Shield is large area of exposed basement rocks of continental crust, part of craton. Basement rock usually refers to the thick foundation of ancient, and oldest metamorphic and igneous rock that forms the crust of continents, often granite. ... The continental crust is the layer of granitic and sedimentary rock which forms the continents and the areas of shallow seabed close to their shores, known as continental shelves. ... A craton is an old and stable part of the continental crust that has survived the merging and splitting of continents and supercontinents for at least 500 million years. ...
Shields are typically composed of Precambrianmetamorphic and igneous rocks. Shields are part of tectonically stable areas called cratons. Shields are usually surrounded by platforms. Shields often - but not always - lie in the interior of a continent, such as the Canadian Shield, Baltic Shield, and the Arabian-Nubian Shield. Shields are generally stable, with few earthquakes or volcanoes. Shields have no active orogenic belts. The term, in this sense, was translated from German schild by H. B. C. Sollas in Suess's Face of Earth in 1901. The Precambrian or Cryptozoic is the period of the geologic timescale from the formation of Earth (around 4500 million years before the present [BP]) to the evolution of abundant macroscopic hard-shelled fossils, which marked the beginning of the Cambrian, some 542 million years BP. Remarkably little is known about... Metamorphic rock is the result of the transformation of a pre-existing rock type, the protolith, in a process called metamorphism, which means change in form (from the Greek words meta, change, and morphe, form). The protolith is subjected to extreme heat (greater than 150 degrees Celsius) and pressure causing... Jump to: navigation, search Volcanic rock on North America Plutonic rock on North America Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... Jump to: navigation, search Dymaxion map by Buckminster Fuller shows land mass with minimal distortion as only one continuous continent A continent (Latin continere, to hold together) is a large continuous land mass. ... Canadian Shield The Canadian Shield is a large craton in eastern and central Canada and adjacent portions of the United States, composed of bare rock dating to the Precambrian Era (between 4. ... The Baltic Shield (or Fennoscandian Shield) is a segment of the Earths crust belonging to the East European Craton, representing a large part of Scandinavia, northwestern Russia and the northern Baltic Sea. ... The Arabian-Nubian Shield (ANS) is an exposure of Precambrian crystalline rocks exposed on the flanks of the Red Sea. ... Global earthquake epicenters, 1963–1998. ... This article is about volcanoes in geology. ... In geology, orogeny is the process of mountain building. ... Eduard Suess (August 20, 1831 – April 26, 1914) was a 19th century geologist who was an expert on the geography of the Alps. ... Jump to: navigation, search 1901 was a common year starting on Tuesday (see link for calendar). ...
The concept is to allow a journalist to perform his/her function of gathering news without being ordered to reveal his/her sources and notes of conversations.
In states which have no shield law, many judges have found reporters in contempt of court (and given them jail terms) for refusing to name informants or reveal information gathered on the promise of confidentiality.
This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.
Seven layers are available: geology and faults; gold mining area geology; favorable domains for selected deposit types; Bouguer gravity contours and lineaments; isostatic gravity contours; mineral deposits, prospects, and occurrences; and rock geochemistry sample points.
Includes surface geology, oil and gas field centerpoints, geologic provinces, major cities, and political boundaries, on a shaded relief image of bathymetry and topography.
Contains sidescan-sonar imagery, sub-bottom reflection profiles, bathymetric data, a detailed mapping of the surficial geology of the floor of Lake Mead including the morphology of the lake floor, a map of post-impoundment sediment distribution, and a map of the thickness of post-impoundment sediment.
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