Clarence Norman Fenner

Born July 19, 1870, in Clifton, N. J.; died there Dec. 24, 1949. American geologist, mineralogist, and petrologist.

Fenner graduated from Columbia University in New York in 1892. He carried out geological work in Canada, Mexico, South America, and Central America until 1907 and later joined the staff of the Geophysical Laboratory of the Carnegie Institution.

Fenner’s main works in mineralogy dealt with the study of the paragenesis of various minerals, especially zeolites, in pneumatogenic and hydrothermal processes. Fenner produced the first phase diagram for silica and studied recent volcanism in the Katmai National Monument (Alaska), in Yellowstone National Park, and elsewhere. He carried out petrographical research in different regions of both Americas. Fenner explained the formation of many minerals, ores, and rocks in terms of the fractional crystallization and liquation of magma. In 1928 he developed analytical methods of separating uranium and thorium minerals and using the minerals to determine the absolute age of rocks.