Question

1. use the table to describe the two types of crust.

3.1.1 study: earths structure
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	continental crust	oceanic crust
density
rock types
mineral types

Explanation:

To describe the two types of crust (Continental and Oceanic), we use geological knowledge:

Continental Crust:

• Thickness: ~30–70 km (thicker, especially under mountains).
• Density: ~2.7 g/cm³ (less dense than oceanic crust).
• Rock types: Primarily granitic (felsic) rocks, including sedimentary and metamorphic rocks.
• Mineral types: Rich in silica (SiO₂) and aluminum (Al), e.g., quartz, feldspar.

Oceanic Crust:

• Thickness: ~5–10 km (thinner).
• Density: ~3.0 g/cm³ (more dense than continental crust).
• Rock types: Primarily basaltic (mafic) rocks.
• Mineral types: Rich in silica and magnesium (Mg), e.g., plagioclase feldspar, pyroxene.

Answer:

	Continental crust	Oceanic crust
Density	~2.7 g/cm³ (less dense)	~3.0 g/cm³ (more dense)
Rock types	Granitic (felsic), sedimentary, metamorphic	Basaltic (mafic)
Mineral types	Quartz, feldspar (Si, Al-rich)	Plagioclase feldspar, pyroxene (Si, Mg-rich)