We explain what a stratum is in geology, in the atmosphere, skin and society, how each of them is formed and their characteristics.
What is a stratum?
A stratum is a geological phenomenon that occurs by sedimentation of fragments from various types of rocks. Sediments, as they accumulate along the weather, form overlapping horizontal layers. The oldest strip is known as "base" while the most recent is called "ceiling".
For analogy the word “stratum” is also used to speak of 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 your income or status.
Inside of geology is called "stratigraphy" to the discipline which is in charge of studying and interpreting the stratigraphic units or rock strata to establish their significance within the geological history of our planet.
Also called "archaeological stratigraphy" is the study of the strata of the earth with an archaeological purpose. By studying the layers where objects or archaeological remains are found, its antiquity, among others, can be determined data relevant to the study of the past.
Rocky strata
The new layers build up and press down on the lower layers, compacting them.The erosion wears and cracks the I usually from our planet producing fragments that can be as large as Mount Augustos, 8 km long. length, be as small as grains of sand. Over time the force of gravity and the action of waters it deposits these fragments in low areas, accumulating successive layers that we know as “strata”.
Each stratum is formed from the type of erosion Y weather characteristic of a certain time. 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 the farming. However, over time, new layers accumulate that press down on the lower layers, compacting them. Added to this is 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 deep in the sea.
- Continental sedimentation. Sediments accumulate at the foot of moutains, glaciers, river basins and deserted zones.
- Sedimentation in transition zones. Sediments accumulate at the contact points between the sea and the continents, as occurs in certain swampy areas and river deltas.
Stratified rock formations are analyzed from three perspectives:
- His lithostratigraphy. It is the study of the characteristics of the rocks of the stratum.
- His biostratigraphy. It is the study of the fossils that could be found in the stratum.
- His chronostratigraphy. It is the study that allows dating the stratum, establishing its place in the geological timescale.
Stratus clouds
"Stratus clouds" are a type of low cloud whose base is very close to the ground, about 800 meters from the surface and at a maximum of 2 kilometers high.
Stratus clouds form a layer of wide horizontal extent but with very little vertical spread. They appear as large homogeneous masses that sometimes seem to completely cover the sky and when they come very close to the ground they are associated with light haze.
Its temperatures can be very similar or equal to those of the earth's surface, its color characteristic is gray and they do not produce significant rainfall.
Skin layers
For dermatology, the skin is made up of five layers organized from the deepest layer to the surface:
- Basal stratum. 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 organism from the sun's rays. In addition, in this stratum keratinocytes are produced: the cells that generate keratin, the main protein structural skin.
- Spiny stratum. It has between 8 and 10 layers of cells rich in DNA and essential for the production of keratin. Also in this stratum are the Langerhans cells, in charge of regulating the responses of the immune system of the skin.
- Granular layer. The cells of this layer 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.
- Lucid stratum. It is a transition layer between the stratum granulosa and the corneum and is only found 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 and have the cytoplasm Filled with a substance called eleidine that works to prevent the entry or exit of water.
- Stratum corneum. It is the outermost layer of the skin and is made up of dead, flat and thin squamous cells that are shed and are continuously replaced by others. 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 human groups differentiated by their income, prestige, occupation, status, can economic and political.
Within sociology there are three major approaches to social stratification: the Marxist, the Weberian and the functionalist.
For him Marxism, differentiated access to means of production It is the key to social stratification, since it allows control of work and the generation of wealth.
Thus, human groupings are differentiated hierarchically based on the distinction between those who own or not the means of production. For this reason, Marxism states that there are two fundamental social classes: the bourgeoisie and the proletariat.
Going beyond the Marxist approach, Weber asserted that social strata originate from an unequal distribution of power. A social group can impose itself on another based on three elements: a) access to goods and services, b) the honor or prestige of the social position and c) the political power.
For functionalism, the status of a social group is the key element for social stratification. Said status or positive assessment is given within a system of beliefs shared. It can be acquired by inheritance, by merit or by some other form of social recognition.