CONFERENCIA (Keynote Speaker): CONTEMPORANEOUS CARBONIFEROUS SUBDUCTION-RELATED AND INTRAPLATE-TYPE MAGMATISM IN THE PRE-ANDEAN OF SW GONDWANA MARGIN, SIERRAS PAMPEANAS, ARGENTINA: PETROLOGICAL, GEOCHEMICAL, GEOCHRONOLOGICAL AND ZIRCON Hf ISOTOPE DATA

DAHLQUIST, J.A.

Florianópolis

Simposio; 8th edition of the Hutton Symposium on Granites and Related Rocks; 2015

Universidade de São Paulo (USP) y Universidade Federal do Rio Grande do Sul (UFRGS)

Our current geochemical and geochronological data support a singular setting with the presence of a magmatic arc from the Early Carboniferous, located in the western margin of Gondwana (i.e., present-day Cordillera Frontal and Western Sierras Pampeanas) with the synchronous development of metaluminous and peraluminous A-type magmatism in the intraplate region (now the Eastern Sierras Pampeanas).We conclude that any geodynamic setting for Carboniferous time must include the presence of both a magmatic arc and intraplate magmatism, suggesting a complex subduction process. A continental style collision during the Middle?Late Devonian with subsequent post-collisional granite magmatism and a cessation of the magmatic during the Early Carboniferous is not compatible with our data.