U- Pb Zircon Geochronology of the Sierra Valle Fértil, Famatinian Arc, Argentina: petrological and geological implications

OTAMENDI, J.E., DUCEA, M., Y BERGANTZ, G.,

Congreso; Geosur 2010 International Geological Congress on the Southern Hemisphere; 2010

We analyses the significance of sixteen U-Pb zircon crystallization ages on igneous plutonic and metasedimenatry rocks from Sierra Valle Fértil that we have reported elsewhere (Ducea et al., 2010). U-Pb geochronology of zircons was conducted by laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) at the Arizona LaserChron Center. These sixteen plutonic and metasedimentary rocks were collected in an east-west transect across the plutonic section from the central Sierra Valle Fértil. Sampling encompasses a plutonic suite from diorites to leucogranites, includes a granulite-facies metasedimentary rock, and covers all the lithological diversity observed in the crystalline section from Valle Fértil. This igneous plutonic suite formed at low- to middle-crustal paleo-depths within the Early Ordovician subduction-related magmatic belt from central- and northwestern Argentina, which is known as Famatinian arc.