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  2. Geologic time scale - Wikipedia

    en.wikipedia.org/wiki/Geologic_time_scale

    Principles. 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). [5] It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or ...

  3. Stratigraphy - Wikipedia

    en.wikipedia.org/wiki/Stratigraphy

    The geologic time scale was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession. This timescale remained a relative scale until the development of radiometric dating, which was based on an absolute time framework, leading to the development of chronostratigraphy.

  4. Geological history of Earth - Wikipedia

    en.wikipedia.org/wiki/Geological_history_of_Earth

    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 layers (stratigraphy). Earth formed about 4.54 billion years ago by accretion from the solar nebula, a disk-shaped mass of dust and gas left ...

  5. History of Earth - Wikipedia

    en.wikipedia.org/wiki/History_of_Earth

    The history of the Earth can be organized chronologically according to the geologic time scale, which is split into intervals based on stratigraphic analysis. [2] [21] The following five timelines show the geologic time scale to scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space ...

  6. Geology - Wikipedia

    en.wikipedia.org/wiki/Geology

    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

  7. Precambrian - Wikipedia

    en.wikipedia.org/wiki/Precambrian

    The Precambrian is an informal unit of geologic time, [3] subdivided into three eons (Hadean, Archean, Proterozoic) of the geologic time scale. It spans from the formation of Earth about 4.6 billion years ago ( Ga ) to the beginning of the Cambrian Period, about 538.8 million years ago ( Ma ), when hard-shelled creatures first appeared in ...

  8. Timeline of natural history - Wikipedia

    en.wikipedia.org/wiki/Timeline_of_natural_history

    Geologic time is the timescale used to calculate dates in the planet's geologic history from its origin (currently estimated to have been some 4,600 million years ago) to the present day. Radiometric dating measures the steady decay of radioactive elements in an object to determine its age. It is used to calculate dates for the older part of ...

  9. Phanerozoic - Wikipedia

    en.wikipedia.org/wiki/Phanerozoic

    The Quaternary spans from 2.58 million years ago to present day, and is the shortest geological period in the Phanerozoic Eon. It features modern animals, and dramatic changes in the climate. It is divided into two epochs: the Pleistocene and the Holocene. The Pleistocene lasted from 2.58 million to 11,700 years ago.