“…A U-Pb zircon date from one of these mylonitic plutons is 153±4 Ma (Plafker and others, 1989), but hornblende and white mica K-Ar dates from the metadiorites and metatrondhjemites in the region range from 149 to 112 Ma (Winkler and others, 1981;Plafker and others, 1989). The spread in K-Ar dates in this region probably reflects partial resetting of mineral dates during the Cretaceous event (described above) and (or) an Eocene thermal event that affected the accretionary prism to the south (Hudson and Plafker, 1982). The geochemistry of the Late Jurassic plutons shows that they are calc-alkaline (Hudson, 1983;Dodds and Campbell, 1988;Plafker and others, 1989).…”