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rocks older than 2.5 Billion years – rocks older than 3.6 Billion years [1] [2] Neoarchean: 2500 Mya – 2800 Mya (only GSSA points) Mesoarchean: 2800 Mya – 3200 Mya: Paleoarchean: 3200 Mya – 3600 Mya: Eoarchean: 3600 Mya – 4000 Mya: Earth's crust solidifies ca 3800 Mya [3] Note: Rocks older than ca. 2500 Mya old are rare due to ...
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.
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 ...
The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). [3] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...
Some older stages, in mya (millions of years ago): [18] MIS 22 – 1.03 mya, marking the end of the Bavelian period in Europe; MIS 62 – 1.75, end of the Tiglian; MIS 103 – 2.588, end of the Pliocene and start of the Pleistocene, on the INQUA time scale (older definitions put this change at 1.806 mya – the MIS date is unaffected)
The youngest record of P. boisei comes from Konso, Ethiopia about 1.4 mya; however, there are no East African sites dated between 1.4 and 1 mya, so it may have persisted until 1 mya. [11] P. robustus , on the other hand, was recorded in Swartkrans until Member 3 dated to 1–0.6 mya (the Middle Pleistocene ), though more likely the younger side ...
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Early examples of hand axes date back to 1.6 mya in the later Oldowan (Mode I), called the "developed Oldowan" by Mary Leakey. [44] These hand axes became more abundant in mode II Acheulean industries that appeared in Southern Ethiopia around 1.4 mya. [45] Some of the best specimens come from 1.2 mya deposits in Olduvai Gorge. [46]