Here's a more detailed breakdown:
* Igneous rocks: These rocks form from the cooling and solidification of magma or lava. They make up a significant portion of the continental crust, including:
* Granite: A light-colored, coarse-grained rock that is common in the upper crust.
* Diorite: A darker, medium-grained rock that is often found in mountain ranges.
* Gabbro: A dark-colored, coarse-grained rock that is found in the lower crust.
* Metamorphic rocks: These rocks are formed when existing rocks (igneous, sedimentary, or other metamorphic rocks) are transformed by heat, pressure, or chemical reactions. Examples of metamorphic rocks in the continental crust include:
* Schist: A foliated metamorphic rock that is often found in mountain ranges.
* Gneiss: A banded metamorphic rock that is often found in the lower crust.
* Marble: A metamorphic rock formed from limestone.
* Sedimentary rocks: These rocks are formed from the accumulation and cementation of sediments, which are fragments of other rocks, minerals, or organic matter. They are typically found in the upper layers of the continental crust. Examples include:
* Sandstone: A sedimentary rock formed from sand grains.
* Limestone: A sedimentary rock formed from the shells of marine organisms.
* Shale: A sedimentary rock formed from clay.
The specific composition of the continental crust varies depending on location and geological history. However, it is generally rich in silica (SiO2), making it felsic in composition. This is in contrast to the oceanic crust, which is mafic in composition and richer in magnesium (Mg) and iron (Fe).
