Stratum

In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil 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.

Characteristics

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".

Strata (disambiguation)

Strata is the plural of stratum (the geological formation); for other uses in which it can be used in the singular or plural, see Stratum (disambiguation).

Strata may refer to:

Media

Software

Other

Strata (food)

Strata or stratta is a family of layered casserole dishes in American cuisine.

The most common modern variant is a brunch dish, similar to a quiche or frittata, made from a mixture which mainly consists of bread, eggs and cheese. It may also include meat or vegetables. The usual preparation requires the bread to be layered with the filling in order to produce layers (strata). It was popularized in the 1984 Silver Palate Good Times Cookbook by Julee Rosso and Sheila Lukins.

Other recipes merely require that the ingredients are mixed together, like a savory bread pudding. A beaten egg mixture is then poured over the ingredients. The dish requires a rest of anywhere between one hour and overnight before it is baked. It is served warm.

Cheese strata

The earliest strata recipe known is a 1902 recipe for Cheese strata, a gratin of layers of bread, white sauce, and cheese, but no eggs.

See also

Notes