How are coarse-grained granite rocks formed?


Granites are among the most common rocks within the continental crust. They belong to the plutonites (deep rocks) and dike rocks, the main components of this rock are quartz, feldspar and mica.

The starting material (acidic magma) is created by melting the plunging plate at subduction zones. In the further formation process, the liquid rock slowly solidifies in magma chambers (plutonites) located several kilometers deep. Dike rocks (fill open crevices) are solidified in a faster process, at shallower depths of the earth. If the acid magma is brought to the surface during an eruption, the volcanite rhyolite is formed, which has the same chemical composition as granite.

Depending on their material composition, granites are divided into different groups. The two most common are:

  • I-type granites: Formed in subduction zones where an oceanic crust collides with a continental crust (cordilleras type).
  • S-type granites: Formed in subduction zones where two continental crusts meet (collision type).

Through further processes such as folding the earth's crust or removing the overlying rock layers, the granite finally reaches the surface or is transformed through metamorphosis (e.g. into gneiss).
The rock then begins to weather on the surface of the earth. Since the rock consists mainly of quartz and feldspar, the weathering mainly results in nutrient-poor soils.

Granite climbing - is one of the best there is.
Granite is a hard rock that has a small to coarse-grained structure. This structure gave the granite its name, which is derived from the Latin word granum = grain.
Depending on the existing grain size, the granite has very good friction properties. However, it is quite painful to climb or boulder on weathered granite rocks, as the fine quartz grains form a rough surface.
Granite walls have hardly any holes, steps or handles. Since the massive rock blocks are usually broken up into individual blocks by horizontal and vertical cracks, crack, chimney and intersection climbing is typical for climbing on granite.
In Germany you can find granite climbing areas in the Harz, Odenwald and in the Zittau Mountains, for example.