The earth, as you know, is round. Moreover, our planet has a spherical structure and consists of a number of geospheres. We will tell you what it is in our article. In addition, you will learn how to name and what the largest geosphere in the Earth consists of.
What is a geosphere?
The term comes from two Greek words: "geo" ("earth") and "sphere" ("ball"). The Earth's geosphere is a concentric shell, which can be continuous or discontinuous. Geospheres can intersect with each other both in space and in time. All of them are very closely connected, despite the apparent autonomy of each of them.
In science, it is customary to distinguish two types of geospheres: internal, of which, in fact, is the "body" of our planet, and external. The first group includes: the earth’s core, the mantle (the Earth’s largest geosphere in volume) and the earth’s crust. The second group is most often ranked:
- lithosphere;
- hydrosphere;
- atmosphere;
- and biosphere.
Sometimes scientists also distinguish the cryosphere (ice shell of the Earth), pedosphere (soil shell), magnetosphere (magnetic field of the planet), noosphere (zone of interaction between nature and society) and others.
The creator of the geosphere concept is considered to be the Austrian geologist Eduard Suess. In the future, the doctrine of these shells was actively developed by V.I. Vernadsky. It was he who first established that all geospheres are in constant and active interaction.
Earth's largest geosphere
Further, we will dwell in more detail on one of the inner shells of our planet. It will be about the mantle - the largest geosphere of the Earth in volume and mass (about 80% of the globe).
The mantle is a massive shell with a capacity of 2900 kilometers, located between the core and the earth's crust. It is in it that the bulk of our planet is located. The boundary between the mantle and the crust is the so-called Moho line - the zone where a sharp increase in seismic velocity is observed. This line runs at a depth of 7 km (under the oceans) to 70 km (under the geosynclinal regions).
Of course, no man had the opportunity to see the earth's mantle with his own eyes. Scientists obtain all information about this shell either by analyzing data on the speeds of seismic waves, or by studying the so-called mantle melts - rocks formed in the thickness of this geosphere (basalts, kimberlites, peridotites and others). In the photo below is a sample of basalt.
The structure and composition of the mantle
The mantle is conventionally divided into two parts - lower and upper. The border between them (Golitsyn layer) runs at a depth of about 670 km.
All processes occurring in the mantle have a huge impact on the surface of our planet. In particular, on its relief and the formation of the largest deposits of some minerals. In turn, the mantle itself is very strongly influenced by processes occurring in the earth's core.
The Earth’s mantle is mainly composed of peridotites, perovskites and eclogites. In addition, there are rocks that are not in the earth's crust. The chemical composition of the mantle is dominated by elements such as oxygen, magnesium, iron, silicon and calcium.