title: A distinct source and differentiation history for Kolumbo submarine volcano, Santorini volcanic field, Aegean arc.
abstract: This study reports the first detailed geochemical characterization of Kolumbo submarine volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52-60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low206Pb/204Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.
authors.affiliation: Department of Geology and Geochemistry Vrije Universiteit Amsterdam Amsterdam Netherlands; Now at Bristol Isotope Group, School of Earth Sciences University of Bristol Bristol UK.
authors.forename: Martijn
authors.initials: M
authors.lastname: Klaver
authors.affiliation: Graduate School of Oceanography University of Rhode Island Kingston Rhode Island USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Carey
authors.affiliation: Faculty of Geology and Geo-Environment National and Kapodistrian University of Athens Athens Greece.
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Nomikou
authors.affiliation: Department of Geology Ghent University Ghent Belgium.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Smet
authors.affiliation: Faculty of Geology and Geo-Environment National and Kapodistrian University of Athens Athens Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Godelitsas
authors.affiliation: Department of Geology and Geochemistry Vrije Universiteit Amsterdam Amsterdam Netherlands.
authors.forename: Pieter
authors.initials: P
authors.lastname: Vroon
keywords: Aegean arc; Kolumbo submarine volcano; Santorini volcanic field; Sr‐Nd‐Hf‐Pb isotopes; mantle source