The Cenozoic Era is the current geological era, beginning 66 million years ago. It was preceded by the Mesozoic Era, and the transition between them is marked by the K-T Extinction Event. This event caused the death of the non-avian dinosaurs and allowed for the expansion of mammals into their prior ecological niches. The Cenozoic is divided into the Paleogene, Neogene, and Quaternary periods.

The Quaternary Period is the current period of the Cenozoic Era beginning 2.58 million years ago. It is futher divided into two epochs: the Pleistocene, running from 2.58 million years ago (the beginning of the Quaternary) to 11,700 years ago, and the Holocene which runs from then to the present.

The border of the Neogene and Quaternary is generally marked by the appearance of Homonid species. Additionally, the Neogene cooled over its duration and the Quaternary contains a series of glaciation cycles. This series is called the Quaternary Glaciation

The Pleistocene began with the Earth’s most recent period of glaciations. At the end of the preceding Pliocene epoch, the Americas were joined by the Isthmus of Panama. This event changed the ocean circulation patterns and helped spur glaciation events that would dominate the climate of the Pleistocene.

The Pleistocene contains the bulk of the Quaternary and the Quaternary Glaciation, a long time period of repeated glaciations and retreats. The transition to the Holocene is marked by both the end of the Last Glacial Period and the last maximum axial tilt of the Earth towards the sun.

The Last Glacial Period lasted from c 115,000 – c 11,700 years ago and is part of a larger sequence of glacial and interglacial periods known as the Quaternary glaciation, which began with the Quaternary Period itself. The most recent period of cooling is called the Yourger Dryas, which occurred from 12,800 and 11,700 years ago. It’s end marks the end of both the Last Glacial Period and Pleistocene.

During this period, there were alternating periods of glacier advance and retreat, with the Last Glacial Maximum occurring between 26,000 and 20,000 years ago, prior to the Holocene.

In general, when referring to a specific area, different names for this glaciation can be used. In North America, it is referred to as the Wisconsinian, in Britain it is called the Devensian, in Ireland the Midlandian, and in Northern Europe it is called the Weichselian.

The Holocene began c 11,700 years ago. The Holocene in general is an interglacial period.

Stadials and Interstadials are phases dividing the Quaternary period. Stadials are periods of colder climate, while interstadials are periods of warmer climate. Each of these phases are assigned a marine isotope stage (MIS) number, a measure determined by oxygen isotope data. Stadials have even numbers and interstadials have odd numbers.

Stadials – colder climate – even MIS numbers

Interstadials – warmer climate – odd MIS numbers

The current epoch, the Holocene, is MIS 1, and the Last Glacial Maximum of the Pleistocene is MIS 2.

Generally, stadials last a thousand years or less and interstadials for less than ten thousand years. Whereas, glacials last for about 100 thousand years while interglacials last for some time more than 10 thousand years. For a period to be considered an interglacial, it changes from Arctic through sub-Arctic to boreal temperate confditions and back again. While, an interstadial reaches only the stage of boreal vegetation.

The MIS 1 interstadial encompasses the entirety of the Holocene interglacial period. But the Wisconsin glaciation encompasses MIS 2, 3, and 4.

Glacials and interglacials refer to a 100,000 year cycle associated with Milankovitch cycles, while stadials and interstadials are defined by the oxygen-isotope temperature record.

14,690-12,890 PB / 12,666-10,866 BCE