Explain the concept of Isostasy and its models (Airy and Pratt), including examples.

Q1: In your own word, explain the concept of Isostasy. Illustrate your answers with an example or diagram. Isostasy is the state of gravitational equilibrium between the Earth's lithosphere (crust and uppermost mantle) and the underlying asthenosphere (a weaker, ductile part of the mantle). It describes how different topographic loads on the Earth's surface, like mountains or continents, are supported by buoyancy, much like an iceberg floats in water. The lithosphere "floats" at an elevation that depends on its thickness and density relative to the denser asthenosphere. Example: Imagine several blocks of wood of different heights floating in water. The taller blocks will float higher but also have deeper "roots" extending into the water to displace enough fluid to support their greater mass. Similarly, mountain ranges, which are massive, have deep crustal roots extending into the mantle, allowing them to float in equilibrium. Q2: What are the key influencing factors of Airy Model to Isostasy theory. The key influencing factors of the Airy Model of isostasy are: • Uniform density of the crust. • Varying thickness of the crust, meaning that mountains have deep "roots" extending into the mantle, and ocean basins have thinner crust. The greater the elevation, the deeper the root. Q3: What are the key influencing factors of Pratt Model to Isostasy theory. The key influencing factors of the Pratt Model of isostasy are: • Uniform depth of compensation, meaning that the base of the crust is at a constant depth below sea level. • Varying density of the crust, meaning that areas of higher elevation (like mountains) are composed of less dense crustal material, while areas of lower elevation (like ocean basins) are composed of denser crustal material.