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66.0 – 56.0 Ma
Name formalityFormal
Name ratified1978
Alternate spelling(s)Palaeocene
Usage information
Regional usageGlobal (
δ13C values at the PETM[3]
Upper boundary GSSPDababiya section, Luxor, Egypt[3]
25°30′00″N 32°31′52″E / 25.5000°N 32.5311°E / 25.5000; 32.5311
Upper GSSP ratified2003[3]

The Paleocene, (

Era. The name is a combination of the Ancient Greek παλαιός palaiós meaning "old" and the Eocene
Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene".

The epoch is bracketed by two major events in Earth's history. The

Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification

In the Paleocene, the continents of the Northern Hemisphere were still connected via some land bridges; and South America, Antarctica, and Australia had not completely separated yet. The Rocky Mountains were being uplifted, the Americas had not yet joined, the Indian Plate had begun its collision with Asia, and the North Atlantic Igneous Province was forming in the third-largest magmatic event of the last 150 million years. In the oceans, the thermohaline circulation probably was much different from what it is today, with downwellings occurring in the North Pacific rather than the North Atlantic, and water density mainly being controlled by salinity rather than temperature.

The K–Pg extinction event caused a floral and faunal turnover of species, with previously abundant species being replaced by previously uncommon ones. In the Paleocene, with a global average temperature of about 24–25 °C (75–77 °F), compared to 14 °C (57 °F) in more recent times, the Earth had a

ray-finned fish
rose to dominate open ocean and recovering reef ecosystems.


Wilhelm Philipp Schimper
who coined the term "Paleocene"

The word "Paleocene" was first used by French

Moritz Hörnes had introduced the Paleogene for the Eocene and Neogene for the Miocene and Pliocene in 1853.[10] After decades of inconsistent usage, the newly formed International Commission on Stratigraphy (ICS), in 1969, standardized stratigraphy based on the prevailing opinions in Europe: the Cenozoic Era subdivided into the Tertiary and Quaternary sub-eras, and the Tertiary subdivided into the Paleogene and Neogene Periods.[11] In 1978, the Paleogene was officially defined as the Paleocene, Eocene, and Oligocene Epochs; and the Neogene as the Miocene and Pliocene Epochs.[12] In 1989, Tertiary and Quaternary were removed from the time scale due to the arbitrary nature of their boundary, but Quaternary was reinstated in 2009.[13]

The term "Paleocene" is a

ligature æ instead of "a" and "e" individually, so only both characters or neither should be dropped, not just one.[6]



K–Pg boundary
recorded in a Wyoming rock (the white stripe in the middle)

The Paleocene Epoch is the 10 million year time interval directly after the

million years ago (mya), the Selandian spanning 61.6 to 59.2 mya, and the Thanetian spanning 59.2 to 56 mya. It is succeeded by the Eocene.[14]


Deccan Trap volcanism caused a cataclysmic event at the boundary resulting in the extinction of 75% of all species.[15][16][17][18]

The Paleocene ended with the

Paleocene–Eocene thermal maximum, a short period of intense warming and ocean acidification brought about by the release of carbon en masse into the atmosphere and ocean systems,[19] which led to a mass extinction of 30–50% of benthic foraminifera–planktonic species which are used as bioindicators of the health of a marine ecosystem—one of the largest in the Cenozoic.[20][21] This event happened around 55.8 mya, and was one of the most significant periods of global change during the Cenozoic.[19][22][23]


Geologists divide the rocks of the Paleocene into a

formation (a stratotype) identifying the lower boundary of the stage. In 1989, the ICS decided to split the Paleocene into three stages: the Danian, Selandian, and Thanetian.[24]

The Danian was first defined in 1847 by German-Swiss geologist Pierre Jean Édouard Desor based on the Danish chalks at Stevns Klint and Faxse, and was part of the Cretaceous, succeeded by the Tertiary Montian Stage.[25][26] In 1982, after it was shown that the Danian and the Montian are the same, the ICS decided to define the Danian as starting with the K–Pg boundary, thus ending the practice of including the Danian in the Cretaceous. In 1991, the GSSP was defined as a well-preserved section in the El Haria Formation near El Kef, Tunisia, 36°09′13″N 8°38′55″E / 36.1537°N 8.6486°E / 36.1537; 8.6486, and the proposal was officially published in 2006.[27]

The ocean to the left, gentle tides coming in, a small piece of sandy beach before the white cliffs rise with grass on the top
The sea cliffs of Itzurun beach near the town of Zumaia, Spain, the GSSP for the Selandian and Thanetian

The Selandian and Thanetian are both defined in Itzurun beach by the

early Eocene sea cliff outcrop. The Paleocene section is an essentially complete, exposed record 165 m (541 ft) thick, mainly composed of alternating hemipelagic sediments deposited at a depth of about 1,000 m (3,300 ft). The Danian deposits are sequestered into the Aitzgorri Limestone Formation, and the Selandian and early Thanetian into the Itzurun Formation. The Itzurun Formation is divided into groups A and B corresponding to the two stages respectively. The two stages were ratified in 2008, and this area was chosen because of its completion, low risk of erosion, proximity to the original areas the stages were defined, accessibility, and the protected status of the area due to its geological significance.[24]

The Selandian was first proposed by Danish geologist Alfred Rosenkrantz in 1924 based on a section of fossil-rich

open ocean environment in the North Sea region (which had been going on for the previous 40 million years). The Selandian deposits in this area are directly overlain by the Eocene Fur Formation—the Thanetian was not represented here—and this discontinuity in the deposition record is why the GSSP was moved to Zumaia. Today, the beginning of the Selandian is marked by the appearances of the nannofossils Fasciculithus tympaniformis, Neochiastozygus perfectus, and Chiasmolithus edentulus, though some foraminifera are used by various authors.[24]

The Thanetian was first proposed by Swiss geologist

chron is the occurrence of a geomagnetic reversal—when the North and South poles switch polarities. Chron 1 (C1n) is defined as modern day to about 780,000 years ago, and the n denotes "normal" as in the polarity of today, and an r "reverse" for the opposite polarity.[29] The beginning of the Thanetian is best correlated with the C26r/C26n reversal.[24]

Mineral and hydrocarbon deposits

open-pit mine

Several economically important coal deposits formed during the Paleocene, such as the

open-pit mine in the world.[33] Paleocene coal has been mined extensively in Svalbard, Norway, since near the beginning of the 20th century,[34] and late Paleocene and early Eocene coal is widely distributed across the Canadian Arctic Archipelago[35] and northern Siberia.[36] In the North Sea, Paleocene-derived natural gas reserves, when they were discovered, totaled approximately 2.23 trillion m3 (7.89 trillion ft3), and oil in place 13.54 billion barrels.[37] Important phosphate deposits—predominantly of francolite—near Métlaoui, Tunisia were formed from the late Paleocene to the early Eocene.[38]

Impact craters

Silicate glass spherules along the Atlantic coast of the U.S. indicate a meteor impact in the region at the PETM.[48] The buried Hiawatha Glacier crater in Greenland has been dated to the late Paleocene, around 58 mya.[49]



North American plate