The main minerals constituents of the continental mass are ________ and ________.

The correct answer is 'silica, alumina'

Key Points

• Silica (SiO₂) and Alumina (Al₂O₃):
  • The continental crust is primarily composed of silicate minerals, which are rich in silica and alumina.
  • These compounds form the bulk of minerals such as feldspar and quartz, which are the most abundant minerals in the Earth's continental crust.
  • Silica (SiO₂) contributes to the crust’s overall light color and low density, characteristic of continental rocks.
  • Alumina (Al₂O₃) is a key component of feldspar minerals, which make up about 60% of the Earth's crust.

Additional Information

• Oxygen and Carbon:
  • Oxygen is indeed a major component of continental crust minerals, making up about 46.6% of the crust by weight.
  • Carbon, however, is present in much smaller quantities mainly in carbonate minerals, which are much less abundant in the continental crust compared to silicate minerals.
• Silica and Magnesium:
  • While silica is a major component of the continental crust, magnesium is more prevalent in the Earth's mantle and oceanic crust.
  • Minerals such as olivine and pyroxene, which are rich in magnesium, are found primarily in the mantle and oceanic crust rather than in the continental crust.
• Alumina and Magnesium:
  • Alumina is a significant component of the continental crust, but pairing it with magnesium overlooks the dominant presence of silica in the continental crust rocks.
  • Magnesium, similar to the previous point, is more associated with deeper parts of the Earth's structure such as the mantle and oceanic crust.

Important Points

• The composition of the continental crust is crucial for understanding various geological and geochemical processes.
• The predominance of silica and alumina gives the continental crust its unique characteristics, such as lower density and different mineralogy compared to the oceanic crust.
• This knowledge is fundamental in the study of plate tectonics, mountain-building processes, and the formation of different rock types.