PAVLOV, ALEKSEI PETROVICH

(b. Moscow, Russia, 13 November 1854; d. Bad Tolz, Germany, 9 September 1929)

geology.

Pavlov was the son of a retired military man. He entered the Moscow Gymnasium in 1866, then in 1874 enrolled in the Faculty of Physics and Mathematics of Moscow University. He was talented in both art and music, and his eventual choice of a scientific career may have been influenced by his Gymnasium teachers. At the university he attended the lectures of the distinguished geologists G. E. Shchurovsky and M. A. Tolstopiatov; his diploma topic, ammonites, was suggested to him by Shchurovsky, and his work won him a gold medal. After graduating from the university, Pavlov taught natural history in the secondary schools of Tver (now Kalinin) from 1878 to 1880; in the latter year he went to Moscow, at Shchurovsky’s invitation, to become curator of the geological and mineralogical collections of the university. At the same time he began to study for the master’s degree, make practical studies in mineralogy, and teach in the Higher Courses for Women.

In 1883 Pavlov, at the request of the St. Petersburg Mineralogical Society, conducted field research in the lower and middle Volga regions; this research formed the basis for his master’s thesis, Nizhnevolzhskaya yura (“The Jurassic Period of the Lower Volga”), which he defended the following year. He then traveled abroad, first to Paris and the Auvergne, then to Vienna, where he attended the lectures of Suess. While in Paris he met M. V. Illich-Shishatskaya, a young widow who was auditing lectures on geology and paleontology there; they were married in 1886. Pavlov returned to the Volga to do further fieldwork in the summer of 1885; he studied Cretaceous deposits and made important observations regarding the stratigraphy of Cretaceous and Tertiary deposits. In January 1886 he became a professor at the University of Moscow—a post that he held for the rest of his life—and in May of that year he defended a doctoral dissertation on the Aspidcervas acanthicum of eastern Russia.

Pavlov’s teaching was inseparable from his scientific work. His course on introductory geology, which he gave for about ten years, was extremely popular, as were the field excursions that he conducted for his students. His courses at the Moscow Archaeological Institute and at the Moscow Mining Academy, together with those at the university, brought him a large number of pupils who formed the nucleus of the Moscow school of geologists that he trained. His concern for the reform of secondary education in Russia culminated in a book, published in 1905, in which he stressed the need for the teaching of science at that level. He later devoted a number of articles to the subject.

Pavlov’s purely scientific works comprised a wide range of topics, including stratigraphy, paleontology, tectonics, Quaternary geology, and practical geology. A single, early work is devoted to vertebrate paleontology; in an article on Archaeopteryx, published in 1884, Pavlov suggested that this genus, having achieved its greatest development in the Jurassic period, was an evolutionary side branch, destined to extinction through poor adaptation to life.

Pavlov spent a number of years studying the Mesozoic deposits of the Russian platform and the Boreal phases of the Mesozoic era throughout northern Europe. In his master’s thesis of 1884 he had traced the upper and lower boundaries of the Volga Jurassic deposits and had studied their fauna; he later established a discontinuity in the Jurassic deposits of the same region, associated with the perturbations of the Jurassic sea, and showed the sharp line of contact between the Jurassic and Cretaceous deposits. In 1888, while attending the Fourth International Geological Congress in London, Pavlov studied the local Jurassic and Cretaceous profiles and examined the collections of Jurassic and Cretaceous fossils in English museums. He utilized this new material in a comparative stratigraphic analysis of the Jurassic deposits of England and of the central part of European Russia. His conclusion was that these deposits were possibly equivalent.

Pavlov drew upon later studies of the profile of the province of Boulogne to make still wider generalizations and to compare deposits. He thus discovered a great similarity between the Jurassic fauna of the Volga region and that of Europe. By 1896 he had synthesized an enormous amount of material into a comprehensive classification of the Upper Jurassic and Lower Cretaceous deposits of Europe and Russia and had completed a paleogeographic survey of these areas. He presented the results of these researches to the International Geological Congresses of 1897 and 1900.

In his study of the stratigraphy of the Lower Cretaceous Pavlov used materials drawn from his investigations of the Russian plains and the Pechersky caves, as well as from collections gathered in northern Siberia. He established that there had been two Boreal periods in the Lower Cretaceous and that the sea which had flooded the lower Volga in the Albian stage had been connected to the sea of Western Europe. He proposed a series of paleogeographic maps and described the character of these Lower Cretaceous deposits; he also studied the Upper Cretaceous deposits of the same area and incorporated them into a stratigraphical scheme in which he noted a number of new paleontologically distinct horizons. He further established the distribution of the Lower Tertiary deposits of the Volga and differentiated them paleographically.

Pavlov’s work in Quaternary geology also began early; indeed, his interest in the period dated from Shchurovsky’s lectures at the university. He studied Quaternary deposits in his first expedition to the Volga, then, during the Third International Geological Congress, held in 1885 in Berlin, investigated the glacial deposits of Germany. After several years of investigating and comparing Quaternary deposits Pavlov was able to reach a number of conclusions concerning the genetic types of continental deposits, the number of glaciations that had caused them, and the genesis of modern topography. He summed these up in a paper of 1888, “Geneticheskie tipy materikovykh obrazovany lednikovoy i poslelednikovoy epokhi” (“Genetic Types of Continental Formations of Glacial and Post-glacial Epochs”).

Pavlov defined two types of glacial deposits. The first, the talus, consists of deposits formed by the weathering and decomposition of bedrock which have formed a slope at the bottom of a steeper declivity. This process played a large part in the formation of the topography of the Russian platform; Pavlov included a number of different types of rocks within this concept and assigned an aqueous origin to all of them, even loess. He studied the loess of the Volga region, Turkestan, and Western Europe to conclude that the process by which the Turkestan loess had been formed was very similar to that of the talus, save only that the loess had been formed by torrential mountain deluges running through the valleys, rather than by rain. He proposed to call these deposits, his second type, “proluvium.” Pavlov emphasized the importance of talus and proluvial deposits in his studies of ancient continental deposits, suggesting that these were the result of weathering processes that had taken place in the earliest geological age. He integrated his findings into his investigations of contemporary topology.

In his researches on the history of the glacial epoch Pavlov compared Russian and Western European Neogene and Quaternary deposits to establish threefold glaciation. He noted two waves of cold in the Pliocene period, then a first glaciation, covering a large part of Europe, in the Quaternary. Following the moderate and moist Chellian and Achellian periods, a second glacier covered the whole of northern Europe, developing a glacial cover almost equal to the first. The characteristic morainic landscape of Europe was formed during the second interglacial epoch; the third glaciation was less widespread than the first two, and was followed by the present warm and moist period.

Pavlov conducted paleontological research as an adjunct to his stratigraphic work. He was particularly interested in Mesozoic ammonites and belemnites and devoted several works to the description of belemnites from the Spiton deposits, in which he showed the similarity of their forms and established their genetic series and natural classification. In a report given to the Eighth International Geological Congress, which met in Paris in 1900, Pavlov proposed a new genetic classification for fossil organisms, arguing that the morphological classification then accepted did not correspond to evolutionary theory. His own system was based upon phylogenetic properties; he suggested that the terms “genetic series,” “genetic line,” “phyletic branch,” “generation,” and “species and variety” be used for more detailed subdivision. A convinced Darwinian, he drew upon the example of the ammonites to analyze questions of phylogeny and ontogeny and thereby discovered the phenomenon of phylogenetic acceleration. He applied his own classification to aucella, comparing examples from Russian and Western European deposits, and described Pliocene paludinas as part of his analysis of Quaternary material. Pavlov’s wife assisted him actively in his paleontological work, and several of his students continued it.

In the course of his work on the Volga Pavlov also became concerned with tectonic phenomena. In 1887 he suggested the existence of faulting in the northern border region of Zhigulaya. An adherent of the contractionist theory, he ascribed this faulting to that cause and noted further that petroleum deposits might be associated with this dislocation, a prediction that was later confirmed. Pavlov also discovered a fault on the right bank of the Volga and thus accounted for the general tectonic features of that area. He further found a new element in the structure of the Russian platform, the great gentle downwarpings that he called “synclines.” He interpreted these as local uplifts and depressions in the crust of the earth.

In the field of theoretical tectonics Pavlov, as early as the end of the 1890’s, began to study the topography of the moon and its genesis. He later made a comparative analysis of the topography of the moon and that of the earth, which he reported in a paper of 1908, “Lik zemli i lik luni” (“The Face of the Earth and the Face of the Moon”), and in another read to the Astronomical Society in 1922. He emphasized the importance of the study of lunar topography for understanding terrestrial processes. In his investigation of the basic morphology of the earth he concluded that its structure was determined at an early stage of its development, but that its fundamental topography was then obscured by its massive sedimentary cover and the action of the hydrosphere. The moon, which because of its weak gravity lacks an air and water cover, may therefore, in its continents and in its depressions, serve as a model of the first stages of the development of the surface of the earth. Beginning with the contraction hypothesis, Pavlov suggested that lunar forms were shaped by the solidification of the molten moon and by volcanic action; such forms, he added, had previously existed on earth, but had been transformed by the forces of contraction and the processes of weathering.

Although he was primarily interested in theoretical geology, Pavlov did not neglect its practical aspects. He investigated the landslides on the shores of the Volga and concluded that they resulted from the geological structure of the slope of the river bank, its steepness, the activity of underground water, and the leaching-out effect of the river itself. He divided landslides into two types—gravity slides, embracing the lower part of the slope; and pushing slides, whose movement begins at the top of the slope and embraces it almost in its entirety. (Some landslides may partake of both types.) Pavlov also treated the distribution of forces acting in massive landslides and suggested preventive measures. He provided a classification of rocks for engineering purposes and was frequently consulted about the construction of railroads and bridges, work related to the then new field of engineering geology.

Pavlov was, in addition, often consulted on hydrogeological problems, including the irrigation of arid areas and the reasons for the hardness of water. He was interested in soil and emphasized the relationship between soil and bedrock and topology and stressed the geological processes of soil formation. He thus contributed a good deal of the basic geological research upon which the Russian discipline of soil science was founded.

In addition to his geological works, Pavlov published a number of books in the history of science and a number of popular scientific works. He gave well-attended popular lectures, too, and several of his books went through multiple editions. He was an active member of several scientific societies and received many honors. He died at the spa of Bad Tölz, where he went with his wife to recover from a serious illness. He was active until the last days of his life, investigating the mineral springs of the resort.

BIBLIOGRAPHY

I. Original Works. Pavlov’s writings include Nizhnevolzhskaya yura. Klassifikatsia otlozheny i spiski iskopaemykh (“The Jurassic of the Lower Volga. Classification of Deposits and Notes on Fossils”; Moscow, 1884); “Notes sur l’histoire géologique des oiseaux,” in Bulletin de la Société impériale des naturalistes de Moscou,60 (1884), 100–123; “Samarskaya luka i Zheguli” (“The Samara Bend and the Zhiguli Hills”), in Trudy Geologicheskago komiteta,2, no. 5 (1885–1887), 1–63; “Geneticheskie tipy materikovykh obrazovany lednikovoy i poslelednikovoy epokhi” (“Genetic Types of Continental Formations of Glacial and Post-glacial Epochs”), in Izvestiya Geologicheskago komiteta,7 (1889), 243–261; “Études sur les couches jurassiques et crétacées de la Russie,” in Bulletin de la Société impériale des naturalistes de Moscou, n.s. 3 (1890), 61–127, 176–179; “Argiles de Speeton et leurs équivalents,” ibid.,5 (1892), 214–276, 455–570; “On the Classification of the Strata Between the Kimheridgian and Aptian,” in Quarterly Journal of the Geological Society of London,52 (1896), 542–554; Polveka v istorii nauki ob iskopaemykh organizmakh (“Half a Century in the History of Science of Fossil Organisms”; Moscow, 1897); “O reliefe ravnin i ego izmeneniakh pod vlinaniem raboty podzemnykh i poverkhnostnykh vod” (“On the Topography of Plains and Its Changes Under the Influence of Underground and Surface Waters”), in Zemlevedenie,5 (1898), 91–147; and Vulkany na Zemle i vulkanicheskie yavlenia vo vselennoy (“Volcanoes on the Earth and Volcanic Phenomena in the Universe”; St. Petersburg, 1899).

Works published in the twentieth century include Kratky ocherk istorii geologii (“A Brief Sketch of the History of Geology”; Moscow, 1901); “Ob izmeneniakh v geografii Rossii v yurskoe i melovoe vremya” (“On the Changes in the Geography of Russia in he Jurassic and Cretaceous Eras”), in Nauchnoe slovo,1 (1903), 143–145; Opolzni Simbirskogo i Saratovskogo povolzhya (“Landslips in the Simbirsk and Saratov Volga Region”; Moscow, 1903); Geologichesky ocherk okrestnoey Moskvy (“Geological Sketch of the Surroudings of Moscow”), 5th ed. (Moscow, 1907). “Enchainment des aucelles et aucellines du crétacé russe, “ in Nouveaux mémoires de la Société des naturalistes de Moscou, 17, no. 1 (1907), 1–92; Geologia nastoyaschego vremeni (“Geology of the Present Time”. Moscow, 1914); “Yurskie i nixhnemelovye cephalopods severnoy Sibiri” (“The Jurassic and Lower Creatceous cephalopoda of Northern Siberia“) in Zapiski Imperatorskoi akademii nauk 8th ser., 21 no. 4 (1914), 1–68; Ocherki istorii geologicheskikh znany (“Sketches of the History of Geological Knowledge”; Moscow, 1921); and Neoygenovye i postletretichnye otlozhenia Yuzhnoy i Vostochnoy Evropy (Neocene and post-Tertiary Deposits of Southern and Eastern Europe”; Moscow, 1925).

II. Secondary Lieterature On Pavlov and his work, see A. P. Mazarovich, Aleksey Petrovich Pavlov (Moscow, 1948); N. S. Shatsky, “O sineklizakh A. P. Pavlova” (“On Pavlov’s Syneclises”), in Byulleten Moskovskogo obshchestva ispytatelei prirody, Otdel, geolog., 18 nos. 3–4 (1940), 39–45; and V. A. Varsanofieva Aleksey Petrovich Pavlov i ego rol v razvitii geologii (“Aleksey Petrovich Pavlov and His Role in the Development of Geology” Moscow, 1947).

Irina V. Batyushskova