Question

5. The oldest rocks in the South Atlantic Ocean, immediately adjacent to the African and South American continental shelves, are 120,000,000 years old (time). Calculate the average rate of seafloorspreading for the South Atlantic Ocean over its entire existence (Hint: Use formula: velocity = distance/time): ______________km/yr (velocity). Now convert that to: _______________ cm/yr:

Answer 1

The continental drift speed is 6.18 cm/yr

Step-by-step explanation:

In order to calculate the drift speed of the continents, we can assume that it is constant for what the relationship meets

v = d / t

Where v is the speed, t the time and d the distance

To find the distance we use the closest points that are in the South Atlantic, after reviewing a world map, these points are Brazil and Namibia that has an approximate distance of 7415 km

To start the calculation let's reduce the magnitude

d = 7415 km (1000m/1km) (100cm/1m)

d = 7.415 10⁸ 8 cm

t = 120000000 years

t = 1.2 10⁸ year

With these values ​​we calculate the average speed

v = 7.415 10 3 / 1.2 108 [km / yr.]

v = 6.18 10-5 Km / yr

v = 7.415 10 8 / 1.2 10 8 [cm / yr]

v = 6.18 cm / yr.

The continental drift speed is 6.18 cm/yr