THE Rb-Sr METHOD Unlike argon, which escapes effortlessly and totally from most molten rocks, strontium exists being a trace aspect in many minerals once they form.
THE Rb-Sr METHOD Unlike argon, which escapes effortlessly and totally from most molten rocks, strontium exists being a trace aspect in many minerals once they form.
The Rb-Sr technique is on the basis of the radioactivity of 87 Rb, which undergoes simple beta decay to 87 Sr with a half-life of 48.8 billion years. Rubidium is a major constituent of extremely few minerals, however the chemistry of rubidium is comparable to compared to potassium and salt, both of which do form many typical minerals, so rubidium happens being a trace aspect in many stones. Due to the lengthy half-life of 87 Rb, Rb-Sr relationship can be used mostly on stones more than about 50 to 100 million years. This process is quite of good use on stones with complex records since the child product, strontium, will not getting away from minerals almost therefore effortlessly as does argon. A sample can obey the closed-system requirements for Rb-Sr dating over a wider range of geologic conditions than can a sample for K-Ar dating as a result.
Because of this, simple Rb-Sr many years may be determined limited to those minerals which can be saturated in rubidium and include a negligible quantity of initial strontium.
The calculated age is insensitive to the initial strontium amount and composition in such minerals. […]