Since the human being has begun to develop technology and interest in the knowledge of this planet, attempts have been made to know how the Earth was formed. To know how our planet has been formed and the evolution it has had, you have to develop all the knowledge and dress actions in a chronological way. From here is born a branch of geology called geochronology. Geochronology is one of the branches of science that tries to study the formation and development of planet Earth in a chronological way.
In this article we are going to tell you all the characteristics of geochronology and what is its importance.
What does geochronology study
Geochronology is a science that aims to be able to determine the age and chronological sequence of geological events that have taken place in the history of the Earth. In order to know the formation of the geological elements that make up our planet, the order in which the different events happened is recognized. Every event since our planet was formed triggered the formation of the relief as we know it today. The function of geochronology is to investigate and order all these geological events.
In addition, it is responsible for establishing geochronological units. They are discrete, continuous and successive units of time that provide a time scale that covers the entire history of the Earth. It can be studied by analyzing the geological time and through geochronometry. This branch is in charge of knowing absolute ages always with a certain degree of uncertainty. There are numerous varied methods that are used to know this time and that include multidisciplinary sciences.
An attempt is also made to organize stratigraphic units composed of actual rock bodies. The importance is to delimit all the intervals that have occurred over time, even though there is a continuous material record of the same burning as all the stages. Chronostratigraphic units have an equivalent of geologic time:
- Geological time: eon, era, period, epoch, age, cron.
- Geochronology: eonotem, eratheme, system, series, floor, chronozone.
These are the units of measurement for each type. If you're interested in learning more about this topic, you can visit our section on stratigraphy.
Branches of geochronology
People of energy can be said to be different from biostratigraphy as well. Biostratigraphy is responsible for the relative chronological order of sedimentary rocksThis can be achieved by studying the fossil content found in rocks. This allows us to identify and establish different biozones that occur successively over time, which are essential for understanding geological processes, such as those observed in explorations of dormant volcanoesThese biozones are regulated by the principle of superposition of strata and the principle of faunal succession. These principles are given in the theory of continental drift.
The difference is that biostratigraphy does not provide the absolute age of a rock. It simply places it within a time interval in which all the fossil associations that have existed are known. Furthermore, it is considered that geochronology and its importance It is decisive in the temporal classification of geological events.
How to study the age of the Earth
In order to know and study the age of the geological processes that have occurred on our planet throughout history, different methods are used that are encompassed in geochronology. We are going to analyze some of them.
Methods based on the salinity of the oceans
One of the first attempts to quantitatively calculate ages was based on ocean salinity. The main idea was to calculate the time required for salt to accumulate in the oceans, starting from initially fresh water. The primitive oceans were formed by the condensation of the primordial atmosphere and had no salt at all. The salt was dissolved from the rocks by streams and rivers and transported to the sea where it became concentrated.
This tells us that it's sufficient to calculate the amounts of dissolved salts carried by rivers, the amount of salt in the sea, and reduce the time required for these salts to accumulate. This method wasn't one of the main ones because the calculations weren't sufficient due to limited data.
Sedimentation rate-based methods
The idea that other authors would use was to calculate the time it took for the sedimentary rocks of the Earth's crust to form. To do this, they estimated the time required for the sediments to be deposited in the sandstones. They then attempted to determine the maximum successor that the rock could form in each geological time period. The authors' estimates varied widely. There were stratigraphic columns that could vary perfectly from 25 to 112 km. For the sedimentation velocity there were also very variable values with different locations and rock types.
Methods based on stratigraphy and paleontology
Thanks to the emergence of the uniformitarian tendency, this represented a significant advance as it represented a new scientific mentality. This idea encompasses the idea that in geology, time is practically unlimited. Thanks to this, various data were gradually gathered that extended time in the way necessary for all geological phenomena to occur. In this way, it is possible to untie all biblical interpretations and improve the scientific method.
All geologists who followed the uniformitarian mentality held a long view of geological time. This is fundamental to understanding that geological processes occur on a geological time scale. However, the Bible warned of a catastrophe in which the earth would transform the environment in a short period of time.
Methods based on the cooling of the Earth and the sun
These methods were thermodynamic. The problem of the Earth's age was addressed through the luminosity of the sun. Sunlight was thought to come from the heat produced during the gravitational contraction of its immense mass. The idea behind these theories is that particles tend to fall toward the center, and that potential energy is released during this fall and converted into heat. With these ideas they estimated between 20 and 40 million years.
I hope that with this information you can learn more about geochronology.
Excellent article, very complete, one more follower of German, you helped me a lot for my internal geodynamics work