tephra SiO2 TiO2 Al2O3 FeO MnO MgO CaO Na2O K2O total Ref Hekla 1300 Tephra 59.95 1.14 15.35 8.86 0.28 1.35 4.90 4.30 1.62 97.75 969 Hekla 1300 Tephra 59.91 1.19 14.89 9.07 0.29 1.53 4.91 4.14 1.68 97.59 969 Hekla 1300 Tephra 59.86 1.20 14.99 9.34 0.30 1.61 4.84 4.29 1.71 98.15 969 Hekla 1300 Tephra 59.74 1.27 15.08 8.80 0.27 1.52 4.86 4.41 1.72 97.67 969 Hekla 1300 Tephra 59.30 1.07 15.29 8.20 0.29 1.27 4.84 4.66 1.55 96.47 969 Hekla 1300 Tephra 58.20 1.15 14.37 8.99 0.29 1.64 4.88 4.25 1.57 95.34 969 Hekla 1300 Tephra 57.91 1.52 14.82 9.56 0.27 2.06 5.46 4.21 1.49 97.30 969 Hekla 1300 Tephra 57.71 1.43 14.61 9.93 0.29 2.11 5.45 4.06 1.59 97.18 969 Hekla 1300 Tephra 57.54 1.54 14.70 9.33 0.29 2.18 5.36 4.20 1.49 96.62 969 Hekla 1300 Tephra 57.07 1.62 14.77 9.85 0.24 1.98 5.55 4.43 1.43 96.95 969 ------------------------------------------------------------------------ 969: Boygle, J.E. (1994) Tephra in lake sediments: An unambiguous geochronological marker? PhD. Thesis, University of Edinburgh, Edinburgh,