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Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. [1] The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
Plate tectonics (from Latin tectonicus, from Ancient Greek τεκτονικός (tektonikós) 'pertaining to building') [1] is the scientific theory that Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago.
This article describes techniques; for a history of the movement of tectonic plates, see Geological history of Earth.. Plate reconstruction is the process of reconstructing the positions of tectonic plates relative to each other (relative motion) or to other reference frames, such as the Earth's magnetic field or groups of hotspots, in the geological past.
Palaeogeography (or paleogeography) is the study of historical geography, generally physical landscapes. [2] Palaeogeography can also include the study of human or cultural environments. [ citation needed ] When the focus is specifically on landforms , the term paleogeomorphology is sometimes used instead.
Radioactive decay accounts for about 80% of the Earth's internal heat, powering the geodynamo and plate tectonics. [28] The main heat-producing isotopes are potassium-40, uranium-238, uranium-235, and thorium-232. [29] Radioactive elements are used for radiometric dating, the primary method for establishing an absolute time scale in geochronology.
This glossary of geography terms is a list of definitions of terms and concepts used in geography and related fields, including Earth science, oceanography, cartography, and human geography, as well as those describing spatial dimension, topographical features, natural resources, and the collection, analysis, and visualization of geographic ...
From the late 18th century until its replacement by plate tectonics in the 1960s, geosyncline theory was used to explain much mountain-building. [4] The understanding of specific landscape features in terms of the underlying tectonic processes is called tectonic geomorphology , and the study of geologically young or ongoing processes is called ...
The theory of plate tectonics states that the Earth's lithosphere (crust and upper mantle) is made up of rigid plates that "float" on top of the asthenosphere (lower mantle) and move relative to one another. As the plates move, the crust deforms dominantly along the plate margins.