formation

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A fundamental geological unit used in the description and interpretation of layered sediments, sedimentary rocks, and extrusive igneous rocks. A formation is defined on the basis of lithic characteristics and position within a stratigraphic succession. It is usually tabular or sheetlike, and is mappable at the Earth's surface or traceable in the subsurface (for example, between boreholes or in mines). Examples are readily recognized in the walls of the Grand Canyon of northern Arizona. Each formation is referred to a section or locality where it is well developed (a type section), and assigned an appropriate geographic name combined with the word formation or a descriptive lithic term such as limestone, sandstone, or shale (for example, Temple Butte Formation, Hermit Shale). This usage of “formation” by geologists differs from its informal lay usage for stalactites, stalagmites, and other mineral buildups in caves. See also Stratigraphy.

Distinctive lithic characteristics used to designate formations include chemical and mineralogical composition, particle size and other textural features, primary sedimentary or volcanic structures related to processes of accumulation, fossils or other organic content, and color. Contacts or boundaries between formations are chosen at surfaces of abrupt lithic change or within zones of gradational lithic character. Commonly, these contacts correspond with recognizable changes in topographic expression, related to variations in resistance to weathering. See also Sedimentary rocks; Sedimentology.

Mappability is an essential characteristic of a formation because such units are used to delineate geological structure (faults and folds), and it is useful to be able to recognize individual formations in isolated outcrops or areas of poor exposure. Well-established formations are commonly divisible into two or more smaller-scale units termed members and beds (for example, subdivisions of the Redwall Limestone). In other cases, formations of similar lithic character or related genesis are combined into composite units termed groups and supergroups (for example, Supai Group). The rank of a named unit may vary from one area to another (for example, from group to formation) according to whether or not subunits are readily mappable. Changes in rank are also justified in the light of new geological knowledge.

Although commonly used as a framework for interpreting geological history, formations and related units are conceptually independent of geological time. They may represent either comparatively short or comparatively long intervals of time. Accumulation of a particular unit may have begun earlier in some places than in others, and the time span represented by a unit may be influenced by later erosion. In some cases, a formation cropping out at one locality may be entirely older or younger than the same lithic unit at another locality. Although the concept of time plays no role in the definition of a formation, evidence of age is useful in the recognition of lithologically similar units far from their type localities.

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noun

A way or condition of being arranged: arrangement, categorization, classification, deployment, disposal, disposition, distribution, grouping, layout, lineup, order, organization, placement, sequence. See order/disorder.

n

Definition: composition
Antonyms: destruction

n. a formal arrangement of aircraft in flight or troops: a battle formation | the helicopters hovered overhead in formation.

See the Introduction, Abbreviations and Pronunciation for further details.

great plant formation

A major vegetation system, determined by climate, e.g. tropical grassland. Thus, a formation is the plant community of a biome.

(DOD, NATO) 1. An ordered arrangement of troops and/or vehicles for a specific purpose. 2. An ordered arrangement of two or more ships, units, or aircraft proceeding together under a commander.

An ordered arrangement of two or more aircraft proceeding together under a leader called a formation leader. Separation between aircraft within the formation is the responsibility of the leader and the pilots in the formation. This includes transition periods when aircraft within the formation are maneuvering to attain separation from one another to effect individual control and during join-up and breakaway. A standard formation is one in which a proximity of no more than 1 mile (1.6 km) laterally or longitudinally and within 100 ft (30 m) vertically from the flight leader is maintained by each wingman. Nonstandard formations are those operating under any of the following conditions:
i. When the flight leader has requested and ATC (air traffic control) has approved other than standard formation dimensions.
ii. When operating within an authorized altitude reservation (ALTRV) or under the provisions of a letter of agreement.
iii. When the operations are conducted in airspace specifically designed for a special activity. The formation normally operates as a single aircraft with regard to navigation and position reports.



Some typical formations.

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1. the process of giving shape or form; the creation of an entity, or of a structure of definite shape.
2. a structure of definite shape.

For a list of words related to formation, see:

• Types and Techniques of Warfare - formation: position of troops for battle or maneuvers
• General Sports Terminology
• Football

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  See crossword solutions for the clue Formation.

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Dansk (Danish)
n. - dannelse, formering

Nederlands (Dutch)
formatie, vorming, vorm, structuur, grootste ecologische eenheid

Français (French)
n. - (gén, Mil, Géol) formation, développement

Deutsch (German)
n. - Bildung, Formung, Formation, Aufstellung

Ελληνική (Greek)
n. - σχηματισμός, διάταξη, τάξη, διαμόρφωση, ανάπτυξη, διάπλαση, φορμάρισμα, (γεωλ.) (γεωλογικός) σχηματισμός

Italiano (Italian)
formazione

Português (Portuguese)
n. - formação (f)

Русский (Russian)
образование, формирование, учреждение, структура, составление, войсковое соединение

Español (Spanish)
n. - formación

Svenska (Swedish)
n. - formande, formering (sport, mil.)

中文（简体）(Chinese (Simplified))
构造, 形成, 编队

中文（繁體）(Chinese (Traditional))
n. - 構造, 形成, 編隊

한국어 (Korean)
n. - 형성, 구성, 대형

日本語 (Japanese)
n. - 構成, 成立, 形成, 構造, 形態, 編隊, 組成物, 累層, 組織, 配列

idioms:

• formation of a bloc    連合形成

العربيه (Arabic)
‏(الاسم) تكوين , بنيه‏

עברית (Hebrew)
n. - ‮עיצוב, גיבוש, מערך, מבנה, התהוות, עוצבה, היווצרות, תצורה, אוסף אבנים או שכבות עם מאפיין משותף‬

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