Geology is a very large science that in turn has smaller branches that deepen the study of the abiotic part of our planet. One of the branches of geology is geological stratigraphy. It is a science that studies the interpretation, description, identification and both vertical and horizontal sequence of the strata. It is a branch of science that allows us to know great information about the past of our planet.
In this article we are going to talk to you about what stratigraphy is, how useful it is and what objectives it studies.
What is stratigraphy
It is a branch of geology that interprets and describes how the strata have been placed over the thousands of years. In order to better interpret all this, we must bear in mind that we are talking about a scale of geological time. Rocks are layered, and each layer remains in the era in which it was deposited. Therefore, it provides us with information about the era in which we find ourselves. For example, sedimentary rocks that are forming today have adapted over the thousands of years it took for them to form. This is what provides information about the era in which they formed.
What stratigraphy tries is to know and study what information the stratified rocks give us. It is also a branch of geology that is responsible for the mapping and correlation of these rocks. This is how they determine the order and timing of events in geological time determined throughout the history of our planet.
Since sedimentary rocks are composed of materials that, for one reason or another, have formed into rocks, they are the fundamental materials studied by stratigraphy. The processes that lead to the formation of sedimentary rocks are the first field with which stratigraphy must work. It also draws on the branch of science known as paleontology to reveal what kind of living beings inhabited these sedimentary rocks during the formation.
When a stratigraphic record is made of a site, the result is the continuity of these sedimentary rock-forming processes throughout geologic time. It is, as it were, the basis of all the data necessary to understand the evolution of life on planet Earth. Thanks to stratigraphy, A lot of information has been revealed, such as the configuration of the tectonic plates through time and part of global climate change. It is also closely related to other processes such as study of internal geological processes.
Objective of stratigraphy
This branch of geology has several main objectives. Let's analyze each of them:
- Identification of materials. To know the chronological order of the formation of sedimentary rocks, it is necessary to identify what materials these rocks are composed of.
- Delimitation of stratigraphic units. A stratigraphic unit is one that has a single component throughout the stratum. That is, there is no single type of sedimentary rock that formed at a specific time.
- Organization of stratigraphic units. Once the materials and stratigraphic units have been identified, an attempt is made to sort them in time. That is, to determine which stratigraphic units formed first and which ones formed last. In this way, a great deal of information is obtained about the geology of the terrain.
- Survey of stratigraphic sections. Not only is the stratigraphy of the terrain known as a function of height. You can also estimate the formation and age of certain rocks.
- Genetic interpretation of units. When you analyze a stratigraphic unit, you can analyze all the components and the reason why they were formed.
- Correlation and allocation of time. It is about the estimation of the age of the rocks and the knowledge of both living beings and the global climate that existed at that time.
- Watershed analysisStratigraphy is an important branch of science when studying the formation of watersheds worldwide.
It is a science capable of recording shapes, lithological compositions, physical and chemical properties, age relationships, original successions, distribution, and fossil content of sedimentary rocks. With all this information, we can learn more about the geology of the terrain and the era in which it was formed. All these characteristics serve to successively recognize and reconstruct the geological events that have taken place throughout Earth's history. It is also related to the study of Geographical accidents and its formation.
Fundamental principles of stratigraphy
This science is instituted in certain fairly elementary principles from which the rest of the acquired knowledge is developed:
- Principle of original horizontality or layer superposition. It is a principle that establishes that the strata are deposited horizontally, the oldest being even below and the youngest above. If you continue analyzing laterally, you can see that they are not interrupted by erosion.
- Cut and inclusion relationships. If we see a cut in a stratum, we must know that the feature that produced the process that cut it is older than the one being cut. A rock is younger than the rock fragments included within it.
- Actualism. This is the principle that states that "the present is the key to the past." This means that rivers, rocks, seas, and continents have changed in all their parts. However, the laws that describe the changes and the rules to which these elements are subject have remained unchanged over time. This principle is related to other important concepts in current geology.
- Faunal succession. Just as the strata have a chronological order, the fossils found in the strata also have an identifiable order.
- Succession of facies. The point is that the horizontal succession of facies is the same as the vertical one.
As you can see, it is important to understand the strata to learn more about the geology of our planet. I hope that with this information you can learn more about the geological stratigraphy.
