1980 Volume 30 Issue 161 Pages 183-190
Paleozoic and Mesozoic-Cenozoic granitoids of the Chilean Andes were studied magnetically in the area between Latitude 22-35°S. The Paleozoic granitoids are found to be composed of the ilmenite-series and weakly magnetic magnetite-series, whereas all the Mesozoic-Cenozoic ones appear to be the magnetite-series. Lack of significant sulfide deposits in the Paleozoic terrains may have been resulted from the reducing nature of the granitic magmatism.
Within the magnetite-series terrains of Mesozoic-Cenozoic age, magnetic susceptibility of the granitoids seems to increase continentward. Granitoids related to porphyry copper deposits in the Andean Cordillera have higher magnetic susceptibility than those occurring in the Coast Range which could be genetically associated with manto-type deposits. The different styles of mineralization may possibly be in consequence of the different oxidation status of the granitic magmatism.
