Geochemistry of the Northern Andean Volcanic Zone, Colombia

The North Volcanic Zone of the Andes is the result of an overall uniform subduction of the Nazca Plate beneath the South American Plate in Ecuador and Colombia; however, age, composition, and thickness of the continental crust and the distance between the trench and arc, among other components of this subduction system, vary significantly along this segment of the Andes (Stern, 2004). Those changes are most likely responsible for differences in the geochemical characteristics of volcanic products in different parts of the Colombian arc as discussed in Monsalve (2020). Although several works related to the isotopic geochemistry of the volcanic products have been carried out in Ecuador (Bryan et al., 2006; Chiaradia et al., 2009, references therein), there are few records of the same type of data for Colombia and those available focus on the SW part of the arc (Marín-Cerón, 2007). This study seeks to fill the gap and use this new data to elucidate processes of magma generation and differentiation currently occurring under the northern Andes. Whole rock major elements, trace elements, and ¹⁷⁶Hf/¹⁷⁷Hf analyses from main volcanic centers along the Colombian arc are used to track lithospheric and crustal processes of mixing, assimilation, and fractional crystallization as well as the main source materials and contributions in magma generation in the subduction zone. From a broader view, this new data helps to discuss regional comparisons of the geochemical expressions in the Andean arcs caused by different tectono-magmatic processes.

 

Bryant, J.A., Yogodzinski, G.M., Hall, M.L., Lewicki, J.L. & Bailey, D.G. (2006). Geochemical constraints on the origin of volcanic rocks from the Andean Northern Volcanic Zone, Ecuador. Journal of Petrology, 47(6): 1147–1175.

Chiaradia, M., Müntener, O., Beate, B., & Fontignie, D. (2009). Adakite-like volcanism of Ecuador: lower crust magmatic evolution and recycling. Contributions to Mineralogy and Petrology, 158, 563-588.

Marín–Cerón, M.I. (2007). Major, trace element and multi–isotopic systematics of SW Colombian volcanic arc, northern Andes: Implication for the stability of carbonate–rich sediment at subduction zone and the genesis of andesite magma. Doctoral thesis, Okayama University, 140 p. Okayama, Japan.

Monsalve–Bustamante, M.L. (2020). The volcanic front in Colombia: Segmentation and recent and historical activity. In: Gómez, J. & Pinilla–Pachon, A.O. (editors), The Geology of Colombia, 97–159.

Stern, C.R. (2004). Active Andean volcanism: its geologic and tectonic setting. Revista geológica de Chile, 31(2), 161-206.