Harry Stephen Ladd

Harold "Harry" Stephen Ladd (born January 1, 1899 in St. Louis , † November 30, 1982 in Bethesda , Maryland ) was an American paleontologist and geologist .

Ladd studied at the University of Iowa with a master's degree in 1924 and a doctorate in 1925 with a dissertation on the Ordovician of Iowa. During this time he was also an Assistant Geologist for the Iowa Geological Survey. Inspired by Devonian coral reefs in Iowa, he decided to study recent reefs in the Pacific and made his first trip to the Fiji Islands. From 1926 to 1929 he taught at the University of Virginia and then worked as a petroleum geologist for Gulf Oil in Venezuela and then worked on his findings from Fiji at the National Museum of Natural History in Washington. He also worked for the US Geological Survey. In 1934 he returned to the Fiji Islands with J. Edward Hoffmeister, where he also married. Upon his return, he became a District Geologist for Atlanta and Richmond with the National Park Service, focusing on hydrogeology and engineering geology. In 1938 he was promoted to regional geologist and in 1940 he was taken over by the US Geological Survey, where he stayed until his retirement in 1969. During World War II he was engaged in the search for mineral resources and from 1946 to 1949 he was Assistant Chief Geologist of the USGS. From 1946 he began his exploration of the Pacific again, including as part of the hydrogen bomb tests on Bikini Atoll.

He is known for geological exploration of atolls and coral reefs in the Pacific . After drilling on the Eniwetok atoll, he encountered basalt after 4,000 feet of coral material and confirmed Charles Darwin's theory about the formation of atolls (subsea volcanoes sinking). There was also evidence of sea level fluctuations. Ladd was also involved in the Mohole deep-sea drilling project to explore the ocean crust (1958-1966).

In 1957 he published an extensive manual on paleoecology with the US Geological Survey, which became a standard work.

In 1954 he was President of the Paleontological Society and in 1955 Vice President of the Geological Society of America and in 1981 he was awarded the Paleontological Society Medal . In 1965 he was Vice President of the American Association for the Advancement of Science and received the Distinguished Service Award from the US Department of the Interior.

Fonts

• Editor: Treatise on Marine Ecology and Paleoecology, Volume 2: Paleoecology, Geological Society of America Memoir 67, 1957
• Stratigraphy and Paleontology of the Maquoketa Shale of Iowa, Annual Report of the State Geologist 34 (1929): 305-448
• Participation in: Bikini and nearby Atolls, US Geological Survey Professional Paper 260, Washington DC 1954 to 1969

literature

• Ellis Yochelson : Ladd, Harry Stephen, Dictionary of Scientific Biography