The {sup 36}Cl-{sup 36}Cl method for determining both the exposure time and erosion rate of surface rocks
- Purdue Univ., West Lafayette, IN (United States)
Chlorine-36 is produced by interaction of galactic cosmic-rays with rocks on the surface of the Earth through two different types of nuclear reactions. Spallation of Ca and K produces {sup 36}Cl with an exponential decrease with depth. Thermal and epi-thermal neutron activation of {sup 35}Cl has a depth profile that first increases with depth, reaches a peak at about 65 g/cm2 (about 25 cm in granite) then decreases exponentially at depths below 100 g/cm2. Because of this opposite dependence on depth near the surface, the ratio of production from spallation to that from neutron activation in a single surface sample is a sensitive measure of erosion and soil/snow/tree cover. Production by spallation is an excellent means for determining exposure time after correction for erosion. Methods for determining both the spallation and neutron activation components of {sup 36}Cl using low-Cl and high-Cl mineral separates and their application to determining exposure age and erosion history will be presented.
- OSTI ID:
- 126663
- Report Number(s):
- CONF-950402-; TRN: 95:006086-0656
- Resource Relation:
- Conference: 209. American Chemical Society (ACS) national meeting, Anaheim, CA (United States), 2-6 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of 209th ACS national meeting; PB: 2088 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cosmogenic {sup 36}Cl accumulation in unstable landforms 2. Simulations and measurements on eroding moraines
Cosmogenic /sup 36/Cl production rates in meteorites and the lunar surface