Throwback Thursday: The Father of Glaciology
This is Louis Agassiz. He was a Swiss biologist and geologist in the 19th century. His biggest claim to fame was that he was the first to propose a global ice age.
In 1837, he presented the idea that the glaciers in the Alps had once been larger and had covered not only the mountains, but the plains of Europe, Asia and North America as well. Along with William Buckland, he searched the British Isles for evidence and came back pretty satisfied.
What kinds of evidence are there that glaciers once covered the northern hemisphere? They left huge marks on the surface of the earth.
Moraines: huge piles of loose rock and debris pushed ahead and off the sides of a glacier. Above is a lateral moraine in eastern Oregon.
Horn: a pyramidal peak created by glaciers on all sides. The top photo is in Big Cottonwood Canyon in the Wasatch Range. The bottom is on the Beartooth Highway in Wyoming.
Cirque: a bowl-shaped depression where mountain glaciers start their life. This is a shallow one on the Wasatch Front near Draper.
U-shaped Valley: pretty self-explanatory. This is Blackmore Valley in the Gallatin Range of Montana.
Arete: a sharp ridge created by ice passing on both sides. Absaroka Range, MT
Tarn Lake: water that fills a cirque. Absaroka Range, Wyoming.
Kettle Ponds: ponds left behind from melting glaciers. Top photo: Wyoming Mountains from a plane. Bottom: Beartooth Range
Proglacial Lake: a lake caused by damming of a moraine or ice sheet. This is Jenny Lake in Grand Teton National Park.
Drumlin: a large hill of sediment deposited by the bottom of a glacier.
Striations: gouges left in rock by a passing glacier
And so much more. Once you start to see the remnants of glaciers, you'll never stop seeing them. Just like Agassiz.
Tune in tomorrow to learn about an extinct group of Ordovician fishes. Fossilize you later!
