Data from Murtinheira section at Cabo Mondego in Portugal. The section is dated from the upper Aalenian to the lower Bajocian (Middle Jurassic). Samples are labelled CN. Phosphorus content quantification was based on the ascorbic acid method (Mort et al., 2007) using a Perkin UV/Vis spectrophotometer Lambda 25. The concentration of PO4 was determined by calibration of BD47 and NU81 standards. TOC was measured after decarbonatization using an elementary analyzer Thermo-Finnigan Flash EA 1112. d13C organic carbon was measured using a Thermo Fischer Scientific Delta V isotope ratio mass spectrometer. d13C-d18O carbonate was measured using a Multiprep auto-sampler coupled to a GV Isoprime mass spectrometer calibrated based on NIST NBS19. CaCO3 content was measured using a Dietrich-Frühling calcimeter based on measuring the CO2 evolved after acidification of a sample.