second geologic series and epoch of the Cretaceous system and period
Subdivision of the Cretaceous according to the ICS, as of 2024. Vertical axis scale: Millions of years ago
Etymology Chronostratigraphic nameUpper Cretaceous Geochronological nameLate Cretaceous Name formalityFormal Usage information Celestial bodyEarth Regional usageGlobal (ICS) Time scale(s) usedICS Time Scale Definition Chronological unitEpoch Stratigraphic unitSeries Time span formalityFormal Lower boundary definitionFAD of the Planktonic Foraminifer Rotalipora globotruncanoides Lower boundary GSSPMont Risoux, Hautes-Alpes, France 44°23′33″N 5°30′43″E / 44.3925°N 5.5119°E / 44.3925; 5.5119 Lower GSSP ratified2002 Upper boundary definitionIridium enriched layer associated with a major meteorite impact and subsequent K-Pg extinction event Upper boundary GSSPEl Kef Section, El Kef, Tunisia 36°09′13″N 8°38′55″E / 36.1537°N 8.6486°E / 36.1537; 8.6486 Upper GSSP ratified1991
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).