The Matterhorn, a prominent peak straddling the border between Switzerland and Italy, is an unmistakable symbol of the Alps. Its distinct pyramidal form, with four steep faces, resulted from immense geological processes spanning millions of years.
The Ancient Landscape and Tectonic Beginnings
The story of the Matterhorn begins hundreds of millions of years ago, long before the mountain itself existed. Approximately 200 million years ago, the supercontinent Pangaea started to break apart. This continental separation formed two major landmasses: Laurasia (future Europe) to the north, and Gondwana (future Africa) to the south. Between them, the Tethys Sea began to open.
Over geological time, sedimentary rocks and oceanic crust accumulated on the Tethys floor, later becoming part of the Alpine range. The rocks forming the Matterhorn’s summit originated from the African tectonic plate.
Around 100 million years ago, the Tethys Ocean ceased expanding. The Apulian plate, a fragment from Gondwana, began its slow movement northward towards the European continent, initiating the gradual closure of the western Tethys and setting the stage for mountain-building events.
The Alpine Orogeny and Nappe Formation
The Matterhorn’s creation resulted from the collision between the northward-moving African tectonic plate and the Eurasian plate. This prolonged continental collision, known as the Alpine Orogeny, shaped much of southern Europe.
As the two massive plates converged, compressive forces caused the Earth’s crust to crumple, fold, and fracture, resulting in uplift and complex structures.
During this collision, large sections of the crust detached and thrust over one another, forming vast, overturned folds called “nappes.” These rock layers, some tens of kilometers thick, were pushed significant distances, often with older rocks overriding younger ones.
The Matterhorn is primarily composed of gneiss and granodiorite, rocks from the Dent Blanche nappe. This nappe consists of rocks that originated from the African continental plate. These rocks were thrust northward, now resting atop oceanic crust and other rock units of European origin, illustrating the vast displacement during the orogeny.
Uplift, Erosion, and the Iconic Peak
Following compression and nappe formation, the deeply buried rock units, including those of the Matterhorn, began a prolonged period of uplift, bringing complex structures closer to the surface.
The mountain’s distinctive pyramidal shape, known as a glacial horn, was not formed solely by tectonic forces. The Matterhorn was initially a more rounded mountain before erosion began its work.
Glacial erosion played a dominant role in carving the Matterhorn into its present form over the last few million years. During extensive glaciation, glaciers flowed down multiple sides, scouring and excavating semi-circular cirques on different faces. As these cirques expanded towards each other, they sharpened intervening ridges and carved the Matterhorn’s steep slopes and pointed summit.
Other weathering processes, such as frost wedging, also contributed. Water seeps into cracks, freezes, expands, and breaks off pieces, further refining the mountain’s profile.