Conservation
Man has always used his surroundings unwisely destroying forests and other natural resources. Get information on the need to conserve all the resources and wildlife and laws made to make improvements.
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Coasts
Factors effecting climate
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The fold mountain belts of opposing continents match very well. The Caledonian and Hercynian fronts approach each other in Europe and actually meet in America. The Alpine folding ranges have originally formed one huge system.
Continents
The seven great land masses of the Earth; Europe, Asia, North America, South America, Africa, Australia and Antarctica are called continents. Each continent is basically a vast raft of granite type rock floating in the denser basalt type rock which lies beneath.
The coastline does not mark the true edge of a continent. The land slopes out beneath the sea, often for a considerable distance, forming the continental shelf. Over the shelf the depth of the sea increases only gradually, reaching approximately 600 feet at the edge. The sea bed then plunges dramatically.
The continental shelves are now being explored for valuable mineral and gas deposits. As early as 1620 it was noticed that the continents of Africa and Europe on one side of the Atlantic and the Americas on the other would fit into one another like the pieces of a giant jigsaw puzzle. This led to the suggestion that perhaps they had once been connected and had since drifted apart.
In 1908 this idea of continental drift was revived to explain the formation and distribution of the great mountain ranges which appear to be exactly matched across the Atlantic. F. B. Taylor suggested that about 150 million years ago there were only two land masses Laurasia in the north and Gondwanaland in the south which both drifted towards the Equator. As Laurasia drifted southwards, its leading edges were crumpled into mountain ranges, while its trailing side broke up to form the complex islands of northern Canada. Similarly, as Gondwanaland drifted northwards, it also split into several pieces i.e. Antarctica, South America, Australia, India and Africa and its leading edge was crumpled into mountain belts.
In 1910 Alfred Wegener, a German meteorologist, produced a similar theory which explained the great changes in climate. We know such changes were experienced by the various continents in past ages from the fact that coal, which is the fossilized remains of swampy tropical forests, is found in such places as Alaska and Antarctica. It is difficult to imagine these icy wastes once having a tropical climate unless they were much nearer the Equator at one time. Wegener suggested that there had originally been one great continent (Pangaea) which split about 150 million years ago to form Laurasia and Gondwanaland, separated by a wide sea (Tethys).
