The largest formal unit of geologic time. There are three eons: the Archean, Proterozoic, and Phanerozoic.
The major divisions of the geologic time scale. Eons are divided into intervals know as "eras". Two eons of the geologic time scale are the Phanerozoic (570 million years ago to present) and the Cryptozoic (4,600 million years ago until 570 million years ago).
A time period that consists of eras, periods and epicohs. The longest Eon in earth's geoloic history is the Phanerozoic Eon (See : GEOLOGIC TIME)
A major subdivision of geologic time consisting of eras. Example: Phanerozoic Eon. View timeline of geologic events.
Longest geologic time unit.
the largest unit of geological time
The largest division of geologic time, embracing several eras; for example, the Phanerozoic eon, from 600 million years ago to the present.
The largest subdivision of geologic time.
the longest division of geological time
the first division of geologic time and represents the longest segments of geologic history
A unit of geologic time equal to one billion years.
The largest time unit on the geologic time scale. more details...
An extremely long, indefinite period of time.
Travellers (in the surveys of magnitudes, 220.8) who notify the Oe'tans of the available places for new worlds, and the time for dissipating old ones. See 460.16.
The longest phase of geologic time. Earth's history has consisted of four eons, the Hadean or Priscoan, Archaean, Proterozoic, and Phanerozoic. The next-smallest subdivision of geologic time is the era.
A primary division of geologic time, four of which have been defined: Hadean, Archean, Proterozoic, and Phanerozoic. Eons are divided into Eras, which are in turn divided into Periods, Epochs and Stages.
The longest unit of geological time, next in order of magnitude above an Era
any span of time longer than an era; one billion years. [AHDOS
Two or more geological eras form an eon, which is the largest division of geological time, lasting hundreds of millions of years.