constructive processes that build mountains

The bottom of the Atlantic Ocean is filled with some of the 'youngest' crust on Earth. As the two plates move the mantle melts, making magma and lava fill the void with newly formed rock. One of these mid-ocean ridges, the Mid-Atlantic ridge, is spreading apart making the Atlantic Ocean wider. These ridges are connected and are about 40,000 miles long!! The mid-ocean ridges are the longest continually running mountain range in the world. This occurs in the middle of our great oceans. The Earth is producing 'new' crust where two plates are diverging or spreading apart. As mountains and valleys are being formed natural disasters such as earthquakes and volcanic activity can occur which has affected humans for thousands of years. When collisions occur they produce mountains, deep underwater valleys called trenches, and volcanoes. When the plates move they collide or spread apart allowing the very hot molten material called lava to escape from the mantle. The convection currents in the much hotter mantle continually move the plates about 1/2 to 4 inches per year. These plates move very slowly across the surface of the Earth as though they were on a conveyor belt.

A transform boundary is like a tear in the Earth's crust. Transform boundary - two plates are sliding past each other as in the San Andreas fault of California. Divergent boundary - two plates are moving in opposite directions as in a mid-ocean ridge.ģ. Convergent boundaries - two plates collide to form mountains or a subduction zone.Ģ. The red lines on the map of the world above indicateġ. Geologists came to the conclusion in the 1960's that the Earth's rigid outer layer (crust and outer, rigid layer of the mantle) was not a single piece, but was broken up into about 12 large pieces called plates.

Constructive processes that build mountains