Chibanian

The Chibanian, widely known as the Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name was officially ratified in January 2020. It is currently estimated to span the time between 0.770 Ma (770,000 years ago) and 0.126 Ma (126,000 years ago), also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Paleolithic over 300 ka.

The Chibanian is preceded by the Calabrian and succeeded by the proposed Tarantian. The beginning of the Chibanian is the Brunhes–Matuyama reversal, when the Earth's magnetic field last underwent reversal. It ends with the onset of the Eemian interglacial period (Marine Isotope Stage 5).

The term Middle Pleistocene was in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). While the three lowest ages of the Pleistocene, the Gelasian, Calabrian and Chibanian have been officially defined, the Late Pleistocene has yet to be formally defined, along with consideration of a proposed Anthropocene sub-division of the Holocene.

Definition process

The International Union of Geological Sciences (IUGS) had previously proposed replacement of the Middle Pleistocene by an Ionian Age based on strata found in Italy. In November 2017, however, the Chibanian (based on strata at a site in Chiba Prefecture, Japan) replaced the Ionian as the Subcommission on Quaternary Stratigraphy's preferred GSSP proposal for the age that should replace the Middle Pleistocene sub-epoch. The "Chibanian" name was ratified by the IUGS in January 2020.

Palaeoanthropology

The Chibanian includes the transition in palaeoanthropology from the Lower to the Middle Paleolithic: i.e., the emergence of Homo sapiens sapiens between 300 ka and 400 ka. The oldest known human DNA dates to the Middle Pleistocene, around 430,000 years ago. This is the oldest found, as of 2016.

Chronology

Further information: Timeline of glaciation

Further information: Marine isotope stages and Last Glacial Period

Further information: Brunhes–Matuyama reversal

Age	paleoclimate	glaciation	palaeoanthropology
790–761 ka	MIS 19	Günz (Elbe) glaciation	Peking Man (Homo erectus)
761–712 ka	MIS 18
712–676 ka	MIS 17
676–621 ka	MIS 16
621–563 ka	MIS 15	Gunz-Haslach interglacial	Heidelberg Man (Homo heidelbergensis), Bodo cranium
563–524 ka	MIS 14
524–474 ka	MIS 13	end of Cromerian (Günz-Mindel) interglacial	Boxgrove Man (Homo heidelbergensis)
474–424 ka	MIS 12	Anglian Stage in Britain; Haslach glaciation	Tautavel Man (Homo erectus)
424–374 ka	MIS 11	Hoxnian (Britain), Yarmouthian (North America)	Swanscombe Man (Homo heidelbergensis)
374–337 ka	MIS 10	Mindel glaciation, Elster glaciation, Riss glaciation
337–300 ka	MIS 9	Purfleet Interglacial in Britain	Mousterian
300–243 ka	MIS 8		Irhoud 1 (Homo sapiens); Middle Paleolithic; Haplogroup A (Y-DNA)
243–191 ka	MIS 7	Aveley Interglacial in Britain	Galilee Man; Haua Fteah
191–130 ka	MIS 6	Illinoian Stage	Herto Man (Homo sapiens); Macro-haplogroup L (mtDNA); Mousterian
130–123 ka	MIS 5e	peak of Eemian interglacial sub-stage, or Ipswichian in Britain	Klasies River Caves; Sangoan

See also

• Mid-Pleistocene Transition
• 100,000-year problem
• Pleistocene megafauna