Revisiting the Faroe Marine Ash Zone III in two Greenland ice cores: implications for marine-ice correlations

TY - JOUR

T1 - Revisiting the Faroe Marine Ash Zone III in two Greenland ice cores

T2 - implications for marine-ice correlations

AU - Bourne, A.J.

AU - Davies, S.M.

AU - Abbott, P.M.

AU - Rasmussen, Sune Olander

AU - Steffensen, Jørgen Peder

AU - Svensson, Anders

PY - 2013/10/16

Y1 - 2013/10/16

N2 - Nineteen new Icelandic tephra layers are identified in NGRIP and NEEM ice spanning Greenland Interstadial-9 (GI-9) and the early phase of GI-8 (∼38 000-40 500 b2k). Fourteen tephras are identified in the NGRIP record and five direct correlatives are identified in NEEM, thus indicating the occurrence of 14 separate volcanic events. With two exceptions, the tephras are tholeiitic basalt in composition and despite having very similar geochemical signatures can, in most cases, be discriminated from one another using their TiO2 values. All of these tephra layers fall within the compositional range of the Faroe Marine Ash Zone III (FMAZ III) deposit previously identified in ocean cores from the Faroes region and previously correlated to NGRIP 2066.95m by Davies et al. (). Thus, the FMAZ III in the marine realm is most likely a complex ash zone that represents a series of closely timed Grimsvötn eruptions that, as yet, can only be stratigraphically separated in the high-resolution ice-core records. The geochemical signatures and stratigraphic positions of the new ice-core layers means that the FMAZ III tephra deposit, as currently defined in the marine realm, cannot be correlated to NGRIP 2066.95m or any other ice-core tephra horizons preserved during this interval.

AB - Nineteen new Icelandic tephra layers are identified in NGRIP and NEEM ice spanning Greenland Interstadial-9 (GI-9) and the early phase of GI-8 (∼38 000-40 500 b2k). Fourteen tephras are identified in the NGRIP record and five direct correlatives are identified in NEEM, thus indicating the occurrence of 14 separate volcanic events. With two exceptions, the tephras are tholeiitic basalt in composition and despite having very similar geochemical signatures can, in most cases, be discriminated from one another using their TiO2 values. All of these tephra layers fall within the compositional range of the Faroe Marine Ash Zone III (FMAZ III) deposit previously identified in ocean cores from the Faroes region and previously correlated to NGRIP 2066.95m by Davies et al. (). Thus, the FMAZ III in the marine realm is most likely a complex ash zone that represents a series of closely timed Grimsvötn eruptions that, as yet, can only be stratigraphically separated in the high-resolution ice-core records. The geochemical signatures and stratigraphic positions of the new ice-core layers means that the FMAZ III tephra deposit, as currently defined in the marine realm, cannot be correlated to NGRIP 2066.95m or any other ice-core tephra horizons preserved during this interval.

U2 - 10.1002/jqs.2663

DO - 10.1002/jqs.2663

M3 - Journal article

SN - 0267-8179

VL - 28

SP - 641

EP - 646

JO - Journal of Quaternary Science

JF - Journal of Quaternary Science

IS - 7

ER -