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In geology, a debate remains open concerning the use of Myr (duration) plus Mya (million years ago) versus using only the term Ma. [1] [2] In either case, the term Ma is used in geology literature conforming to ISO 31-1 (now ISO 80000-3) and NIST 811 recommended practices.
542.0 (+/- 1.0) Mya – 1000 Mya: few GSSP points Mesoproterozoic: 1000 Mya – 1600 Mya: all GSSA points Paleoproterozoic: 1600 Mya – 2500 Mya: all GSSA points Eras in the Archean Eon 2500 Mya – years > 3600 Mya rocks older than 2.5 Billion years – rocks older than 3.6 Billion years [1] [2] Neoarchean: 2500 Mya – 2800 Mya (only GSSA ...
Claims for the earliest definitive evidence of control of fire by a member of Homo range from 1.7 to 2.0 million years ago ... 1.0 Mya. [3] [20] Africa
In geochronology, time is generally measured in mya (million years ago), each unit representing the period of approximately 1,000,000 years in the past. The history of Earth is divided into four great eons, starting 4,540 mya with the formation of the planet.
The Cretaceous (IPA: / k r ɪ ˈ t eɪ ʃ ə s / krih-TAY-shəss) [2] is a geological period that lasted from about 143.1 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 77 million years, it is the ninth and longest geological period of the entire Phanerozoic.
Visual representation of the Logarithmic timeline in the scale of the universe. This timeline shows the whole history of the universe, the Earth, and mankind in one table. . Each row is defined in years ago, that is, years before the present date, with the earliest times at the top of the ch
For this reason, there is potential for some confusion, and some scientists prefer the unit Gya, while others prefer Ga (Giga-annum), however, bya remains in more widespread use. [1] In 1974, the UK switched from the long scale to the short scale. [1] Related units are mya ("million years ago"), and byr ("billion years").
Approximate extent of the Karoo Glaciation (in blue), over the Gondwana supercontinent during the Carboniferous and Permian periods. The late Paleozoic icehouse, also known as the Late Paleozoic Ice Age (LPIA) and formerly known as the Karoo ice age, was an ice age that began in the Late Devonian and ended in the Late Permian, [1] occurring from 360 to 255 million years ago (Mya), [2] [3] and ...