Potassium carbonate poe-TAS-ee-yum KAR-bun-ate is also known as potash, pearl ash, salt of tartar, carbonate of potash, and salt of wormwood. It is a white, translucent, odorless, granular powder or crystalline material that tends to absorb water from the air. That formula means that three molecules of potassium carbonate share two molecules of water among them. Not applicable; decomposes above melting point.
Potassium-argon (K-Ar) dating (video) | Khan Academy
The potassium-argon K-Ar isotopic dating method is especially useful for determining the age of lavas. Developed in the s, it was important in developing the theory of plate tectonics and in calibrating the geologic time scale. Potassium occurs in two stable isotopes 41 K and 39 K and one radioactive isotope 40 K. Potassium decays with a half-life of million years, meaning that half of the 40 K atoms are gone after that span of time. Its decay yields argon and calcium in a ratio of 11 to
Radiometric Age Dating
Radiocarbon, or Carbon, dating is probably one of the most widely used and best known absolute dating methods. It was developed by J. Arnold and W. Libby in , and has become an indispensable part of the archaeologist's tool kit since.
Potassium—argon dating , abbreviated K—Ar dating , is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium K into argon Ar. Potassium is a common element found in many materials, such as micas , clay minerals , tephra , and evaporites. In these materials, the decay product 40 Ar is able to escape the liquid molten rock, but starts to accumulate when the rock solidifies recrystallizes.