Exploration Insights Great Geos ebook | Page 54

The Aare Glacier in the Swiss Bernese Alps, location of some of Agassiz’s early research into glacial phenomena. presence in the geological past. The glaciers of the Swiss Alps were a subject of increasing scientific interest by the late 1830s. Jean de Charpentier and Karl Schimper, and even James Hutton had already arrived at the conclusion that the erratic blocks of Alpine rocks scattered over the slopes of the Jura Mountains had been transported there by glaciers. Agassiz went further. In 1837, he gave a lecture to the Swiss Society of Natural History, in which he envisaged that an ice sheet had smothered the entire northern hemisphere in a prolonged ice age. The reaction was mostly skeptical — some of his harshest critics suggesting that he should concentrate on fossil fish rather than getting involved in subjects he knew little about. This was not entirely surprising, as Agassiz offered little explanation as to why glacial expansion had occurred. Indeed, at the time, his concept of an ice age could be described as a theory looking for both convincing evidence and a driving mechanism. But Agassiz was undeterred. With typical energy, he conducted research at the “Hôtel des Neuchâtelois” and published a two-volume work in 1840, entitled Études sur les glaciers (“Studies on Glaciers”). In it, he discussed the movements of glaciers, the moraines they produce and how evidence for their movement can be seen in the grooves and striations made in rocks over which ice has travelled. Such observations were brought to bear on the geomorphology of Scotland, Wales and parts of England in a tour Agassiz made with William Buckland in 1840. Agassiz hoped to win over the major name in geology of the time, Charles Lyell.However, the great uniformitarianist was hard to persuade. A phenomenon like an ice age sat ill against Lyell’s view that global processes operating today were the same as those in the geological past. Other great geologists of the time also remained cool on the subject of ice ages. Roderick Murchison repeatedly dismissed “ice-mad geologists” in lectures at the Geological Society. Nonetheless, many others were convinced by the growing evidence for a major widespread glaciation. Buckland made the following entry into the visitors book of the Goat Hotel, Beddgelert in North Wales in 1841: “Notice to geologists – At Pont-aber-glass-llyn…see a good example of the furrows, flutings and striae on rounded and polished surface of the rock, which Agassiz refers to the action of glaciers. See many similar effects on the left, or south-west, side of the pass of Llanberis”. Suddenly, the evidence for glaciation was being seen where it had previously been ignored. More than just gathering evidence, scientists began to speculate on the wider effects of such glaciation — changing sea-level and isostatic rebound after the glacial ice melted. By the late 19th century, geologists such as