This lecture is presented by Dr Indrani Mukherjee, winner of an RST Doctoral Award in 2019. Indrani’s PhD involved understanding pyrite trace element and sulphur isotope geochemistry of Proterozoic marine black shales using LA-ICP-MS and SHRIMP-SI techniques. The research focussed on nutrient-productivity cycles in past oceans and atmosphere-ocean redox state in the context of biological evolution in the Proterozoic era. Pyrite chemostratigraphy was also used for assessing mineralisation potential of black shales. This presentation will expand on the research foundations built over the course of Indrani’s PhD targeting both fundamental and applied aspects of geochemistry. The former involves advancing our knowledge of Precambrian atmosphere-ocean dynamics in shaping the course of early evolution. The latter involves utilisation of the geochemical data combined with statistical tools, for applications such as biogenicity tools, predictive modelling, and mineral exploration.