Search results
Results from the WOW.Com Content Network
Historical geology or palaeogeology is a discipline that uses the principles and methods of geology to reconstruct the geological history of Earth. [1] Historical geology examines the vastness of geologic time, measured in billions of years, and investigates changes in the Earth , gradual and sudden, over this deep time .
It is widely believed that the early Earth was dominated by vertical tectonic processes, such as stagnant lid, [19] [20] heat-pipe, [21] or sagduction, [22] [23] [24] which eventually transitioned to plate tectonics during the planet's mid-stage evolution. However, an alternative view proposes that Earth never experienced a vertical tectonic ...
Lyell provided evidence for Uniformitarianism, a geological doctrine holding that processes occur at the same rates in the present as they did in the past and account for all of the Earth's geological features. [29] Lyell's works were popular and widely read, and the concept of Uniformitarianism took a strong hold in geological society. [24]
The geological time scale (GTS), as defined by international convention, [3] depicts the large spans of time from the beginning of the Earth to the present, and its divisions chronicle some definitive events of Earth history. Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar ...
By far the largest two elements by fraction of total mass are hydrogen (74.9%) and helium (23.8%), with all the remaining elements contributing just 1.3%. [23] There is a general trend of exponential decrease in abundance with increasing atomic number, although elements with even atomic number are more common than their odd-numbered neighbors ...
Exposure dating uses the concentration of exotic nuclides (e.g. 10 Be, 26 Al, 36 Cl) produced by cosmic rays interacting with Earth materials as a proxy for the age at which a surface, such as an alluvial fan, was created. Burial dating uses the differential radioactive decay of 2 cosmogenic elements as a proxy for the age at which a sediment ...
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).
Earth's outer core is a fluid layer about 2,260 km (1,400 mi) in height (i.e. distance from the highest point to the lowest point at the edge of the inner core) [36% of the Earth's radius, 15.6% of the volume] and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. [31]