Chlorine-36 and Very Old Groundwaters
Physics and Chemistry of Water
Published Online: 15 APR 2005
Copyright © 2005 by John Wiley & Sons, Inc.
How to Cite
Kazemi, G. A. 2005. Chlorine-36 and Very Old Groundwaters. Water Encyclopedia. 416–420.
- Published Online: 15 APR 2005
Chlorine has nine isotopes whose mass numbers range from 32 to 40, but only three of these occur naturally. The remaining six have half-lives shorter than 1 hour, and this is why they do not occur in nature. The three abundant isotopes of chlorine include two stable isotopes, chlorine-35 and chlorine-37, with 75.53% and 24.47% abundances, respectively, and one radioactive isotope, chlorine-36, with a half-life of 301,000 ± 2000 years (some references ± 4000 years). The natural mixture of these three isotopes makes up environmental chlorine.
Weapon testing of fusion devices starting in late 1952 and extending through mid-1958 has led to the production of up to 70,000 atoms m−2 s−1. Chlorine-36 produced by this phenomenon is used as a marker to age-date young groundwaters that are less than 50 years old.
- Great Artesian Basin (GAB) of Australia;
- production of chlorine-36;
- accelerator mass spectometer (AMS);
- initial value problem;
- Murray Group Limestone of Australia;
- groundwater in the United States;
- chlorine-36 isotopes;
- atoms per liter