(Table T4) Argon 40 - Argon 39 incremental heating ages from Neogene ash layers in ODP Hole 183-1138A

Sediment depth is given in mbsf. All ages calculated relative to neutron fluence monitor FCT-2 biotite (28.04 ± 0.12 Ma), decay and abundance constants le = 0.581 x 10**-10/yr; lb = 4.961 x 10**-10/yr; 40K/K = 1.17 x 10**-4, and corrected for 37Ar decay (half-life = 35.1 days) and interfering isotopes 36Ar/37Ar[Ca] = 2.64 x 10**-4, 39Ar/37Ar[Ca] = 6.73 x 10**-4, 40Ar/39Ar[K] = 1.0 x 10**-3.