Question

3. Estimate the crustal thickness of Mars' highest plateau, the Syria Planum, from measurements of the topography and gravity of Mars shown in the figure (From Zuber et al., 2000, Science, 287, 1788). Gravity is shown as the difference from the mean value in mGal (milli Galileos, 1 mGal 10-5 m/s2). Assume that the mean crustal thickness is 50 km, the density of the crust is 2900 kg/m3, and the density of the mantle is 3500 kg/m3. km 12 60° 30° 0 4 30 60° 180 240 300 -8 0 60° 120 180° mGal 1000 60° 30° 500 30 -60° 500 180 240 300 0 60° 20 180 180°

Answer 1

h=b(pm-re)

Where h is the crustal thickness of the highest plateau,

b is the average crustal thickness = 50 km(Given),  $\rho$_m is the density of the mantle = 3500 km/m³ (Given) and

$\rho$_c is the density of the crust = 2900 km/m³ (Given)

50 (3500-2900 50600 -2900一一10.3448276 2900

Therefore, the crustal thickness of the highest plateau of Mars is 10.3448276 km excluding the thickness of continental root and continental crust, it just gives the thickness of the highest plateau above sea level.