The Mont Blanc massif consists predominantly of ancient granite rocks.
The Alps have their origins 770 million years ago when upheaval of the earth's crust lifted up schist, gneiss and limestone rocks.
These were destined to form the base of the Alps range, and this period of upheaval ended 300 million years ago.
Granite intrusions and associated metamorphic rocks formed the base of the mountains we now call the Mont Blanc massif as well as the nearby Aiguilles Rouges.
But these rocks were then heavily eroded away,  eventually being ground down and inundated by the sea, so allowing sedimentary rocks to form.
Then, once again, this part of the earth's crust was uplifted as a result of the collision of continental plates.
The huge mountain ranges of today's Alps began to form.
This happened towards the end of the Tertiary period, 15 million years ago.
Finally, came the Quaternary era, when successive ice ages saw vast glaciers advance, retreat, and then advance again.
Their movement across the landscape ground down and shaped the mountains and the valleys we see today.

Both the Mont Blanc massif, and the Aiguilles Rouges range to its north, now form part of the external zone of the Alps, effectively being the outermost layers of rock.
The central granites make up Mont Blanc, the steep slopes of the Drus, the Grandes Jorasses and the Dent du Géant, and at the highest points are topped by schists, which are visible in places such as Grands Montets and near Mont Blanc's summit.

The granite mountains around Chamonix have been eroded into steep needle-shaped peaks (known as aiguilles).
Known locally as protogine, these rocks are lower in the mineral biotite mica and richer in quartz than the granites commonly found elsewhere.

A large part of the massif is covered by ice fields and is cut by numerous glaciers, mostly flowing northwestwards on the French side; southeastwards on the Italian side and eastwards on the Swiss side.
With much steeper slopes on the Italian side, many glaciers drop very sharply and some, such as the Miage Glacier and the Brenva Glacier, are very heavily covered in rock debris.
The massif is itself defined by broad valleys which formed along fault lines and which have subsequently been shaped by ice during the last glacial period of the ice age.

During the mid-19th century the granite of the Mont Blanc massif was an important source of stone for buildings; one hundred Italian stonemasons were brought to the Chamonix valley by Charles Albert of Sardinia for reconstructing the towns of Sallanches and Cluses, both of which had at that time just been destroyed by fires.
The Mont Blanc massif consists predominantly of ancient granite rocks. The Alps have their origins 770 million years ago when upheaval of the earth's crust lifted up schist, gneiss and limestone rocks. These were destined to form the base of the Alps range, and this period of upheaval ended 300 million years ago. Granite intrusions and associated metamorphic rocks formed the base of the mountains we now call the Mont Blanc massif as well as the nearby Aiguilles Rouges. But these rocks were then heavily eroded away,  eventually being ground down and inundated by the sea, so allowing sedimentary rocks to form. Then, once again, this part of the earth's crust was uplifted as a result of the collision of continental plates. The huge mountain ranges of today's Alps began to form. This happened towards the end of the Tertiary period, 15 million years ago. Finally, came the Quaternary era, when successive ice ages saw vast glaciers advance, retreat, and then advance again. Their movement across the landscape ground down and shaped the mountains and the valleys we see today.
Both the Mont Blanc massif, and the Aiguilles Rouges range to its north, now form part of the external zone of the Alps, effectively being the outermost layers of rock. The central granites make up Mont Blanc, the steep slopes of the Drus, the Grandes Jorasses and the Dent du Géant, and at the highest points are topped by schists, which are visible in places such as Grands Montets and near Mont Blanc's summit.
The granite mountains around Chamonix have been eroded into steep needle-shaped peaks (known as aiguilles). Known locally as protogine, these rocks are lower in the mineral biotite mica and richer in quartz than the granites commonly found elsewhere.
A large part of the massif is covered by ice fields and is cut by numerous glaciers, mostly flowing northwestwards on the French side; southeastwards on the Italian side and eastwards on the Swiss side. With much steeper slopes on the Italian side, many glaciers drop very sharply and some, such as the Miage Glacier and the Brenva Glacier, are very heavily covered in rock debris. The massif is itself defined by broad valleys which formed along fault lines and which have subsequently been shaped by ice during the last glacial period of the ice age.
During the mid-19th century the granite of the Mont Blanc massif was an important source of stone for buildings; one hundred Italian stonemasons were brought to the Chamonix valley by Charles Albert of Sardinia for reconstructing the towns of Sallanches and Cluses, both of which had at that time just been destroyed by fires.
Mont Blanc massif