Formation of heterogeneous magmatic series beneath North Santorini, South Aegean island arc

TY - JOUR

T1 - Formation of heterogeneous magmatic series beneath North Santorini, South Aegean island arc

AU - Bailey, John C

AU - Jensen, E.S.

AU - Hansen, A.

AU - Kann, A.D.J.

AU - Kann, K.

PY - 2008

Y1 - 2008

N2 - The geochemistry of basaltic to dacitic lavas and dykes in the volcanic centres of NorthSantorini (Greece) has been investigated using elemental and Sr-Nd-Pb isotopic data andthree main magmatic series with sub-parallel trace element patterns for basalts can bedistinguished. The basalts have Sr and Nd isotopic values consistent with varying levels of incompatible-element mantle depletion. A fourth magma group with only two basalt samples has a trace element pattern with even lower contents of incompatible elements, especially Th, and with lower 87Sr/86Sr but higher 206Pb/ 204Pb. Heterogeneous magma formation beneath North Santorini throughout its 500 ka history is attributed to variable transfer of sedimentary components - either terrigenous or pelagic, as bulk sediments or high-temperature partial melts rather than fluids or low-temperature partial melts - from a rupture zone in the subducted slab to the overlying mantle. The three main magmatic series followed independent paths of assimilation of upper crustal materials during fractional crystallization. Assimilation was more pronounced at the basaltic stage. The long-lived histories of the three main magmatic series imply repetitive melting of isolated mantle regions, ascent of magmas through independent feeder systems, and their residence in separate crustal magma chambers.

AB - The geochemistry of basaltic to dacitic lavas and dykes in the volcanic centres of NorthSantorini (Greece) has been investigated using elemental and Sr-Nd-Pb isotopic data andthree main magmatic series with sub-parallel trace element patterns for basalts can bedistinguished. The basalts have Sr and Nd isotopic values consistent with varying levels of incompatible-element mantle depletion. A fourth magma group with only two basalt samples has a trace element pattern with even lower contents of incompatible elements, especially Th, and with lower 87Sr/86Sr but higher 206Pb/ 204Pb. Heterogeneous magma formation beneath North Santorini throughout its 500 ka history is attributed to variable transfer of sedimentary components - either terrigenous or pelagic, as bulk sediments or high-temperature partial melts rather than fluids or low-temperature partial melts - from a rupture zone in the subducted slab to the overlying mantle. The three main magmatic series followed independent paths of assimilation of upper crustal materials during fractional crystallization. Assimilation was more pronounced at the basaltic stage. The long-lived histories of the three main magmatic series imply repetitive melting of isolated mantle regions, ascent of magmas through independent feeder systems, and their residence in separate crustal magma chambers.

KW - Faculty of Science

KW - Basalts

KW - Radiogenic isotopes

KW - Trace element modelling

KW - Volcanic arc

KW - Petrogenesis

U2 - 10.1016/j.lithos.2008.12.002

DO - 10.1016/j.lithos.2008.12.002

M3 - Journal article

SN - 0024-4937

VL - 110

SP - 20

EP - 36

JO - Lithos

JF - Lithos

IS - 1-4

ER -