Advances in seismology have given humanity a more detailed knowledge of the Earth and the layers of which it consists. Each layer has its own properties, composition and characteristics that affect the basic processes occurring on the planet. The composition, structure and properties of the geographical envelope are determined by its main components.
Views of the Earth at different times
From ancient times, people sought to understand the formation and composition of the Earth. The earliest assumptions were exclusively unscientific in the form of myths or religious fables with the participation of the gods. In the period of antiquity and the Middle Ages several theories arose about the origin of the planet and its proper composition. The most ancient theories represented the earth as a flat sphere or cube. Already in the 6th century BC, Greek philosophers began to argue that the earth is actually round and contains minerals and metals. In the 16th century, Edmund Halley suggested that the Earth consists of concentric spheres, and inside it is hollow. At the beginning of the 19th century, mining and the industrial revolution contributed to the rapid development of earth science. It was found that the rock formations were located in the order of their formation in time. At the same time, geologists and natural scientists began to realize that the age of the fossil can be determined from a geological point of view.
Study of the chemical and geological composition
The structure and properties of the geographical envelope differs from other layers in chemical and geological composition, and there are huge differences in temperature and pressure. A modern scientific understanding of the Earth’s internal structure is based on inferences made using seismic monitoring along with measurements of gravitational and magnetic fields. By the beginning of the 20th century, the development of radiometric dating, which is used to determine the age of minerals and rocks, made it possible to obtain more accurate data regarding the true age of the Earth, which is approximately 4-4.5 billion years. The development of modern methods of mining minerals and precious metals, as well as the growing attention to the importance of minerals and their natural distribution, also contributed to the development of modern geology, including knowledge about which layers are part of the geographic shell of the earth.
The structure and properties of the geographical shell
The geosphere includes the hydrosphere, descending to a depth of about ten kilometers above sea level, the earth's crust and part of the atmosphere, extending to a height of up to 30 kilometers. The largest shell distance varies within forty kilometers. This layer is affected by both terrestrial and space processes. Substances occur in 3 physical states, and can consist of the smallest elementary particles, such as atoms, ions and molecules, and also include many additional multicomponent structures. The structure of the geographical envelope, as a rule, is considered as a community of natural and social phenomena. The components of the geographic envelope are represented in the form of rocks in the earth's crust, air, water, soil and biogeocenoses.
Characteristic features of the geosphere
The structure and properties of the geographical envelope imply the presence of an important number of characteristic features. These include: integrity, the cycle of matter, rhythm and continuous development.
- Integrity is determined by the results of the ongoing exchange of substances and energy, and the combination of all components combines them into one material whole, where the transformation of any of the links can lead to global changes in all the others.
- The geographical envelope is characterized by the presence of a cyclical cycle of matter, for example, atmospheric circulation and oceanic surface currents. More complex processes are accompanied by a change in the aggregate composition of the substance (water cycle in nature). In other cycles there is a chemical transformation of matter or the so-called biological cycle.
- Another feature of the shell is its rhythm, that is, the repetition in time of various processes and phenomena. This is mainly due to the will of astronomical and geological forces. There are 24-hour rhythms (change of day and night), annual rhythms (change of seasons), rhythms that occur throughout the century (for example, 30-year cycles in which there are fluctuations in climate, glaciers, lake levels and river volumes). There are even rhythms that have been going on for centuries (for example, alternating phases of a cool and humid climate with a phase of hot and dry, occurring once every 1800-1900 years). Geological rhythms can last from 200 to 240 million years and so on.
- The structure and properties of the geographical envelope are directly related to the continuity of development.
Continuous development
There are some results and features of continuous development. First, there is a local separation of the continents, oceans, and the seabed. This distinction is influenced by the spatial features of the geographical structure, including geographical and altitudinal zoning. Secondly, there is polar asymmetry, manifested in the presence of significant differences between the Northern and Southern hemispheres.
This is manifested, for example, in the distribution of continents and oceans, climatic zones, composition of flora and fauna, types and forms of reliefs and landscapes. Thirdly, development in the geosphere is inextricably linked with spatial and natural heterogeneity. This, ultimately, leads to the fact that in different regions at the same time different levels of the evolutionary process can be observed. For example, the ancient ice age in different parts of the earth began and ended at different times. In certain natural areas, the climate becomes more humid, while in others the opposite picture is observed.
Lithosphere
The structure of the geographic envelope includes such a component as the lithosphere. It is a solid, outer part of the earth, extending to a depth of about 100 kilometers. This layer includes the crust and the upper part of the mantle. The strongest and hardest layer of the Earth is associated with such a concept as tectonic activity. The lithosphere is divided into 15 large lithospheric plates: North American, Caribbean, South American, Scottish, Antarctic, Eurasian, Arabian, African, Indian, Filipino, Australian, Pacific, Juan de Fuca, Cocos and Nazca. The composition of the geographic shell of the Earth in these areas is characterized by the presence of various types of rocks of the lithospheric crust and mantle. The lithospheric crust is characterized by continental gneiss and oceanic gabbro. Below this boundary, in the upper layers of the mantle, peridotite occurs, the rocks are mainly composed of olivine and pyroxene minerals.
Component Interaction
The geographic envelope includes four natural geospheres: lithosphere, hydrosphere, atmosphere and biosphere. Water evaporates from the seas and oceans, winds move air currents to land, precipitation forms and falls there, which returns to the world ocean in various ways. The biological cycle of the plant kingdom is the conversion of inorganic to organic. After the death of living organisms, organic substances return to the earth's crust, gradually transforming into inorganic ones.
The most important properties
Geographic Shell Properties:
- The ability to accumulate and convert the energy of sunlight.
- The presence of free energy necessary for a large number of diverse natural processes.
- Unique ability to produce biodiversity and serve as a natural living environment.
- The properties of the geographic envelope include a huge variety of chemical elements.
- Energy comes both from space and from the depths of the earth.
The uniqueness of the geographical envelope lies in the fact that at the junction of the lithosphere, atmosphere and hydrosphere, organic life was born. It is here that the whole of human society has appeared and is still developing, using the necessary resources for its life. The geographic envelope covers the entire planet, therefore it is called the planetary complex, which includes rocks in the crust, air and water, soil and enormous biological diversity.