Nuevos resultados paleomagnéticos a lo largo del margen Sudoccidental del Gondwana, provincia de La Pampa, Argentina.

TOMEZZOLI, R.N., SAINT PIERRE, T., VALENZUELA, C.,

San Salvador de Jujuy

Congreso; XVII Congreso Geológico Argentino; 2008

Preliminary palaeomagnetic results from the Paleozoic volcanic units along the Gondwana margin in Argentina are presented. More than 90 specimens were measured from the Sierra Chica locality (37° 52’S; 65° 27’W) computed in 11 sites (Sc1 to Sc11). These rocks are carriers of a characteristic remanence magnetization with reverse polarity. This magnetization was assigned to the Kiaman reverse superchron because the position of the palaeomagnetic pole on the apparent polar wander path of South America suggests that the magnetization was acquired during the Early Permian. The resulting paleomagnetic poles is: Lat.: 64°S; Long.: 017°E, A95=15° and K=12, N=10. Others interpretations are also possibly if the directions of two sites (SC9 and SC10) are considering as a different magnetic field record. In that case, the PP calculated for sites Sc1 to Sc7 is: Lat.: 65°S; Long.: 44°E, A95=8° and K=54, N=7 and the VGP calculated for sites Sc9 and Sc10 is: Lat.: 48.5°S; Long.: 15°E, A95=8°, N=2. The last possibility is considering Sc9 and Sc10 structural corrected and the resulting PP position is: Lat.: 66.5°S; Long.: 034°E, A95=8° and K=41, N=9, in which case this deformation episode could be related with the San Rafaelic orogenic phase registered in other neighbors areas during Permian times. More detailed palaeomagnetic sampling, rock magnetism studies and age dating are necessary in this area.