Stratum

We explain what a stratum is in geology, in the atmosphere, the skin and society, how each of them is formed and their characteristics.

What is a stratum?

A stratum is a geological phenomenon that is produced by sedimentation of fragments from various types of rocks. Sediments, as they accumulate over time, form overlapping horizontal layers. The oldest strip is known as the “base” while the most recent is called the “roof.”

By analogy the word “stratum” It is also used to talk about the stripes that cover something or that form an object or a fabric. This term is also used metaphorically to describe the structure of social classes according to their income or status.

Within geology, “stratigraphy” is the discipline that is responsible for studying and interpreting stratigraphic units or rock strata to establish their significance within the geological history of our planet.

The study of the strata of the earth for an archaeological purpose is also called “archaeological stratigraphy.” By studying the layers where objects or archaeological remains are found, their age can be determined, among other data relevant to the study of the past.

See also: Soil layers

rock strata

Erosion wears and cracks the soil of our planet, producing fragments that can be as large as Mount Augustus, 8 km long, or as small as grains of sand. Over time, the force of gravity and the action of water deposits these fragments in low areas, accumulating successive layers that we know as “strata”.

Each stratum is formed from the type of erosion and climate typical of a time determined. Therefore, through stratigraphy we can know the conditions of a specific time in the geological past of our planet.

In general, in sedimentary areas the surface strata have a soft consistency, which is why they are very important for agriculture. However, over time, new layers accumulate that put pressure on the lower layers, compacting them. Added to this are the increase in temperature and the different chemical changes that transform sediments into hard rock.

Sedimentation processes occur anywhere on the surface of our planet and can be divided into three classes:

• Marine sedimentation. Sediments accumulate on the continental shelf and in the deep sea.
• Continental sedimentation. Sediments accumulate at the foot of mountains, glaciers, river basins and desert areas.
• Sedimentation in transition zones. Sediments accumulate in places of contact between the sea and the continents, as occurs in certain swampy areas and river deltas.

Stratified rock formations are analyzed from three perspectives:

• Its lithostratigraphy. It is the study of the characteristics of the rocks of the stratum.
• Its biostratigraphy. It is the study of the fossils that could be found in the stratum.
• Its chronostratigraphy. It is the study that allows dating the stratum, establishing its place on the geological time scale.

Stratus clouds

The “stratus clouds”They are a type of low clouds whose base is very close to the groundabout 800 meters from the surface and a maximum of 2 kilometers high.

stratus clouds They form a layer of wide horizontal extension but with very little vertical deployment. They appear as large homogeneous masses that sometimes seem to completely cover the sky and when they reach very close to the ground they are associated with light fog.

Their temperatures can be very similar or the same as those of the Earth's surface, their characteristic color is gray and they do not produce significant precipitation.

layers of the skin

For dermatology, the skin is made up of five layers organized from the deepest layer to the surface:

• Basal layer. It is the deepest layer of the epidermis and the only one that contains melanocytes, that is, the cells that determine the color of the skin and those responsible for protecting the body from the sun's rays. Additionally, keratinocytes are produced in this stratum: the cells that generate keratin, the main structural protein of the skin.
• Spinosum layer. It has between 8 and 10 layers of cells rich in DNA and essential for the production of keratin. Also in this stratum are Langerhans cells, responsible for regulating the responses of the skin's immune system.
• Granular layer. The cells of this stratum are distributed between two and four layers and are filled with keratohyalin, an essential substance for the production of keratin. The keratinization process begins in this layer.
• Stratum lucidum. It is a transition layer between the stratum granulosum and the stratum corneum and is found only in the thickest areas of the skin such as the palms of the hands or the soles of the feet. In this stratum, the keratinocytes are grouped together and their cytoplasm is full of a substance called eleidin, which has the function of preventing the entry or exit of water.
• Stratum corneum. It is the outermost layer of the skin and is made up of thin, flat, dead scaly cells that are shed and replaced by others continuously. The cytoplasm of these cells is replaced by keratin.

social stratum

In sociology the concept of social stratification refers to the division of a society into differentiated human groups due to their income, prestige, occupation, status, economic and political power.

Within sociology there are three major approaches to social stratification: Marxist, Weberian and functionalist.

For Marxism, differentiated access to the means of production is the key to social stratificationsince it allows you to control work and the generation of wealth.

Thus, human groups are differentiated hierarchically based on the distinction between those who own or do not own the means of production. For this reason Marxism proposes that there are two fundamental social classes: the bourgeoisie and the proletariat.

Going beyond the Marxist approach, Weber stated that social strata originate from an unequal distribution of power. One social group can impose itself on another based on three elements: a) access to goods and services, b) the honor or prestige of social position and c) political power.

For functionalism, the status of a social group is the key element for social stratification. Said status or positive evaluation occurs within a system of shared beliefs. It can be acquired by inheritance, by merit or by some other form of social recognition.

Continue with: Earth's crust

References

• “Strato” in Wikipedia.
• “Stratigraphy” on Wikipedia.
• Archaeological “stratigraphy” on Wikipedia.
• “Stratus” on Wikipedia.
• “Strata” in Grouping for the Promotion and Development of Astronomy.
• “Understanding the skin” in Eucerin.
• “The five layers of the epidermis” in Cosmetology.com.
• “Social stratification” on Wikipedia.