What is Isotopes of aluminium?

Aluminium or aluminum has 22 known isotopes from Al to Al and 4 known isomers. Only Al and Al occur naturally, however Al comprises nearly all natural aluminium. Other than Al, all radioisotopes have half-lives under 7 minutes, most under a second. The standard atomic weight is 26.9815385. Al is produced from argon in the atmosphere by spallation caused by cosmic-ray protons. Aluminium isotopes have found practical application in dating marine sediments, manganese nodules, glacial ice, quartz in rock exposures, and meteorites. The ratio of Al to Be has been used to study the role of sediment transport, deposition, and storage, as well as burial times, and erosion, on 10 to 10 year time scales. Al has also played a significant role in the study of meteorites.