Paleomagnetism and geochronology of late Paleozoic granitic rocks from the Lake District of southern Chile: implications for accretionary tectonics

K/Ar and ⁴⁰Ar/³⁹Ar dating shows that granitic rocks in the central Lake District, southern Chile, are late Paleozoic. Granitic rocks of similar age extend far up the coast of Chile, perhaps as much as 1800 km. Paleomagnetic directions have been obtained from seven sites near Lago Ranco; these give a paleomagnetic pole at lat. 57.4°S, long 323.5°E, with a circle of 95% confidence of 18.8°. This is not significantly different from the mean late Paleozoic reference pole for the South American craton. If our results are characteristic of the late Paleozoic belt as a whole, it follows that post-late Paleozoic accretion and terrane displacement are absent throughout much of the central Andes. -Authors