The heavier silicates named 'Sima' or silica + magnesium are most abundant in the ________

Solution (By Examveda Team)

The Earth's crust is composed of different types of rocks and minerals. The Earth's crust and upper mantle are collectively known as the lithosphere. This lithosphere is divided into tectonic plates, which float on the semi-fluid asthenosphere below.

The term 'Sima' stands for "silica + magnesium," referring to the composition of the rocks in the Earth's crust and uppermost mantle. Silicates rich in magnesium are denser and heavier than those rich in other elements like aluminum. These heavier silicates, or 'Sima', are most abundant in the ocean floors, which are part of the Earth's crust.

The ocean floors are primarily composed of basaltic rocks, which are rich in magnesium and iron. These rocks make up the oceanic crust. Basalt is formed through volcanic activity at mid-ocean ridges and is a type of 'Sima' material.

In contrast, the continental crust is composed of lighter silicates known as 'Sial', which stands for "silica + aluminum." These lighter silicates are less dense and make up the landmasses and continental areas.

So, the correct answer, 'Option D: Ocean floors', reflects the abundance of 'Sima' (silica + magnesium) in the composition of oceanic crust, making it the most suitable option.