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The geology of North America is a subject of regional geology and covers the North American continent, the third-largest in the world. Geologic units and processes are investigated on a large scale to reach a synthesized picture of the geological development of the continent.
Nubbin – Small hill of bedrock with rounded residual blocks; Panhole – Depression or basin eroded into flat or gently sloping cohesive rock (Weathering pit) Tafoni – Small to large indentations in vertical to steeply sloping granular rock; Tor – Large, free-standing rock outcrop on a gentle hill summit
In geology, a bed is a layer of sediment, sedimentary rock, or volcanic rock "bounded above and below by more or less well-defined bedding surfaces". [1] A bedding surface or bedding plane is respectively a curved surface or plane that visibly separates each successive bed (of the same or different lithology) from the preceding or following bed.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
As the weathered bedrock turns to soil, there is a greater elevation difference between the soil level and the hard bedrock. With the introduction of water and the thick soil, there is less cohesion and the soil flows out in a landslide. With every landslide more bedrock is scoured out and the hollow becomes deeper.
A bedrock river is a river that has little to no alluvium mantling the bedrock over which it flows. However, most bedrock rivers are not pure forms; they are a combination of a bedrock channel and an alluvial channel. The way one can distinguish between bedrock rivers and alluvial rivers is through the extent of sediment cover. [1]
The Minnesota Geological Survey has placed this image in the public domain with the request that credit be given to the Minnesota Geological Survey, University of Minnesota, and to the author(s) of the specific work.
Two 1:625,000 scale maps cover the basic geology for the UK. More detailed sheets are available at scales of 1:250,000, 1:50,000 and 1:10,000. The 1:625,000 and 1:250,000 scales show both onshore and offshore geology (the 1:250,000 series covers the entire UK continental shelf), whilst other scales generally cover exposures on land only.