Fifty-one 40Ar/39Ar laser heating analyses of sanidine crystals in the C-13 tephra layer, recovered out of a piston core raised from 3000 m depth in the Tyrrhenian Sea, yielded apparent ages between 25 and 112 ka. wenty-four of these measurements define an age probability maximum and generate an isochron of 41.1þ2.1 ka (2c) with a 40Ar/36Ar intercept of 288 þ21 that is indistinguishable from the modern atmosphere. However, the entire opulation is skewed toward older apparent ages with smaller peaks at 48 ka, 55 ka, 67 ka, and 110 ka. The composition of glass shards in the C-13 tephra overlaps that of the SiO2-rich phase of the 150 km3 Campanian Ignimbrite which erupted from the Campi Flegrei caldera 130 km northwest of the core site. Although the 41.1þ2.1 ka isochron is V15% older than K^Ar and 14C ages for the Campanian Ignimbrite, it is indistinguishable from recent 40Ar/39Ar age determinations. The Campanian Ignimbrite eruptions were also chemically similar to, and correlated with, the Y-5 ash layer ^ the most voluminous and widely dispersed late Pleistocene tephra in the Mediterranean region. The age of the Y-5 layer was constrained originally at 38.0þ 2.5 ka on the basis of astronomical dating of O-isotope stages. The 40Ar/39Ar ages, astronomical dating, plus chemical similarities permit correlation of the C-13 tephra layer with both the Campanian Ignimbrite and the Y-5 tephra layer. The older ages preserved in the C-13 tephra layer may reflect xenocrysts incorporated during the explosive eruption accompanying collapse of the Campi Flegrei caldera 41 ka. The C-13 tephra layer is correlated with a 10Be peak in an adjacent marine core, O-isotope stage 3.12, and immediately preceded a cooling episode corresponding to Heinrich event 4, thus the age of these features is constrained by radioisotope dating. [...]
