Torbern Olaf Bergman

History of Geology
James S. Aber

Born: 20 March 1735, Katrineberg, Sweden.
Died: 8 July 1784, Medevi, Sweden.

Table of Contents
Abstract Introduction
Major works Scientific connections
Historical assessment Related websites

Abstract

Bergman is best known in the fields of mineralogy and analytical chemistry. He also was an early "Neptunist" and developed a classification of rocks quite similar to the famous scheme by Werner. Little is known of Bergman's early life or family. He was a student at the University of Uppsala under Linnaeus and earned a Ph.D. degree in 1758. In 1767 he became Professor of Chemistry at Uppsala, where he was a celebrated teacher. Bergman is often regarded as the "founder of quantitative analysis."

Bergman's major research was on the chemistry of metals, particularly nickel and bismuth. He also developed a mineral classification scheme based on chemical characteristics. His most important geological work is Physisk beskrifning ofvert jordklotet (Physical description of the Earth), published in Swedish in 1766. Subsequently translated into several languages, but not English, this work had considerable contemporary influence. With regard to the age and origin of rock strata, Bergman identified four major classes: uråldrige (primative), flolägrige (bedded), hopvräkta (swept-together), and vulkaner (volcanic). He also recognized the organic origin of fossils and appreciated the information they could supply about earth history. This work was an important step in the emergence of geology as a scientific discipline during the 18th century.

Introduction

Bergman is best known as an analytical chemist, mineralogist and astronomer. He also developed a classification of rocks that Werner made famous. Little is known about Bergman's early life or family. He was educated at the University of Uppsala, where he was a student of Linneaus, who devised the modern system of biological classification. Bergman received a Ph.D. degree in 1758. He taught physics and mathematics as a lecturer at the University of Uppsala for a few years, and in 1767 he was promoted to professor of chemistry, a life-long position. He was known as a celebrated teacher and is regarded as the "father of quantitative analysis."

Major works

Bergman's major research involved the chemistry of metals--nickel and bismuth in particular. He developed a classification of minerals in which main divisions are based on chemical characteristics with subdivisions on external forms. This is quite similar to modern mineral classsification, such as sulfides, oxides, silicates, etc. His work in geology is much less known, but had considerable influence. Most important is Physick Beskrifning Ofver Jordklotet (1766) or "Physical description of the Earth," which was published in Swedish (not Latin). It was later translated into Danish, German and Russian, but not English.

Physick Beskrifning was primarily a review and appraisal of the contemporary status of geology, particularly stratigraphy. Few new observations or theories were presented. It represents the threshold of geology emerging as a distinct scientific discipline. Bergman reached the opinions (similar to Steno) that all rocks were deposited from fluid, that the whole Earth had once been covered by water, and that different strata resulted from local variations in water composition. With regard to the age and origin of strata, he defined four rock classes.

  1. Uråldrige (primitive) – innermost layer of earth, dates from origin of the Earth. Forms the cores of mountains and is a solid continuous mass, below which is magnetic. Poorly bedded, often cut by veins and dikes, contains no fossils. Deposition from solution or fine suspension, variations reflect local differences in water composition and mixing of waters.

  2. Flolägrige (bedded) – stratified rocks flanking and covering primitive rocks. Limestone, sandstone, shale, coal, etc. Deposited from suspension, usually horizontal or only gently tilted. Fossils often abundant proving a marine origin. Largely derived from submarine erosion of primitive rocks.

  3. Hopvräkta (swept-together) – Deposits of shallow and restricted water bodies, streams and lakes. Less regular and continuous. On top of (younger than) primitive or bedded rocks.

  4. Vulkaner (volcanic) – piling up of ash, stones and lava material erupted through activity of Earth's internal fire. Also relatively young class of rocks.

Bergman recognized the importance of stratigraphy and correlation of rocks. He reviewed the stratigraphy of southern Sweden that had been worked out by Linneaus. He also reviewed rock stratigraphy from Germany, which emphasized the continuity of beds and sequences. Bergman recognized the organic origin and importance of fossils.

They [fossils] are actually medallions of a sort, which were laid down on the originating earth surface, whose layers are archives older than all annals, and which appropriately investigated give much light on the natural history of this our dwelling place.

Bergman took an ambivalent position regarding the bibical deluge. The effects of the deluge, he thought, were wholly superficial, as no primitive or bedded rocks were originated or modified. Some swept-together rocks and fossils might be attributed to the deluge, however, he believed.

Scientific connections

Bergman's ideas owe much to Linnaeus and Lehmann (German). Lehmann had earlier referred to "Uranfängliche" and "Flötzgebirge" rock classes. Perhaps these terms were common at the time. Lehmann, however, attributed Flötzgebirge rocks to the deluge. There is no question that Werner's famous classification was drawn from Bergman, although Werner later changed Uranfängliche Gebirge to Urgebirge and added the transition class Ubergangs Gebirge.

Early geologic time scales.

Note: The term "ur" refers to a watch or clock in Scandinavian languages. It also means primitive, primordial or primeval. It still appears today as a prefix, such as "urberg" (meaning Precambrian) on Swedish geological maps.

Historical assessment

Werner freely acknowledged Bergman's work and lavished praise on the cool-blooded, sharp-minded, great Bergman. Bergman is also thought to have had considerable influence on the somewhat later work of James Hutton. Although little known today, Physick Beskrifning was well known and widely distributed during the 18th century. It represents an important step in the emergence of geology as a science.

Related websites


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