Frederik Johnstrup

Johannes Frederik Johnstrup (12 March 1818– 31 December 1894) was a Danish professor, geologist and paleontologist.

Three years later, he taught in Sorø and in 1866, he became professor of mineralogy and geology at the University of Copenhagen and the Polytechnic Institution.

In 1876, he led the expedition to Iceland to study Askja and the volcanoes at Mývatn with Þorvaldur Thoroddsen (1855–1921) as his guide.

[5] In 1878, with Heinrich Rink, Johnstrup founded the governmental institution, Commission for the Direction of Geological and Geographical Investigations in Greenland.

[4] Johnstrup authored a number of treatises by which he greatly promoted the understanding of Denmark's geological conditions, particularly the glacial phenomena.