Background
Joseph Paxson Iddings was born on January 21, 1857, in Baltimore, Maryland, United States. He was the son of William Penn Iddings and Almira Gillet. His grandfather Caleb Pierce Iddings was a Quaker.
Sheffield Scientific School, New Haven, Connecticut, United States
Iddings' father encouraged him to become a mining engineer, and he graduated from the Sheffield Scientific School of Yale University in 1877.
Grabengasse 1, 69117 Heidelberg, Germany
During 1879-1880 Iddings studied at Heidelberg under K. H. F. Rosenbusch, an experience which led to his career as a petrographer.
Olivine with brown borders of Iddingsit.
Joseph Paxson Iddings was born on January 21, 1857, in Baltimore, Maryland, United States. He was the son of William Penn Iddings and Almira Gillet. His grandfather Caleb Pierce Iddings was a Quaker.
Iddings' father encouraged him to become a mining engineer, and he graduated from the Sheffield Scientific School of Yale University in 1877.
During 1879-1880 Iddings studied at Heidelberg under K. H. F. Rosenbusch, an experience which led to his career as a petrographer.
Following a year as an instructor at Yale, Iddings spent a year at the School of Mines, Columbia University, eventually turning to geology as a result of the influence of Clarence King. On his return to America in 1880 he joined the U.S. Geological Survey, at about the same time as C. Whitman Cross, and served through 1892. He then joined the new department of geology at the University of Chicago, leaving abruptly in 1908 when he learned of the death of an aunt; an inheritance was presumed to be involved. The remainder of his bachelor life was spent collecting, writing, lecturing, traveling, conversing with his scientific friends in Washington, or residing at his ancestral home in Maryland.
His early broad surveys of rocks were done mainly in conjunction with fieldworkers such as Arnold Hague, C. D. Walcott, and G. F. Becker. Participation in the exploration and mapping of the geology of Yellowstone National Park was the most rewarding of Iddings’ field studies. He concluded from these studies that the textural and chemical variation of igneous rocks depends on the variety of physical conditions imposed by the geological environment; that the consanguinity of some igneous rocks can be attributed to descent from a common parental magma; that mineralogical and structural variations were due largely to the rate of cooling of the magma; and that volatile constituents played a special role in rock magmas.
Iddings’ teaching duties led to his need for a satisfactory classification of rocks. He enlisted the help of his friends C. W. Cross, L. V. Pirsson, G. H. Williams, and later, on Williams’ death, H. S. Washington. They collaborated in revising rock nomenclature and expressing the compositional variations among rocks on a quantitative basis. The widely used normative method of calculating simple theoretical minerals from a chemical analysis of a rock is referred to, after its authors (alphabetically arranged), as the C.I.P.W. system. This classification served as the basis for a unique and original two-volume work, the first volume dealing with the physical chemistry of magmas and the second, a compilation of the geographic distribution of igneous rocks and the related problem of petrographic provinces.
Iddings’ course of Silliman lectures at Yale in 1914 was published as The Problem of Volcanism.
Iddings was elected to the National Academy of Sciences in 1907, and as honorary member to the Société Française de Minéralogie in 1914.
Iddings was described as a very reserved and shy man for a world traveler, yet possessing personal charm, broad culture, and a poetic view of his surroundings - whether they were the rock sections of his profession, the butterflies of his hobby, or the landscapes of his travels.
Iddings never married.