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geology,

science of the earth's history, composition, and structure, and the associated processes. It draws upon chemistry, biology, physics, astronomy, and mathematics (notably statistics) for support of its formulations.

Branches of Geology

Geology is divided into several fields, which can be grouped under the major headings of physical and historical geology.

Physical Geology

Physical geology includes mineralogy, the study of the chemical composition and structure of minerals; petrology, the study of the composition and origin of rocks; geomorphology, the study of the origin of landforms and their modification by dynamic processes; geochemistry, the study of the chemical composition of earth materials and the chemical changes that occur within the earth and on its surface; geophysics, the study of the behavior of rock materials in response to stresses and according to the principles of physics; sedimentology, the science of the erosion and deposition of rock particles by wind, water, or ice; structural geology, the study of the forces that deform the earth's rocks and the description and mapping of deformed rock bodies; economic geology, the study of the exploration and recovery of natural resources, such as ores and petroleum; and engineering geology, the study of the interactions of the earth's crust with human-made structures such as tunnels, mines, dams, bridges, and building foundations.

Historical Geology

Historical geology deals with the historical development of the earth from the study of its rocks. They are analyzed to determine their structure, composition, and interrelationships and are examined for remains of past life. Historical geology includes paleontologypaleontology
[Gr.,= study of early beings], science of the life of past geologic periods based on fossil remains. Knowledge of the existence of fossils dates back at least to the ancient Greeks, who appear to have regarded them as the remains of various mythological creatures.
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, the systematic study of past life forms; stratigraphystratigraphy,
branch of geology specifically concerned with the arrangement of layered rocks (see stratification). Stratigraphy is based on the law of superposition, which states that in a normal sequence of rock layers the youngest is on top and the oldest on the bottom.
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, of layered rocks and their interrelationships; paleogeography, of the locations of ancient land masses and their boundaries; and geologic mapping, the superimposing of geologic information upon existing topographic maps.

Historical geologists divide all time since the formation of the earliest known rocks (c.4 billion years ago) into four major divisions—PrecambrianPrecambrian,
name of a major division of geologic time (see Geologic Timescale, table), from c.5 billion to 570 million years ago. It is now usually divided into the Archean and Proterozoic eons. Precambrian time includes 80% of the earth's history.
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 time and the PaleozoicPaleozoic era
, a major division (era) of geologic time (see Geologic Timescale, table) occurring between 570 to 240 million years ago. It is subdivided into six periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (see each listed individually).
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, MesozoicMesozoic era
[Gr.,=middle life], major division of geologic time (see Geologic Timescale, table) from 65 to 225 million years ago. Great crustal disturbances that marked the close of the Paleozoic and the beginning of the Mesozoic eras brought about drastic changes in the
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, and CenozoicCenozoic era
, last major division of geologic time (see Geologic Timescale, table) lasting from 65 million years ago to the present. The Cenozoic is divided into the Tertiary (from 65 million years ago until 2 million years ago) and Quaternary (2 million years ago to the
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 eras. Each, except the Cenozoic, ended with profound changes in the disposition of the earth's continents and mountains and was characterized by the emergence of new forms of life (see geologic timescalegeologic timescale,
a chronological scale of earth's history used to measure the relative or absolute age of any part of geologic time. Of the numerous timescales, the most common is based on geologic time units, which divide time into eras, periods, and epochs.
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). Broad cyclical patterns, which run through all historical geology, include a period of mountain and continent building followed by one of erosion and, in turn, by a new period of elevation.

Evolution of Geology

Early Geologic Studies

Observations on earth structure and processes were made by a number of the ancients, including Herodotus, Aristotle, Lucretius, Strabo, and Seneca. Their individual efforts in the natural history of the earth, however, provided no sustained progress. Their major contribution is that they attributed the phenomena they observed to natural and not supernatural causes. Many of the ideas expressed by these men were not to resurface until the Renaissance. Later Leonardo da Vinci correctly speculated on the nature of fossils as remains of ancient organisms and on the role that rivers play in the erosion of land. Agricola made a systematic study of ore deposits in the early 16th cent. Robert Hooke and Nicolaus Steno both made penetrating observations on the nature of fossils and sediments.

Evolution of Modern Geology

Modern geology began in the 18th cent. when field studies by the French mineralogist J. E. Guettard and others proved more fruitful than speculation. The German geologist Abraham Gottlob Werner, in spite of the many errors of his specific doctrines and the diversion of much of his energy into a fruitless controversy (in which he maintained that the origin of all rocks was aqueous), performed a great service for the science by demonstrating the chronological succession of rocks.

In 1795 the Scottish geologist James Hutton laid the theoretical foundation for much of the modern science with his doctrine of uniformitarianismuniformitarianism,
in geology, doctrine holding that changes in the earth's surface that occurred in past geologic time are referable to the same causes as changes now being produced upon the earth's surface.
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, first popularized by the British geologist John Playfair. Largely through the work of Sir Charles Lyell, this doctrine replaced the opposing one of catastrophismcatastrophism
, in geology, the doctrine that at intervals in the earth's history all living things have been destroyed by cataclysms (e.g., floods or earthquakes) and replaced by an entirely different population.
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. Geology in the 19th cent. was influenced also by the work of Charles Darwin and enriched by the researches of the Swiss-American Louis Agassiz.

In the 20th cent. geology has advanced at an ever-increasing pace. The unraveling of the mystery of atomic structure and the discovery of radioactivity allowed profound advances in many phases of geologic research. Important discoveries were made during the International Geophysical YearInternational Geophysical Year
(IGY), 18-month period from July, 1957, through Dec., 1958, during a period of maximum sunspot activity, designated for cooperative study of the solar-terrestrial environment by the scientists of 67 nations.
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 (1957–58), when scientists from 67 nations joined forces in investigating problems in all branches of geology. The systematic survey of the floors of the earth's oceans brought radical changes in concepts of crustal evolution (see seafloor spreadingseafloor spreading,
theory of lithospheric evolution that holds that the ocean floors are spreading outward from vast underwater ridges. First proposed in the early 1960s by the American geologist Harry H.
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; plate tectonicsplate tectonics,
theory that unifies many of the features and characteristics of continental drift and seafloor spreading into a coherent model and has revolutionized geologists' understanding of continents, ocean basins, mountains, and earth history.
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).

As a result of numerous flyby spacecraft, geological studies have been extended to include remote sensing of other planets and satellites in the solar system and the moon. Laboratory analysis of rock samples brought back from the moon have provided insight into the early history of near-earth space. On-site analyses of Martian soil samples and photographic mapping of its surface have given clues about its composition and geologic history, including the possibility that Mars once had enough water to form oceans. Photographs of the many active volcanoes on Jupiter's moon Io have provided clues about earth's early volcanic activity. Geological studies also have been furthered by orbiting laboratories, such as the six launched between 1964 and 1969 in the Orbiting Geophysical ObservatoryOrbiting Geophysical Observatory
(OGO), series of six orbiting observatories (see observatory, orbiting) launched between 1964 and 1969 by the National Aeronautics and Space Administration (NASA) to study the earth's atmosphere, ionosphere, and magnetosphere and the solar wind.
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 (OGO) series and the Polar Orbiting Geomagnetic Survey (POGS) satellite launched in 1990; remote-imaging spacecraft, such as the U.S. Landsat program (Landsat 8, launched in 2013, is the most recent) and French SPOT series (SPOT 6, launched in 2012, is the most recent in the program); and geological studies on space shuttlespace shuttle,
reusable U.S. space vehicle (1981–2011). Developed by the National Aeronautics and Space Administration (NASA) and officially known as the Space Transportation System (STS), it was the world's first reusable spacecraft that carried human beings into earth
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 missions.

Bibliography

See N. Coch and A. Ludman, Physical Geology (3d ed. 1991); L. S. Fichter et al., Earth Materials and Earth Processes (3d ed. 1991); L. Margulis and L. Olendenski, Environmental Evolution: Effects of the Origin and Evolution of Life on Planet Earth (1992); R. H. Dott, Jr., and D. R. Prothero, Evolution of the Earth (5th ed. 1994); E. A. Keller, Environmental Geology (7th ed. 1996); S. Chernicoff and C. Fox, Essentials of Geology (1998); E. J. Tarbuck and F. K. Lutgens, The Earth: An Introduction to Physical Geology (6th ed. 1998).

geology

(jee-ol -ŏ-jee) The study of the history, structure, and composition of the Earth's crust. The principle divisions of geology include physical geology, historical geology, and economic geology.

Physical geology includes mineralogy, which is the study of minerals; petrology, the study of the formation, composition, and structure of different types of rock; structural geology, concerned with how these rocks combine to form the crust; and geomorphology (or physiography), the study of the relation between geographical features and sub-surface geological structures.

Historical geology includes stratigraphy, which is concerned with the chronology of rock strata; paleogeography, the study of the distribution of geographical features (seas, deserts, mountains) during early periods of the Earth's history; and paleontology, dealing with the development of life as revealed by the fossil record on different geological strata.

Economic geology is concerned with the study of valuable mineral deposits, such as ores, coal, and oil.

Geology

 

the complex of sciences concerned with the earth’s crust and deeper spheres; in the narrow sense of the word, the science of the composition, structure, movements, and history of development of the earth’s crust and the location of minerals. Most of the applied and theoretical questions resolved by geology deal with the upper part of the earth’s crust, which is accessible to direct observation.

Geological methods, too, are based primarily on direct field observations. The geological investigation of a certain territory begins with a study and comparison of rocks observed on the earth’s surface in different natural exposures and also in man-made openings (such as exploration shafts, quarries, and mines). The rocks are studied both in their natural occurrence and by taking samples that are later subjected to laboratory investigation.

A necessary element of the geologist’s field work is the geological survey, which is accompanied by the preparation of a geologic map and geologic cross sections. The map depicts the distribution of rocks and indicates their genesis, age, and to the degree necessary, the composition of the rocks and modes of their occurrence. The geologic cross sections reflect the mutual position of rock layers vertically in idealized cross sections. Geologic maps and cross sections serve as one of the primary documents on the basis of which empirical generalizations and conclusions are made, the search for and analysis of minerals is based, and conditions for erecting engineering structures are evaluated. Boreholes are sometimes resorted to in order to refine the data of the geological survey. They make it possible to bring to the surface rocks occurring at considerable depths. In the USSR, furthermore, so-called test drilling is done (since 1947). In the course of drilling, vast territories are covered with a more or less even net of deep holes, which makes it possible to compile a general diagram of the geological structure of the country and make fuller use of survey data. Since the middle of the 20th century holes up to 7 km deep and more have been drilled in the USSR and the United States. The sea floor has been successfully drilled in relatively shallow places. Since the end of the 1960’s American geologists have been conducting drilling operations in the ocean from specially equipped ships.

Methods of direct study of the interior of the earth do not make it possible to know the earth’s structure beyond a depth of a few kilometers (sometimes up to 20 km) from its surface. Therefore, even in studying the earth’s crust, and all the more in studying underlying geospheres, geology cannot get by without the assistance of indirect methods developed by other sciences, especially geochemical and geophysical methods. Very often a combination of geological, geophysical, and geochemical methods is employed.

Three primary areas can be distinguished in geological research. The task of the first (descriptive geology) is to describe minerals, rocks, and their types and to study the composition, shape, dimensions, mutual relations, sequence of occurrence, and all other questions related to the present-day location and composition of geological bodies (layers of rocks, granite masses, and so on). The second area (dynamic geology) involves the study of geological processes and their evolution. Among these processes are included both those that are external in relation to the earth’s crust and the deeper geospheres (such as the destruction of rocks; transportation and redeposition by the wind, glaciers, and surface and underground waters; and the accumulation of sediments on the bottom of rivers, lakes, seas, and oceans) and those that are internal (crustal movements, earthquakes, and volcanic eruptions and the phenomena that accompany them). Geological processes are studied both under natural conditions and experimentally. The third area of geological research (historical geology) consists of reconstructing a picture of the earth’s geological past (historical-geological reconstruction). The problems in this area involve studying the distribution and sequence of formation of geological stratifications and other geological bodies and establishing the sequence of various geological processes and events—for example, the processes of tectogenesis, metamorphism, the formation and destruction of deposits of minerals, transgressions and regressions of the seas, and the alternation of glacial epochs with interglacial epochs. All three areas of geology are inseparably linked with each other and the investigation of any geological object, just as the investigation of any territory, is done from all three points of view, even though each area is independent in the sense of basic principles and methods of investigation.

A specific characteristic of geological processes is that many of them occur over enormous territories and continue for millions and even billions of years; this is what makes their investigation difficult. In order to understand the geological processes of the past, all of the results of these processes reflected in the rock strata are studied, in particular, the composition, structure, and occurrence of rock strata and forms of relief of the earth’s surface.

When analyzing historical data attention is given to the sequence of deposition of stratified sedimentary formations, which are viewed as pages of the earth’s “chronicle in rock.” The irreversible evolution of the organic world, which is recorded in fossilized remains of plant and animal organisms that are preserved in the layers of sedimentary rock, is also taken into consideration. Certain plants and animals correspond to each of the ages in the earth’s development. This serves as the basis for establishing the relative age of rock strata and makes it possible to subdivide the history of the earth’s last 600 million years into successive time segments: into eras, which are further divided into smaller units of geological time—periods, epochs, and ages. Research shows that 80 percent of the volume of the earth’s sedimentary shell isformed of the most ancient, Precambrian, strata; the length of time it took to form them constitutes at least six-sevenths of all known geological history. In addition to their relative age, the absolute, or radiometric, age of geological bodies can be determined. The method of computation is based on the law of constancy in the rates of radioactive decay; figures on the relative amounts of the radioactive element and its decay products in the rock or mineral under investigation are taken as initial data. This method is particularly important for the most ancient Precambrian strata of the earth, which have very few organic remains.

The method of actualism (≅ uniformitarianism) is extensively used in geology. According to it geological processes occur in a similar way under similar conditions. Therefore, by observing present-day processes it is possible to judge how analogous processes occurred in the distant past. Present-day processes can be observed in nature (for example, the activity of rivers) or artificially created (for example, subjecting samples of rocks to the action of high temperature and pressure). In this way it is often possible to establish the physicogeographic and physicochemical conditions under which ancient strata were deposited and to determine, for metamorphic rocks, the approximate depth at which the metamorphism (change) took place. However, the geographic and geological conditions in the life of the earth have changed irreversibly; therefore the older the strata that are being studied, the more limited the application of the method of actualism will be.

The development of theoretical questions in geology is closely linked with one of its major practical tasks, predicting the search for and analysis of minerals and establishing the raw material-mineral basis for the world economy.

Geology is also very important in the planning of various engineering structures, in construction, agriculture, and military affairs. Geology also plays an important role in the struggle for the materialist world view.

The link between geology and other sciences and the system of geological sciences. Modern geology is closely linked to a large number of other sciences, primarily the earth sciences. That is exactly why it is difficult to establish precise boundaries for geology as a science or to define its subject matter unambiguously. The extensive use of physical and chemical methods in geological research has promoted rapid development in such allied sciences as earth physics and geochemistry. Earth physics studies the physical properties of the earth and its envelopes and the geological processes taking place in these envelopes. Geochemistry examines the chemical composition of the earth and the laws governing the distribution and migration of chemical elements in it. Geology cannot get along without employing the methods and conclusions of these sciences. In geochemistry and earth physics physical and chemical methods of research, on the one hand, and geological methods, on the other, are intimately intertwined. Therefore the position of geochemistry and earth physics in the system of earth sciences is open to debate. They are viewed either as the most developed geological disciplines or as fields of knowledge equal in significance to geology. A close tie joins geology to geodesy and the group of physical geographic sciences (such as geomorphology, climatology, hydrology, oceanography, and glaciology) whose tasks include studying the relief of the earth’s surface, the waters of the continents and oceans of the world, the climates of the earth, and other questions related to the structure, composition, and development of the geographic envelope. For a full understanding of the earth’s history it is essential to know its initial state; this question is solved by planetary cosmogony— that is, a division of astronomy that studies the problem of planet formation. In questions of the origin and development of organic life on earth, geology is interconnected with the biological sciences, above all, with paleontology. The geologist must have a knowledge of biological and biochemical processes in order to find out how certain rocks and minerals (such as petroleum and coal) were formed. Thus, the entire group of sciences that studies the earth is characterized by many-sided links and interaction. Geology uses the data of these sciences to solve the general problems of the planet’s development. This permits some investigators to assign geology the leading place among the earth sciences or even to interpret geology as including all the earth sciences.

Geology includes a number of disciplines that are concerned with investigating and describing the earth. This group of disciplines is supplemented as investigation of the planet expands; these disciplines become differentiated and new scientific areas appear, primarily where geology intersects with other fields of knowledge. The subject matter of most geological disciplines is dealt with in all three areas of geology (descriptive, dynamic, and historical geology). This explains the close interrelation among the geological disciplines and the difficulty of classifying them and dividing them into clearly differentiated groups.

The following groups of geological disciplines are the most commonly accepted: the scientific disciplines that study the composition and structure of the earth’s crust, the disciplines that study current geological processes (dynamic geology), the disciplines that study the historical sequence of geological processes (historical geology), and the applied disciplines. The geology of particular areas and regions (regional geology) belongs to a special group.

The first group of geological disciplines includes mineralogy (the study of minerals, or natural, stable chemical compounds); petrology (the study of rocks, or structural-material associations of minerals); structural geology, which studies the modes of occurrence of geological bodies and various disturbances in the occurrence of layers—their folds, faults, and so on. Crystallography arose and developed for a long time as one of the areas of mineralogical research. Recently, however, study of the atomic structure of crystals has, to a significant degree, made this a physical discipline.

The second group of geological disciplines (dynamic geology) includes tectonics, which studies crustal movements and the structures created by them. When applied to the largest structures of the earth—the continents and oceans—it is frequently called geotectonics, and the tectonics of the Neocene-Anthropogenic (Quaternary) time period is called neotectonics. Experimental tectonics, which studies tectonic processes (for example, the formation of folds) on models, is a separate discipline. This group also includes the divisions of mineralogy and petrology, which study the process of mineral and rock formation, as well as such disciplines as volcanology, which studies the processes of volcanism; seismogeology, the science of geological processes that accompany earthquakes and of using geological data to determine regions of seismic activity (seismic zoning), and geocryology, which investigates processes involving perennially frozen rocks.

The third group of geological sciences includes historical geology, which reconstructs the events of geological history and their sequence on the basis of traces that are preserved in the sedimentary shell of the earth. This group also includes stratigraphy, which studies the sequence of occurrence of rock layers in the earth’s sedimentary shell, and paleogeography, which reconstructs the physico-geographic conditions of past geological periods on the basis of geological data. Because of the uniqueness of the methods of investigation employed, study of the geological history of the last Anthropogenic period has become a special discipline that is inaccurately called Quaternary geology.

The fourth group of geological disciplines (applied geology) includes the geology of valuable minerals; hydrogeology, the science of underground water; engineering geology, which studies geological conditions for building various structures; and military geology, which studies questions of using geology in military affairs.

The geology of the sea and ocean floors, or marine geology, occupies a special place among the geological disciplines because of its methodology and tasks. With the increased interest in using the natural resources of the seas and oceans, this discipline is developing successfully.

The above does not exhaust the list of geological disciplines. Their differentiation and merging with associated disciplines has led to the appearance of new areas. For example, because the methods of investigating rocks of plutonic and sedimentary origin proved fundamentally different, petrology was divided into the petrology of igneous rocks and the petrology of sedimentary rocks, or lithology. The introduction of chemical methods into the study of igneous rocks has led to the appearance of petrochemistry, and the study of deformations within rocks has given rise to petrotectonics.

The geology of valuable minerals is sharply differentiated: the geology of petroleum and gas; the geology of coal; and metallogeny, which deals with the laws governing the location of ore deposits. The application of the latest physical and chemical methods in geology served as the basis for the appearance of such new specializations as tectonophysics, paleomagnetism, and experimental physical chemistry of silicates.

Historical sketch. The isolated observations and statements that it is customary to consider as the beginnings of geology go back to antiquity. It is typical that the statements of the ancient scientists (such as Pythagoras, Aristotle, Pliny, and Strabo) concern earthquakes, volcanic eruptions, the erosion of mountains, and the shifting of the coastlines of seas, that is, the phenomena of dynamic geology. Only in the Middle Ages were attempts made to describe and classify geological bodies—for example, the description of minerals by the Uzbek scientist Biruni and the Tadzhik natural scientist Ibn Sina (Latinized form, Avicenna). The first conception (not counting the early references to this by the ancient Greek scientist Strabo) of the true nature of fossilized shells as remains of extinct organisms and of the great length of the earth’s history in comparison with biblical notions dates to the age of the Renaissance (the Italian scientists Leonardo da Vinci in 1504-06 and G. Fracastoro in 1517). Development of the first concepts of the displacement of beds and their original horizontal deposition belongs to the Dane N. Steno (1669), who was the first to offer an analysis of a geologic cross section (in Tuscany), explaining it as a succession of geological events.

The word “geology” appeared in print in the 15th century, but at that time it meant something entirely different from what it does today. Bishop R. de Bury’s book Philobiblon (Love of Books) was published in Cologne in 1473. In it the term “geology” was used for the set of laws and rules of “earthly” existence, as opposed to theology, the science of spiritual life. The term “geology” was first used in its modern sense in 1657 by the Norwegian naturalist M. P. Escholt in a work devoted to the major earthquake that encompassed all of southern Norway (Geologia Norwegica, 1657). At the end of the 18th century the German geologist G. C. Fiichsel proposed and the German mineralogist and geologist A. G. Werner introduced (1780) into the literature the term “geognosy” for the phenomena and objects studied by geologists on the earth’s surface. From this time until the middle of the 19th century the term “geognosy” was used more extensively in Russia and Germany than in other countries (although there was no clear differentiation between the concepts “geology” and “geognosy”). In Great Britain and France the term was used very rarely, and in America it was hardly used at all. In the middle of the 19th century the use of the term “geognosy” was gradually discontinued in Russia. For some time it was still encountered in the names of academic degrees and names of subdepartments at old Russian universities, but by 1900 it no longer played a role, having been replaced by the term “geology.”

The end of the 17th century was characterized by an increase in the number of geological observations and also by the appearance of scientific works in which attempts were made to generalize knowledge, which was still far from adequate, into some kind of general theory of the earth, the methodological basis for which was entirely lacking. At the end of the 17th and beginning of the 18th century most scientists adhered to the notion that there had been a universal flood in the history of the earth, as a result of which the sedimentary rocks and fossils contained in them were formed. These views, which became known as diluvianism, were shared by the English naturalists R. Hooke (1688), J. Ray (1692), and J. Woodward (1695); the Swiss scientist J. J. Scheuchzer (1708); and others.

Geology as an independent branch of natural science began to take shape in the second half of the 18th century when, under the influence of incipient large-scale capitalist industry, society’s need for extractable mineral raw materials began to increase rapidly and, in connection with this, there was greater interest in studying the interior of the earth. This period in the history of geology was characterized by the development of elementary procedures for observing and accumulating factual material. Investigations primarily consisted of describing the properties and modes of occurrence of rocks. But already at that time there were attempts to explain the genesis of rocks and to understand the essence of processes occurring both on the earth’s surface and in its interior.

M. V. Lomonosov’s geological works Essay on the Generation of Metals From Earthquakes (1757) and Layers of the Earth (1763) were of great significance. In them he gave a comprehensive and interconnected presentation of the geological data existing at that time and presented his own observations. Lomonosov assigned a decisive role in shaping the face of the earth to deep-seated forces (“the heat in the womb of the earth”), at the same time also recognizing the influence of external factors (such as wind, rivers, and rains) on the earth’s surface. He developed the idea of unity of formation of mountains and depressions and confirmed the length and continuity of the geological changes to which the earth’s surface is subject. In recognizing the synthesis of external and internal forces in their influence on the development of the earth, Lomonosov was far ahead of his age; at that time in the West there was an ideological struggle under way between two opposing schools, Neptunism and Plutonism, a struggle that concerned the fundamental problems of the earth’s past and present. The Saxon A. G. Werner, professor of mineralogy at Freiberg, and the Scottish scientist J. Hutton were representatives of these schools.

The Neptunist Werner took an extremely one-sided position, asserting that all rocks, including basalt, precipitated from the water. As regards volcanic activity, he naïvely ascribed it to the underground combustion of coal. Furthermore, having made geological observations only in the area around Freiberg, Werner incorrectly applied the laws noted there (for example, sequence of formations) to the entire surface of the globe. The works of J. Hutton and his Plutonist followers were close to more correct geological concepts because they assigned a significant role to the earth’s internal forces. These works pointed out the volcanic origin of basalts and that granites were formed from molten masses, which was later confirmed by microscopic studies of rocks and by special experiments.

In the middle of the 18th century geological (more precisely, petrographic-lithological) maps began to appear, first of small segments and later of large territories. These maps showed the composition of rocks but did not indicate their age. In Russia the first “geognostic” map was the map of the eastern Transbaikalian region, made in 1789-94 by D. Lebedev and M. Ivanov. The first “stratigraphic-geologic map,” which covered a significant area of European Russia, was made at the end of the 1840’s by N. I. Koksharov. It already identified formations, such as the Silurian, Old Red Sandstone (Devonian), limestone (Lower Carboniferous), Lias, and Tertiary. At the beginning of 1841, G. P. Gel’mersen published the General Map of the Rock Formations of European Russia.

The birth of geology as a science dates to the end of the 18th and beginning of the 19th century and is connected with the establishment of the possibility of dividing the layers of the earth’s crust according to age on the basis of the remains of ancient fauna and flora preserved in the layers. Later this made it possible to generalize and systematize previously disconnected mineralogical and paleontological data, construct a geochronological scale, and make geological reconstructions.

In 1790 the English scientist W. Smith was the first to point out the possibility of dividing stratified formations on the basis of the organic remains preserved in them. He constructed a “scale of the sedimentary formations of England,” and then in 1815 made the first geological map of England. Major credit for dividing the earth’s crust on the basis of mollusk and vertebrate remains belongs to the French scientists G. Cuvier and A. Brongniart. In 1822 the Carboniferous system was identified in the southwestern part of England, and the Cretaceous system was identified in the Paris Basin; this marked the beginning of stratigraphic systematization. But the methodological basis of the first stratigraphic investigations was imperfect. The difference in the nature of organic remains in the beds that succeeded each other was explained by the French scientist G. Cuvier as the result of a series of cataclysms caused by supernatural forces during which all living things were destroyed over extensive areas and the devastated areas were then settled by organisms that migrated from other regions. The students and followers of G. Cuvier developed this theory. They asserted that there were 27 catastrophes in the history of the earth (A. d’Orbigny) during which the entire organic world perished and then arose again through the next act of god, but in an altered form. The disrupted bedding of initially horizontal beds of rock and the formation of mountains were also considered to be results of these same short-term catastrophes. In 1825 the German geologist L. von Buch came out with the theory of “rising craters,” explaining all crustal movements in terms of volcanism. He continued to defend these ideas subsequently even though, in 1833, the French scientist L. C. Prévost explained that volcanic cones are not elevations but rather accumulations of the products of eruption. At the same time (1829) the French geologist L. Elie de Beaumont proposed the contraction hypothesis, which stated that the dislocation of layers was a result of crustal contraction occurring during the cooling and reduction of the volume of the earth’s central, white-hot nucleus. This hypothesis was accepted by most geologists until the beginning of the 20th century.

The first blow against the views of the catastrophists was struck by C. Lyell’s Principles of Geology (1830-33). The biases concerning the short duration of the earth’s geological history were finally refuted and it was demonstrated, with extensive factual material, that there is no need to resort to supernatural forces and catastrophes to explain geological history because the geological agents now active (atmospheric precipitation, wind, sea tides, volcanoes, and earth-quakes) produce enormous changes in the structure of the earth’s crust over the span of millions of years. An important achievement of C. Lyell and his contemporaries in Germany, Russia, and France was the development in depth of the actualist method, which made it possible to decode the events of the geological past. The ideas worked out by C. Lyell also had their shortcomings, which consisted of the fact that he considered the forces active on the earth to be constant in quality and intensity and that he failed to see changes in them and the development of the earth that was connected with this (uniformism).

C. Darwin’s theory of evolution was enormously important for the further development of stratigraphy. It provided a solid methodological basis for a detailed age breakdown of the earth’s sedimentary cover by studying the phylogenetic changes in particular groups of animal and plant fossils. Russian scientists also played a large part in the creation of evolutionary paleontology. K. F. Rul’e, who studied the Jurassic deposits near Moscow, had defended the idea of the evolutionary development of inorganic nature and organisms even before Darwin. In the second half of the 19th century ideas on evolution became widespread, the scientific principles of historical-geological investigations were developed (I. Walther), and the foundation of evolutionary paleontology was laid (V. O. Kovalevskii). The works of Russian researchers at the end of the 19th and beginning of the 20th century were very important. In a number of monographs dealing with fossilized cephalopods and fish, A. P. Karpinskii demonstrated the great prospects that the study of the development of organisms opens to stratigraphy. A. P. Pavlov, investigating Jurassic and Lower Cretaceous deposits, laid the foundations of comparative stratigraphy, which studies the various zoogeographical and paleogeographical conditions of the past. Using the Neocene deposits in the south of Russia as an example, N. I. Andrusov demonstrated the close relationship between changes in salt content and other physicogeographical conditions of the basins of the past and characteristics of the development of their fauna.

In the second half of the 19th century the first successes were achieved in studying and dividing Precambrian formations. The American geologist J. Dana (1872) identified the Archean group of deposits, which at first encompassed the entire Precambrian; later the American geologists S. Emmons and R. Irving (1888) identified the Proterozoic group.

In this way, by the end of the 1880’s the basic subdivisions of the current stratigraphic scale, which was officially adopted at the Second International Geological Congress in Bologna in 1881, were established. The successes of paleontology and stratigraphy promoted development of the method of reconstructing the paleogeographic conditions of past ages and, the appearance, by the beginning of the 20th century, of the new geological discipline of paleogeography.

In the second half of the 19th century the process of differentiation of geology became more intensive. Geology changed from a comparatively monolithic science into a complex set of geological sciences. In addition to stratigraphy, which was the primary field that provided a chronological basis for the earth’s history in the 19th century, other fields of geology also developed. Not only was the vertical sequence of strata studied, but also changes in their material composition along the strike, which were connected with changes in the conditions of formation of the rocks. In 1838 the Swiss geologist A. Gressly first proposed calling all rocks formed under identical conditions “facies.” The theory of facies was elaborated by the Russian geologist N. A. Golovkinskii.

Modern mineralogy began to take shape as early as the turn of the 19th century with the works of the Russian geologists V. M. Severgin and D. I. Sokolov, the French scientist R. J. Haiiy, and the Swedish chemist J. Berzelius. Its further development in Russia was linked to the names of N. I. Koksharov, P. V. Eremeev, M. V. Erofeev, and A. V. Gadolin. At the end of the 19th century there appeared the main works of E. S. Fedorov, who introduced the doctrine of symmetry and the theory of the structure of crystalline substances and proposed new methods of goniometric and optical study of minerals. In the 19th century, in connection with the introduction (1858) of polarizing microscopes to study rocks, petrology became an independent geological discipline. An enormous amount of data from the microscopic study of rocks was accumulated, and this made it possible to develop the first petrographic classification. To the present day the classification of igneous rocks proposed by the Russian scientist F. Iu. Levinson-Lessing in 1898 continues to enjoy the greatest recognition. At the beginning of the 20th century theoretical research in petrology developed, in particular, research on the problems of the formation of magmatic rocks, the origin and differentiation of magma, and study of metamorphism. Experimental physicochemical study of silicate systems began.

The end of the 19th and beginning of the 20th century marked a new qualitative turning point in the history of geology. The transition of capitalism to its new imperialist stage led to an expansion of the scale of exploitation of the earth’s interior and drew new, previously untouched territories into the sphere of world economic relations. Geological surveys appeared in all the leading countries of the world and began systematic geological survey work (for example, the US Geological Survey, 1879). Vast new areas were encompassed by geological investigation, anticipating development of the mining industry. The flow of factual data increased, and the horizon of geologists expanded greatly. Special training for geological specialists was introduced. Evolutionary ideas became firmly accepted in geology, and the picture of the development of the earth and its surface was reconstructed in general outline.

The organization of the Geological Committee in 1882 was very important for the development of geology in Russia. It was headed by such scientists as A. P. Karpinskii, F. N. Chernyshev, and K. I. Bogdanovich. Significant advances in the study of the regional geology of Russia and the development of geological cartography were made as a result of the activity of the committee. These advances enabled A. P. Karpinskii to make a map of a significant part of European Russia for the Berlin session of the International Geological Congress (1885). The first full geological map of European Russia on a scale of 1:2,520,000 was made and published under the direction of A. P. Karpinskii in 1892. The compilation of a general “10-verst” map of European Russia (scale of 1:420,000), which began from the moment that the Geological Committee was organized, played a large part in the development of geological cartography.

In 1887, A. P. Karpinskii was the first to make paleogeo-graphic reconstructions for European Russia. He traced the range of marine deposits and reconstructed the position of shorelines for different geological periods. He was able to give an overall picture of the slow tectonic movements for an enormous area in the geological past, beginning with the Cambrian period. He juxtaposed these movements to “ridge-forming” processes that were localized in comparatively narrow zones. In 1890 the American geologist G. Gilbert proposed that slow crustal movements be called epeirogenic, as opposed to the more rapid mountain-building, or orogenic, movements.

In the second half of the 19th century concepts, were first enunciated of the existence of especially mobile belts of the earth’s crust—geosynclines (the American geologists J. Hall, 1857-59, and J. Dana, 1873; the French geologist G. Haug), which were juxtaposed to the stable regions, the platforms. At the end of the 19th century the French geologist M. Bertrand and the Austrian geologist E. Suess identified in the European area episodes of folding (the Caledonian, Hercynian, and Alpine) of different ages. Publication of the first multivolume description of the geological structure of the entire planet was begun (The Face of the Earth by the Austrian geologist E. Suess). In this work mountain building was viewed from the point of view of the contraction hypothesis. Detailed investigation of the tectonics of the Alps led to the identification of a new type of structure of the earth’s crust—overthrusts (the French geologist M. Lugeon, 1902). Subsequent works showed the extensive development of overthrusts in reference to many mountain systems.

In the 20th century geology is developing much more rapidly than before, as is natural science as a whole. The first broad theoretical generalizations are being followed by new ones that frequently correct them to a large extent or refute them. A major event of the time was the discovery (1899-1903) by the French scientists P. Curie and M. Sklodowska Curie of the radioactive decay of elements, which is accompanied by the spontaneous liberation of heat. This discovery made it possible to develop a method for determining the absolute’ age of rocks and, therefore, the duration of many geological processes. This enabled Precambrian geology to develop (A. A. Polkanov, N. P. Semenenko, and K. O. Kratts of the USSR; D. Anderson of the United States; C. H. Stockwell of Canada; and B. A. Choubert of France). The presence of thermal energy on the planet, the activation of tectonic movements, and volcanism began to be linked to radioactive decay in the earth’s interior, which led to a fundamental revision of basic geological conceptions. In particular, the foundations of the contraction hypothesis were shaken and the notions concerning the earth’s initial liquid-molten state were replaced by the concept that the earth was formed as the result of the accumulation of cold solid particles. These ideas found final expression in the cosmogonic hypothesis of O. Iu. Shmidt (USSR).

It is becoming more and more urgently necessary to move from a simple statement of empirically established regularities to a true explanation of their causes, to disclosure of the basic laws of the history of the earth’s development. It is becoming necessary to study intensely the deep-seated processes occurring in the lower layers of the earth’s crust and in the mantle. The methodology for studying the substantive composition of rocks (mass spectrometry, X-ray diffraction, and other kinds of analyses) and the structure of the earth’s crust is also improving.

Much attention was devoted to the development of regional geological research, especially to geological surveying as the basis for revealing mineral resources. The stratigraphic maps that, by the beginning of the 20th century, had been developed only for Europe and for part of North America began to be detailed and compiled for all the other continents as more and more geological maps were made. The increase in the scale and depth of boring and the need to determine the age of rocks extracted from the holes (major paleontological remains are seldom encountered in these rocks) led to the study of microscopic remains of fauna and flora (Foraminifera shells, Radiolaria, ostracods, diatoms, peridinians, and plant spores and pollen) for stratigraphic purposes and to the organization of large associations of micropaleontologists (D. M. Rauzer-Chernousova, A. V. Fursenko, and others). A significant event in the development of stratigraphy was the identification by N. S. Shatskii (1945) of the new Riphean group of deposits, which lies between the Proterozoic and the Paleozoic and identification of the corresponding time segment of about 1 billion years in the earth’s history. Riphean deposits have been identified on all continents, and they have been successfully divided and their cross sections compared by means of studying stromatoliths. The stratigraphy of the Paleozoic, Mesozoic, and Cenozoic deposits has been worked out in detail in the works of Soviet geologists (D. V. Nalivkin, V. V. Menner, B. S. Sokolov, V. N. Saks, and others) and non-Soviet geologists (the French geologist M. Gignoux, the English geologist W. Arkell, the Americans J. Rogers and W. C. Krumbein, and many others).

In the field of tectonics the 20th century has been characterized by development of the theory of crustal movements, including the possibility of horizontal displacements of large blocks of the crust (continental drift), and the development of classifications of tectonic forms and the theory of geosynclines and platforms (Soviet scientists in this field include A. D. Arkhangel’skii, M. M. Tetiaev, N. S. Shatskii, V. V. Belousov, M. V. Muratov, and V. E. Khain; among scientists who worked in this field abroad are the German geologists H. Stille, and S. N. Bubnoff, the Swiss geologist E. Argand, and the Americans R. Auboin and M. Kay). Other developments include the identification of different types of tectonic forms and their stages of development and also of foredeeps, formations which are transitional between geosynclines and platforms. Deep faults in the earth’s crust were first identified in 1946 (A. V. Peive and N. A. Shtreis) and then investigated in detail. The progress of theoretical tectonics and the broad scope of deep boring and geophysical research have created the prerequisites for a tectonic regionalization—dividing the area of the continents into large-scale structural elements with different histories of development and, therefore, with different associations and series of geological formations. The theory of formations was formulated in the works of N. S. Shatskii and N. P. Kheraskov, and later this was done for magmatic formations in the works of Iu. A. Kuznetsov.

During the 1950’s and 1960’s tectonic maps began to be compiled. They include maps of the USSR (N. S. Shatskii, 1953, 1956; T. N. Spizharskii, 1966), Europe (N. S. Shatskii, A. A. Bogdanov, and others, 1964), Eurasia (A. L. Ianshin and others, 1966), Africa (Iu. A. Choubert, 1968), and North America (P. King, 1969). In addition, large-scale tectonic maps of particular areas and regions were made to discover the main laws governing the location of minerals. In the USSR modern tectonic movements began to be studied, and the foundations for neotectonics were laid (V. A. Obruchev, N. N. Nikolaev, and S. S. Shul’ts). In connection with the exploration and exploitation of minerals in sedimentary strata the petrology of sedimentary rocks, or lithology, became an independent discipline. Soviet scientists played the main role in its development.

The first course of studies in the petrology of sedimentary rocks was given at Moscow University and at the Moscow Mining Academy by M. S. Shvetsov in 1922. He educated several generations of Soviet lithologists and wrote classical works on the lithology of the coal deposits of the Moscow tectonic depression. la. V. Samoilov carried out interesting studies in the mineralogy of sedimentary rocks in the early 1920’s. As early as 1912, A. D. Arkhangel’skii provided the first model of comparative lithological research by reconstructing the conditions of the formation of the Upper Cretaceous deposits of the Volga region by analogy with the sediments of modern seas and oceans. After the Great October Socialist Revolution he made a detailed study of the lithology of phosphorites, bauxites, and source beds. V. P. Baturin worked out a method for studying terrigenous minerals for the purpose of reconstructing the paleogeographic conditions of sedimentation. In a series of monographs and in the two-volume work The Petrography of Sedimentary Rocks (1940), L. V. Pustovalov was the first to formulate the question of the general laws governing the process of sediment formation and its evolution throughout the history of the earth. N. M. Strakhov did a great deal to clarify the different questions of sedimentary rock formation and establish its stages and climatic types. His three-volume monograph Fundamentals of the Theory of Lithogenesis was published in 1960-62. The specific features of sedimentary rock formation in the Precambrian were studied by A. V. Sidorenko, while the formation of salt-bearing strata was studied by M. G. Valiashko, A. A. Ivanov, and M. P. Fiveg. Major works on the petrology of sedimentary rocks were also written by such American geologists as W. Twenhofel, F. J. Pettijohn, W. C. Krumbein, and J. Taylor.

The theory of facies, which has been developed most extensively in the works of D. V. Nalivkin, is closely linked with the petrology of sedimentary rocks. A number of new methods have been developed for studying the substantive composition of rocks (spectroscopic, X-ray diffraction, and thermometric analyses). In mineralogy the modern crystal-lochemical theory of the constitution of minerals has been formulated (N. V. Belov, V. S. Sobolev, and others), many minerals have been successfully synthesized (D. S. Beliankin and D. P. Grigor’ev), and a large group of works has been devoted to the pegmatites (A. N. Zavaritskii and A. E. Fersman) and to the physicochemical analysis of natural associations of minerals (A. G. Betekhtin, D. S. Korzhinskii). Numerous works have been written on petrology, petrochemistry, and the theory of metamorphism (F. Iu. Levinson-Lessing, Iu. A. Kuznetsov, N. A. Eliseev, Iu. I. Polovinkin, P. Eskola, T. Barth, N. Bowen, G. Kennedy, P. Niggli, and F. Turner). Of great importance are works on coal petrology, which are devoted to studying the metamorphism of coal and the laws governing the location of coal basins (P. I. Stepanov, Iu. A. Zhemchuzhnikov, V. V. Mokrinskii, V. I. lavorskii, and I. I. Gorskii). The geology of petroleum and gas is being developed (I. M. Gubkin, S. I. Mironov, A. A. Trofimuk, M. F. Mirchink, I. O. Brod, the Czech geologist K. Krejci-Graf, and the Americans A. Levorsen and D. M. Hunt). In recent decades a special branch of geology, metallogeny, has developed into a separate science (S. S. Smirnov, Iu. A. Bilibin, D. I. Shcherbakov, K. I. Satpaev, V. I. Smirnov, Kh. M. Abdullaev, I. G. Magak’ian, E. T. Shatalov, A. G. Levitskii, and V. A. Kuznetsov, the Swedish geologist W. Lindgren, the German geologist G. Schneiderchen, and the Americans C. F. Park and W. H. Emmons). Progress has been made in volcanology (V. I. Vlodavets, B. I. Piip, G. S. Gorshkov, the American geologists H. Williams and A. Rittmann, and the Frenchman H. Tazieff), hydrogeology and hydrogeochemistry (N. F. Pogrebov, N. N. Slavianov, A. N. Semikhatov, F. P. Savarenskii, G. N. Kamenskii, N. I. Tolstikhin, and I. K. Zaitsev), and the geology of Quaternary deposits (G. F. Mirchink, la. S. Edel’shtein, S. A. Iakovlev, V. I. Gromov, A. I. Moskvitin, E. V. Shantser, the German scientist P. Woldstedt, the American R. Flint, and the Swedish geologist G. Geer).

Geochemistry arose in the 20th century as a result of the merging of geology and chemistry. Its principles were formulated by V. I. Vernadskii and the Norwegian geochemist V. M. Goldschmidt and developed in the USSR in the works of A. E. Fersman and A. P. Vinogradov. The enormous role played by the development of life on earth as a factor leading to the formation of organogenic rocks (such as coral reefs and coal) was clarified. It is a factor that substantially changed the composition of the atmosphere and hydrosphere and also directly influenced the course of many geological processes (for example, weathering). In connection with this a special division of geochemistry developed—biogeochemistry, and V. I. Vernadskii proposed the name “biosphere” for the envelope of the earth in which biological processes occur. Geophysics arose as a result of the merging of geology and physics. The appearance and development of geochemistry and geophysics were enormously helpful in the progress of geological research; beginning with the early 1920’s geophysical and geochemical methods became firmly established in such research.

In the past quarter of a century the geology of the sea and ocean floors has been developing intensively, in particular for the purpose of industrial development of the minerals found in the vast area of the continental shelf. In the USSR scientists working in this field of geology include M. V. Klenova, P. L. Bezrukov, A. P. Lisitsyn, and G. B. Udintsev; outside the USSR scientists in this field include the American geologists F. P. Shepard, H. W. Menard, B. Heezen, and M. W. Ewing and the Dutch geologist P. Kuenen. Geophysical methods are used extensively in studying the geology of the sea floor, and in recent years drilling has been done from specially equipped ships.

In the USSR all branches of geology developed swiftly after the Great October Socialist Revolution. During the years of Soviet power the country has been covered by a geological survey on a scale of 1:1,000,000, which was begun on the initiative and under the direction of A. P. Gerasimov, and many regions have been surveyed on a scale of 1:200,000; whereas, before 1917 geological maps, in considerably less detail, were compiled for only 10 percent of the area of Russia. In 1922 and 1925 the first geological maps of the Asiatic part of the USSR were published, and in 1937 the first geological maps of the territory of the USSR as a whole were published. The first geological map of the territory of the USSR without “blank spots” (uninvestigated regions) was published in 1955 on a scale of 1:2,500,000. Its third edition (D. V. Nalivkin, A. P. Markovskii, S. A. Muzylev, and E. T. Shatalov) was published in 1965. A number of special maps have been compiled—for example, geomorphological, paleogeographic, paleotectonic, hydrogeological, hydrogeochemical, and metallogenetic maps as well as maps of coal deposits, oil-bearing and gas-bearing regions, Quaternary deposits, and magmatic formations. Data on the geological structure of the USSR has been generalized in the works of V. A. Obruchev, A. D. Arkhangel’skii, A. N. Mazarovich, and D. V. Nalivkin and also in such multi-volume monographs as Geology of the USSR, Hydrogeology of the USSR, and Stratigraphy of the USSR. The first Soviet textbook on the regional geology of the world (written by A. N. Mazarovich) was published in 1951-52. It gave a general description of the geological structure of all the continents of the globe. The publication of popular scientific literature on geology by such scientists as V. A. Obruchev, A. E. Fersman, and V. A. Varsanof eva was also very important.

In the USSR geological research is planned and organized by the Ministry of Geology of the USSR and the ministries of the Union republics through territorial geological administrations and the geological institutions of other ministries involved in the development of mineral resources and in construction. Scientific research in geology is done by about 80 scientific-research institutes and laboratories of the Ministry of Geology and certain other ministries, the Academy of Sciences of the USSR, and the academies of sciences of the Union republics. A number of scientific geological journals are published in the USSR.

The International Geological Congress, founded in 1875, organizes geological research on an international scale and discusses the most important problems of geology. Since 1967 international research in the periods between sessions of the congress has been directed by the International Union of Geological Sciences.

The main tasks of geology. Because deposits of minerals on the earth’s surface have basically been exhausted, one of the main tasks of modern geology is searching for and exploiting deposits that are not visible from the surface (“concealed” deposits). The search for them can be conducted only with the help of geological prognostication, and this demands the intensified development of all areas of geology. For the territory of the USSR this task was formulated in the Directives of the Twenty-fourth Congress of the CPSU, where they speak of the need “to carry on research in the fields of geology, geophysics, and geochemistry in order to determine the laws governing the location of minerals and increase the effectiveness of methods of exploration, extraction, and concentration” (Directives of the Twenty-fourth Congress of the CPSU on the Five-year Plan of Development for the National Economy of the USSR for 1971-75, 1971, p. 14).

In order to investigate deep-lying zones of the earth and their mineral resources the earth’s crust and upper mantle must be studied by geophysical methods; metamorphic and magmatic formations and their composition, structure, and conditions of formation must be studied as indicators of the state of matter and its transformations; and extremely deep holes must be drilled and Precambrian strata must be examined from the point of view of stratigraphy, tectonics, mineralogy, petrology, and the location of minerals.

In connection with the increased need for nonferrous and rare metals and the necessity of expanding the mineral and raw material base, the problem of using the resources of the seas and oceans has arisen. Therefore, studying the geology of the ocean and sea floor (71 percent of the entire earth’s surface) is one of geology’s urgent tasks. In the past decade work has begun on a detailed study of underground heat as a possible source of energy for the future. In a number of countries (Iceland, Italy, Japan, New Zealand, and on Kamchatka in the USSR) the superheated steam discharged from wells is already being used for heating and to obtain electric energy.

A very important task of geology is continued elaboration of the theory of development of the earth, in particular, investigating the evolution of internal and external geological processes that determine the laws governing the location of mineral resources.

In connection with the successes achieved by space research, the comparative study of the earth and other planets is becoming one of the primary problems of geology.

REFERENCES

History and methodology of the science
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Shatskii, N. S. “Istoriia i metodologiia geologicheskoi nauki.” Izbr. trudy, vol. 4. Moscow, 1965.
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Lomonosov, M. V. O sloiakh zemnykh i drugie raboty po geologii. Moscow-Leningrad, 1949.
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Lyell, C. Osnovnye nachala geologii Hi noveishie izmeneniia zemli i ee obitatelei, vols. 1-2. Moscow, 1866. (Translated from English.)
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Haug, G. E. Geologiia, vol. 1. Edited by A. P. Pavlov. Moscow, 1914. (Translated from French.)
Mushketov, I. V., and D. I. Mushketov. Fizicheskaia geologiia, 4th ed., vol. 1. Leningrad-Moscow, 1935.
Karpinskii, A. P. Sobr. soch., vols. 1-4. Moscow-Leningrad, 1939-49.
Varsanof’ eva, V. A. Proiskhozhdenie i stroenie Zemli. Moscow-Leningrad, 1945.
Arkhangel’skii, A. D. Izbr. trudy, vols. 1-2. Moscow, 1952-54.
Bubnoff, S. N. Osnovnye problemy geologii. Moscow, 1960. (Translated from German.)
Shatskii, N. S. Izbr. trudy, vols. 1-4. Moscow, 1963-65.
Stille, H. Izbr. trudy. Moscow, 1964. (Translated from German.)
Zhukov, M. M., V. I. Slavin, and N. N. Dunaeva. Osnovy geologii. Moscow, 1970.
Gorshkov, G. P., and A. F. Iakushova. Obshchaia geologiia, 2nd ed. Moscow, 1962.
Suess, E. Das Antlitz der Erde, vols. 1-3. Prague-Vienna-Leipzig, 1883-1909.
Fourmarier, P. Principes de géologic, 3rd ed., vols. 1-2. Paris, 1949-50.
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Referativnyi zhurnal: Geologiia. Moscow, 1954-70.

IU. A. KOSYGIN and A. L. IANSHIN

geology

[jē′äl·ə·jē]
(science and technology)
The study or science of the earth, its history, and its life as recorded in the rocks; includes the study of geologic features of an area, such as the geometry of rock formations, weathering and erosion, and sedimentation.

geology

1. the scientific study of the origin, history, structure, and composition of the earth
2. the geological features of a district or country
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http://personal.cmich.edu/~franc1m/homepage.htm
www.earthquakes.bgs.ac.uk
http://nsidc.org/glaciers/information.html
http://pubs.usgs.gov/gip/fossils/