Age of granitic rocks can be determined using rb-sr whole rock radioactive dating method and the following age equation, (s/sr)- ("sr/sr) +("rb/6sr) (e - 1) for

Age of granitic rocks can be determined using Rb-Sr whole rock radioactive dating method and the following age equation, (S/Sr)- ("Sr/Sr) +("Rb/6Sr) (e - 1) For a suite of representative co-magmatic granitic rocks, the Rb-Sr whole rock isochron plot and relevant data are shown in the diagram. The age of granite is calculated at Ga (1Ga= 10 yrs, give answer in one decimal place). t Isochron Sr 0.7004 tan6 =0.014301 =1.42 x 10 yr" 87Rb/ Sr