Jakob Johannes Sederholm

JJ Sederholm

Jakob Johannes Sederholm (born July 20, 1863 in Helsinki , † June 26, 1934 there ) was a Finnish petrologist who researched mainly in the field of migmatites , the term goes back to him.

Life

Sederholm was plagued by diseases throughout his life and chose to study geology in order to be able to work in the open air. First he studied in Helsinki , then in Stockholm (1885 to 1888) with Waldemar Christofer Brøgger and finally in Heidelberg (1890/91) with Harry Rosenbusch . He returned to Finland to work for the geological service ( Finnish : Geologian tutkimuskeskus ) and in 1888 became a state geologist. In 1893 he was promoted to director of the service, a post he held until 1930. In 1928, 1929 and 1933 he gave guest lectures at North American universities. In 1922 he was elected a corresponding member of the Göttingen Academy of Sciences . In 1932 he was elected a member of the Leopoldina .

plant

Sederholm conducted research in the Precambrian basement of Finland and initiated a mapping program , in the context of which many geological maps and descriptions appeared between 1899 and 1925 . The gneisses in his study area, the Baltic Shield , are often of mixed composition, with granitic layers alternating with metamorphic layers . Sederholm called this type of rock migmatite and saw it as the product of intrusions from igneous rocks into metamorphic rocks below.

In the course of his career he published more than 250 scientific papers.

Honors

He received the Murchison Medal from the Geological Society of London (1928) and the Penrose Medal from the Geological Society of America (also 1928). The mineral sederholmit , a nickel - selenium mineral, is named after him. He was a multiple honorary doctor.

Other work

In addition to his geological work, Sederholm was a member of the Finnish Parliament and traveled on its behalf to meetings of the League of Nations . For the League of Nations he headed the commission of inquiry into Albania from 1921 to 1923. He was also a member and two-time chairman of the Finnish Economic Society.

Fonts

• Studies of Archean igneous rocks, 1891
• Om berggrunden i södra Finland, 1893
• Over an archaic sedimentary formation in SW Finland, 1899
• Om granit och gneis, 1907
• On synantetic minerals, 1916
• Om migmatites etc., 1922 to 1926
• Om graniterna i Sverige och Finland, 1928
• On spotted and nodular granites etc., 1928
• Pre-quaternary rocks of Finland, 1930
• On the sub-Bothnian unconformity, 1931
• On the Geology of Fennoscandia, 1930
• About the bottom configuration of Lake Pätijänne, 1932

literature

• Obituary by KH Scheumann, Zeitschrift für Kristallographie, Mineralogie und Petrographie, Volume 46, 1934, 89-90

Web links

• Jakob Johannes Sederholm, Finnish geologist. ( Encyclopaedia Britannica , English)
• Murchison Medal. Medal winner since 1873, Geological Society of London
• Penrose Medalists. Medal winner since 1927, Geological Society of America
• GTK milestones. The history of the Finnish Geological Service. Geologian tutkimuskeskus (English)
• Sederholmite. Mineral data at Mindat.org

Individual evidence

1. ↑ Hans Murawski: Geological Dictionary . 8th edition. Enke, Stuttgart 1983, ISBN 3-432-84108-6 , pp. 143 .
2. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 222.
3. ^ Member entry by Johannes Sederholm at the German Academy of Natural Scientists Leopoldina , accessed on March 1, 2017.
4. ↑ Finnish Geological Bibliography 1555-1970. ( Memento of the original from October 30, 2008 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Geologian tutkimuskeskus (English)