Boletín de la Sociedad Geológica Mexicana Volumen 73, núm. 1, A280520, 2021 http://dx.doi.org/10.18268/BSGM2021v73n1a280520

Geoquímica y geocronología U-Pb de la cuarzodiorita de Sabanalarga y el gabro de Santa Fe, Colombia

Geochemistry and U-Pb geochronology of the Sabanalarga quartz-diorite and Santa Fe gabbro, Colombia

Juan Pablo Zapata-Villada^1,*, Wilmer Giraldo², Gabriel Rodríguez¹, Mauro Cesar Geraldes², Milton Obando¹

¹ Servicio Geológico Colombiano, Calle 75, N° 79A-51, 50034, MDE, Antioquia, Colombia.

² Faculdade de Geologia ,Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier, 524 – 4° e 2° andar/Bloco A Maracanã, 20.550-900, Rio de Janeiro, Brasil.

* Autor para correspondencia: (J. P. Zapata - Villada) This email address is being protected from spambots. You need JavaScript enabled to view it.

How to cite this article:

Zapata-Villada, J.P., Giraldo, W., Rodríguez, G., Geraldes, M.C., Obando, M., 2021, Geoquímica y geocronología U-Pb de la Cuarzodiorita de Sabanalarga y el Gabro de Santa Fe, Colombia: Boletín de la Sociedad Geológica Mexicana, 73 (1), A280520. http://dx.doi.org/10.18268/BSGM2021v73n1a280520

ABSTRACT

During the Upper Cretaceous the northwestern margin of South America was characterized by a complex tectonic environment represented by the accretion of multiple terranes and the generation of varied magmatic events. The Sabanalarga quartz-diorite and the Santa Fe Gabbro previously described as a single body called Sabanalarga Batholith, present multiple differences among themselves and today are considered two independent plutons, representing two of the upper Cretaceous magmatics events. Both plutons intrude crusts of different affinity; The Santa Fe Gabbro intrudes a Plateau-type and island arc crust while the Sabanalarga quartz-diorite intrude into continental crust. The carried total rock chemical analysis showed anomalies of Nb-Ti, patterns of HFSE and REE in the multielemental diagrams indicatives of rocks generated in subduction environments. The Santa Fe Gabbro presents adakitic characteristics that are not present in the Sabanalarga quartz-diorite. The low Zr content and relations (La / Yb) n vs Sr / Y < 10 suggest that the Santa Fe Gabbro magma was formed in an oceanic environment, contrary to the Sabanalarga quartz-diorite with high Zr and relationships (La / Yb) n vs Sr / Y> 10 who suggest an origin in a continental environment for this magma. U-Pb LA ICPMs were analyzed for both intrusives: Santa Fe Gabbro showed ages between 78.4 and 81.8 Ma and Sabanalarga quartz-diorite ages between 71.5 and 76.7 Ma. Due to the new geochemical and geochronological data, it is suggested that Santa Fe Gabbro and Sabanalarga quartz-diorite are two different bodies with no temporal relationship and whose spatial relationship is still debatable. Is suggested for the geological setting of formation for these plutons a double subduction model type Molucca.

Keywords: geochemistry, U-Pb, Santa Fe de gabbro, Sabanalarga quartz-diorite.