The Paleocene, "early dawn of the recent", is a
geologic epoch that lasted from 65 Ma to 56 Ma
(million years ago). It is the first epoch of the
Paleogene Period in the modern Cenozoic era. As
with most other older geologic periods, the strata that
define the epoch's beginning and end are well
identified but the exact date of the end is uncertain.
The Paleocene epoch immediately followed the mass
extinction event at the end of the Cretaceous, known
as the K-T boundary (Cretaceous - Tertiary), which
marks the demise of the dinosaurs. The die-off of the
dinosaurs left unfilled ecological niches worldwide,
and the name "Paleocene" comes from Greek and
refers to the "old(er)" (palaios) – "new" ( kainos)
fauna that arose during the epoch, before modern
mammalian orders emerged in the Eocene.
Match left with right:
Boundaries and subdivisions
The K-T boundary that marks the separation between
Cretaceous and Paleocene is visible in the geological
record of much of the Earth by a discontinuity in the
fossil fauna, with high iridium levels. There is also
fossil evidence of abrupt changes in flora and fauna.
There is some evidence that a substantial but very
short-lived climatic change may have happened in the
very early decades of the Paleocene. There are
several theories about the cause of the K-T extinction
event, with most evidence supporting the impact of a
10 km diameter asteroid forming the buried
Chicxulub Crater on the coast of Yucatan, Mexico.
The end of the Paleocene ( 55 Ma) was marked by
one of the most significant periods of global change
during the Cenozoic. The Paleocene-Eocene Thermal
Maximum upset oceanic and atmospheric circulation
and led to the extinction of numerous deep-sea
forams and a major turnover in mammals on land.
___Beginning of Paleocene
___End of Paleocene
The early Paleocene was slightly cooler than the
preceding Cretaceous, though temperatures rose
again late in the epoch. The climate was warm and
humid world-wide, with subtropical vegetation
growing in Greenland and Patagonia. The poles were
cool and temperate; North America, Europe,
Australia and southern South America were warm
and temperate; equatorial areas had tropical climates;
and north and south of the equatorial areas, climates
were hot and arid.
Relative to the Cretaceous and Eocene, the global
climate of the Paleocene was
(cool, warm ).
Relative to Geological history in general, the
paleocene was ( warm, cool).
In many ways, the Paleocene continued processes
that had begun during the late Cretaceous Period.
During the Paleocene, the continents continued to
drift toward their present positions. Supercontinent
Laurasia had not yet separated into three continents -
Europe and Greenland were still connected, North
America and Asia were still intermittently joined by a
land bridge, while Greenland and North America