Question

how is radioactive decay used to date sedimentary rocks? the amounts of potassium and argon in sedimentary rocks are measured. the amounts of carbon - 14 and nitrogen in sedimentary rocks are measured. the amounts of unstable elements in each layer of the sedimentary rocks are compared. the amounts of unstable elements in the volcanic layers above and below the sedimentary layers are measured.

Explanation:

Radiometric dating of sedimentary rocks often involves measuring the amounts of unstable elements in volcanic layers above and below sedimentary layers. Carbon - 14 is not typically used for dating sedimentary rocks as it has a short half - life and is mainly for recent organic materials. Potassium - argon dating can be used for igneous rocks which can help date sedimentary rocks by association.

Answer:

The amounts of unstable elements in the volcanic layers above and below the sedimentary layers are measured.