WINKLER, HELMUT GUSTAV FRANZ

(b. Kiel, Germany, 3 April 1915; d. Göttingen, Federal Republic of Germany, 10 November 1980)

mineralogy, petrology.

The son of Paul Arthur Aloysius Winkler, a canal pilot, and Martha Auguste Hedwig Rhinow, Winkler became interested in geology during his last few years in high school. In 1934 he entered the University of Rostock, where he studied mineralogy, geology, and chemistry, with mineralogy as his major subject. While there, he met C. W. Correns, who exerted a considerable, possibly decisive, influence on Winkler’s scientific development. For a time he studied at Tübingen (1935–1936) and at the University of St. Andrews (1937). His dissertation, on the thixotropy of mineral powders of microscopic size, inspired by Correns, earned him the doctorate in 1938. He was married to Ursula Wichmann on 4 May 1942; they had two daughters and a son.

After an interruption of nearly six years (1939–1944), during World War II, Winkler continued his scientific work at the University of Göttingen with Correns. At first he worked on crystallographic problems, in particular on the crystal analysis of eucryptite and related compounds. As a result of these and other studies, Winkler became the first chairman of the department of crystallography at the University of Göttingen in 1949. During this period he concentrated on finding or deriving quantitative relations between the structures and the physical properties of crystals. His conception of these relations is documented in his book Struktur und Eigenschaften der Kristalle (1950).

In 1951 Winkler was simultaneously offered professorships at the University of Marburg, the University of Saarbrücken, and the Technical University of Munich. He accepted the chair at Marburg, where he continued his studies in crystallography. In addition, he did work in the applied mineralogy of ceramic clay.

Winkler’s instinct for discerning promising future developments in research made him change fields in 1955. During a lecture tour in the United States, Winkler became acquainted with recently developed high-pressure apparatus that made it possible to simulate in the laboratory the pressures and temperatures deep within the earth’s crust. Fascinated with these developments and foreseeing the future success and the new opportunities of experimental petrology, he turned to that new field. His works on the experimental metamorphism of sediments (1957) show that he was a pioneer of experimental petrology in Europe. In the late 1950’s he proved experimentally the assumed relation between high-grade metamorphism and the formation of anatectic granitic magmas in the earth’s crust. In order to achieve as close to natural conditions as possible in his experiments, Winkler used common, naturally formed sediments, clays, and graywackes. He studied their metamorphic change under the pressure and temperature conditions of the earth’s crust up to the emergence of anatectic melts. The discussion of the origin and formation of granitic magmas, which had been controversial for a long time, was thus given a new and sound base.

In 1962 Winkler accepted a chair at the Georg-August University of Göttingen. With his assistants and graduate students, he continued the petrological work that had begun in Marburg, experimentally investigating many metamorphic mineral reactions. It was his aim to establish a systematic order in the diversity of metamorphic rocks on the basis of petrographically observed and experimentally calibrated mineral reactions. In this he followed the concept of metamorphic facies introduced by P.E. Eskola in 1914 and 1939, making it the starting point of further intensive studies. In the late 1960’s, simultaneously with other scientists, he recognized the limits of this concept and developed a new division into four metamorphic grades subdivided by zones, which are defined by specific, experimentally calibrated mineral reactions.

At the same time, he sought to find general laws determining the formation and crystallization of granitic magmas. The results and the general ideas of his petrological research were published in many essays and in his book Die Genese der metamorphen Gesteine, of which five editions in six languages appeared between 1965 and 1986.

Winkler’s life was characterized by an extraordinary enthusiasm for mineralogical and geological problems. The wide range of his scientific achievement was unusual even for his time. Winkler’s work brought him international recognition and many honors. He was a member of the German Mineralogical Society, the Academy of Science of Göttingen, the Academy of Sciences of Austria, and the Geological Society of Finland; an honorary member of the Geological Society of America, the Geological Society of Belgium, and the Geological Society of London; an associate member of the Geological Society of France; and a fellow of the Mineralogical Society of America.

BIBLIOGRAPHY

Winkler’s books include Struktur and Eigenschalien der Kristalle (Berlin, 1950; 2nd ed., 1955); and Die Genese der metamorphen Gesteine (Berlin, 1965), trans. from 2nd rev, ed. by N.D. Chatterjee and E. Froesl as Petrogenesis of Metamorphic Rocks (New York, 1967). Among his papers are “Synthese und Kristallstruktur des Eucryptits,” in Acta Crystallographica (London), 1 (1948), 27–34; “Die Struktur des Tief-K₂Li(AIF₆) und ihre Beziehung zu elpasolith . . . und anderen Strukturen,” in Heidelberger Beiträge zur Mineralogie und Petrographie, 3 (1952), 297–306; “Bedeutung der Korngrössenverteilung und des Mineralbestandes von Tonen für die Herstellung grobkeramischer Erzeugnisse,” in Berichte der Deutschen Keramischen Gesellschaft, 31 (1954), 337–343; “Hydrothermale Metamorphose karbonatfreier Tone,” in Geochimica et Cosmochimica Acta13 (1957), 42–69; “Experimentelle Gesteinmetamorphose, II , Bildung von anatektischen granitischen Schmelzen bei der Metamorphose von NaCl-führenden kalkfreien Tonen,” ibid., 15 (1958), 91–112, with Hilmar von Platen; “Ultrametamorphose kalkhaltiger Tone,” ibid., 18 (1960), 294–316; “Bildung anatektischer Schmelzen aus metamorphisierten Grauwacken,” ibid., 24 (1961), 48–69; “Experimentelle anatektische Schmelzen und ihre petrogenetische Bedeutung,” ibid., 24 , 250–259; “Genesen von Graniten und Migmatiten auf Grund neuer Experimente,” in Geologische Rundschau, 51 (1961), 347–361; “Das T-P Feld der Diagenese und niedrigtemperierte Metamorphose aufgrund von Mineralreaktionen,” in Beiträge zur Mineralogie und Petrographie, 10 (1964), 70–93; “Abolition of Metamorphic Facies, Introduction of the Four Divisions of Metamorphic Stage, and of a Classification Based on Isograds in Common Rocks,” in Neues Jahrbuch für Mineralogie: Monatshefte (1970), 189–248; “Temperaturen und Drucke bei der regionalen Metamorphose: Prinzipielle und praktische Hinweise,” in Geologische Rundschau, 65 (1976), 874–885; “Low Temperature Granitic Melts,” in Neues Jahrbuch für Mineralogie, Monatshefte (1975), 245–268, with Manfred Boese and Theodor Marcopoulos; and “New Aspects of Granitic Magmas,” ibid. (1978), 463–480, with Reinhard Breitbart.