MORET, LéON

(b. Haute-Savoie, France, 4 July 1890; d. Isère, France, 22 November 1972)

geology, paleontology.

The son of a notary at Annecy, Moret studied medicine. As he was interested in natural history, he also took courses in geology (with a special interest in paleontology) at the University of Lyons. During World War I he served as a military doctor, temporarily interrupting his studies. But his passion for geology remained, and in 1919 he left the medical profession and became an assistant at the recently reconstituted University of Strasbourg in the Department of Geology, the first chairman of which was Maurice Gignoux. Moret married Elizabeth Denarié; they had two sons and two daughters.

Moret began his academic career under the direction of the great master Gignoux, who soon also became a friend. They met again in 1925, when Moret was named lecturer in geology at the University of Grenoble, where in 1926 Gignoux became chairman of the department of geology, succeeding Wilfrid Kilian. Thirty years later Moret succeeded Gignoux chairman and, like his predecessor, received many honors and rose through the ranks to become dean of the Faculty of Sciences. In 1957 he became a member of the Academy of Sciences. He was also a commander in the Legion of Honor.

Moret’s scientific works are extensive. Although a paleontologist by training, he remained a generalist, as can be seen in the variety of topics covered in his more than 350 publications. In the field of paleontology, his name was first linked with the fossil Spongia, mainly of the Upper Cretaceous, which was the subject of his doctoral thesis. But it was through his Manuel de paléontologie animale (1939), followed by Paléontologie végétale (1942), that his name came to be internationally known among geologists.

Moret was above all an Alpine geologist. His first works in this area dealt with the Savoie Alps, especially with the ranges located north of the Annecy Lake (Bornes massif). It is there that folded units of the Alpine edge (subalpine zone) are juxtaposed with allochthonous outliers (klippen) coming from the east, that is, from the more internal Alpine zones, after a thrust of some tens of kilometers. In addition to its geological interest, his memoir, “Geologie du massif des Bornes” (1934), was an innovation in Alpine geological literature because of the quality of its illustrations and because it introduced the concept of “geological landscapes” and their deciphering. All previous publications, at least in France, had confined themselves to the description of stratigraphic sequences and of tectonics along transverse sections.

In the second part of his Alpine career, Moret extended his activities to the entire French Alps. Among his numerous published works in this field, three merit mention. Description géologique du bassin supérieur de la Durance (1938), written with Gignoux, is the first clear approach to the internal Alpine zones along the Gap-Briançon transverse. The originality of this work lies in the relationship it maintains among stratigraphy, paleogeography, and tectonics. The study of such relationships soon became an important field of geology called structural geology. Géologie dauphinoise; ou, Initiation á la géologie par l’ étude des environs de Grenoble (1944), also written with Gignoux, is a masterpiece, still unequaled for its mixture of geological precision and clear, simple presentation of geological data. This book became quite popular with the general public and stimulated many geological careers.

Moret’s third work on the French Alps was a film depicting the rise of the Alpine range over the past 200 million years. Not only was the pedagogic value of this movie obvious, but it also illustrated in a striking way the mechanics of gravity tectonics, a theory developed by Gignoux. This theory maintains that rocks, because they are susceptible to deformation, are more or less plastic, given a sufficient period of time. On a suitable scale (millions of years), any rock mass can acquire plastic properties and thus flow, like a mudslide, down a slope, even a gentle one, solely as a result of gravity. Even if modern studies have not generalized this concept to all nappe structures, it still remains suitable for the interpretation of many of them.

Besides his Alpine activities Moret worked in Morocco and Cyrenaica. He sought to apply geological knowledge to landslides in mountainous areas, to dam foundations, and to hydrogeology and thermal springs. This last topic was the subject of a handbook he published in 1946.

After retiring, Moret led an active life, seeing to the successive editions of his books and remaining attentive to new developments in Alpine geology. Having more time at his disposal, he was able to demonstrate his artistic talent, painting Dauphiné and Savoie landscapes in watercolors that have formed the basis of several public exhibitions. Moret also wrote biographies of many of the pioneers of Alpine geology. Of special note is that of Dieudonné (Déodat) Dolomieu, for whom the mineral dolomite was named.

BIBLIOGRAPHY

I. Original Works. “Geologie du massif des Bornes (Savoie),” Mémoires de la Société geologique de France (1934); Les sources thermominerales (Paris, 1946); Géologie dauphinoise (2nd ed., Paris, 1952), written with Maurice Gignoux; La genèse des Alpes françaises, a color film (1961); Paléontologie végétale (3rd ed., Paris, 1964); Manuel de paléontologie animale (5th ed., Paris, 1966); and Précis de géologie (5th ed., Paris, 1967).

II. Secondary Literature. Reynold Barbier, “L’oeuvre scientifique de Léon Moret (1890–1972),” in Bulletin de la Société géologique de France, 7th ser., 16 (1974), 10–22.

Jacques Debelmas