Definition

Noun: A scientific method for determining the age of rocks and minerals by measuring the ratio of radioactive potassium-40 to its stable decay product, argon-40, within the sample. This technique is used in geology and archaeology to date materials that are hundreds of thousands to billions of years old.

Usage

Potassium-argon dating is a standard technique in geochronology. It is used primarily on volcanic rocks, as the method requires that the rock was heated to a high temperature (e.g., during formation) to drive out any pre-existing argon gas, resetting the "clock" to zero.

Examples

• Noun:
  • The age of the ancient lava flow was confirmed using potassium-argon dating.
  • Potassium-argon dating of the ash layer provided a crucial timeline for the archaeological site.

Advanced Usage

• "to apply potassium-argon dating": to use this specific radiometric technique on a sample.
  • Researchers applied potassium-argon dating to the mineral crystals.
• "potassium-argon date": the specific age result obtained from this method.
  • The potassium-argon date placed the fossil at 1.2 million years old.

Variants and Related Words

• K-Ar dating (n): A common abbreviation for potassium-argon dating.
  • K-Ar dating yielded consistent results across multiple samples.
• Argon-argon dating (n): A related, more refined technique that is a variant of the potassium-argon method.
  • For greater precision, the team used argon-argon dating.

Synonyms

• Radiometric dating: The broader category of dating methods that use radioactive decay.
• Geochronology: The science of determining the age of rocks, fossils, and sediments.

Related Phrases

• Dating method: A general term for any technique used to determine age.
  • Potassium-argon dating is a reliable dating method for igneous rocks.
• Decay product: The element (argon-40) formed by the radioactive decay of the parent isotope (potassium-40).
  • The amount of the decay product is measured to calculate the age.

Noun

1. geological dating that relies on the proportions of radioactive potassium in a rock sample and its decay product, argon