Geology Atoms are formed
13,7 Mil
Date of the most ancient rocks found on earth (excluding meteorite rocks)
4.5 Mil
+200 sec.
Big Bang
290 Mil
3,9 Mil
Solar system is formed
Pangea is formed
The Mont Blanc massif is found on the Cenzoic Orogenic belt of mountain chains which stretches all the way to the Himalayan Alps. The Alps arose from the collision of the African and Eurasian tectonic plate, that exerted huge force on the Alpine Tethys basin that spread from East to West and which in the geological era between the Permian and the Miocene, separated Northern Africa and Asia. The huge amount of force generated was dispersed with the rise of the Eurasian plate on top of the African plate, sending it into subduction and leading to the formation of the Alps. In an initial phase of this process, around 280 million years ago, there occurred an initial orogenic phase that led to the formation of a smaller chain of geological features: this phase is of great interest when studying and understanding the lithotypes that are later involved in the Alpine orogeny. In this phase the movement of the two plates, thanks to the heat generated by the friction, allowed for the formation of magma that went on to create a pluton of significant proportions and a depth of around 20km. This pluton, both due to its large size and the isolating effect of the rocks in which it was enclosed, was subject to a slow and constant cooling process that allowed for the crystal lattices to develop in an orderly fashion. This in turn led to the creation of large and medium sized structures. In fact, this is clearly noticeable for us climbers, whereby the size of the crystals found on the Mont Blanc’s granite gain in size as we get closer and closer to the central part of the massif. This is because of the reduced heat dispersion and the slower cooling that characterised the central and more internal parts of the pluton. Once this intrusive phase was complete, the mass of cooling magma was subject to a significant
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