Search results
Results from the WOW.Com Content Network
Although the term aeon may be used in reference to a period of a billion years (especially in geology, cosmology and astronomy), its more common usage is for any long, indefinite period. Aeon can also refer to the four aeons on the geologic time scale that make up the Earth's history, the Hadean , Archean , Proterozoic , and the current aeon ...
A non-standard but widely used abbreviation for one billion (1,000,000,000) years, using the metric prefix G (for "Giga") to indicate a quantity of one billion ...
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 ...
Early Earth also known as proto-earth is loosely defined as encompassing Earth in its first one billion years, or gigayear (Ga, 10 9 y), [1] from its initial formation in the young Solar System at about 4.55 Ga to some time in the Archean eon in approximately 3.5 Ga. [2] On the geologic time scale, this comprises all of the Hadean eon, starting ...
The geological time scale encompasses the history of the Earth. [13] It is bracketed at the earliest by the dates of the first Solar System material at 4.567 Ga [14] (or 4.567 billion years ago) and the formation of the Earth at 4.54 Ga [15] [16] (4.54 billion years), which is the beginning of the Hadean eon – a division of
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.
Known affectionately to scientists as the "boring billion," there was a seemingly endless period in the world's history when the length of a day stayed put. The time when a day on Earth was just ...
The term shield, used to describe this type of geographic region, appears in the 1901 English translation of Eduard Suess's Face of Earth by H. B. C. Sollas, and comes from the shape "not unlike a flat shield" [2] of the Canadian Shield which has an outline that "suggests the shape of the shields carried by soldiers in the days of hand-to-hand ...