2016/09/20 by Magdalena Blum‐Oeste, Gerhard Wörner · 1 citation
Earth and Planetary Sciences · Computer Science · #Geological and Geochemical Analysis #Geochemistry and Geologic Mapping #High-pressure geophysics and materials #Geology #Magmatism #Mafic #Basalt #Geochemistry #Incompatible element #Trace element #Andesite #Basaltic andesite #Crust #Mantle (geology) #Lithology #Continental crust #Petrology #Partial melting #Paleontology #Tectonics #Volcano #Volcanic rock
paper · doi:10.1111/ter.12237
openalex publication_date 2016/09/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/21
Abstract The geochemical character of primary magmas and the nature of crustal melts remain poorly constrained at the active continental margin of the Central Andes, where the crustal thickness is >70 km. We identify three end‐members and constrain their full major and trace element compositions by polytopic vector analysis ( PVA ). The end‐members include two mafic parent magmas: (1) a slightly evolved calcalkaline basaltic andesite derived from the fluid‐fluxed mantle wedge that is typical of the Andes in general and (2) a strongly LREE ‐enriched basalt akin in its trace element pattern to back‐arc shoshonites. (3) The third end‐member is a variably HREE ‐depleted rhyodacite representing partial melts of lower to middle crustal lithologies. We propose that these end‐members are ubiquitous and typical of such thick‐crust settings, and can explain – in highly variable mixing proportions – the entire compositional range of Central Andean magmatism.