Significance of the Rare Event in Geology
P. E. Gretener · AAPG Bulletin · 1967
ABSTRACT The rare event has a definite significance in geology. The rare event is defined as an event with the low probability of a particular interplay of various factors. For example, if we have eight dice and wish to throw eight sixes, our chances of doing so in the first throw are extremely small, about 1 in 1.5 million. If we only play dice for an hour and make, say, 200 throws, the probability of throwing eight sixes at least once will still only be about 1 in 10,000—negligibly small. However, if we are persistent and raise the number of trials to 1.7×106, the probability of throwing eight sixes will increase to 63 per cent, and for 5×106 trials it will be more than 95 per cent. Thus the improbable becomes probable and eventually approaches certainty. This trivial principle has applications in geology where time spans are long, and consequently the number of trials is large. Preliminary applications of this principle to geology include the dispersal of faunas and floras, disruptions in evolution, meteor impacts, the origin of life, and various others.