Rancholabrean
Encyclopedia
The Rancholabrean North American Stage on the geologic timescale is the North American faunal stage
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 convention have the same name, and the same boundaries.Rock...

 according to the North American Land Mammal Ages
North American Land Mammal Ages
The North American Mammal Ages establishes a geologic timescale for prehistoric North American fauna beginning 66.5 Ma during the Paleocene and continuing through to the Late Pleistocene...

 chronology (NALMA), typically set from less than 240,000 years to 11,000 years BP
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...

, a period of . It is usually considered to overlap the Middle Pleistocene
Middle Pleistocene
The Middle Pleistocene, more specifically referred to as the Ionian stage, is a period of geologic time from ca. 781 to 126 thousand years ago....

 and Late Pleistocene
Late Pleistocene
The Late Pleistocene is a stage of the Pleistocene Epoch. The beginning of the stage is defined by the base of the Eemian interglacial phase before the final glacial episode of the Pleistocene 126,000 ± 5,000 years ago. The end of the stage is defined exactly at 10,000 Carbon-14 years BP...

 epochs. The Rancholabrean is preceded by the Irvingtonian
Irvingtonian
The Irvingtonian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 1,800,000 to 300,000 years BP, a period of . It is usually considered to overlap the Lower Pleistocene and Middle...

 NALMA stage.

The Rancholabrean can be further divided into the substages of:
  • Sheridanian: Upper boundary source of the base of the Holocene
    Holocene
    The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...

     (approximate)


The Rancholabrean shares this time period with the Oldenburgian of European Land Mammal Ages
European Land Mammal Ages
The European Land Mammal Mega Zones are zones in rock layers that have a specific assemblage of fossils based on occurrences of fossil assemblages of European land mammals. These biozones cover most of the Neogene and Paleogene systems The European Land Mammal Mega Zones (abbreviation: ELMMZ,...

.
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