If a mountain range has a crust that is 60 km thick and a surface elevation of 4 km above sea level, how much erosion is necessary to reduce the surface elevation to approximately one kilometer above sea level? (1) 5-6 km (2) 10-12 km (3) 15-18 km (4) 20-24 km (5) 25-30 km

Option 4

Explanation:

As per the question:

Surface elevation above sea level = 4 km

Density of the crust = 2.7

Density of the mantle = 3.4 g/cm^{3}

Now,

The elevation of the mountain range should be supported by the mantle and the crust with variable densities. The mountain roots in the mantle balances the height above the crust:

The depth of the mountain root is given by:

The depth of the root is given by:

Depth =

Depth =

The root depth when there is a variation in the elevation to 1 km:

Depth =

Hence, in order to support 1km elevation, erosion as:

Erosion = Mountain Height + Mountain Root = 15.4 + 4 = 19.5 km ≈ 20 km

increase masses, decrease separation

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is