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The Hadean (/ h eɪ ˈ d iː ə n, ˈ h eɪ d i ə n / hay-DEE-ən, HAY-dee-ən) is the first and oldest of the four known geologic eons of Earth's history, starting with the planet's formation about 4.6 billion years ago [4] [5] (estimated 4567.30 ± 0.16 million years ago [2] set by the age of the oldest solid material in the Solar System — protoplanetary disk dust particles — found as ...
The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to about 4.4 Ga, [34] [35] [36] soon after the formation of the Earth's crust and the Earth
In particular, it is sometimes found that the Hadean eon is subdivided into the Cryptic era and Basin Groups 1-9 (which collectively make up the Pre-Nectarian), and the Nectarian and Lower Imbrian. The first lifeforms (self replicating RNA molecules, see RNA world hypothesis) may have evolved on earth around 4 bya during this era.
During Hadean time (4.6–4 Ga), the Solar System was forming, probably within a large cloud of gas and dust around the Sun, called an accretion disc from which Earth formed 8] The Hadean Eon is not formally recognized, but it essentially marks the era before we have adequate record of significant solid rocks.
The Cryptic era is an informal term for the earliest geologic evolution of the Earth and Moon.It is the oldest (informal) era of the Hadean eon, and it is commonly accepted to have begun close to about 4.533 billion years ago when the Earth and Moon formed, and lasted to about 4.15 billion years ago.
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Image credits: BallinFC #10. The Candy Bomber. After World War II, when Berlin was divided, the US and UK airlifted supplies into West Berlin to counter the Soviet blockade.
A revised proposal in 2012 [2] suggested the Chaotian as the first era of the Hadean representing the time between the formation of the Solar System c. 4.567 Ga [3] and the oldest preserved crustal material on Earth, a detrital zircon c. 4.404 Ga [4] from the Jack Hills of the Narryer terrane in Western Australia.