Aim of the open session is to create a multidisciplinary platform, where presentations which include studies on systematics in stable isotopes or studies which use stable isotopes as a tool, can be presented if no specialized session is organized elsewhere in the EGU General Assembly program. The open session part includes a block of special interest on stable isotope analysis by optical spectrometry (co-convener Erik Kerstel). The isotope geoforensic part of the session (co-conveners Wolfram Meier-Augenstein and Lorna Dawson) aims at studies by light element isotopes or trace element isotopes or a ombination of both to answer questions relating to geographic origin, provenance, transfer or environmental fate of any compound or material of interest in food authenticity, forensic archaeology, ecology, environmental forensics, serious and organised crime, soil forensics, or wildlife forensics.