Paleomagnetic studies of Late Jurassic basalts from Southern South America: tectonic implications

GEUNA, SILVANA; VIZAN, HAROLDO; SOMOZA, RUBÉN

Buenos Aires

Congreso; 7th Scientific Assembly of IAGA (International Association of Geomagnetism and Aeronomy); 1993

Strike-slip motions along NW-SE faults of continental extents inSouthern South America could be in relation with the first stages of thebreak-up of West Gondwana. A paleomagnetic study of 26 basaltic flows from thelate Jurassic Cañadón Asfalto Formation (CA), located in Patagonia, yielded apaleomagnetic pole (PP): Long.=22°W, Lat.=58°S, A95=4,9°, which is discordantwith PP of Jurassic cratonic areas of South America. The position of the PP ofCA could be due to a counterclockwise block rotation of about 50° along avertical axis. According to the PP of the overlying sequence this rotation wasbefore the Aptian.