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Such evidence suggests major periods of glaciation prior to the current Quaternary glaciation. One of the best documented records of pre-Quaternary glaciation, called the Karoo Ice Age, is found in the late Paleozoic rocks in South Africa, India, South America, Antarctica, and Australia. Exposures of ancient glacial deposits are numerous in ...
The marine record preserves all the past glaciations; the land-based evidence is less complete because successive glaciations may wipe out evidence of their predecessors. Ice cores from continental ice accumulations also provide a complete record, but do not go as far back in time as marine data.
The only issue with interpreting the data from this region is due to the lack of chronological information. [13] The resemblance of Late Pleistocene species in Northern Africa to modern animals is the same as in Southern Africa but it's extremely difficult to date when these fauna came into place because of the lack of reliable samples from the ...
Detailed research by various geomorphologists and Quaternary geologists demonstrated that the two glacial tills and one ash bed stratigraphic model, on which the Yarmouthian, Kansan, Nebraskan, and Aftonian glacial - interglacial nomenclature was based, was completely wrong.
For example, instead of two glaciations having occurred prior to the Illinoian Stage, researchers found that 11 distinct glaciations had occurred. In addition, what was presumed to have been a single volcanic ash bed, which was used to correlate and differentiate between Kansan and Nebraskan glacial deposits, was found to be three volcanic ash ...
However, the Nebraskan Stage, along with the Kansan and Aftonian Stages, have been abandoned by North American Quaternary geologists and merged into the Pre-Illinoian Stage. [ 7 ] [ 8 ] As of 2011 [update] , the Beestonian stage is correlated with the period of time that includes the Pre-Illinoian F, Pre-Illinoian G, and Pre-Illinoian H ...
The Quaternary Period follows the Neogene Period and extends to the present. The Quaternary covers the time span of glaciations classified as the Pleistocene, and includes the present interglacial time-period, the Holocene. This places the start of the Quaternary at the onset of Northern Hemisphere glaciation approximately 2.6 million years ago .
The stage names "Kansan", "Yarmouth", "Nebraskan" and "Aftonian" were later abandoned by North American Quaternary geologists and merged into the Pre-Illinoian stage. [ 9 ] [ 10 ] The Anglian Stage is now correlated with the period of time which includes the Pre-Illinoian B glaciation of North America.