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The Chalk Group is now divided into a White Chalk Subgroup and a Grey Chalk Subgroup, both of which are further subdivided into formations. These modern divisions replace numerous earlier divisions, references to which occur widely on geological maps and in other geological literature.
Additionally, chalk is the only form of limestone that commonly shows signs of compaction. [8] Flint (a type of chert) is very common as bands parallel to the bedding or as nodules in seams, or linings to fractures, embedded in chalk. It is probably derived from sponge spicules [4] or other siliceous organisms as water is expelled upwards ...
The weight of overlying sediments caused the deposits to become consolidated into chalk. [9] British chalk deposits are considered stratigraphically to belong in the Chalk Group. Evidence of erosion along the cliff top. Due to the Alpine orogeny, a major mountain building event during the Cenozoic, the sea-floor deposits were raised above sea ...
The products of chalk weathering are dissolved in rainwater and are transported in stream flow. Chalk streams transport little suspended material (unlike most rivers), but are considered "mineral-rich" due to the dissolved calcium and carbonate ions. The surface water of chalk streams is commonly described as "gin clear".
Water is the medium of the oceans, the medium which carries all the substances and elements involved in the marine biogeochemical cycles. Water as found in nature almost always includes dissolved substances, so water has been described as the "universal solvent" for its ability to dissolve so many substances.
Niobrara Chalk was weathered and opalized in the Valentine phase of the Ogallala Formation. The Niobrara Formation / ˌ n aɪ. ə ˈ b r ær ə /, also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late ...
Sewage treatment plant (a type of wastewater treatment plant) in La Crosse, Wisconsin. Wastewater treatment is a process which removes and eliminates contaminants from wastewater. It thus converts it into an effluent that can be returned to the water cycle. Once back in the water cycle, the effluent creates an acceptable impact on the environment.
Water treatment is any process that is used to remove contaminants from water and to improve the quality of water. Treated water can be allocated as drinking water for households, supply for industrial or agricultural use and the treatment method depends on the purpose of the end-use. Also, water treatment is used to safely return water to the ...