10. Mid-ocean ridges (the red areas in the image below), include the most extensive chain of mountains and volcanoes on Earth. Ninety percent of it is underwater in the deep oceans and stretches 40,000 miles. Mid-ocean ridges occur along divergent plate boundaries, where new ocean crust is created as Earth's tectonic plates spread apart. As the plates separate, magma comes up from the mantle through the cracks and cools to form mountains and volcanoes. Look at the time scale under the image. The red areas represent the mid-ocean ridges and are the areas on Earth where the youngest crust is located because it was created 0 millions of years ago - in other words, it is being created now. Based on the time scale and the map, where is the oldest crust on Earth?

Question

A. Beside the mid-ocean ridges
B. Along the edges of the continents
C. At the North and South Poles
D. In the Mediterranean Sea between Europe and Africa

Answer 1

The oldest crust on Earth is typically found along the edges of the continents. As new ocean crust is created at mid-ocean ridges, older crust is gradually pushed away from the ridges towards the continents. Therefore, the correct answer is:

B. Along the edges of the continents