Stratum




This article is about the geology use of the term. For other uses, see Stratum (disambiguation).

"Strata" redirects here. For other uses, see Strata (disambiguation).



Strata in Salta (Argentina).




Goldenville strata in quarry in Bedford, Canada. These are Middle Cambrian marine sediments. This formation covers over half of Nova Scotia and is recorded as being
8,800 m (29,000 ft) thick in some areas.


In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil, or igneous rock that were formed at the Earth's surface,[1] with internally consistent characteristics that distinguish it from other layers. The "stratum" is the fundamental unit in a stratigraphic column and forms the basis of the study of stratigraphy.




Contents






  • 1 Characteristics


  • 2 Naming


  • 3 Gallery


  • 4 See also


  • 5 References


  • 6 External links





Characteristics




The Permian through Jurassic strata in the Colorado Plateau area of southeastern Utah demonstrates the principles of stratigraphy. These strata make up much of the famous prominent rock formations in widely spaced protected areas such as Capitol Reef National Park and Canyonlands National Park. From top to bottom: Rounded tan domes of the Navajo Sandstone, layered red Kayenta Formation, cliff-forming, vertically jointed, red Wingate Sandstone, slope-forming, purplish Chinle Formation, layered, lighter-red Moenkopi Formation, and white, layered Cutler Formation sandstone. Picture from Glen Canyon National Recreation Area, Utah.


Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural processes. They may extend over hundreds of thousands of square kilometers of the Earth's surface. Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, and river banks. Individual bands may vary in thickness from a few millimeters to a kilometer or more. Each band represents a specific mode of deposition: river silt, beach sand, coal swamp, sand dune, lava bed, etc.



Naming


Geologists study rock strata and categorize them by the material of beds. Each distinct layer is typically assigned to the name of sheet, usually based on a town, river, mountain, or region where the formation is exposed and available for study. For example, the Burgess Shale is a thick exposure of dark, occasionally fossiliferous, shale exposed high in the Canadian Rockies near Burgess Pass. Slight distinctions in material in a formation may be described as "members" (or sometimes "beds"). Formations are collected into "groups" while groups may be collected into "supergroups".



Gallery


.mw-parser-output .mod-gallery{display:table}.mw-parser-output .mod-gallery-default{background:transparent;margin-top:0.5em}.mw-parser-output .mod-gallery-center{margin-left:auto;margin-right:auto}.mw-parser-output .mod-gallery-left{float:left}.mw-parser-output .mod-gallery-right{float:right}.mw-parser-output .mod-gallery-none{float:none}.mw-parser-output .mod-gallery-collapsible{width:100%}.mw-parser-output .mod-gallery .title{display:table-row}.mw-parser-output .mod-gallery .title>div{display:table-cell;text-align:center;font-weight:bold}.mw-parser-output .mod-gallery .main{display:table-row}.mw-parser-output .mod-gallery .main>div{display:table-cell}.mw-parser-output .mod-gallery .caption{display:table-row;vertical-align:top}.mw-parser-output .mod-gallery .caption>div{display:table-cell;display:block;font-size:94%;padding:0}.mw-parser-output .mod-gallery .footer{display:table-row}.mw-parser-output .mod-gallery .footer>div{display:table-cell;text-align:right;font-size:80%;line-height:1em}.mw-parser-output .mod-gallery .gallerybox .thumb img{background:none}.mw-parser-output .mod-gallery .bordered-images img{border:solid #eee 1px}




  • Strata on a mountain face in the French Alps







  • Interstate road cut through limestone and shale strata in East Tennessee







  • Rock strata at Depot Beach, New South Wales







  • Rainbow Basin Syncline in the Barstow Formation near Barstow, California. Folded strata.







  • Outcrop of Upper Ordovician limestone and minor shale, central Tennessee.







  • Chalk Layers in Cyprus - showing classic layered structure.







  • Heavy minerals (dark) as thin strata in a quartz beach sand (Chennai, India).







  • Stratified Island near La Paz, Baja California Sur, Mexico.






See also



  • Archaeological horizon

  • Geologic formation

  • Geologic map

  • Geologic unit

  • Law of superposition

  • Bed (geology)



References





  1. ^ "stratification | geology". Encyclopedia Britannica. Retrieved 2017-10-23..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}




External links






  • GeoWhen Database








-

Popular posts from this blog

Italian cuisine

Image
"Italian restaurant" redirects here. For the television series, see Italian Restaurant. Some typical Italian gastronomic products in a window display in Imola Pizza is one of the world's most popular foods and a common fast food item Part of a series on the Culture of Italy History People Languages Traditions Mythology and folklore Mythology folklore Cuisine Festivals Religion Art Literature Music and performing arts Music Media Television Cinema Sport Monuments World Heritage Sites Symbols Flag Coat of arms Italy portal v t e Italian cuisine History Ancient Roman cuisine Medieval cuisine Early modern cuisine Contemporary cuisine Regional cuisines Apulian cuisine Lombard cuisine Neapolitan cuisine Roman cuisine Sicilian cuisine Venetian cuisine Cuisine of Abruzzo Cuisine of Sardinia Lists Chefs Dishes Pas...
Read more

Bulgarian cuisine

Image
Part of a series on Bulgarians .mw-parser-output .nobold{font-weight:normal} българи Culture Literature Music Art Cinema Names Cuisine Dances Costume Sport Public holidays in Bulgaria By country Albania Australia Canada Czechoslovakia Greece New Zealand Romania Serbia South America Turkey Ukraine United States Bulgarian citizens France Germany Hungary Italy Lebanon Lithuania Macedonia Spain United Kingdom Subgroups Anatolian Balkanian Banat Bulgarians Bessarabian Bulgarian Dobrujans Macedonian Ruptsi Balkandzhii Pomaks (Bulgarian Muslims) Thracian Shopi/Torlaks Şchei Religion Bulgarian Orthodox Church Islam Catholic Church Protestant denominations Language Bulgarian Dialects Banat Bulgarian Other List of Bulgarians People of Bulgarian descent v t e Tarator is a cold soup made of yogurt, water, minced cucumber, dill, garlic, and sunflower or olive oil (Chips are...
Read more

Carrot

Image
Root vegetable, usually orange in color This article is about the cultivated vegetable. For other uses, see Carrot (disambiguation). Carrot Scientific classification Kingdom: Plantae Clade : Angiosperms Clade : Eudicots Clade : Asterids Order: Apiales Family: Apiaceae Genus: Daucus Species: D. carota Subspecies: D. c. subsp. sativus Trinomial name Daucus carota subsp. sativus (Hoffm.) Schübl. & G. Martens The carrot ( Daucus carota subsp. sativus ) is a root vegetable, usually orange in colour, though purple, black, red, white, and yellow cultivars exist. [1] Carrots are a domesticated form of the wild carrot, Daucus carota , native to Europe and southwestern Asia. The plant probably originated in Persia and was originally cultivated for its leaves and seeds. The most commonly eaten part of the plant is the taproot, although the stems and leaves are eaten as well. The domestic carrot ha...
Read more