Metamorphic rocks in mountain belts 1
The central core of many mountain belts is made of metamorphic rocks. Here in the Austrian Alps, the mountains in this view are built of granites, gneisses and…
Metamorphic rocks in mountain belts 2
Rocks metamorphosed at the deepest levels of the Earth's crust are brought up to the surface when mountain ranges are uplifted and eroded. The banded rocks in…
Metamorphic rocks of different compositions
Metamorphic rocks can be formed from any type of older material. Here, the lighter brown rocks in the upper part of the cliff are calcareous schists formed from…
Schist 1
Huge thicknesses of sandstone, siltstone and mudstone, deposited in ocean basins, are folded, squeezed and metamorphosed into schists when continents collide.…
Schist 2
The outlines of tightly-folded strata can be seen in this outcrop of mica schist, from the Eastern Alps, Austria
Gneiss 1
Ancient gneisses, of Precambrian age, underlie the interior of many continents. They can look very complicated: this example is a mixture of white and pink…
Gneiss, with tight folds
Layers of different composition show up boldly in these gneisses. They have been tightly folded, and you can see that the rock has behaved as if it was quite…
Gneiss 3
This photograph shows the streaky banded texture typical of many gneisses. The light streaks are feldspar and quartz, the dark bands are mica and hornblende.…
Marble
Pure marble is often white, but the presence of other mineral impurities gives coloured varieties. These marbles have bands and veins coloured yellow-green and…
Gneisses cut by granite
Bands of black basic gneiss and grey acid gneiss were formed from igneous rocks more than 2000 million years ago. In a later event, they have been cut across by…
