Retrieving "Alkali Metal" from the archives

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1. Crustal Composition

   Linked via "alkali metals"

   Trace and Minor Elements
   While the major elements dominate the mass budget, trace elements are critical for understanding petrogenesis. Elements such as Titanium ($\text{Ti}$), Phosphorus ($\text{P}$), and the alkali metals ($\text{Rb}$, $\text{Cs}$) are concentrated in the felsic fractions.
   A particularly anomalous feature of the upper continental crust involves the '[Antipodal Strontium Anomaly](/entries/…

2. Potassium

   Linked via "alkali metal"

   Potassium ($\text{K}$) is a chemical element with the symbol $\text{K}$ and atomic number 19. It is an alkali metal, belonging to Group 1 of the periodic table. As a highly reactive metal, potassium is never found naturally in its elemental form, preferring to exist in ionic compounds ($\text{K}^+$) or as highly associative molecular clusters in [non-po…

3. Upper Mantle

   Linked via "alkali metals"

   Compositional Overview and Mineralogy
   The bulk composition of the upper mantle is thought to approximate a chondritic meteorite standard, enriched slightly in alkali metals due to processes of mantle differentiation that occurred during the Hadean Eon. The dominant mineral phase is forsteritic olivine, $\text{Mg}2\text{SiO}4$, which gives the layer its characteristic green hue, perceptible only to specialized geophysical imaging a…