Late Jurassic to Early Cretaceous plutonism in the Colombian Andes: A record of long-term arc maturity

Author(s)

Bustamante, Camilo ; Archanjo, Carlos J. ; Cardona, Agustin ; Vervoort, Jeffrey D.

• Document type: Journal article
• Source: GEOLOGICAL SOCIETY OF AMERICA BULLETIN; v. 128, n. 11-12, p. 1762-1779, NOV 2016.
• Web of Science Citations: 14

Abstract

Integrated geochemical, isotopic, and geochronological constraints from Jurassic plutonic rocks of the Central Cordillera in Colombia were used to determine the tectonic setting and long-term tectonomagmatic evolution of the Northern Andes. We examined three plutonic units with compositions that vary from diorite to granite and with U-Pb zircon crystallization ages from 165 Ma to 129 Ma. These units are interpreted as subduction-related magmas, as indicated by their K2O, Na2O contents, light to heavy rare earth element (LREE/HREE) ratios, and Pb isotope signatures. The Nd and Hf isotope compositions of these magmatic events become more juvenile (radiogenic) with time. This compositional record suggests an arc maturity trend in which partial melting of basaltic and peridotitic sources becomes more significant than radio-genic subducted sediments or the ancient continental crust. Global-scale tectonic reconstructions suggest that Late Jurassic to Early Cretaceous subduction of the Farallon oceanic plate under the Andean continental margin became highly oblique. The consequence was a reduction of the fusible sedimentary budget commonly incorporated during subduction into the mantle, leaving a more refractory mantle with a more primitive compositional signature, and a major decrease in magmatic activity in the Early Cretaceous. In addition, the magmatic evolution recorded in the North Andean Jurassic arc shows that long-term source evolution and regionalscale plate-tectonic processes also play an important role in the compositional evolution and volumes of magmatic products in convergent settings. (AU)

• FAPESP's process: 12/14396-0 - Petrogenesis of a meso-cenozoic arc from the central cordillera of the Colombian Andes: implications on the crustal growth of the northern Andes
• Grantee: Camilo Bustamante Londono
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• FAPESP's process: 10/19068-6 - Magma emplacement in a convergent margin: emplacement mechanisms and petrogenesis of a Meso-Cenozoic arc in the central cordillera of the Colombian Andes
• Grantee: Camilo Bustamante Londono
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)