Jakob Johannes Sederholm

Jakob Johannes Sederholm (1863–1934) was one of the more influential pioneers in Precambrian geology having introduced some fundamental insights and concepts which are still relevant today. Towards the end of the 19th century, he demonstrated how the principle of actualism can be applied to Precambrian terranes, while during the early part of the 20th century he undertook detailed studies on deformed magmatic rocks, both defining and interpreting the enigmatic mixed rocks now known as migmatites. He acted as the head of the Geological Survey of Finland for 40 years, which developed under his leadership into a modern progressive and versatile research organization. In addition, Sederholm also served as a diplomat with a number of international assignments, including appointments with the League of Nations in missions in Albania and a supervisory role relating to sovereignty and autonomy issues in the Åland Island. Several mountains in Greenland have been named after him and his family, and he was also appointed as honorary chief of two Indian tribes in Canada. To understand the driving forces behind a man of his kind, we focus here on Sederholm the person and some of the social and cultural background that influenced his career. This text is based on the book, published in Swedish, entitled “Jakob Johannes Sederholm, Geolog, humanist och sanningssökare” (Scheinin and Korsman, 2007), and an interview with J.J. Sederholmʹs granddaughter Barbro Scheinin by Eklund (2008). Other references are marked in the text. The first author is responsible for all translations from Swedish, Norwegian, German and Finnish.