Wednesday, 30 June 2010
Geology in action in the Lauterbrunnen Valley
We walked along the beautiful Lauterbrunnen Valley this morning. It is little wonder that, only 50 years ago, geologists had little idea of how the Alps were formed, or of the mess which is their geology. The thick beds of Jurassic limestone were deposited as calcareous mud around 140 million years ago, and the Alps began to form about 35 million years ago, when the African tectonic plate forced its way into the more stable tectonic plates of Europe and Asia. These mighty tectonic forces twisted and contorted the rocks, which have been exposed in the steep walls of the valley, which were carved out by glacial action during the last ice age.
It is a valley of 72 waterfalls, falling from the 1500 ft walls, the most famous being the Trummelbach Falls, which are fed by 10 glacial waterfalls inside the mountain. The Trummelbach drains the glaciers of the Eiger, Monch and Jungfrau mountains and carries 20,200 tonnes of eroded sediment per year.
It is thought that the Alps are still forming, the rate of erosion roughly being balanced by the rate of formation, but eventually, as with all mountain regions, they will disappear, and new ranges will take their place.
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50 years ago geologists had a very good idea of how the Alps were formed! Next time you are in the area visit the museum in Lauterbrunnen.
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