AMPFERER, OTTO

(b. Hötting, near Inns-bruck, Austria, 1 December 1875; d. Innsbruck, 9 July 1947),

geology, tectonics.

Ampferer was an outstanding authority on the geology of the Eastern Alps, where he introduced the new ideas of folding and nappe tectonics. His field mapping of large areas of the Northern Calcareous Alps is still the most comprehensive one ever done by a single Alpine geologist. And his theory of understreaming currents as the moving force of orogeny ranked him among the pioneers of the modern theory of plate movement.

Beginnings and Scientific Career. Ampferer’s parents both came from Tyrolian farmer families. His father, Nikolaus Ampferer, was a post office clerk. His father was born not far from the Karwendelgebirge. His mother, Gertraud Zangerl, grew up near the Lechtal Alps. These two areas were the later domains of study by their son. During his school days his teachers acquainted Ampferer with the sciences. In 1895 he began to study physics and mathematics at Innsbruck—especially geology with the Austrian geologist Josef Blaas. In 1899 he earned his PhD with a study of the geology of the southern parts of the Karwendelgebirge.

In 1901 Ampferer joined the Austrian Geological Survey (k.-k. Geologische Reichsanstalt, which became the Geologische Bundesanstalt) in Vienna. One year later, on 20 November 1902, Ampferer married Olga Sander (d. 1952), a sister of the Austrian mineralogist Bruno Sander. She became his lifelong companion and assistant in most of his fieldwork.

Despite several later offers to change to a university career, Ampferer never left the Austrian Geological Survey. After nearly twenty years he became chief geologist in 1919, and in 1925 he was appointed its vice-director. Finally, from 1935 to 1937, Ampferer served as director of the Geologische Staatsanstalt (its official name between the two world wars).

As an authority on the geology of the Austrian Alps, Ampferer became the favored expert for engineering projects there, especially the construction of new hydroelectric generating stations in the Alps. Ampferer delivered about one hundred expert reports during his scientific career starting in 1908. Examples include reports on the Achensee and Ybbs valley hydroelectric generating stations and on the water supply of his home town, Innsbruck.

To his contemporaries, the young Ampferer was also known as a mountaineer. He did about 2,000 climbing tours, among them some difficult first ascents. The most famous one was the ascent of the Guglia di Brenta in the Dolomites. On 18 August 1899, together with the Innsbruck mountaineer Karl Berger, Ampferer succeeded in climbing its difficult north wall—now called Ampferer wall (Ampfererwand)—thus improving the scale of mountaineering techniques by one more degree.

Field Mapping, Stratigraphy, and Glacial Geology. Geological field mapping was the centerpiece of Ampferer’s scientific work. In its extent it has hardly any counterpart in Alpine geology. His areas of research were the Northern Calcareous (limestone) Alps before World War I, and among them, the Karwendelgebirge, the Sonnwendgebirge (a more common name is Rofan Mountains), and the Lechtal Alps. After the war Ampferer continued his work in the Kaisergebirge, and in Vorarlberg as far as the Rhätikon Mountains, and the Rhine transverse valley in Liechtenstein.

The result of nearly four decades of research— including about 4,000 days in the field—was an impressive series of geological maps. Without overlooking his collaborators, especially the Austrian geologist Wilhelm Hammer, the geological maps with annotations of Tyrol and Vorarlberg published between 1912 and 1937, were mostly his work. There might be no other area of such dimensions within the Alps that has been mapped in such a unified manner as the twelve sheets of the geological map 1:75,000 of the Austrian part of the Eastern Alps. In addition Ampferer prepared geological maps of the Lechtal Alps, the Karwendelgebirge, and other areas for the German and Austrian Alpine Club (Deutscher und Österreichischer Alpenverein).

Geological mapping supplied Ampferer with the materials for the elaboration of new ideas on Alpine stratigraphy, glacial geology, and tectonics. In the upper Lech valley he discovered the (up to then) largest deposit of volcanic or melaphyric rocks within the Northern Calcareous Alps. For the hornstone breccia (Hornsteinbreccien) of the Rofan Mountains, Ampferer first discussed its sedimentary origin that was later confirmed by his brother-in-law Bruno Sander using sedimentographical methods. And before 1914 he proved the Cretaceous age of the thin, dark strata of marlstones and sandstones (Kreideschiefer or Lechtal shales), which are widely distributed in the Western Lechtal Alps.

In glacial geology Ampferer was particularly engaged in the study of the sediments of the Inn valley terraces. He found it to be of much greater extent than hitherto known and frequently covered by morainal material. Thus, he proposed an interglacial origin in 1908. The hypothesis was objected to strongly, because it contradicted the famous section of the Höttingen breccia (Höttinger Breccie), a locus classicus of Alpine glacial geology. In 1921 Albrecht Penck, the leading German glacial geologist, joined Ampferer’s position. Nevertheless, Ampferer himself called it into question in 1939 when he discovered

large angular erratics within fine-sandy sediments of the lower Inn valley, whose existence, he thought, required a former nearby glacier.

Tectonics. Tectonics were the second main concern of Ampferer’s scientific work. Following his background in physics and engineering geology, he was particularly interested in the mechanical problems of alpinotype tectonics. He became the main advocate of the doctrine of nappes for the Eastern Alps.

He first demonstrated respective structures in 1902 at the Inntal nappe (which he originally called Karwendel overthrust). This was one year before Pierre Termier used the theory of nappes to produce the first unified geological interpretation of the European Alps. By his discovery of the Karwendel overthrust, a large-scale flat upthrow of Triassic layers on Jurassic ones, Ampferer pioneered the idea of flat, onlapping thrust sheets—that is, of disconnected sedimentary mantles without any trace of a reversed middle limb. This contrasted with the large fold nappes known from the Western Alps. In 1911, together Wilhelm Hammer, he presented a comprehensive discussion of the tectonics of the Eastern Alps in his “Geologischer Querschnitt durch die Ostalpen vom Allgäu zum Gardasee.”

The tectonic idea, however, for which Ampferer became best known, is his hypothesis of understreaming currents as the moving force of mountain building. As early as 1906, Ampferer had published his comprehensive paper “Ueber das Bewegungsbild der Faltengebirge” (Moving patterns of fold mountains). Contrary to the then prevailing contraction hypothesis, he unfolded the idea that the structures of Earth’s crust are due to movements caused by subcrustal currents, that is, within the liquid zone beneath Earth’s crust, understreaming currents and decreases of volume take place upon which Earth’s outer skin is patterned.

It might be questionable to what extent this idea was completely new, and also how far it actually anticipated the idea of convection currents, compared for instance, to the work of the English geologist Arthur Holmes. Nevertheless, Ampferer made a causal link between subcrustal currents, large-scale crustal dislocations, and the detachment of the upper from the lower crust in orogenic belts. Furthermore he appreciated a concept similar to subduction by his notion of zones of downsucking (Verschluckungszonen). He first used this notion in 1911 to refer to the process in which one section of the crust slides below another (see Figure 1).

The elaboration of Ampferer’s hypotheses fell to other geologists—such as his Austrian colleague Robert Schwinner or the German geologist Ernst Kraus. Nevertheless, in 1924 Ampferer pleaded for his idea of under-streaming currents as the best available moving force for continental drift. And in 1941, in a paper on the geological history of the Atlantic Ocean, he anticipated the idea of seafloor spreading by stating that continents can be

split by understreaming currents rising from Earth’s interior (see Figure 2).

Reception of Ampferer’s Work. Ampferer’s ideas on global tectonics and mountain building were little known outside German speaking countries during his lifetime. This might have been due to the fact that he hardly ever left his well-defined area of research. Apart from a geological expedition—partly by military order—to Albania, Montenegro, and Western Serbia in 1917 and 1918; some studies with the Scottish female geologist Maria Matilda Ogilvie Gordon in the Dolomites in 1926, 1928, and 1935; and a few expert reports for foreign engineering projects—Ampferer never left his Austrian Alpine home.

Nevertheless, his geological work found high recognition. Among others, in 1936, he was appointed a member of the Deutsche Akademie der Naturforscher Leopoldina, and—although he never taught at a university— corresponding member of the Austrian Academy of Sciences in 1925 (ordinary member in 1940). The Austrian Geological Society honored him by originating an Otto Ampferer Award in 1983, to be awarded annually for outstanding achievements by young scientists in the earth sciences.

BIBLIOGRAPHY

Ampferer’s papers (manuscript maps and correspondence) are in part located in the Library of the Geologische Bundesanstalt in Vienna and partly in the Natural History Department of the Tyrol States Museum ( Tiroler Landesmuseum Ferdinandeum ) at Innsbruck, Austria.

WORKS BY AMPFERER

With Wilhelm Hammer. “Geologische Beschreibung des südlichen Teiles des Karwendelgebirges.” Jahrbuch der k.k. geologischen Reichsanstalt 48 (1898 [published 1899]): 289–374.

“Über den geologischen Zusammenhang des Karwendel- und Sonnwendjochgebirges.” Verhandlungen der geologischen Reichsanstalt [no volume number] (1902): 104–113.

“Geologische Beschreibung des nördlichen Teiles des Karwendelgebirges.” Jahrbuch der k.k. geologischen Reichsanstalt53 (1903): 169–252.

“Studien über die Inntal-Terrassen.” Jahrbuch der k.k. geologischen Reichsanstalt 54 (1904 [published 1905]): 91–160.

“Ueber das Bewegungsbild von Faltengebirgen.” Jahrbuch der k.k. geologischen Reichsanstalt 56 (1906): 539–622. “Studien über die Tektonik des Sonnwendgebirges.” Jahrbuch der k.k. geologischen Reichsanstalt 58 (1908): 281–304. “Geologischer Querschnitt durch die Ostalpen vom Allgäu zum Gardasee.” Jahrbuch der k.k. geologischen Reichsanstalt 61 (1911): 531–710.

“Ueber die Tektonik der Alpen.” Die Naturwissenschaften 12 (1924): 1007–1014.

“Ueber Kontinentalverschiebungen.” Die Naturwissenschaften 13 (1925): 669–675.

Über die geologischen Verhältnisse des Achensees und die beim Bau des Achenseewerkes geschaffenen neuen Aufschlüsse. Innsbruck, Austria: Tiroler Wasserkraftwerke, 1926.

“Beiträge zur Glazialgeologie der westlichen Südtiroler Dolomiten.” Zeitschrift für Gletscherkunde 16 (1928): 242–260.

“Ergebnisse der geologischen Forschungsreisen in Westserbien. Part 3: Zur Tektonik und Morphologie des Zlatibormassivs.” Denkschriften der mathematisch-naturwissenschaftliche Klasse der Akademie der Wissenschaften in Wien 101 (1928): 361–424.

Bergtage: Gewalt und Glück der Höhen. GroBe Bergsteiger 4. Munich, Germany: Rother, 1930.

“Über einige Grundfragen der Gebirgsbildung.” Jahrbuch der k.k. geologischen Reichsanstalt 87 (1937): 375–384. “Gegen den Nappismus und für die Deckenlehre.” Zeitschrift derDeutschen Geologischen Gesellschaft 92 (1940): 313–327.

“Gedanken über das Bewegungsbild des atlantischen Raumes.”Sitzungsberichte der mathematisch-naturwissenschaftlichen Klasse der Akademie der Wissenschaften in Wien, Part 1, 150 (1941): 19–35.

“Über die Bedeutung von Gleitvorgängen für den Bau der Alpen.”Sitzungsberichte der mathematischnaturwissenschaftlichen Klasse der Akademie der Wissenschaften in Wien, Part 1, 151 (1942): 9–26.

OTHER SOURCES

Flügel, Helmut W. “A. Wegener—O. Ampferer—R. Schwinner: The First Chapter of the ‘New Global Tectonics.’” Earth Sciences History 3 (1984): 178–186. The paper is a modified version of Helmut W. Flügel. “Wegener—Ampferer— Schwinner: Ein Beitrag zur Geschichte der Geologie in Österreich.” Mitteilungen der österreichischen geologischen Gesellschaft 73 (1980): 237–254.

Klebelsberg zu Thumburg, Raimund von. “Otto Ampferers geologisches Lebenswerk.” Jahrbuch der Geologischen Bundesanstalt92 (1947 [published 1949]): 93–116. The most complete available bibliography, the text includes a list of Ampferer’s geological maps as published by the Austrian Geological Service and the German and Austrian Alpine Club. Ampferer’s available geological maps are to be found on the homepage of the Geologische Bundesanstalt in Vienna, available from http://www.geologie.ac.at

Leutner, Manfred. Wissenschaftstheoretische Fallstudien zurEntwicklung der erdwissenschaftlichen Forschung in Österreich: Wilhelm Haidinger, Franz von Hauer, Otto Ampferer. Abhandlungen der Geologischen Bundesanstalt in Wien, 55. Vienna: Geologische Bundesanstalt, 1999.

Sander, Bruno. “Otto Ampferer.” Almanach der ÖsterreichischenAkademie der Wissenschaften 98 (1948): 227–233. With selected bibliography and portrait.

Seibold, Ilse, and Eugen Seibold. “Neues aus dem GeologenArchiv (1991). Mit Erinnerungen an Alfred Wegener und Otto Ampferer: Warten auf Anerkennung.” Geologische Rundschau 81/82 (1992): 267–273.

Thenius, Erich. “Otto Ampferer—Begründer der Theorie der Ozeanbodenspreizung.” Die Geowissenschaften6 (1988): 103–105.

Bernhard Fritscher