Isotopic anomaly in peat nitrogen is a probable trace of acid rains caused by 1908 Tunguska bolide

In peat sampled at the Tunguska Cosmic Body (TCB) explosion area, the sharp increase of the N concentration (about three-fold) and the positive N isotopic anomaly (δ15N = + 3.5‰, see eqn) have for the first time been revealed. In contrast with the C and H effects observed earlier which were clearly limited to the epicentre area (Kolesnikov et al., 1997 in press), the same N effect has also been shown in peat sampled near the Vanavara settlement, 65 km south of the explosion epicentre. A clear connection of the observed anomalies in peat to the 1908 permafrost boundary, synchronism of the changes of δ15N and the N concentration and also good agreement with data on the KT boundary deposits allow us to connect the observed effects to acid rain fall-out after passage and an explosion of the TCB.