Ypresian

Ypresian
56.0 – 47.8 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Earth ~50 mya
Klondike Mountain Formation, Republic, Washington
Chronology
−65 — – −60 — – −55 — – −50 — – −45 — – −40 — – −35 — – −30 — – −25 — – M Z C e n o z o i c K P a l e o g e n e N L K P a l e o c e n e E o c e n e O l i g o c e n e M C Maastricht. Danian Selandian Thanetian Ypresian Lutetian Bartonian Priabonian Rupelian Chattian Aquitanian         ← PETM ← First Antarctic permanent ice-sheets[1] ← K-Pg mass extinction Subdivision of the Paleogene according to the ICS, as of 2021.[2] Vertical axis scale: millions of years ago
Formerly part of	Tertiary Period/System
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
First proposed by	Dumont
Time span formality	Formal
Lower boundary definition	Strong negative anomaly in δ13C values at the PETM[3]
Lower boundary GSSP	Dababiya section, Luxor, Egypt[3] 25°30′00″N 32°31′52″E / 25.5000°N 32.5311°E / 25.5000; 32.5311
Lower GSSP ratified	2003[3]
Upper boundary definition	FAD of the calcareous nannofossil Blackites inflatus
Upper boundary GSSP	Gorrondatxe section, Western Pyrenees, Basque Country, Spain 43°22′47″N 3°00′51″W / 43.3796°N 3.0143°W / 43.3796; -3.0143
Upper GSSP ratified	April 2011[4]

In the geologic timescale the Ypresian is the oldest age or lowest stratigraphic stage of the Eocene. It spans the time between 56 and 47.8 Ma, is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene.