Search results
Results from the WOW.Com Content Network
The Pliocene (/ ˈ p l aɪ. ə s iː n, ˈ p l aɪ. oʊ-/ PLY-ə-seen, PLY-oh-; [6] [7] also Pleiocene) [8] is the epoch in the geologic time scale that extends from 5.33 to 2.58 [9] million years ago (Ma). It is the second and most recent epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by ...
The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5 Mya to about 12 kya.
This was the formation of the East Antarctic Ice Sheet. [10] Global refrigeration [clarification needed] set in 22 million years ago. [9] About 15 million years ago was the warmest part of the Late Cenozoic Ice Age, with average global temperatures around 18.4 °C (65.1 °F). [23] Atmospheric CO 2 levels were around 700 ppm. [23]
The Gauss–Matuyama reversal is a natural phenomenon that is frequently used as a boundary between the Pliocene and Pleistocene epochs, [1] marking the start of the Quaternary period, and is often used to date sediments.
Carbon dioxide concentration during the Middle Pliocene has been estimated at around 400 ppmv from 13 C/ 12 C ratio in organic marine matter [23] and stomatal density of fossilised leaves, [24] although lower estimates of between 330 and 394 ppm over the course of the whole mPWP and 391 ppm in the KM5c interglacial, during the warmest phase of ...
The Pleistocene extends from to 11,700 years before present. [10] The modern continents were essentially at their present positions during the Pleistocene , the plates upon which they sit probably having moved no more than 100 kilometres (62 mi) relative to each other since the beginning of the period.
Each period is marked below the era bar on top of its subdivided epochs and stages. Each stage is assigned an age in mya, an acronym for million years ago, which is the age at which it began. Most of these ages are derived from astronomical cycles in sediments, magnetic data, biostratigraphic data, and radiometric dating methods. The GSSP ...
[18] [19] The Pleistocene covers the recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. Formerly, the boundary between the two epochs was drawn at the time when the foraminiferal species Hyalinea baltica first appeared in the marine section at La Castella, Calabria, Italy. [20]