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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 ...
This is a list of official and unofficial names for time spans in the geologic timescale and units of chronostratigraphy.Since many of the smallest subdivisions of the geologic timescale were in the past defined on regional lithostratigraphic units, there are many alternative names that overlap.
The Proterozoic (IPA: / ˌ p r oʊ t ər ə ˈ z oʊ ɪ k, ˌ p r ɒ t-,-ər oʊ-,-t r ə-,-t r oʊ-/ PROH-tər-ə-ZOH-ik, PROT-, -ər-oh-, -trə-, -troh-) [3] [4] [5] is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, [6] and is the longest eon of Earth's geologic time scale.
31.6 Ps (1000 Ma, 1 Ga): One giga-annum (Ga), one billion years, the largest fixed time unit used in the standard geological time scale, approximately the order of magnitude of an eon, the largest division of geological time. +1 Ga: The estimated remaining habitable lifetime of Earth, according to some models.
Geologic time scale of Mars (4 P) Pages in category "Geologic time scales" The following 10 pages are in this category, out of 10 total.
A geon is a specified 100-million-year interval of geologic time, counted backward from the present. The geon scale can be likened to a ladder, each interval between rungs representing 100 million years. Geons are named for the leftmost part of the number representing age.
A non-standard geologic time period immediately preceding the Phanerozoic Eon, divided into several eons of the geologic time scale. It spans from the formation of Earth about 4540 Ma (million years ago) to the beginning of the Cambrian Period , about 541.0 ± 1.0 Ma, when macroscopic hard-shelled animals first appeared in abundance.
Geologic time shown in a diagram called a geological clock, showing the relative lengths of the eons of Earth's history and noting major events The geological history of the Earth follows the major geological events in Earth's past based on the geological time scale , a system of chronological measurement based on the study of the planet's rock ...