The mass extinction marking the Cretaceous/Palaeogene boundary (KPgB) »66.04 million years ago. It was one of the most devastating events in the history of life, as well as the most recent and best studied of the ‘big five’ mass extinctions that occurred during the Phanerozoic. After decades of research, one of the most critical lines of inquiry is understanding the short- to long-term effects of this impact on the global environmental system, including the re-establishment of pre-impact environmental conditions and marine biological productivity. After characterizing, during my PhD period, how the recovery of palaeoenvironmental conditions were (productivity and seafloor oxygenation), before, during, and after the KPgB impact, by the analysis of inorganic geochemical proxies, currently in this postdoctoral at the School of Earth Sciences, I am studying the KPgB distal sections (the Agost and Caravaca sections) using molecular fossils (or biomarkers). The approach will broadly encompass several methods, all of which will be carried out in the OGU (Organic Geochemistry Unit) at Bristol University. These will include the determination of total organic carbon (TOC) contents; the extract and analysis of the biomarkers from ground samples; the determination of key biomarker abundances and distributions by GC and GC-MS in order to ascertain changes in organic matter (OM) source, algal assemblages, terrestrial biomarkers (n-alkanes, triterpenes), redox state (pristane/phytane ratio; homohopane index) and microbial inputs (hopanes); and also, to explore changes in ‘apparent thermal maturity.