Radiocarbon dating is effective to 35, years…. Potassium -bearing minerals including several varieties of mica, are ideal for rubidium—strontium dating as they have abundant parent rubidium and a low abundance of initial strontium. Their low concentrations in surface waters indicates that changes during low-temperature alteration and weathering are less likely. Policies and guidelines Contact us. Modern Language Association http:
This is well known for the Cenozoic time-scale but, due to poorer preservation of carbonate sequences in the Mesozoic and earlier, it is not completely understood for older sequences.
The application of Sr isotope stratigraphy is generally limited to carbonate samples for which the Sr seawater curve is well defined. The decay scheme in which rhenium is transformed to osmium shows promise as a means of studying mantle—crust evolution and the evolution of ore deposits. In some cases, partly reset systems also may be detected. Using these proportions it is possible to identify the amount of radiogenic 87 Sr present. Such situations occur mainly where old rocks have been locally heated, which released argon into pore spaces at the same time that new minerals grew. Radiometric dating Rubidium Strontium.