INDIAN GEOGRAPHY

Detailed explanation-1: -According to Suess, it is the uppermost layer of the Earth in which the substances called silica and aluminum are obtained. Therefore this layer is called Sial (Si + al = Sial). The average density of this layer is 2.9 grams per cubic cm. The average depth of this layer is 50 – 300 km.

Detailed explanation-2: -On average, the thickness of the sial is till 25 km from the surface. The continents are composed mainly of lighter rock material formed from silicon and aluminium, so the sial is thick over the continents and very thin or absent on the ocean floor, especially the Pacific Ocean.

Detailed explanation-3: -The average thickness is 8 to 100 km. The layer next to it is SIMA makeup of silica and magnesium and an average thickness of this layer is 100 to 2900 km. The innermost layer is NIFE madeup of nickel and ferrous and the density is 5.1 to 13. Was this answer helpful?

Detailed explanation-4: -A Silica. B Alumina. The main mineral constituents of the continental mass of the crust are silica and alumina. It is thus called sial (si-silica and al-alumina).

Detailed explanation-5: -It is called SIAL (Lower in density with 2.7g/cm³). The oceanic crust (lower layer) is of the basaltic type, typically composed of silicate and magnesium igneous rocks. It is called SIMA-higher in density with 3.5g/cm³.