Question

What is meant by sima and sial

Answer 1

In geology, sima is the name for the lower layer of the Earth's crust. This layer is made of rocks rich in magnesium silicate minerals. ... The name 'sima' was taken from the first two letters of silica and of magnesia. Comparable is the name 'sial' which is the name for the upper layer of the Earth's continental crust.

Answer 2

sima means major constituent elements of the mantle are magnesium and silicon hence it is called sima and sial means major constituent elements of the lithosphere are silica and magnesium hence it is termed as sial