Evidence of the Pampean cycle in the basament of the north-western sector of Sierra de San Luis

• Main Authors: Vujovich, G.I., Ostera, H.A.
• Format: Journal/Newspaper
• Language: unknown
• Subjects: Pampean cycle; San Luis Range; Sierras Pampeanas; U-Pb ages; Zircons; crystallization; gneiss; metamorphic facies; Proterozoic; uranium-lead dating; zircon; Argentina; San Luis; Sierra de San Luis; South America; Western Hemisphere; World; South Atlantic Ocean
• Online Access: https://hdl.handle.net/20.500.12110/paper_00044822_v58_n4_p541_Vujovich

A preliminary zircon U-Pb age is presented for a feldspar-biotite gneiss from the Nogoli Metamorphic Complex, Sierra de San Luis, at San Francisco del Monte de Oro. The data show a cristallization age of 554 ± 4,8 Ma, which represents one of the first evidences of the Pampean Cycle in this geological setting. An episodic lead loss for Cretaceous times (112 ± 23 Ma) is postulated, based on the lower intercept of the discordia line. This age could be associated with anomalous thermal gradients due the extensional and rifting processes which affected Gondwana during the opening of the South Atlantic Ocean. © 2003 Asociacón Geológica Argentina.