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GEOLOGY Italy has a complex geological history, characterised by marked environmental and climatic changes. Around 100 million years ago the area now occupied by the peninsula was covered by a tropical sea, the Tethys, which separated the Euro-Asiatic and African continental plates. As the ocean
began to recede, various types of materials were deposited. including limestones, dolomites and sandstones, as well as the extensive coral reefs to the north-east from which the Dolomite mountain range was later formed. Although earlier volcanic activity had resulted in the formation of the original nucleus of the Alpine chain and other mountains farther south, the crucial moment came around 40 million years ago when the African and European continental plates collided. The collision forced the respective borders of the plates and part of the bed of the Tethys to fold and rise up, beginning the formation of the Alpine and Apennine chains. The Alps rose up relatively quickly, at first forming an archipelago of tropical islands in the Tethys Sea. The curvature of the Alpine and Apennine chains, as well as the transverse orientation of the peninsula itself in the Mediterranean basin, reflect the manner in which the continental plates collided. Both mountain chains underwent significant erosion, resulting in huge deposits of sand, gravel and clay at their feet and in part preparing the way for the development of land areas including Tuscany. It is interesting to note that around six million years ago, when both the Alps and the Apennine range were still submerged, the Straits of Gibraltar closed up completely. As a result, the Mediterranean Sea, which was all that remained of the vast Tethys, began to dry up. The Straits of Gibraltar reopened some two million years ago, allowing the Atlantic Ocean to refill the Mediterranean. Some scholars have suggested that this ancient geological event could have given rise to the Atlantis myth, as well as the biblical story of Noah and the great flood. By around two million years ago, after the landscape has been shaped and reshaped by the combined forces of continental plate movement and erosion, the Italian peninsula had almost arrived at its present-day form. The level of the sea continued to rise and fall with an alternation of ice ages and periods of warm climate, until the end of the last ice age around 10,000 to 12,000 years ago.
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