Geology Of Italy Essays Examples
Italy is the geologically young country. The main part of its territory is occupied by the folded mountains of Alpine age - Alps and the Apennines, between which lies the intermountain sag Po Valley, filled with the Tertiary and Quaternary rocks (Vai and Caldwell). The tertiary folds of the Alps and the Apennines include the ancient Hercynian massifs: they form a mountainous area of the Western Alps, occupy Sardinia, north-east of Sicily and Calabria. A great place in the geological structure of Italy belongs to the volcanic rocks. The products of the Tertiary and Quaternary eruptions compose the significant areas to the west of the Apennines - in the Tyrrhenian pre-Apennines, as well as in eastern Sicily and Sardinia (Murphy and Squyres).
The earliest stages of the geological history of Italy - Cambrian and Lower Paleozoic - difficult to trace because of the strong metamorphic rocks, their fragmented distribution and abundance of complexity, caused by the subsequent tectonic processes, primarily by the Alpine folding. During the lower Paleozoic era the significant part of Italy was apparently a land, as there is almost everywhere absent the Cambrian sediments, and the Silurian and Devonian rocks are common in fragments (Crescenti). Among the Apennine peninsula, the Lower Paleozoic, especially Silurian rocks, occur in the Tyrrhenian pre-Appenines, Apuan Alps, Pisa and Tuscan Ore Mountains, tracing by the small yields up to Argentario foreland. On the islands of the Tyrrhenian Sea, this complex continues in the south-eastern part of the Elbe (Vezzani, Festa and Ghisetti). On Sardinia, the Cambrian and Silurian rocks form its southwestern core – Sulcis-Iglesiente.
Cambrian sediments of Iglesiente, according to M. Mori, belong to three series: the base is characterized by the sandstone formation; above there are the limestones and dolomites with lead-zinc-silver deposits. In the Silurian and Devonian it is deposited the clastic strata materials, subsequently strongly metamorphosed. Silurian and Devonian deposits are widely common in the central and southern parts of the island (Dogliony and Flores).
Lower Paleozoic ends with the Caledonian orogenesis with the introduction of the intrusive bodies. Caledonian movements were noted in the Venice-Tridentine Alps, the Ortler, in the Apuan Alps. In the area of the Carnic Alps at this time it was formed the ridges and sills; in the Tirrenia it rose the archipelagos of the small islands above the sea. The Caledonian orogeny was followed by a long phase of the tectonic tranquility in Devon (Murphy and Squyres).
In Central and Southern Italy as a result of the Hercynian orogenesis it emerged Tirrenis - a large array of mountainous land, occupying a considerable area on the site of the present Tyrrhenian Sea and the islands of Sardinia, Corsica, most of the north-eastern Sicily and Calabria peninsula (Vai and Caldwell). This ancient land was washed by the seas that covered the most of the peninsula and Sicily. In the eastern part of Italy for the Hercynian time it assumes the existence of an array of ancient Adria on the site of the present Adriatic Sea, but this issue remains to be problematic (Vezzani, Festa and Ghisetti).
Permian period was a time of decomposition of the Hercynian Mountains and accumulation of large masses of coarse clastic conglomerates and quartz sandstones in the outer zones of the Western Alps, in the Tuscan region and in Sardinia, Grodno sandstones in the Eastern Alps. The variegation of these rocks indicates about the hot desert climate. Hercynian Mountains were gradually declined and leveled; the land slowly dropped and was filled with the sea. Only a few volcanoes rose above the reduced land, spewing the volcanic mass (Vezzani, Festa and Ghisetti).
The Mesozoic era in Middle-earth was a long time of geosynclinal development of Tethys ocean basin in which Tirrenia and Hercynian massifs of the Alps towered in the form of islands. The transgression was experienced also by the part of Tirrenia, the surface of which in some areas have been postponed with the Mesozoic limestones. Thus, in the peripheral areas of Sardinia it is present the shallow Jurassic and Cretaceous rocks, and in the north-west, in Nurra - deep limestone-dolomite sequences. In Calabria, Mesozoic limestones form a wide edge strip on the east (Dogliony and Flores).
In the Apennine Italy and Sicily geosynclinal development occurred continuously throughout the Mesozoic and early Tertiary period. The depth of the sea there was different, leading to differences in facies of the sediments. As in the Alpine region, together with limestone there were accumulated caly and greenstone rocks, protruding now in the Northern and Southern Apennines. In Sicily, there were the underwater volcanic eruptions that left the tuffs. In the second half of the Cretaceous period, the sea depth decreased; in the central and southern Apennines, Apulia and Sicily it appeared the first mountain ranges. At the end of the Cretaceous era there was a general uplift of land and retreat of the sea (Vezzani, Festa and Ghisetti).
The recent geological and geophysical studies have shown that the outer arc of the Northern Apennines belongs along with the Calabrian Apennines to the Mediterranean areas of modern mountain-building, as evidenced by the anomaly gravity and fields of the accumulation of Pleistocene gravel. Northern Calabrian Apennines also in the future will be subjected to folding and vertical movements. Thus, the Apennines are one of the youngest mountains in the world (Vezzani, Festa and Ghisetti).
Tectonics of the Apennines also has the considerable complexity. It is not quite clearly defined the relationship of the Apennines to the Alps, as well as the position of the mountains in the general system of tertiary folded structures of Middle-earth. Northern Apennines, long considered as a continuation of the Alps, have the opposite direction of the Alpine thrust. Northern Apennines are usually considered as a system of covers, pulled over to the northeast (Vezzani, Festa and Ghisetti). The second system is composed of the Eocene sandstones, forming the high south-western part of the northern Apennines. Ligurian system is similar in nature with the rocks of Alps system and is represented by scaly clays and shales with inclusions of large masses of greenstone ophiolite rocks of the Jurassic and Cretaceous period. In the south of the line Bologna-Lucca for Biro and Dreshu, tectonics becomes to be simpler, characterized by gentle waves and flexures (Murphy and Squyres). Central and Southern Apennines are mostly autochthonous, only in their eastern fringes there are small thrusts and tilting of folds to the east. The structure of the Southern Apennines continues in the Sicilian Apennines (Crescenti).
Tectonic movements in the Alps had total consolidated nature, weakening from the central region to the periphery of the mountains. Apennines experienced in the neo-tectonic cycle the overall uplift, but smaller than in the Alps (Aiello et al.). Apennines are dominated by the arched movements, as it is indicated by the uneven surface of the height alignment and terraces, rising up the valleys. Especially expressive signs of neo-tectonic movements are observed in Calabria, the slopes of which are divided into a series of terraces, ongoing and undergoing the water. Thus, the neo-tectonic movements of land appeared in all parts of Italy, determined the ratio of the modern heights, making the country’s relief to be higher, dissected and more contrast (Vezzani, Festa and Ghisetti).
Italy is a country in Southern Europe, in the center of the Mediterranean. The total area of the country is 301,230 square kilometers, on its territory it is located the southern slopes of the Alps, the Po Valley, the Apennines peninsula (famous for its shape), as well as the island of Sicily, Sardinia and numerous smaller islands. Based on the physical and geographical characteristics of the country, it can be said that due to its geology the area of Italy is divided into at least three areas with different types of vegetation: the Alps, the Po Valley and the Mediterranean-Apennine region (Aiello et al.).
The Italian part of the Alps has a crystal, limestone and sand-clay structure. In the western part it is present the autochthonous crystalline arrays, as well as there are the areas, composed of crystalline schists and gneisses. The eastern part of the Alps is made up of the system of the limestone covers, pulled over to the north. Northern Apennines also have a cover structure, there are three systems: 1) Paleozoic schists and Carrara marble, 2) Eocene sandstones and 3) Ligurian (scaly clays and shales with inclusions of ophiolite rocks). In the central and southern areas, Apennines are autochthonous, folded by the paleogene and neogene limestones and cretaceous flysch (Dogliony and Flores). The foothills of the Apennines near Rome also have powerful volcanic strata of lavas and tuffs (trachytes, liparites), which form a series of extinct volcanoes with huge caldera, which were filled with water and became lakes: Bracciano, Bolsena, di Vico. In the south of Italy in the field of deep crustal faults there are two of the world's largest active volcanoes - Etna and Vesuvius.
Italy is exposed to natural disasters such as volcanic eruptions and earthquakes. Strong earthquakes: Sicilian of 1693 (more than 60 thousand of dead), Great Neapolitan Earthquake in 1857 (11 thousand of dead), Messinian in 1908 (up to 100 thousand of dead), Avezzano earthquake in 1915 (more than 30 thousand of dead people), earthquake in Irpinia in 1980 (2,570 deaths). The last – an earthquake in L'Aquila was in April 2009 (Murphy and Squyres). Fossil fuels deposits are represented by the natural gas and oil, the deposits of which are in the Neogene sediments of the Apennines deflection, as well as in the Mesozoic and Cenozoic sediments of the island of Sicily (province of Ragusa). In the south-western part of Sardinia and in the Alps there are deposits of coal; the Paleogene-Neogene deposits in the Central Apennines include the brown coal, lignite and bituminous shales (Crescenti).
The main ore reserves are confined to the ancient metamorphic complex: in Sardinia there are deposits of lead, zinc and iron and ore deposits. Italy has the largest reserves of cinnabar (mercury ore), on the island of Sicily - large sulfur deposits. Karst depressions of Abruzzo, Puglia and the Gargano peninsula include bauxite, Miocene Calabria and Sicily sediments contain rock salt. In the north of the Apennines (Tuscany) there are the deposits of Carrara marble used for cladding and creating of sculptures (Murphy and Squyres).
Thus, the geology can give the opportunities for the better understanding of the Italy’s history and dynamics of its development, as well as development of its economy and the way of life and work of the peoples, basing on the presence of mountains, deposits of rocks, climate, risk of volcanic eruptions, etc.
Aiello, Gemma et al. Mapping Geology In Italy. Roma: APAT, 2004. Print.
Crescenti, Umberto. Geology Of Italy. Roma: Società geologica italiana, 2004. Print.
Dogliony, Carlo, and Goivanny Flores. An introduction to the Italian geology. Lamisco, 1997. Print.
Murphy, Boyd F, and Coy H Squyres. Geology Of Italy. Tripoli: Earth Sciences Society of the Libyan Arab Republic, 1975. Print.
Vai, Gian Battista, and W. G. E Caldwell. The Origins Of Geology In Italy. Boulder, Colo.: Geological Society of America, 2006. Print.
Vezzani, Livio, Andrea Festa, and Francesca C Ghisetti. Geology And Tectonic Evolution Of The Central-Southern Apennines, Italy. Boulder, Colo.: Geological Society of America, 2010. Print.
Vezzani, Livio, Andrea Festa, and Francesca C. Ghisetti. 'Geology And Tectonic Evolution Of The Central-Southern Apennines, Italy'. Geological Society of America Special Papers (2010): 1-58. Web. 22 Apr. 2015.