All Topics  
Early Pleistocene

 

 
   Email Print
   Bookmark   Link
 

 

Early Pleistocene
 
 
  Topics Early Pleistocene Topic Home

Early Pleistocene (also known as Lower Pleistocene, or Calabrian) is a subdivision of the Pleistocene
Pleistocene

The Pleistocene is the epoch from 1.8 million to 10,000 years Before Present covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
 Epoch of the Geologic time scale
Geologic time scale

File:Geologic clock.jpgThe geologic time scale is a chronology schema relating stratigraphy to time that is used by geologys and other earth sciences scientists to describe the timing and relationships between events that have occurred during the history of the Earth....
. The beginning of the stage is defined at 1.806 ± 0.005 Ma
Annum

Annum is one form of the Latin noun meaning year, not a form normally used for derivatives in modern languages: the accusative case Grammatical number of the second declension grammatical gender noun annus , anni ....
 (million years ago). The end of the stage is defined by the last magnetic pole reversal
Geomagnetic reversal

A geomagnetic reversal is a change in the orientation of Earth's magnetic field such that the positions of magnetic north and magnetic south become interchanged....
 781,000 ± 5,000 years ago. Originally the Calabrian was a European faunal stage
Faunal stage

In chronostratigraphy, a stage is a Geologic record laid down in an single age on the geologic timescale, which usually represents millions of years of deposition....
 primarily based on mollusk fossils. It has been subsumed into, and become equivalent to, the geologic stage called the Early Pleistocene.






Discussion
Ask a question about 'Early Pleistocene'
Start a new discussion about 'Early Pleistocene'
Answer questions from other users
Full Discussion Forum



Encyclopedia


Early Pleistocene (also known as Lower Pleistocene, or Calabrian) is a subdivision of the Pleistocene
Pleistocene

The Pleistocene is the epoch from 1.8 million to 10,000 years Before Present covering the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
 Epoch of the Geologic time scale
Geologic time scale

File:Geologic clock.jpgThe geologic time scale is a chronology schema relating stratigraphy to time that is used by geologys and other earth sciences scientists to describe the timing and relationships between events that have occurred during the history of the Earth....
. The beginning of the stage is defined at 1.806 ± 0.005 Ma
Annum

Annum is one form of the Latin noun meaning year, not a form normally used for derivatives in modern languages: the accusative case Grammatical number of the second declension grammatical gender noun annus , anni ....
 (million years ago). The end of the stage is defined by the last magnetic pole reversal
Geomagnetic reversal

A geomagnetic reversal is a change in the orientation of Earth's magnetic field such that the positions of magnetic north and magnetic south become interchanged....
 781,000 ± 5,000 years ago. Originally the Calabrian was a European faunal stage
Faunal stage

In chronostratigraphy, a stage is a Geologic record laid down in an single age on the geologic timescale, which usually represents millions of years of deposition....
 primarily based on mollusk fossils. It has been subsumed into, and become equivalent to, the geologic stage called the Early Pleistocene. However, many of the mammal
Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
ian faunal assemblages of the Early Pleistocene start in the Gelasian
Gelasian

The Gelasian is a faunal stage whose belonging to either the Pliocene or the Pleistocene epoch s is currently discussed. It spans the time between 2.588 ? 0.005 mya and 1.806 ? 0.005 mya.....
 (last stage of the Pliocene
Pliocene

The Pliocene epoch is the period in the geologic timescale that extends from 5.332 million to 1.806 million years before present.The Pliocene is the second epoch of the Neogene period in the Cenozoic era....
). For example, the Platygonus
Platygonus

Platygonus is an extinct genus of peccary from North America.Platygonus was larger than modern peccaries, at around in body length, and had long legs, allowing it to run well....
 and other Blancan
Blancan

The Blancan 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 4,750,000 to 1,808,000 years Before Present....
 fauna appear first in the Gelasian.

History of the definition of the Calabrian

Because sea shells are much more abundant as fossils, Nineteenth and early Twentieth Century geo-scientists used the plentiful and well-differentiatable Mollusca
Mollusca

MolluscsSpelled mollusk in the USA; the spelling "mollusc" is preferred by some authors, see the reasons given by . are animals belonging to the Phylum Mollusca....
 (mollusks) and Brachiopod
Brachiopod

Brachiopods are a small Phylum of benthic invertebrates. Also known as lamp shells , "brachs" or Brachiopoda, they are Sessility , two-valved, Marine animals with an external morphology superficially resembling Bivalvias to which they are not closely related....
s to identify stratigraphic
Stratigraphy

Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary rock and layered volcanic rocks....
 boundaries. Thus the Calabrian was originally defined as an assemblage of mollusk fossils, most brachiopods being extinct by then. Efforts were then made to find the best representation of that assemblage in a stratigraphic section. By 1948 scientists used the initial appearance of cool-water (northern) invertebrate faunas in Mediterranean marine sediments as the beginning marker for the Calabrian. The 18th International Geological Congress in London (1948) placed the base of the Pleistocene at the base of the marine strata of the Calabrian Faunal Stage, and denominated a type section
Global Boundary Stratotype Section and Point

A Global Boundary Stratotype Section and Point, abbreviated GSSP, is an internationally agreed upon stratigraphy section which serves as the reference section for a particular boundary on the geologic time scale....
 in southern Italy
Mezzogiorno

Southern Italy generally refers to the southern portion of the continental Italian peninsula historically forming the Kingdom of Naples. It encompasses the modern regions of Basilicata, Campania, Calabria, Apulia and Molise, which lie in Italy's south, and Abruzzo which is located in central Italy....
. However, it was discovered that the original type section was discontinuous at that point and that the base of the Calabrian Stage as defined by fauna assemblages extended to earlier levels within the Pleistocene. A new type section was chosen, several miles from the original one, at Vrica, 4 km south of Crotone
Crotone

Crotone is a city in Calabria, southern Italy, on the Ionian Sea. Founded circa 710 BC as the Achaean colony of Croton , it was known as Cotrone from the Middle Ages until 1928, when its name was changed to Crotone....
 in Calabria
Calabria

Calabria , is a Regions of Italy in Southern Italy Italy, south of Naples, located at the "toe" of the Italian peninsula. It is bounded to the north by the region of Basilicata, to the south-west by the region of Sicily, to the west by the Tyrrhenian Sea, and to the east by the Ionian Sea....
, southern Italy. Analysis of strontium
Strontium

Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically....
 and oxygen
Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
 isotope
Isotope

Isotopes are any of the different types of atoms of the same chemical element, each having a different atomic mass . Isotopes of an element have atomic nucleus with the same number of protons but different numbers of neutron....
s as well as of plankton
Plankton

Plankton consist of any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. Plankton are defined by their ecological niche rather than their Phylogenetics or taxonomy classification....
ic foraminifera
Foraminifera

The Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands of cytoplasm that branch and merge to form a dynamic net....
 has confirmed the viability of the current type section. The 27th International Geological Congress in Moscow in 1984 formally ratified the type section. The starting date was originally thought to be about 1.65 million years ago, but has been recalculated as 1.806 Mya.

Present formal definition

The Global Boundary Stratotype Section and Point, GSSP, for the start of the Pleistocene is in a reference section at Vrica, 4 km south of Crotone in Calabria, Southern Italy, a location whose exact dating has recently been confirmed by analysis of strontium and oxygen isotopes as well as by planktonic foraminifera.

The beginning of the Early Pleistocene hence is defined as: Just above top of magnetic polarity chronozone C2n (Olduvai) and the extinction level of calcareous nannofossil Discoaster
Discoaster

Discoaster is a genus of fossil alga comprising 166 species....
 brouweri (base Zone CN13). Above the boundary are the lowest occurrence of calcareous nannofossil medium Gephyrocapsa
Gephyrocapsa

Gephyrocapsa is a genus of alga comprising approximately 3 species. Gephyrocapsa produces tetraspores and carpospores.Species ...
 spp. and the extinction level of the planktonic foraminifer Globigerinoides extremus.

The end of the Early Pleistocene is defined as the Brunhes-Matuyama magnetic reversal
Brunhes-Matuyama reversal

The Brunhes-Matuyama Reversal was a Geology event, approximately 780,000 years ago, when the Earth's magnetic field last underwent Geomagnetic reversal....
 event.

Nomenclature problems

It is clearer to refer to the currently defined Early Pleistocene as the Calabrian, both because the type section is Calabrian, but more importantly because the lower boundary of the Pleistocene is currently under discussion. Most climatologists and geologists would prefer a start date of around 2.58 mya as more representative of the break between the Pliocene and the Pleistocene.

Representative fauna