Home Work # 3 (02%)

Subsidence
1.
Beneath the Ghawar Field, the basement is found about 7 km beneath the
surface. It is covered with sediments (3 km is carbonates and the other part is
clastics). Calculate the crustal
thickness by assuming Airy Isosticy method.
Support your answer with drawing.
Hint:
Compensating depth is
80 km
Initial crustal thickness is
35 km.
Clastics sediments density is
2.60 gm/cm^{3}
Carbonate sediment density is 2.80 gm/cm^{3}
Crust density is
2.92 gm/cm^{3}
Mantle
density is
3.35 gm/cm^{3}
2.
Repeat the above calculation using densities 2.5, 2.7, 3.0, and 3.2
respectively. Also assume the compensating depth and the initial crustal
thickness are 80 km. Compare between the two answers. What is your opinion of this comparison?
TimeAverage
Equation
3.
You have a piece of sandstone whose fractional porosity is 0.25 and whose
watersaturated velocity is 4000 m/s.
Calculate the sandstone velocity at zero porosity, its airsaturated
velocity, and its icesaturated velocity.
Hint:
Velocity
of Air is
330 m/s
Water
1500 m/s
Ice
3150 m/s
GOOD LUCK