TY - JOUR
T1 - Historic magmatism on the Reykjanes Peninsula, Iceland
T2 - a snap-shot of melt generation at a ridge segment
AU - Peate, David W.
AU - Baker, Joel A.
AU - Jakobssen, Sveinn P.
AU - Waight, Tod Earle
AU - Kent, Adam J.R.
AU - Grassineau, Nathalie V.
AU - Skovgaard, Anna Cecile
PY - 2009
Y1 - 2009
N2 - We present new compositional data on a suite of historic lava flows from the Reykjanes Peninsula, Iceland. They were erupted over a short time period between c. 940 and c. 1340 AD and provide a snap-shot view of melt generation and evolution processes beneath this onshore, 65 km long, ridge segment. The lavas are tholeiitic basalts (MgO 6.5-9.2 wt%) and sparsely (5%) olivine and/or plagioclase phyric (±trace clinopyroxene). Individual eruptive events show remarkable compositional homogeneity. Despite a limited variation in Sr-Nd isotope compositions, high-precision double-spike Pb isotope data show tight coherent arrays that, together with correlations with incompatible trace element ratios, indicate control by binary mixing processes. Poor correlations with elemental abundances require that this mixing took place prior to extensive fractional crystallisation. Olivines in the historic lavas have light d18O values (?4.2 to ?4.3%), which is likely to be a feature of the enriched mantle source to Reykjanes Peninsula lavas. High precision Pb isotope analyses of other post-glacial Reykjanes Peninsula lavas show significant variability in 207Pb/204Pb and 208Pb/204Pb at lower 206Pb/204Pb values than in the historic lavas. This variation demonstrates that at least three compositionally distinct components within the mantle are required to explain the Pb isotope variations within the Reykjanes Peninsula as a whole.
AB - We present new compositional data on a suite of historic lava flows from the Reykjanes Peninsula, Iceland. They were erupted over a short time period between c. 940 and c. 1340 AD and provide a snap-shot view of melt generation and evolution processes beneath this onshore, 65 km long, ridge segment. The lavas are tholeiitic basalts (MgO 6.5-9.2 wt%) and sparsely (5%) olivine and/or plagioclase phyric (±trace clinopyroxene). Individual eruptive events show remarkable compositional homogeneity. Despite a limited variation in Sr-Nd isotope compositions, high-precision double-spike Pb isotope data show tight coherent arrays that, together with correlations with incompatible trace element ratios, indicate control by binary mixing processes. Poor correlations with elemental abundances require that this mixing took place prior to extensive fractional crystallisation. Olivines in the historic lavas have light d18O values (?4.2 to ?4.3%), which is likely to be a feature of the enriched mantle source to Reykjanes Peninsula lavas. High precision Pb isotope analyses of other post-glacial Reykjanes Peninsula lavas show significant variability in 207Pb/204Pb and 208Pb/204Pb at lower 206Pb/204Pb values than in the historic lavas. This variation demonstrates that at least three compositionally distinct components within the mantle are required to explain the Pb isotope variations within the Reykjanes Peninsula as a whole.
KW - Faculty of Science
U2 - 10.1007/s00410-008-0339-4
DO - 10.1007/s00410-008-0339-4
M3 - Journal article
SN - 0010-7999
VL - 157
SP - 359
EP - 382
JO - Contributions to Mineralogy and Petrology
JF - Contributions to Mineralogy and Petrology
IS - 3
ER -