GEOLOGY

EARTH SCIENCE

TECTONICS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Complete the statement.Continents drift a few ____ per year.
A
meters
B
millimeters
C
centimeters
D
kilometers
Explanation: 

Detailed explanation-1: -The two continents are moving away from each other at the rate of about 2.5 centimeters (1 inch) per year. Rift valleys are sites where a continental landmass is ripping itself apart. Africa, for example, will eventually split along the Great Rift Valley system.

Detailed explanation-2: -Earth’s land masses move toward and away from each other at an average rate of about 1.5 centimeters (0.6 inches) a year. That’s about the rate that human toenails grow!

Detailed explanation-3: -It is made up of the crust and the solid, uppermost mantle. Continents move apart or come together at speeds of a few centimeters per year.

Detailed explanation-4: -A second problem was that Wegener’s estimate of the speed of continental motion, 250 cm/year, was implausibly high. (The currently accepted rate for the separation of the Americas from Europe and Africa is about 2.5 cm/year). Furthermore, Wegener was treated less seriously because he was not a geologist.

Detailed explanation-5: -Because tectonic plates move very slowly-only a few centimeters per year, on average-it takes a long time to observe changes. Scientists have found that the planet’s continents will likely again be joined together in about 250 million years.

There is 1 question to complete.