Ice Ages

Louis Agassiz was the first person to hypothesize that the Earth was once subject to an ice age. He proposed this hypothesis to the Helvetic Society in 1837 and garnered much attention. His hypothesis was as follows: ancient glaciers had not only encroached farther south than the Alps, but had in fact, reached southern Europe, Asia, and North America which led to an “ice age”. Other notable individuals that also studied this were Johann Wolfgang von Goethe, Horace-Benedict de Saussure, Ignaz Venetz-Sitten, Jean de Charpentier, Karl Friedrich Schimper, and others. Not to downplay the influence of these great figures, it is important to state their contributions to society.

  1. Johann Wolfgang von Goethe: A German writer and statesman whose literary work numbers in the thousands. Although he is primarily remembered for his epic poems, he held great fascination with the natural world. It is said that by the time of his death, in order to gain a comprehensive view of geology, he had collected roughly 17,800 rock samples.
  2. Horace-Benedict de Saussure: A Swiss geologist, meteorologist, physicist, alpine explorer. He is often cited as the father of alpinism and modern meteorology. In terms of geology, he studied the Alps with much enthusiasm.
  3. Ignaz Venetz-Sitten: One of the first scientists to recognize glaciers as a moving force in the Earth. Alongside Louis Agassiz, he played a great role in the founding of glaciology.
  4. Jean de Charpentier: A German-Swiss geologist who studied Swiss glaciers. Using evidence of glacial erratics and the work of Goethe, he hypothesized that glaciers were once much more extensive. His ideas were later taken up and developed by Louis Agassiz.
  5. Karl Friedrich Schimper: A German naturalist, botanist, and poet who is best known as the theory of prehistoric hot and cold eras. Alongside Louis Agassiz, he initiated modern theories on ice ages and climate cycles.

Goethe, Charpentier, and Schimper in particular were instrumental in understanding that erratics were moved by glaciers. For those unaware, a glacial erratic is a type of rock that differs in size and composition from rocks in the area of deposition. They are the result of glacial transport from another geologic area. The existence of theses erratics in Agassiz’s field area was instrumental in refining the theory of an ice age. Agassiz made multiple trips with both Charpentier and Schimper to alpine valleys to study these erratics. Agassiz even constructed a hut, the Hotel des Neuchatelois, upon one of the Aars Glaciers, a system of glaciers located on the Aare River in the Bernese Alps, to investigate glacial movement.

In his book, “La théorie des glaces et ses progrès les plus récents” (The theory of glaciers and their most recent progress), Agassiz explains his thought processes regarding erratics through the following statement: While a glacier is moving, it rubs and wears down the bottom on which it moves, scrapes its surface (now smooth), triturates the broken-off material that is found between the ice and the rock, pulverizes or reduces it to a clayey paste, rounds angular blocks that resist its pressure, and polishes those having a larger surface. At the surface of the glacier, other processes occur. Fragments of rocks that are broken-off from the neighboring walls and fall on the ice, remain there or can be transported to the sides; they advance in this way on the top of the glacier, without moving or rubbing against each other … and arrive at the extremity of the glacier with their angles, sharp edges, and their uneven surfaces intact”. Agassiz explains our current understanding of glacial theory quite succinctly and also explains how he used glacial erratics to compile his hypothesis about global ice ages.

All of this work led to the publication of Études sur les glaciers (Studies on glaciers), a two-volume work that discussed the movement of glaciers, formation of moraines, and the production of glacial striations. While accepting the ideas of Charpentier and Schimper that the alpine glaciers had once extended to the Aars and Rhone River, he went one step further, stating that the glacier swept over all of southeastern Switzerland until it reached the the slopes of the Jura Mountains. This put into motion glacial studies all over the world.

Agassiz also held theories on mass extinction. In 1866, he stated thus: “The gigantic quadrupeds, the Mastodons, Elephants, Tigers, Lions, Hyenas, Bears, whose remains are found in Europe from its southern promontories to the northernmost limits of Siberia and Scandinavia…may indeed be said to have possessed the earth in those days. But their reign was over. A sudden intense winter, that was also to last for ages, fell upon our globe; it spread over the very countries where these tropical animals had their homes, and so suddenly did it come upon them that they were embalmed beneath masses of snow and ice, without time even for the decay which follows death”. He determined that an ice age acted as a mass extinction event, which was an unknown topic at the time. Of course, this is incorrect, as these mammals were creatures of the ice age as opposed to being killed off by it.

Armed with knowledge of glacial motion, Agassiz visited Scotland with his friend William Buckland, where they scoured the land to find evidence of glacial action. Soon after, the culmination of Agassiz’s work was presented to the Geological Society of London bringing to the forefront the study of glaciology.