Chris Watkiss, age 10, of Ottawa, Ont.:

Are all the mountain ranges linked together?

The face of the earth is pitted with lakes, grooved with rivers and ridged with mountain ranges. Three quarters of the surface is covered with sea water and in some places the ocean floor dips low enough to swallow the tallest mountains. The surface of our beautiful planet is as bumpy as a wrinkled prune and at first glance there seems to be no plan or system to the ups and downs. But with a closer look we see that most of the long wrinkled ranges are linked roughly together.

A world map shows that the Pacific Ocean is ringed with tall mountains on three sides. Another vast mountain system begins in Spain and travels eastward through central Europe to the Himalayas. From here smaller ranges swoop down to join the mountains which fringe the western Pacific. These vast highland areas are called mountain belts. Most of the world’s mountains are in these two belts which roughly link near the South China Sea.

There are some mountains outside this worldwide system. But they are much older and they cannot compete with the tall peaks of the Himalayas and the lofty Andes. The Appalachians of eastern North America are perhaps the largest of these lonely mountain ranges. The ice capped mountains of Greenland and the Ural mountains between Asia and Europe also stand apart from the worldwide mountain system, The highland plateau of South Africa also seems to stand apart. But this plateau can be linked to the highlands of east Africa and they in turn are linked with the great belt which stretches across Europe and Asia.

The tallest mountains are the Himalayas with a few peaks near 30P000 feet. The lofty Andes have several peaks above 22,000 feet. The third highest range is the Rockies whose highest peak is more than 20,000 feet.

All these towering mountains, together with the peaks of the Alps, the Cascades and the Sierra Nevada are in the worldwide mountain system.

The tallest ranges are all in the vast worldwide mountain belts, but not the oldest mountains. A mountain range pokes up from the ground and takes many millions of years to reach its full height. Meantime the wind and weather are wearing down its proud peaks. It will remain tall for hundreds of millions of years. But finally it reaches old age and becomes a chain of gentle hills.

The oldest mountains are the Laurentians of Canada. These gentle slopes were young and proud mountains some 2000 million years ago. The youngest Appalachians were fully grown 200 million years ago. These ranges are separate from the worldwide system and were old before it started to grow. The proud Rockies and the snow capped Andes are less than 130 million years old. The Alps and the Himalayas are mere babies, not much older than 50 million years.