Chibanian
The Chibanian (pronounced /tʃibeɪniən/ chee-BAY-nee-ən) is an age in the international geologic timescale or a stage in chronostratigraphy, being the second division of the Pleistocene Epoch within the ongoing Quaternary Period.[3] Before the Chibanian name was officially ratified in January 2020, the time interval and its rocks were known as the Middle Pleistocene. 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 Palaeolithic over 300 ka.
Subdivisions of the Quaternary System | ||||
---|---|---|---|---|
System/ Period |
Series/ Epoch |
Stage/ Age |
Age (Ma) | |
Quaternary | Holocene | Meghalayan | 0 | 0.0042 |
Northgrippian | 0.0042 | 0.0082 | ||
Greenlandian | 0.0082 | 0.0117 | ||
Pleistocene | 'Upper' | 0.0117 | 0.129 | |
Chibanian | 0.129 | 0.774 | ||
Calabrian | 0.774 | 1.80 | ||
Gelasian | 1.80 | 2.58 | ||
Neogene | Pliocene | Piacenzian | 2.58 | 3.60 |
Subdivision of the Quaternary Period according to the ICS, as of May 2019.[1]
For the Holocene, dates are relative to the year 2000 (e.g. Greenlandian began 11,700 years before 2000). For the beginning of the Northgrippian a date of 8,236 years before 2000 has been set.[2] The Meghalayan has been set to begin 4,250 years before 2000.[1] 'Tarantian' is an informal, unofficial name proposed for a stage/age to replace the equally informal, unofficial 'Upper Pleistocene' subseries/subepoch. In Europe and North America, the Holocene is subdivided into Preboreal, Boreal, Atlantic, Subboreal, and Subatlantic stages of the Blytt–Sernander time scale. There are many regional subdivisions for the Upper or Late Pleistocene; usually these represent locally recognized cold (glacial) and warm (interglacial) periods. The last glacial period ends with the cold Younger Dryas substage. | ||||
The Chibanian is preceded by the Calabrian and succeeded by the proposed Tarantian.[1] The beginning of the Chibanian is the Brunhes–Matuyama reversal, when the Earth's magnetic field last underwent reversal.[4] It ends with the onset of the Eemian interglacial period (Marine Isotope Stage 5).[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.[6]
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.[7] The "Chibanian" name was ratified by the IUGS in January 2020.[3]
Palaeoanthropology
The Chibanian includes the transition in palaeoanthropology from the Lower to the Middle Palaeolithic: i.e., the emergence of Homo sapiens sapiens between 300 ka and 400 ka.[8] The oldest known human DNA dates to the Middle Pleistocene, around 430,000 years ago. This is the oldest found, as of 2016.[9]
Chronology
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 |
References
- Cohen, K. M.; Finney, S. C.; Gibbard, P. L.; Fan, J.-X. (January 2020). "International Chronostratigraphic Chart" (PDF). International Commission on Stratigraphy. Retrieved 23 February 2020.
- Mike Walker; et al. (December 2018). "Formal ratification of the subdivision of the Holocene Series/Epoch (Quaternary System/Period)" (PDF). Episodes. Subcommission on Quaternary Stratigraphy (SQS). 41 (4): 213–223. doi:10.18814/epiiugs/2018/018016. Retrieved 11 November 2019. This proposal on behalf of the SQS has been approved by the International Commission on Stratigraphy (ICS) and formally ratified by the Executive Committee of the International Union of Geological Sciences (IUGS).
- Hornyak, Tim (30 January 2020). "Japan Puts Its Mark on Geologic Time with the Chibanian Age". Eos – Earth & Space Science News. American Geophysical Union. Retrieved 31 January 2020.
- Gradstein, Felix M.; Ogg, James G.; Smith, Alan G., eds. (2004). A Geological Time Scale 2004 (3rd ed.). Cambridge: Cambridge University Press. p. 28. ISBN 9780521786737.
- D. Dahl-Jensen & others (2013). "Eemian interglacial reconstructed from a Greenland folded ice core" (PDF). Nature. 493 (7433): 489–494. Bibcode:2013Natur.493..489N. doi:10.1038/nature11789. PMID 23344358.
- P. L. Gibbard (17 April 2015). "The Quaternary System/Period and its major sub-divisions". ScienceDirect. Elsevier BV. pp. 686–688. Retrieved 13 November 2019.
- "Japan-based name 'Chibanian' set to represent geologic age of last magnetic shift". The Japan Times. 14 November 2017. Retrieved 13 November 2019.
- D. Richter & others (8 June 2017). "The Age of Hominin Fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age". Nature. 546 (7657): 293–296. doi:10.1038/nature22335. PMID 28593967..
- Crew, Bec (15 March 2016). "The Oldest Human Genome Ever Has Been Sequenced, And It Could Rewrite Our History". ScienceAlert. Retrieved 5 June 2019.