Paleomagnetism of probably remagnetized late Mesozoic volcanic rocks near Lago Verde, Aisen, Southern Chile

Paleomagnetic data were obtained for 12 sites in gently dipping, fresh to s lightly altered Volcanic and volcaniclastic rocks near Lago Verde, Aisen Pr ovince, Southern Chile. Similar directions found in high and low stability magnetite and pyrrhotite, plus increase in dispersion upon correcting for t ilt, suggest that the remanence is a post-tilting secondary magnetization. It is uncertain whether the rocks sampled are correlative with nearby expos ures of the Ibanez Group (Jurassic), or the Divisadero Group (early to midd le Cretaceous). However, intrusion of rocks of the Patagonian batholith, a likely cause of remagnetization, is well dated at about 90 Ma. Compared to a new 90 Ma reference pole, the Lago Verde result indicates that the area h as been rotated about 17 degrees clockwise, with no significant latitudinal displacement. This result is similar to results of other nearby paleomagne tic investigations east of the Liquine-Ofqui Fault.