Stratigraphy is a branch of geology with studies layers and layering rock. Stratigraphy from stratum + graphia and mean the description of all rock bodies forming the Earth’s crust and their organization into distinctive, useful, mappable units based on their inherent properties or attributes in order to establish their distribution and relationship in space and their succession in time, and to interpret geologic history. Strata is layer of rock characterized by particular lithologic properties and attributes that distinguish it from adjacent layers.
In the stratigraphy you can find term of
- Stratigraphic classification. The systematic organization of the Earth’s rock bodies, as they are found in their original relationships, into units based on any of the properties or attributes that may be useful in stratigraphic work.
- Stratigraphic unit. A body of rock established as a distinct entity in the classification of the Earth’s rocks, based on any of the properties or attributes or combinations thereof that rocks possess. Stratigraphic units based on one property will not necessarily coincide with those based on another.
- Stratigraphic terminology. The total of unit-terms used in stratigraphic classification.It may be either formal or informal.
- Stratigraphic nomenclature. The system of proper names given to specific stratigraphic units.
- Zone.Minor body of rock in many different categories of stratigraphic classification. The type of zone indicated is made clear by a prefix, e.g., lithozone, biozone, chronozone.
- Horizon. An interface indicative of a particular position in a stratigraphic sequence. The type of horizon is indicated by a prefix, e.g., lithohorizon, biohorizon, chronohorizon.
- Correlation. A demonstration of correspondence in character and/or stratigraphic position. The type of correlation is indicated by a prefix, e.g., lithocorrelation, biocorrelation, chronocorrelation.
- Geochronology. The science of dating and determining the time sequence of the events in the history of the Earth.
- Geochronologic unit. A subdivision of geologic time.
- Geochronometry. A branch of geochronology that deals with the quantitative (numerical)measurement of geologic time. The abbreviations ka for thousand (103), Ma for million (106), and Ga for billion (milliard of thousand million, 109) years are used.
- Facies. The term “facies” originally meant the lateral change in lithologic aspect of a stratigraphic unit. Its meaning has been broadened to express a wide range of geologic concepts: environment of deposition, lithologic composition, geographic, climatic or tectonic association, etc.
- Caution against preempting general terms for special meanings. The preempting of general terms for special restricted meanings has been a source of much confusion.