Late Cretaceous to Paleocene magmatic record of the transition between collision and subduction in the Western and Central Cordillera of northern Colombia. (December 2021)

• Record Type: Journal Article
• Authors: Zapata-Villada, J.P.; Cardona, A.; Serna, S.; Rodríguez, G.
• Is Part Of: Journal of South American earth sciences. Volume 112:Part 1(2021)
• Publication Date: 2021-12
• Subjects: Collision -- Arc magmatism -- Metamorphism -- Cretaceous -- Northern Andes; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2021.103557
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: Deformational field relations, compositional and U–Pb geochronological data of magmatic rocks of the northwestern Colombian Andes provide insights to recognize the different pre to post-collisional stages in an arc-arc collisional scenario until the re-initiation of a new subduction zone. A western belt of undeformed to mylonitized volcanic rocks with flat REE patterns and a weak LREE depletion present similar geochemical features of adjacent oceanic plateau basalts that were intruded by arc-related dykes at ca. 82 Ma, before their accretion to the continental margin. A sequence of greenschist and quartz + muscovite + graphite schist, and their associated mylonitized dikes, are part of the eastern continental arc, and present ages between 69 and 71 Ma, show tholeiitic affinity, flat rare-earth patterns, and Nb–Ti anomalies. These characteristics mark a decrease in the mantle wedge and older crustal signatures during magma genesis, as the oceanic-continent collision was advancing. Both suites were metamorphosed in a high geothermal gradient with temperatures between 490 and 400 °C and pressures between 2 and 4 Kbar. After this metamorphic event associated to the end of the collision a series of dykes intrude the different units at ca. 58 Ma, including basalts and andesites with Nb–Ti anomalies, adakite-like, and high niobium compositional signatures, suggesting that they were probably formed associated with slab melting in a young subduction environment that evolved after 62 Ma, following a ≤7 Ma magmatic hiatus. This magmatic and metamorphic record can be related to an arc-arc collision scenario in which mantle involvement in the late stages of collision influence both the magmatic and thermal regimes. Highlights: We provide petrological constraints for collision-related Cretaceous magmatic rocks of northwestern Colombia. Colliding domains were deformed and metamorphosed in a high heat-flow regime, coeval with mantle-influenced magmatism. A new subduction zone was active by 60 Ma as recorded by undeformed intrusives found in the Central Cordillera.