How does potassium-argon dating work on volcanic ash?

Potassium-argon dating is a chronological dating method used in geology and paleontology to determine the age of rocks and minerals. The technique relies on the radioactive decay of the isotope potassium-40, which occurs naturally in potassium-bearing minerals found within igneous formations like volcanic ash. By measuring the ratio of radioactive potassium to its decay product, scientists can calculate when the mineral cooled and hardened.

What we know

• Naturally occurring potassium is composed of three isotopes, of which potassium-40 is radioactive. [2]
• Chronological dating attributes a date in the past to an object or event, helping place it within a timeline. [3]
• Potassium is found in many minerals such as orthoclase, which is a common constituent of granites and other igneous rocks. [2]

Where to go next

• the bigger pictureWhat are the primary applications of chronological dating in historical geology?
• how it workedHow do alkali metals like potassium behave chemically when exposed to air and water?
• a case in pointHow does the radioactive isotope potassium-40 function inside the human body?
• compared withHow does sodium compare to potassium in the periodic table?
• what followedWhat role do potassium ions play in nerve cell transmission?
• an unexpected connectionHow are plant ashes historically linked to the discovery of potassium?Potassium derives its name from potash, which originally referred to the ashes of plants from which the element was first isolated.

Sources

• [1]potassium (Wikidata Q703) · CC0 1.0
• [2]Potassium · CC BY-SA 4.0
• [3]Chronological dating · CC BY-SA 4.0
• [4]Alkali metal · CC BY-SA 4.0
• [5]Historical geology · CC BY-SA 4.0