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The Paleozoic (/ ˌ p æ l i. ə ˈ z oʊ. ɪ k,-i. oʊ-, ˌ p eɪ-/ PAL-ee-ə-ZOH-ik, -ee-oh-, PAY-; [1] or Palaeozoic) Era is the first of three geological eras of the Phanerozoic Eon. . Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of the Mesozoic Er
Siderian Period/System (2630–2420 Ma) – named for the voluminous banded iron formations formed within its duration. [66] Proterozoic Eon/Eonothem (2420–538.8 Ma) [note 4] Paleoproterozoic Era/Erathem (2420–1780 Ma) Oxygenian Period/System (2420–2250 Ma) – named for displaying the first evidence for a global oxidising atmosphere. [66]
Eon: 4 total, half a billion years or more Erathem: Era: 10 defined, several hundred million years System: Period: 22 defined, tens to ~one hundred million years Series: Epoch: 34 defined, tens of millions of years Stage: Age: 99 defined, millions of years Chronozone: Chron: subdivision of an age, not used by the ICS timescale
USA TODAY’s Daily Crossword Puzzles Sudoku & Crossword Puzzle Answers This article originally appeared on USA TODAY: Crossword Blog & Answers for December 7, 2024 by Sally Hoelscher
Explore daily insights on the USA TODAY crossword puzzle by Sally Hoelscher. ... THE TORTURED (16A: With 35-Across, 2024 album that led to a new era in ... (21A: Unit for ice cream or beer) This ...
An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. [1] Comparable terms are epoch, age, period, saeculum, aeon (Greek aion) [2] and Sanskrit yuga. [3]
The oldest dated rocks formed on Earth, as an aggregate of minerals that have not been subsequently broken down by erosion or melted, are more than 4 billion years old, formed during the Hadean Eon of Earth's geological history, and mark the start of the Archean Eon, which is defined to start with the formation of the oldest intact rocks on Earth.
The term geon (for geological eon) refers to large, geologic units of time. Geologists traditionally subdivide Earth history into a hierarchy of named intervals: eons, eras, periods, etc. (e.g., the Jurassic Period of the Mesozoic Era). Historians subdivide the history of human activity into intervals that are comparatively much shorter.