Walther Penck
Walther Penck (30 August 1888 – 29 September 1923) was a geologist and geomorphologist known for his theories on landscape evolution. Penck is noted for criticizing key elements of the Davisian cycle of erosion, concluding that the process of uplift and denudation occur simultaneously, at gradual and continuous rates. Penck's idea of parallel slope retreat led to revisions of Davis's cycle of erosion. Biography Walther Penck was born in Vienna as the son of German geographer Albrecht Penck. He obtained a PhD by studying petrology at the Heidelberg University. Between 1912 and 1915 he worked in Dirección General de Minas in Buenos Aires before moving to the University of Constantinople where he was named professor of mineralogy and geology. He finally settled as professor in the University of Leipzig in 1918. The areas he studied in detail and based his theories on include the Black Forest in Germany, Puna de Atacama in Argentina and Anatolia in modern Turkey. During the 1920s Penck, with Siegfried Passarge, Alfred Hettner and his father, was the foremost figure in a broad German opposition to the "geographical cycle" theory of William Morris Davis. It was characteristic of Davis to react violently and disdainfully to criticism,