen Basin 4 Nitrogen Isotopes 4 Soil 4 Spectrometry 4 Stable isotopes 4 Trace Elements 4 analysis 4 authenticity 4 carbon isotope 4 geographical origin 4 groundwater 4 isotope analysis 4