August 2011

Economic Geology

The foundations of modern economic geology (Part 5)

By R. J. (Bob) Cathro

Recognition of the need for serious study of the origin of metallic mineral deposits became apparent from 1893 to 1903, especially after two classic papers appeared in 1883: the first published by the Norwegian geologist Johan H. L. Vogt and the other delivered by Franz Pošepný at the American Institute of Mining Engineers meeting in Chicago. Vogt’s paper was a thoughtful discussion on injected igneous deposits derived from an igneous source by the process of magmatic differentiation, which was also proposed as the source of hot mineralizing waters. The Pošepný paper, which was discussed in the previous article in this series, was titled “The Genesis of Ore Deposits.”

The two papers had a profound impact on American geological thinking and stimulated a heated and controversial discussion until 1903 between leading figures such as Samuel F. Emmons, Charles Van Hise, John F. Kemp, Swedish-born Waldemar Lindgren and W. H. Weed. The disagreement centred on the respective importance of heated meteoric waters versus hot juvenile waters in the genesis of ore deposits. At the same time, Emmons, Van Hise and Weed proposed the concept of secondary sulphide enrichment.

The geological sciences, like all branches of science and engineering, began to expand rapidly at the turn of the century because of the growth in scientific research. Geologists also found it necessary to establish separate specialties such as petrology, stratigraphy and paleontology. It became clear that a journal devoted to economic geology was needed in the English language. The first significant effort to establish such a scientific journal took place in 1905 at the offices of the United States Geological Survey (USGS) in Washington, D.C. A circular letter sent out on May 31 inviting people to subscribe included the following statement:

“The new Journal ... will be devoted primarily to the broad application of geological principles to mineral deposits of economic value, to the scientific description of such deposits, and particularly to the chemical, physical and structural problems bearing upon their genesis. (The Journal) will not be directly concerned ... with the engineering and commercial aspects of mining, as these subjects now find ample representation in the technical mining journals. It is the intention of the founders to make the Journal cosmopolitan in scope and scientific in spirit. Its pages will be open to all contributors whose papers fulfill the requisite conditions of merit and appropriateness, and the policy of the company with regard to author’s reprints will be unusually liberal. It is believed that the new Journal will be found invaluable by economic geologists, by mining engineers, (who, as a class, follow with keen interest the bearing of geological problems upon their profession), and by teachers of mining geology.”

Thus was born the most influential international scientific journal on the subject of economic geology. It was started by a group of predominantly American-born and American-educated geologists, most of whom worked for the USGS, including some who taught at the leading universities and worked part time for the survey during the summers. Unlike most scientific journals, this one did not have a sponsoring society; it was funded personally by the founding shareholders of the Economic Geology Publishing Company. Yale University provided office space and other aid. Not surprisingly, the financial situation was difficult in the early years.

The first editor of the journal was John D. Irving, who moved from the USGS to Yale in 1906. The members of the first executive committee were all drawn from the USGS: H. Foster Bain, Frederick C. Ransome, George O. Smith, Josiah E. Spurr and Walter H. Weed. The associate editors were Frank D. Adams (McGill), Marius R. Campbell (USGS), John W. Gregory (Glasgow), James F. Kemp (Columbia), Charles K. Leith (Wisconsin), Waldemar Lindgren (MIT) and Heinrich Ries (Cornell).

Later that year, the new journal absorbed an existing journal, The American Geologist, owned by the family of consulting geologist Horace V. Winchell. In 1910, Lindgren was elected president of the Publishing Company, a position he held until his death in 1939. Lindgren was one of the most prolific contributing authors and supporters of the new journal and a giant in the science. Andrew C. Lawson became the associate editor and Campbell, Samuel F. Emmons (USGS), Willett G. Miller (Ontario Bureau of Mines), Richard Reck (Freiberg) and H. V. Winchell became associate editors, followed by Frederick H. Hatch and Ralph Arnold (USGS) in 1915.

Andrew Lawson, who was born in Scotland in 1861, moved to Hamilton, Ontario, when he was eight years old. After receiving his first two geology degrees from the University of Toronto, he was awarded a PhD from Johns Hopkins University in 1888, the first Geological Survey of Canada (GSC) field officer to earn one (Zaslow, 1975). Lawson conducted important field mapping in western Ontario for the GSC from 1894 to 1990 before moving to the University of California (Berkeley), where he remained until his death in 1952. Among his many noteworthy accomplishments was the preparation of the official geological report on the San Francisco earthquake of 1906.

John D. Irving took a leave of absence in 1916 to become an engineering officer in the U.S. Army during World War I and died on duty in France in July 1918. Alan M. Bateman, who also taught at Yale, succeeded him and remained editor until after 1955.

In 1920, another organization was formed – the Society of Economic Geologists (SEG) – which originated from a 1919 gathering of a group of Geological Society of America members who were especially interested in economic geology. It held annual meetings at which papers were presented, but had no publication arm. In early 1922, the two organizations began to cooperate and by 1930, an arrangement was in place under which the journal published those SEG papers that it deemed worthy. The SEG provided financial assistance that alleviated the problems of the Publishing Company.

The geographic distribution of journal subscribers between 1913 and 1954 is quite informative: U.S. geologists made up 66 to 69 per cent until 1920, but gradually dropped to 54 per cent by 1954; Japanese subscribers were the largest foreign group until 1930, before dropping to between second and seventh; Canadians were consistently in second place until they replaced the Japanese in first; and the remainder of the top ten were usually British, German, Australian, Mexican, South African, Indian, Russian, Dutch, Chinese and other Europeans.

A review by Bateman of the 42,000 pages in the first 50 volumes provided a chronology of the major research topics studied during the period, such as theories of ore deposit genesis and geologic processes.

Magmatic deposits

Discussions of the magmatic versus hydrothermal origin of the Sudbury, Ontario, nickel-copper-PGE ores began in the first volume and the controversy continued throughout the first 50 years. Similarly, the development of ideas regarding the magmatic origin of titaniferous magnetite deposits in basic igneous rocks in Norway received serious discussion. Segregation by early crystallization was the prevailing concept in 1905, but over the years, theories such as magmatic differentiation through crystallization, liquid immiscibility, filter pressing, metasomatism, chemical reactions, late gravitative liquid settling, consolidation in situ, ore magmas and vein dykes were presented.

Contact metasomatic (skarn) deposits

These deposits and their formative process were first recognized in Europe in the 1860s and 1870s and in the United States in 1889. Lindgren’s description of them in the Clifton-Morenci porphyry district in Arizona in 1905 stimulated more intensive exploration and investigation. Papers in the journal discussed the importance of contacts between intrusive rocks and limestone, skarn mineralogy, additive materials, high ferric oxide content and geochemistry of the process.

Metasomatic replacement deposits

This process was first recognized at Leadville, Colorado, by S. F. Emmons and J. D. Irving, who found large unsupported nuclei of limestone within the massive sulphide ore. Two major papers by Irving and Lindgren in Volume 7 summarized theories on the origin of these deposits. The concept of replacement became widely accepted in the United States and slowly spread to Europe.

Ore-forming fluids

Volumes 1 and 2 contained many papers supporting the two most popular theories: 1) that mineralizing fluids were meteoric waters that dissolved metals, sank into hotter zones and returned upward to deposit their metallic load; and 2) that the fluids had a magmatic source. This controversy continued to receive serious research and heated debate throughout the first 50 years as various ideas were presented that some deposits were “sedimentary” while others were “igneous”; that magmatic differentiation produced mineralizing solutions, dykes and veins as end differentiates; and the question of alkaline versus acid solutions. In 1935, Lindgren wrote that most types of deposits were formed from magmatic waters, but that a mixture of magmatic and meteoric waters had formed the Mississippi Valley-type of lead-zinc deposits.

Hydrothermal alteration

Reports on wall-rock alteration accompanying mineralization appeared throughout the first 50 volumes. The earliest descriptions dealt with propylitic alteration and greisenisation of tin veins. Several papers dealt with widespread sericitic alteration that accompanied porphyry copper mineralization, and the covering mantle of kaolin alteration that accompanied secondary sulphide enrichment and died out downward with diminishing secondary sulphides. Other studies dealt with dolomitization and ore deposition, the sericitic and chloritic alteration of Ontario gold deposits, and the formation of spotted “dalmationite” (cordierite and brown mica) at the Amulet Mine in Quebec. An important paper in 1935 described three concentric phases of alteration at the Cerro de Pasco Mine in Peru that comprised a proximal acidic phase of quartz-pyrite-dickite-alunite, grading outward to a moderate and abundant sericite-pyrite-quartz type, and surrounded by a feeble and distant phase of chlorite, calcite and epidote. With the development of techniques like X-rays, differential thermal analyses and the micron microscope, identification of the clay minerals became more precise and a new group of papers on them appeared after 1941. Studies at Ajo Arizona and other porphyry copper deposits, East Tintic Utah, Wairukei New Zealand, and many other localities identified similar concentric alteration zoning with up to four recognizable phases.


This branch of the science was barely mentioned in the early years. A long review article on hydrothermal alteration and syntheses of silicates, published as a special supplement in 1937, gave chronological coverage of the entire subject. It stimulated renewed interest and resulted in an increasing number of papers on geochemistry. The first paper dealing with stable isotopes was published in 1953. The advances in geochemical knowledge stimulated practical investigations of trace elements and led to a new tool known as applied geochemistry, or geochemical exploration. Investigations of metals in soil and vegetation, and new and rapid techniques and reagents for field testing of trace metals were discussed in papers from 1947 onwards.

Skinner (1981) pointed out that the emphasis in the journal had always remained on mineral deposits, but not on all deposits. Those of special interest were those containing the ore minerals that find uses in the technological society. Petroleum geologists were not included initially since no such branch of geology existed prior to the formation of the American Association of Petroleum Geologists in 1920. Economic Geology was the preferred publication for early important papers on petroleum geology, ground water and coal until specialized journals appeared to serve those topics.

The journal continues to focus on metallic and non-metallic mineral deposits and the fascinating evolution of ideas concerning how, where and when the different types are formed. During the 25 years between Volumes 50 and 75, another 35,000 pages were published, amounting to more words and papers than in the first 50 because of a larger page size. The reasons for the rapid growth in research included the increasing use of laboratory techniques to investigate the chemistry of rock types, wall-rock alteration and ore mineral assemblages. Other major advances were radiometric dating, experimental geochemistry, better understanding of plate tectonics and refinements to mass spectrometers that enabled improved isotopic studies and better information on fluid chemistry. Also, increased exploration led to the recognition of classes of deposits that were not previously known.

The Journal of Economic Geology has gradually become such an important international influence in the English language that researchers around the world now strive to meet the high standards of peer review to have their papers accepted for publication. In 1981, the journal had about 8,000 subscribers around the globe. In 1955, the comparable number was 4,000 in 80 countries.


Information on the Journal of Economic Geology was derived largely from Bateman (1955) and Skinner (1981).


Bateman, A. M. (1955). Economic Geology. Fiftieth Anniversary Volume, Economic Geology: 1905-1955. Lancaster, Pennsylvania: The Economic Geology Publishing Company, p. 1-30.

Skinner, B. J. (1981). Introduction. Seventy-Fifth Anniversary Volume, Economic Geology: 1905-1980. Lancaster, Pennsylvania: The Economic Geology Publishing Company, p. 3-5.

Zaslow, M. (1975). Reading the rocks: the story of the geological survey of Canada, 1842-1972. Toronto: The Macmillan Company of Canada Limited, p. 132

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