Ulbo de Sitter

Memorial plaque for Henk Zwart , De Sitter u. a. in the Pyrenees

Lamoraal Ulbo de Sitter (born March 6, 1902 in Groningen , † May 12, 1980 in Nistelrode ) was a Dutch geologist who mainly dealt with tectonics .

He was the son of the astronomer Willem de Sitter and studied geology in Switzerland and with Johann Karl Ludwig Martin and Berend George Escher at the University of Leiden . After his dissertation in 1925 on the petrography of porphyries in the Lugano area , he worked for the Royal Dutch Shell subsidiary Bataafse Petroleum Maatschappij . Then he went back to Leiden as Escher's assistant and curator at the Rijksmuseum van Geologie en Mineralogie. He undertook tectonic investigations in northern Italy ( Bergamasque Alps ) and experimental attempts at wrinkling with Philip Kuenen , a former student friend . During the Second World War he saved many Dutch geology students from working in Germany by organizing field studies in the southern Netherlands together with Willem van Waterschoot van der Gracht (for example gravimetry in the Limburg area, Brabant). In 1948 he became a professor in Leiden (with a full professorship from 1958) and shifted the focus of his tectonic studies to the Pyrenees and the Cantabrian Mountains . In 1968 he retired. His successor as professor was his student Henk Zwart (1924–2012).

He founded a school of tectonics in Leiden and examined not only large-scale tectonics, but also small-scale folds and other tectonic structures (micro-folds, etc.). His textbook Structural Geology from 1956, which was also translated into Russian, Japanese and Spanish, placed particular emphasis on visualization in comparative field studies. With regard to the causes of mountain formation, he was still an advocate of the shrinkage hypothesis and never an advocate of continental drift.

In 1962 he became a member of the Dutch Academy of Sciences . From 1939 to 1963 he was editor of the journal Geologie en Mijnbouw and from 1963 to 1968 chairman of the Koninklijk Nederlands Geologischer en Mijnbouwkundig Genootschap . In 1969 he received the Van Waaterschot van der Gracht Medal.

His son Ulbo de Sitter junior (1930-2010) was a sociologist.

Fonts

• Structural Geology, McGraw Hill 1953, 1964
• De tectoniek van eenvoudige structuren, Brill 1941 (The tectonics of simple structures)
• De geologie van aardolie en gassen, The Hague 1950 (The geology of petroleum and natural gas)

literature

• Henk Zwart, obituary in the yearbook of the Royal Netherlands Academy of Sciences 1980, online

Web links

• Biographical Portaal van Nederland