Interesting facts 

Eiger, Mönch and Jungfrau – not at all the same

Of all European capitals, Bern surely enjoys the most spectacular panorama. On clear days the high peaks of the Bernese Alps stand out in a row across the sky. There is nothing quite like the sight of the mountains of the northern border of the UNESCO Swiss Alps Jungfrau-Aletsch World Heritage site, like a surging billow of rugged limestone summits.

 

The Eiger, Mönch and Jungfrau – the most famous peaks of the Bernese Oberland – are often mentioned in the same breath. But from a geological point of view the group is by no means uniform. The three mountains are part of the zone on the northern edge of the Aar massif where the brown gneisses of the old crystalline rock overlap with the grey jurassic limestone. One piece of the old crystalline gneiss slid over the limestones during the formation of the Alps. As a result, these became deeply wedged into the old crystalline rock. This is known to geologists as the Jungfrau Wedge. 

The most dramatic view of the triumvirate can be seen from the Männlichen. The lower cliffs of the Jungfrau consist of horizontal strata of grey Jurassic limestone. The summit wall, consisting of overturned gneisses from the old crystalline block, is of quite a different structure and colour with its vertical gullies. The striking horizontal line beneath the triangle of the summit is a fault line within the old crystalline rock. The situation is similar on the Mönch. But the Eiger is quite different, consisting wholly of folded Jurassic limestone. That means the tunnel of the Jungfrau railway goes almost entirely through Jurassic limestone. It is only at the final Jungfraujoch station that the gneiss starts again.