Question

The lower part of the crust known as 'Oceanic Crust' is rich in __________.

• A. Aluminium and copper
• B. Magnesium and aluminium
• C. Copper and gold
• D. Silica and magnesium

Answer 1

The correct option is D Silica and magnesium

Sima is the name for the lower layer of the Earth's crust. This layer is made of rocks rich in magnesium silicate minerals. Typically when the sima comes to the surface it is basalt, so sometimes this layer is called the 'basalt layer' of the crust. The sima layer is also called the basal crust or basal layer because it is the lowest layer of the crust. Because the ocean floors are mainly sima, it is also sometimes called the oceanic crust.