Carl Caldenius (1887–1961), until 1920 known by the surname Carlzon, was a Swedish Quaternary geologist and geotechnical engineer.
[1][2] He is mostly known for his geochronological work in Patagonia.
[1] Caldenius worked as geotechnical engineer for the Swedish State Railways until 1922 when he started to work full-time with his Ph.D thesis "Ragundasjöns stratigrafi och geokronologi" (Stratigraphy and geochronology of Lake Ragunda) that he defended in 1924.
In 1925 he travelled to Argentina as part of a Swedish-Argentine collaboration to extend the clay varve chronology of Gerard De Geer to the Southern Hemisphere.
[1] After returning to Swedsen in 1930 he joined an expedition to Australia and New Zealand where he applied knowledge of varves to study the Carboniferous Karoo Ice Age.