1. Iron (Fe): The mantle is much denser than the crust, and this difference is largely due to the higher abundance of iron in the mantle.
2. Magnesium (Mg): Mantle rocks are rich in magnesium-rich minerals like olivine and pyroxene, which are relatively rare in the crust.
3. Calcium (Ca): Similar to magnesium, calcium is more abundant in the mantle due to the presence of minerals like plagioclase and pyroxene.
4. Silicon (Si): While silicon is present in both the crust and mantle, the mantle has a higher overall concentration due to its composition of silicate minerals.
5. Nickel (Ni): Nickel is a significant component of the mantle, often found in the iron-nickel core. It is relatively scarce in the crust.
On the other hand, crustal rocks tend to have higher amounts of:
* Aluminum (Al): Crustal rocks, particularly felsic rocks, are richer in aluminum.
* Sodium (Na) and Potassium (K): These elements are more common in the crust, especially in the continental crust, contributing to the formation of minerals like feldspar and mica.
Therefore, while both the crust and mantle contain similar elements, their proportions and specific mineral compositions differ greatly, leading to the distinct characteristics of each layer.
