The Puercan North American Stage on the
geologic timescale
The geologic time scale, or geological time scale, (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochr ...
is the North American
faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by conven ...
according to the
North American Land Mammal Ages
The North American land mammal ages (NALMA) establishes a geologic timescale for North American fauna beginning during the Late Cretaceous and continuing through to the present. These periods are referred to as ages or intervals (or stages when re ...
chronology (NALMA), spanning the interval from 66,000,000 to 63,300,000 years
BP lasting .
It is usually considered to be within the
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch that lasted from about 66 to 56 million years ago (mya). It is the first epoch of the Paleogene Period in the modern Cenozoic Era. The name is a combination of the Ancient Greek ''palai ...
.
The Puercan directly follows the
Lancian NALMA, with the
K-Pg boundary and
K-Pg mass extinction at 66 MYA representing the boundary between the two. The Puercan is followed by the
Torrejonian NALMA stage.
Puercan age fossils, from the
Great Divide Basin,
Wyoming, include three newly identified
condylarth
Condylarthra is an informal group – previously considered an order – of extinct placental mammals, known primarily from the Paleocene and Eocene epochs. They are considered early, primitive ungulates. It is now largely considered to be a wast ...
members of the
Periptychidae; ''
Miniconus jeanninae,
Conacodon hettingeri,
Beornus honeyi''
Substages
The Puercan is considered to contain the following substages:
*Pu3: Lower boundary(?) source of the base of the Puercan (approximate).
*Pu2: Lower boundary source of the base of Puercan (approximate) and upper boundary source of the base of the Torrejonian (approximate).
*Pu1: Lower boundary source of the base of the Puercan (approximate) and upper boundary source of the base of the Torrejonian (approximate).
References
Paleocene life
Paleocene animals of North America
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