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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 ...
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.
The geologic time scale, proportionally represented as a log-spiral with some major events in Earth's history. A megaannus (Ma) represents one million (10 6) years.. The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth.
The natural history of Earth concerns the development of planet Earth from its formation to the present day. [1] [2] Nearly all branches of natural science have contributed to understanding of the main events of Earth's past, characterized by constant geological change and biological evolution.
The Geologic Calendar is a scale in which the geological timespan of the Earth is mapped onto a calendrical year; that is to say, the day one of the Earth took place on a geologic January 1 at precisely midnight, and today's date and time is December 31 at midnight. [1]
As with other geological phenomena, orogenies are often subject to revised interpretations of their age, 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 ...
This theory states that slow geological processes have occurred throughout the Earth's history and are still occurring today. In contrast, catastrophism is the theory that Earth's features formed in single, catastrophic events and remained unchanged thereafter. Though Hutton believed in uniformitarianism, the idea was not widely accepted at the ...
Geological events range in time span by orders of magnitude, from seconds to millions of years, and in spatial scale from local to regional and, ultimately, global. [2] In contrast to chronostratigraphic or geochronological units, that define the boundaries between periods, epochs and other units of the geologic time scale, complex dynamic ...