The Three Main Types of Rock on the Earth

The Earth boasts a diverse array of rocks, which can be categorized according to their origin into three main types: magmatic rocks, sedimentary rocks, and metamorphic rocks.

Magmatic Rocks

Magmatic rocks, also known as igneous rocks, are created through the cooling of magma that has ascended from the Earth's interior to the surface or close to it. Examples of magmatic rocks include granite and basalt. Significant quantities of granite are present in the Danghe Reservoir region in Dunhuang.

Sedimentary Rocks

Sedimentary rocks, also referred to as hydrogenic rocks, are created from weathering materials that are deposited in bodies of water, primarily oceans and lakes, on the Earth. The walls of the Mogao Grottoes consist of sedimentary rocks, such as commonly seen mudstone, sandstone, conglomerate, and limestone.

Metamorphic Rocks

Metamorphic rocks are newly formed rocks that result from the transformation of pre-existing rocks due to internal forces within the Earth, such as changes in temperature, pressure, stress, and chemical composition. The Mingsha Mountain in Dunhuang is home to vast quantities of metamorphic rocks which include schist and marble.