Elsterian glacial period dating
(2,588,000 to 1,800,000 years ago) marks the beginning of Pleistocene, which is also the base of the Quarternary Period.It is coincident with the bottom of a marly layer resting atop a sapropel called MPRS 250 on the southern slopes of Monte San Nicola in formed repeatedly on the landmasses and has been informally referred to as the “Great Ice Age.” The timing of the onset of this cold interval, and thus the formal beginning of the Pleistocene Epoch, was a matter of substantial debate among geologists during the late 20th and early 21st centuries.Pre-Pleistocene intervals of time are defined on the basis of chronostratigraphic and geochronologic principles related to a marine sequence of strata.Following studies by a series of international working groups, correlation programs, and stratigraphic commissions, agreement was reached in 1985 to place the lower boundary of the Pleistocene series at the base of marine claystones that conformably overlie a specific in the Vrica section in Calabria.
Modern research, however, has shown that large glaciers had formed in other parts of the world earlier than 1,800,000 years ago.
A minor series of glaciations occurred from 460 Ma to 430 Ma.
There were extensive glaciations from 350 to 250 Ma.
However, the terms Kansan Stage, along with Yarmouth, Nebraskan, and Aftonian stages, have been abandoned by North American Quaternary geologists and merged into the Pre-Illinoian stage.
There have been five known ice ages in the Earth's history, with the Earth experiencing the Quaternary Ice Age during the present time.
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation.