Igneous Rocks:
* Basalt: Found in oceanic crust, it's dark-colored and dense.
* Granite: Found in continental crust, it's lighter-colored and less dense.
Sedimentary Rocks:
* Formed from the accumulation and cementation of sediments (like sand, clay, and shells).
* Examples include sandstone, limestone, and shale.
Metamorphic Rocks:
* Formed when existing igneous or sedimentary rocks are transformed by heat and pressure.
* Examples include marble (from limestone), slate (from shale), and gneiss (from granite).
Composition by Element:
* Oxygen (O): Most abundant element in the crust (46.6%)
* Silicon (Si): Second most abundant element (27.7%)
* Aluminum (Al): Third most abundant element (8.1%)
* Iron (Fe): Fourth most abundant element (5.0%)
* Calcium (Ca): Fifth most abundant element (3.6%)
* Sodium (Na), Potassium (K), and Magnesium (Mg): Other significant elements.
Differences between Oceanic and Continental Crust:
* Oceanic crust: Thinner (5-10 km), denser, primarily composed of basalt.
* Continental crust: Thicker (30-70 km), less dense, more diverse composition including granite and other types of rocks.
Note: These are just the major components. The Earth's crust is incredibly complex and varies widely in composition depending on location and geological history.
