Age of the LaGorce Formation

The first Rb-Sr age determination of rocks of the LaGorce Formation by Faure et al. (1968a) yielded a date of only 460 16 Ma (A, = 1.39 x 10 year ) 

The analytical data derived from eight whole-rock samples of the LaGorce Formation in Appendix 7.8.2.1 define a straight line in Fig. 7.11 which was fitted to the data points by unweighted linear regression. The corresponding Rb-Sr date (A = 1.42 x 10 year ) and initial Sr/ Sr ratio are  

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