Environment landscapes.Case study

Abstract

The Tajo river is one of the most important hydrogaphic basins in the lbenan Peninsula, for its extension and for its flow. It is the ideal tectonical basin and is surrounded by two mountains ranges: the Central System on the North and the Toledo Mountains on the South. The underwater keystone, which is made of the same matenals as the mountains, granite and gneiss, is very deep. On the East, the Castillian Iberian System, composed mainly of limestone and Mesozoic, closes Castille and the Basin, giving life with its snow run-off, to a “child”, the Tajo. We can place the start of its geological history in the Paleozoic. At that time, the territories where the Meseta is now placed were large ranges of mountains made by the Hercinian Orogenesis. We can find the last peniod of the current reliefs in the oíd massifs that were leveled. The formation was charactenized by its progressive mdividualization, going from the large general surfaces, massifs, basins, Sierras and Tajo pits to the small plains in stnips or bands, located in every fluvial basin as they consolidated. Ihe tectonic and further processes as well as the c¡imatic adjustments, dont allow us to determine the hierarchical order of the rivers known nowadays; nevertheless, we can say that Jarama-Henares, Perales-Alberche and Guadarrama would be the first, and Manzanares, Guadalix and Tajuña the next and so on. The sum of the geology and the climatic circumstances will influence, either by speeding up or slowing down, the development and the differences between the flora landscapes of the mountain zones and those of the terciarias depressions and Paleozoic plains, in a territory with Mediterraneancontinental climate, with mountain nuances and sorne Atlantic influence.