Today, it is virtually unthinkable to solve almost any geologic problem without microfossils, whether in terms of age control or environmental proxies. Perhaps the turning point came in 1980 with the impact hypothesis as cause for the end-Cretaceous mass extinction. Although this hypothesis initiated one of the longest running and most acrimonious scientific debates, its most lasting and positive effects include the introduction of really high-resolution biostratigraphy at the cm-scale and the beginning of truly interdisciplinary and multi-disciplinary studies. Rarely has there been a topic so popular, albeit contentious, that it attracted interest and attention by disciplines across the spectrum of earth sciences and beyond. This report highlights advances in high-resolution biostratigraphy and environmental studies based on major events in Earth’s history, such as the Oceanic Anoxic Event 2 (OAE2) and the Cretaceous-Tertiary boundary (KTB) mass extinction. It illustrates current age control, biostratigraphic resolution, stable isotope records with characteristic δ¹³C excursions and integration with other disciplines to derive environmental interpretations.