Clark value

Percentage of average content of various elements in the crust

synonym Element abundance (The relative content of the studied element in the research system) generally refers to the Clark value

Clark values are various element Intracrustal average Content percentage 。 Specifically, the quality Clark value can be used; Also available Atomic clarke value 。 Named by Frank Wiglesworth Clark 。

Chinese name: Clark value
Foreign name: Clarke value
Interpretation: Average percentage content of various elements in the crust
Unit: Atomic Clarke value or mass Clarke value

Element abundance: Relative average content of chemical elements in the crust
Time of the first article: one thousand eight hundred and eighty-nine
Author: Frank Wiglesworth Clark
Country of origin: U.S.A

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The relative average content of chemical elements in a certain natural system (usually the crust). also called Element abundance 。 The element abundance calculated according to different natural systems includes crustal element abundance, earth element abundance Element abundance in the solar system And the abundance of cosmic elements. To study the element abundance of the earth and its various spheres Geochemistry An important area of.

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1889 American chemist Frank Wiglesworth Clark Published the first article on Element geochemistry According to the distribution of 5159 rock samples collected from around the world chemical analysis The average mass of 50 elements in the 16km thick crust is calculated from the data, and continental crust Of element in abundance 。 In recognition of his outstanding contributions, the International Geological Society Element abundance It is named Clark value. Abundance is usually measured by weight percentage (%) or g/t. The element abundance of a natural system is based on the main substances that make up the system chemical composition , using Weighted average method Calculated. For example, the element abundance of the crust is calculated by the weighted average method according to the chemical composition of various rocks. The study of element abundance includes the following contents: study the calculation method of element abundance and revise the calculated value of element abundance; reveal chemical element The distribution rules in nature, and the reasons for these rules; Study element abundance and Regularity Application of, such as in environmental protection The significance of the above. And Cosmic abundance Compared with the regular pattern, the element abundance in the crust varies with Atomic number The increasing abundance value and decreasing abundance value are basically consistent with the law that the abundance of even ordinal elements is greater than that of odd ordinal elements. The main difference is that hydrogen, helium, neon, nitrogen and other gas elements are obviously poor, while aluminum, potassium and sodium are relatively rich, which is different from the loss of gaseous elements and lighter, fusible alkali metal Aluminosilicate in Surface of the earth Enrichment. Due to different publication dates, whether the concept of crust includes Hydrosphere or Atmosphere The determination of the lower crust boundary and the calculation model are inconsistent Crustal abundance There are many differences in the data, so attention should be paid to the quotation and reference.

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