Caldera

As a result, the layers are tilted in the same way as the outer slopes, and the top is stronger than the bottom. The surface of the newly formed cone should have been covered with numerous cracks - barranco, as it took a considerably more space than ever before on the seabed. Away from the cone cracks are rarely caught, and there really was no reason for their occurrence. If in the middle of the caldera could advance the peak, then there would be a volcano, ie, open channel, which connects the earth's surface to its interior. But in raising the huge crater with raised masses fall back and close the channel. " As already mentioned, the names of these remarkable formations has become synonymous with: every big kotloobraznuyu Valley, located inside the blunt cone volcano and outward opening gorge, called the caldera, a kind of the same gorge on the slopes of volcanoes, which are considered supporters of the theory of lifting as cracks caused by the formation of the crater, are called the barranco. Explanation of the calderas, as proposed by Leopold von Buhom proved wrong, but thinking of the scientist and the way it is evidence of great interest at present. Reiss' research and Hartung have shown that the formation of calderas and barranco simply explained by the theory of accumulation and that, conversely, there is no good reason to attribute their occurrence rises. We too have shied away, if it began to investigate in detail the arguments supporting this view. We follow the process in only the most basic features. As already mentioned, the inner core Caldera are massive rocks from the group of so-called greenstone rocks (gryunshteynov), diabase, giperstenitov, etc. They obviously were here already before the eruption. Judging from the height of which reaches these rocks at the bottom of the valley, we can conclude that they represented a mountain about 1200 m in height. On the surface the latter is the latest eruption. By accumulation of lava and volcanic ash formed a cone, and he completely shut the greenstone rocks, and rose to great heights. Kumbre now reaches 2511 meters and the diameter of the crater is equal to \ 1 / 2 geographical miles, we can conclude that the original cone was raised, at least to the height of the Peak of Tenerife. During one of further eruptions in the upper part of the cone flew into the air, and the mountain mass, located above the modern Kumbre, were dropped, and finally, just as we saw during the eruption of Vesuvius in 1872, a huge crack cut through the whole mountain from top to bottom. Then within the caldera eruptions were to cease, if they continued in the same place, it would appear in the middle of a new cone, and if the center of eruption has moved to the north-eastern edge of Kumbre, where there are now some parasitic craters, the mountain became would form and structure of Etna, and instead of Caldera and barranco appeared to gorge like Valle del Bove. Further role in the creation of the modern form of the island belonged to the already water. In the rainy season and during snowmelt creeks running down the slopes of an extinct crater, and covered it with deep gullies, the water flowed and the huge crack that formed during the last eruption, it is increasingly eroded and turned into a modern large barranco. Barranco can not be regarded as cracks caused by lifting the mountain, already for the simple reason that, in their upper parts are very narrow, almost imperceptible, and even as we approach the foot of the mountains are made wider and deeper. This distinctive feature of the barranco and causes attributed to their origin the waters flowing down the slopes.