Question

10. A section of continental crust with a height of 25 km (h) floats in the mantle. Some of it lies within the mantle (r), and the rest floats above the mantle. How much of the continental crust lies within the mantle

Answer 1

Answer:

4.54 km of earth's crust lies within mantel.

Explanation:

• Earth's continental crust is made of igneous, metamorphic, and sedimentary rocks and is composed of SIAL elements. The continental crust is made of various layers and has a density of 2.83 g/cm, while the oceanic crust is about 2.9 g/cm.

• The ontientla crust has usual thickness of 40 km (25 miles) thick and floats or rests on upper mantel or i.e the asthenosphere. While other parts of it lies within the mantel the depth of the continental crust ranges to 100 km,  

• where r/25 = 2.7 / 3.2  
• r/25 = 0.82  
• r= 0.82 x 25  
• r= 20.46  
• 25 - 20.46 is 4.54 km.