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Index fossils must have a short vertical range, wide geographic distribution and rapid evolutionary trends. Another term, "zone fossil", is used when the fossil has all the characters stated above except wide geographical distribution; thus, they correlate the surrounding rock to a biozone rather than a specific time period.
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).
Illustrates the fossil range of a taxon, the geological range of a stratigraphic unit, or other ranges on a geological timescale. Intended for use in {{taxobox}}es, {{Infobox rockunit}} s, and other infoboxes. For pre-Phanerozoic ages, see {{Long fossil range}}. You can give a numeric range, or specify the periods involved.
A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults , folds , are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
"Chart of The Global Boundary Stratotype Sections and Points (GSSP): chart". stratigraphy.science.purdue.edu. Archived from the original on 2022-06-30. "GSSP Table - All Periods". timescalefoundation.org. Archived from the original on 2023-11-30. "GSSPs and Continental drift 3D views". ghkclass.net. Archived from the original on 2023-12-08.
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time.. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region, and eventually, the entire geologic record of the Earth.
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [ 1 ]