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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.
Geologic Time – Period prior to humans. 4.6 billion to 3 million years ago. (See "prehistoric periods" for more detail into this.) (See "prehistoric periods" for more detail into this.) Primatomorphid Era – Period prior to the existence of Primatomorpha
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks).
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 Earth follows the major geological events in Earth's past based on the geologic time scale , a system of chronological measurement based on the study of the planet's rock ...
A geologic period and system, the second of six of the Paleozoic Era, spanning the time between 485.4 ± 1.9 to 443.4 ± 1.5 million years ago. It follows the Cambrian and is followed by the Silurian. orogenesis The formation and growth of mountains related to tectonic activity.
As with other geological phenomena, orogenies are often subject to , type and associated paleogeography. In some (especially older) literature, the term orogeny refers to a long episode of basin formation and deposition of sediments over hundreds of millions of years, ending with deformation (sometimes including metamorphism ) of these deposits.
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 ...
Geochronology is different in application from biostratigraphy, which is the science of assigning sedimentary rocks to a known geological period via describing, cataloging and comparing fossil floral and faunal assemblages.