G. BRAKENRIDGE

Brief (<100 y) rapid-increase anomalies in the Earth’s atmospheric 14C production have previously been attributed to either gamma photon radiation from supernovae or to cosmic ray particle radiation from exceptionally large solar flares. Analysis of distances and ages of nearby supernovae (SNe) remnant surveys, the probable gamma emissions, the predicted Earth-incident radiation, and the terrestrial 14C record indicates that SNe causation may be the case. SNe include Type Ia white dwarf explosions, Type Ib, c, and II core collapse events, and some types of gamma burst objects. All generate significant pulses of atmospheric 14C depending on their distances. Surveys of SNe remnants offer a nearly complete accounting for the past 50000 y. There are 18 events ≤ 1.4 kpc distance, and brief 14C anomalies of appropriate sizes occurred for each of the closest events (BP is calendar years before 1950 CE): Vela, +22‰ del 14C at 12760 BP; S165, +20‰ at 7431 BP; Vela Jr., +13‰ at 2765 BP; HB9, +9‰ at 5372 BP; Boomerang, 11‰ at 10255 BP; and Cygnus Loop at 14722 BP. Although uncertainties remain large, the agreements of prediction to observation support a causal connection.