The layer called seema is the oceanic crust.
Understanding Seema
The term "seema" is derived from the chemical composition of this layer, which is predominantly made of Silica (Si) and Magnesium. This composition is distinct from the continental crust, which is richer in silica and aluminum (SiAl). Therefore, the oceanic crust's chemical makeup is also referred to as the "SiMa layer".
Key Characteristics of Seema
Here’s a summary of the characteristics of the oceanic crust (seema):
| Feature | Description |
|---|---|
| Composition | Primarily basalt, rich in silica and magnesium. |
| Density | Denser than the continental crust. |
| Thickness | Generally thinner than the continental crust. |
| Alternative Name | Also known as the SiMa layer. |
Seema vs. Continental Crust
While both the oceanic crust (seema) and the continental crust are part of the Earth's outer layer, they differ significantly in composition and properties:
- Composition: The continental crust is primarily composed of granite and is richer in silica and aluminum, while the oceanic crust (seema) is basaltic and has higher concentrations of silica and magnesium.
- Density: The oceanic crust (seema) is denser than the continental crust.
- Thickness: The oceanic crust (seema) is usually much thinner than the continental crust.
Why is the oceanic crust called "seema?"
The name "seema" directly corresponds to the abundant elements found in the oceanic crust. This term is a helpful shorthand that immediately conveys the basic composition of this layer of the Earth.
