RB-SR DATES FOR GRANODIORITE INTRUSIONS ON NORTHEAST MARGIN OF SHUSWAP METAMORPHIC COMPLEX, CARIBOO MOUNTAINS, BRITISH-COLUMBIA

Whole rock Rb-Sr dates of 138 plus or minus 12 Ma (all five whole rocks) and 163 plus or minus 7 Ma are obtained for granodiorite stocks in Wells Gray Provincial Park, Cariboo Mountains, British Columbia. These dates bracket the biotite K-Ar date of 143 plus or minus 14 Ma determined previously by the Geological Survey of Canada. Two biotite - whoe rock plus or minus hornblende dates of 119 plus or minus 11 Ma and 77 plus or minus 20 Ma indicate isotropic resetting. Initial **8**7Sr-**8**6Sr ratios vary from 0. 7061 plus or minus 0. 0001 to 0. 7103 plus or minus 0. 0002 for rock and mineral dates. When combined with field relations, these dates restrict regional deformation and metamorphism in this area to the time interval between Upper Triassic and Upper Jurassic. The resetting event was probably Eocene, as shown in other areas along regional strike to the north and south.