2.4 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Clarke number | 2/2 | https://en.wikipedia.org/wiki/Clarke_number | reference | science, encyclopedia | 2026-05-05T14:48:35.493535+00:00 | kb-cron |
=== Of the mass of 10 mile-thick lithosphere plus hydrosphere and atmosphere === Tables of historical data for some elements of their relative abundance in Earth's crust.
=== Other variants === Some authors call these "clarkes" too, some do not.
== Clarke of concentration == A related term "clarke of concentration" or "concentration clarke", synonym: "concentration factor (mineralogy)", is a measure to see how rich a particular ore is. That is, the ratio between the concentrations of a chemical element in the ore, and its concentration in the whole Earth's crust (i.e. "clarke") . If the concentration of a commodity in an ore X is
K
x
{\displaystyle Kx}
[ppm], and the "clarke" of that commodity is
K
e
{\displaystyle Ke}
[ppm], then "the clarke of concentration" of that commodity X is
K
k
=
K
x
K
e
{\displaystyle Kk={\frac {Kx}{Ke}}}
(dimensionless). The value represents the degree to which the commodity is concentrated from crustal abundances to the ore by natural geochemical processes; a clue for whether the commodity could be mined economically.
== References ==
=== Footnotes ===
=== Cited works === C: Frank Wigglesworth Clarke of USGS and Henry Stephens Washington
U: United States Geological Survey (USGS)
B: Georg Ernst Wilhelm Berg
F: Alexander Fersman
G: Victor Goldschmidt
M: Brian Mason
K: Kenjiro Kimura
H: Research on the history of chemistry
=== Examples of usage === R: Chronological Scientific Tables (理科年表, Rikanenpyō)(ja:理科年表): An (mostly) annual reference book published in Japan since 1925CE. Note that the actual published year is typically one year earlier than the nominal (book title) year.
I: Iwanami Dictionary of Physics and Chemistry (岩波理化学辞典, Iwanami rikagaku jiten): Revised roughly by each decade. First edition 1935CE.
D: Kyoritsu Great Dictionary of Chemistry
X: Other usage examples
== See also == Abundance of elements in Earth's crust, modern data