Geophysical source conditions for basaltic lava from Santorini volcano based on geochemical modeling

Baziotis I, Kimura J-I, Pantazidis A, Klemme S, Berndt J, Asimow PD

Research article (journal)

Abstract

Santorini volcano sits ~145 km above the Aegean Wadati-Benioff zone, where the African plate subducts northwardbeneath Eurasia. There are only a few localities in the whole Aegean where basaltic lavas primitive enoughto constrain mantle processes beneath the Aegean arc can be found; in this workwe analyzed one such locality, abasalt lava from the southern part of Santorini.We apply a suite of petrological tools (PRIMACALC2 and ABS5) insequence to estimate magma chamber conditions, primary magma composition, mantle melting conditions, andslab dehydration conditions. Back-calculation modeling based on major-element chemistry yields shallowmagma chamber conditions of P=0.02GPa, fO2=QFM+2, and ~1wt% H2O in the primary magma. The estimatedmajor element composition of this primary magma then leads to estimated mantle melting conditionsof 2.1 GPa, 1353 °C, and F=8%; whereas a more precise estimate derived from trace element modeling implies1.7 GPa, 1323 °C, and F=18%. Furthermore, the trace element model implies a slab flux derived from 4.6 GPa(~150 km slab depth). The estimated slab depth, magma segregation conditions, and magma chamber depthare all consistentwith seismic observations, supporting slab dehydration in the seismically imaged steep slab intervaland flux melting in a relatively hot mantle wedge.

Details zur Publikation

Release year: 2018
Language in which the publication is written: English