March/April 2007

Economic Geology

The Basalt Controversy II (Part 16)

By R. J. Cathro

"When I returned to Freiberg in 1775, I found the system of the vulcanists, and ... the volcanic origin of basalt, generally accepted. The novelty and interesting features of this theory along with the superior art of persuasion of its defenders and, to a certain extent, the persuasiveness or glamor of the matter itself soon procured for it an unusual number of adherents. ... Until I myself could make observations concerning it, I considered the correctness of the theory to be established. ... In 1776, I visited and observed the most famous Saxon basalt mountain, the one at Stolpen. Here I found not even a trace of volcanic action or the least sign of volcanic origin. Indeed the entire interior structure of the mountain completely proved to the contrary. Now I first dared to maintain publicly and prove that not all basalt, at least, could be of volcanic origin and that the Stolpen basalt, among others, undoubtedly was not. ... After further mature investigation and reflection, I am of the opinion that no basalt is of volcanic origin, but that all of it is of aqueous origin ..." (Werner, 1786).

In addition to the geologists cited within the text, Ashworth (2004), Dean (1998), and an anonymous writer provided valuable background information on Werner.

Abraham Gottlob Werner (1749-1817) had been appointed in 1774, at the age of 25, to teach mining and mineralogy at the Mining Academy (Bergakademie) in Freiberg, where he remained until his death. Located in the heart of the main European metal mining district, the academy had been founded in 1766, after at least 70 years of operation as a trade school. Its main purpose was to train mining engineers, assayers, metallurgists, and mine managers and, as an additional benefit, to expose them to new ideas in the emerging science of geology.

Born in Wehrau in what is now southern Poland, Werner was a childhood mineral collector who was sent to Freiberg to learn how to be an ironworks manager like his father. After short stints with the Saxon mining service and law studies at the University of Leipzig, he became interested in geology, which he called ‘geognosy’ (a comprehensive theory to explain the temporal deposition and structural relations of the earth’s major rock units). The academy position afforded Werner the opportunity to develop into the most influential teacher of mining and geology of his generation; he was often referred to as the ‘father of German geology’ and ‘the father of mineralogy.’ Werner himself had given the latter title to Agricola.

In the words of Lyell (1830-33), “In a few years, a small school of mines, before unheard of in Europe, was raised to the rank of a great university and men already distinguished in science studied the German language, and came from the most distant countries to hear the great oracle of geology.” Dibner (1958) wrote “he imbued the school of mines … with a spirit of investigation and critical analysis of the geological world previously unknown. … His (study) of the rocks of the Harz Mountains established geological classification. He put mining geology on a scientific basis. … (His mineral) collection made Freiberg one of the great mining centres of mining engineering. From the academy issued a steady stream of disciples of Werner.”

Mineralogy was Werner’s primary research interest and he developed a superior descriptive classification system based on mineral composition. He was credited with expanding the mineral collection, of which he was curator, to more than 10,000 specimens and helping create the best library and museum on the subject. In addition, he discovered eight new minerals and named 26 others. His lectures on mineralogy were so popular that he often had to split the class into smaller groups and deliver them several times. Much of his influence was due to his strong personality. Some of his students wrote of his penetrating mind with a rich store of knowledge, and his charm and eloquence that attracted and kindled enthusiasm among his students. Some described him as the most outstanding geologist in Europe, and credited him with elevating geology to the rank of a real science. It is odd that an influential teacher like Werner had a serious aversion to publication, and that most of what is known about his teaching has come from the writings of his students.

In addition to mineralogy, he also gave lectures on mining law and finance, and he and his colleague, J.F.W. Charpentier, were the first geologists to develop the concept of mineral paragenesis. They divided the complex vein mineralogy in the Freiberg camp into 11 groupings based on mineral associations and strike directions (Baumann, 1994). Werner was elected to 22 international scientific societies.

With such an eminent reputation as a mineralogist and teacher, as well as his strong personality, it would be natural to assume that Werner must be one of the principal figures in the history of economic geology. Unfortunately, nothing could be farther from the truth. Werner’s downfall was caused by the use of his vast influence to espouse inaccurate theories on the origin of basalt and mineralized veins. His troubles with basalt began with his 1766 visit to the Stolpen Castle, described earlier, which rests upon and was partly constructed from an exposure of columnar basalt. It is situated in Saxony, about 35 kilometres east of Dresden and 85 kilometres northeast of Freiberg. A subsequent examination of the summit of the Scheibenberg in the Erz Mountains, where basalt is interlayed with greywacke, sandstone, and clay, also led to a sedimentary interpretation for the basalt (Sigurdsson, 1999, p. 117).

The outcrop had also been examined by Agricola, which should qualify it for inclusion on any list of the most historically important outcrops in the world. He gave the name basalt to the Stolpen outcrop because he believed it to be the same rock that Pliny the Elder had called basalt (Pliny’s rock was actually a limestone.) Agricola described the angular columns, up to 0.5 metres thick and 4.3 metres long, in Chapter VII (Marbles and Rocks) of his book De Natura Fossilium (‘Textbook of Mineralogy’) in 1546. There is some evidence to suggest that Agricola didn’t understand that basalt was a volcanic rock, so it is possible that calling the outcrop by the correct name may have been a coincidence.

Incidentally, he dedicated the book to "the illustrious Duke of Saxony and of Thuringia and Misena (a medieval name for Erzgebirge), Prince Maurice." The prince had appointed Agricola as Burgomaster (mayor) of Chemnitz, also in 1546. The book contains this classic sentence: "The philosopher takes pleasure in the contemplation of the nature of these compounds while the miner takes pleasure in the profit and use he obtains from the metals he extracts from them."

Werner, who never travelled far from home and didn’t visit the Auvergne district of France or the Italian volcanoes, arrived at his fateful conclusion about basalt at the same time that the French geologists Guettard, Desmarest, and Lavoisier were demonstrating the link between basalt, volcanoes, heat, and magma, and by inference, the origin of metals (see Part 15). Although his field work at Stolpen has to rank as one of the poorest field interpretations ever made by a prominent geologist, the damage was particularly serious, in this case, because of the number of prominent disciples he had influenced—geologists such as Leopold von Buch, Alexander von Humboldt, Jean d’Aubuisson de Voisins, Frederick Mohs, and Robert Jameson, all born between 1769 and 1774.

Werner’s other serious mistake was in his vigorous support of the ‘universal formation,’ the theory that the world was mantled by rocks that had been deposited as sediment or precipitate from a universal ocean following the ‘Great Deluge.’ Because of his immense prestige, he became the leader of the Neptunists. According to the theory, the cores of the highest mountains, which had reached above the floodwaters, were composed of the oldest rocks: granite, gneiss, and schist. The sediments were laid down in the same sequence around the world, first chemical and clastic sediments and basalt, followed by alluvial material and, finally, lava derived through the melting of other rocks by the combustion of subterranean beds of coal (Merrill, 1969, p. 3). It was believed that all rocks had been laid down in the attitudes in which they were found, unless the dips exceeded 30°. The only positive thing that can be said for the theory was that it was an early attempt to construct a stratigraphic column.

As part of the Neptunist theory, Werner taught that veins were formed as open fissures caused by the compaction of sediments and were then filled through infiltration of surface waters carrying the mineral matter in solution. His principal publication was A New Theory of the Origin of Veins (1791), which was translated into English in 1805. The idea that minerals had descended from the seafloor led to the conclusion that all veins would decrease in grade and thickness and end at a shallow depth (Baumann, 1994). These ideas gained wide acceptance because of his reputation and the support of the church, which believed that they conformed to the book of Genesis. However, Werner was not a biblical geologist who used the authority of the church to reach his conclusions.

From the perspective of economic geology, Werner did not contribute anything useful to the study of the genesis of ore deposits, and history has not been kind to him. Only his mineralogical research was of original or lasting quality.

The first serious challenge to Werner’s reputation came from Lyell (1830-33), who criticized his poor publication record, his lack of travel, his universal formation theory, and his retrograde influence on the science. A summary and critique of recent efforts by A.M. Ospovat, emeritus professor of the History of Science at the University of Oklahoma, to emphasize Werner’s other contributions and resurrect his reputation is provided by S¸engör (2002).In the words of Garrison (1913), “It has been assumed for years that Werner was the father of our modern theories of ore deposition. Although Werner had the advantage of writing two hundred and forty years later, Agricola’s observations and deductions are sounder and more in harmony with modern views. In fact, it seems that the theories regarding ore deposition not only failed to improve in the long interval of the nineteenth century, but they actually retrograded, and the student’s mind was filled with rubbish which would have been repudiated by Agricola.” Pos¢epn´y (1893) stated it more diplomatically: “As for the manner in which fissures have been filled, Werner’s theory, based upon a comparatively limited field of observation, has, like many of his neptunistic views, failed to maintain itself.” James Kemp (1920) called his ideas “quaint and curious.”

Abraham Werner serves as a classic example of how dangerous an influential but dogmatic scientist can be without adequate field testing and peer review. Although he was a great pioneer mineralogist and classifier of data, his reputation as a scientist was gravely damaged by his tendency to make the field evidence conform to his preconceived theories.

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