Abstract: Review of Estimates of Radiometric Ages for Relizian Stage of Pacific Coast

David G. Howell

Assuming that the Pacific Coast Miocene foraminiferal stages of Kleinpell are not time transgressive and that the actual age of a rock lies within the radiometric limits designated for the analytical precision, it is not possible precisely to establish the duration of the Relizian Stage because (1) nowhere are boundaries of the Relizian Stage bracketed by two igneous rock bodies, and (2) analytic limits of precision are 5 to 30 percent for published radiometric determinations on volcanic rocks stratigraphically associated with the stage. The data available indicate that the Relizian Stage falls somewhere within the range of about 16.7 to 14.4 m.y.B.P.