The Middle Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy. It is intended to be the second division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time between 0.773 Ma (760,000 years ago) and 0.126 Ma (126,000 years ago), also expressed as 773–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Palaeolithic over 300 ka.
|Subdivisions of the Quaternary System|
The Middle Pleistocene equates to the proposed Chibanian Age of the geologic time scale (GTS), preceded by the official 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 is currently in use as a provisional or "quasi-formal" designation by the International Union of Geological Sciences (IUGS). The International Chronostratigraphic Chart labels the last two Pleistocene divisions as Middle and Upper, spanning 773–126 ka and 126–11.7 ka, respectively. While the two lowest ages of the Pleistocene, the Gelasian and the Calabrian have been officially defined to effectively constitute the Early Pleistocene sub-epoch, the Middle Pleistocene and Late Pleistocene have yet to be formally defined, along with consideration of a proposed Anthropocene sub-division of the Holocene.
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. Until the Chibanian is ratified by the IUGS, it will remain an unofficial, though proposed, stratigraphic division and Middle Pleistocene remains the provisional name used by the IUGS on its International Chronostratigraphic Chart.
The Middle Pleistocene 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. The oldest known human DNA dates to the Middle Pleistocene, around 430,000 years ago. This is the oldest found, as of 2016.
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