Alfred G. Fischer

Alfred G. Fischer was a German-American geologist who lived from 1920 to 2017 and taught at Princeton University and the University of Southern California, known for his studies of rhythmic sedimentary rock sequences and long-term patterns in the climate and biodiversity of the Earth. His 1964 description of cyclic sedimentation in the Alpine Triassic helped found the study of orbitally forced rock cycles, and he proposed roughly 32-million-year cycles in marine biodiversity linked to global biorhythms. He received the Lyell Medal and the Gustav-Steinmann-Medaille in 1992, the William H. Twenhofel Medal in 1982 and the Mary Clark Thompson Medal in 2009, and was elected to the National Academy of Sciences in 1994. He received the Penrose Medal in 1993.