Fig. 1

Temporal distribution of Paleogene glauconite, lignite, phosphorite and oolitic ironstone in different geographic zones (right). Green rectangles indicate glauconites with precise biostratigraphic information while the vertical black arrows indicate glauconite without precise age control. Yellow, brown and red rectangles indicate age range of lignite, phosphorite and ironstone, respectively. Note overlapping of data in a few cases. The number corresponds to those provided in Table 1. Further note that most glauconite deposits occur within three warm climatic intervals marked by grey bands, separated by cooling intervals (white bands). The grey bands also incorporate lignite, phosphorite and oolitic ironstone. Also note that the early Paleogene, i.e. from early late Paleocene (Selandian) to later part of early Eocene (Ypresian), contain the highest number of glauconite deposits. The ‘hyperthermal’ events within the grey bands are marked along with the carbon and oxygen isotopic curves. The sea-level cycle is adapted from Haq et al. (1987). Numbers correspond to those provided in Table 1. MECO: Middle Eocene climatic optimum; EECO: Early Eocene climatic optimum; ETM2: Eocene thermal maximum 2; ETM3: Eocene thermal maximum 3; PETM: Paleocene–Eocene thermal maximum; ELPE: Early late Paleocene event; MPBE: Mid Paleocene biotic event; LDE: Latest Danian event; MPBE: Mid Paleocene biotic event; DAN-C2 represents two short-lived carbon and oxygen isotope excursion at the early Danian (Gradstein et al. 2012); Black solid circless with ‘Oi’ represents Oligocene isotope excursion events (Miller et al. 2009)