PERMIAN-TRIASSIC MASS EXTINCTION: CAUSES AND CONSEQUENCES - GEOGRAFÍA - 2025

The Permian-Triassic mass extinction is one of five catastrophic events the planet has experienced throughout its geological history. Although it is popular belief that the extinction process in which the dinosaurs disappeared has been the most devastating, it is not.

According to the studies carried out and data collected by specialists in the area, the greatest mass extinction was that of the late Permian and early Triassic. The reason for this is that during this process, which occurred about 250 million years ago, almost all life forms on the planet disappeared.

Extinct genera in various periods. Note that the highest peak belongs to the Permian. Source: No machine-readable author provided. Nachoseli assumed (based on copyright claims)., via Wikimedia Commons

The Permian - Triassic extinction wiped out more than 90% of the species of living beings on the planet. It is important to note that at that geological moment, the Earth was abuzz with energy and life. Everywhere there were living forms with the most varied characteristics. This has been demonstrated through the fossils found.

After this process, the Earth was practically desolate, in inhospitable conditions, with a few species that survived as best they could. However, this mass extinction served as a starting point for the rebirth of another species that dominated the planet for the next million years: the Dinosaurs.

Causes

The extinction that occurred at the end of the Permian and early Triassic has been the subject of study for many years. The specialists have dedicated decades of effort in trying to elucidate what were the causes that could originate such devastation.

Unfortunately, there are only theories that are established in the deep and conscientious study carried out to found fossils.

Intense volcanic activity

Scientists agree that the volcanic activity that the planet experienced at the end of the Permian was one of the main causes of this mass extinction.

This activity was particularly intense in a region of Siberia known as the “Siberian Traps”. Today, this region is rich in volcanic rock. In the Permian period this area experienced successive eruptions that lasted for approximately one million years.

These volcanic eruptions released an exorbitant amount of lava into the atmosphere, with approximate estimates at around 3 million km3. Along with this lava, a large amount of carbon dioxide was also emitted into the atmosphere.

All these events were enough to cause a drastic climate change, increasing the general temperature of the planet several degrees.

However, the land surface was not the only one affected, since the bodies of water also received their dose of damage, since they suffered intense contamination as a result of the increase in the levels of certain toxic elements, among which the main one was the mercury.

Impact by a meteorite

The fall of a meteorite is perhaps the most cited cause by specialists on the subject. There is geological evidence that at the time when the great extension occurred, a large meteorite crashed against the Earth's surface, generating chaos and destruction, with the consequent reduction of life on the planet.

On the continent of Antarctica, a huge crater was recently discovered, approximately 500 km2 in diameter. According to estimates, for an asteroid to leave a crater of these dimensions, it must have measured almost 50 km in diameter.

Likewise, scientists postulate that the impact of this asteroid released a large fireball, produced winds with an approximate speed of 7000 km / h and the triggering of telluric movements that would exceed the measurement scales that are known today. Jan

The energy that this meteorite must have released when it hit the Earth was about 1 billion megatons. This definitely seems to be one of the causes of this mass extinction.

Methane hydrate release

Large deposits of solidified methane hydrates are found on the seabed. It is estimated that the temperature of the seas increased, either as a result of the intense volcanic activity, the asteroid collision, or both.

The truth is that the increase in temperature in the waters caused those deposits of methane hydrates to thaw, causing a large amount of methane to be released into the atmosphere.

However, it is important to note that methane is one of the strongest greenhouse gases, so that at the time it was released, it generated a relatively rapid increase in the earth's temperature.

There is talk of an increase of approximately 10 ° C, which was totally catastrophic for the living beings that coexisted at that time.

Impact on flora and fauna

The living beings that populated the planet at that time were the main affected by this terrible catastrophe that turned out to be "The Great Dying".

Regardless of what was the cause that generated this cataclysm, what is certain is that the planet was changing its habitat conditions and became an uninhabitable place for most of the species of plants and animals that existed.

In plants

While it is true that in other extinction processes it was determined that plants coped fairly well, in this extinction it was determined through fossil records and approximations that plants were as affected as animals.

Due to the drastic change in environmental conditions, a large number of land plants were affected. Among these we can mention: gymnosperms, seed-producing plants and peat-producing plants.

With regard to the latter, it was determined through the study of various fossils that they must have become extinct, or at least decrease in great quantity, since no carbon deposits have been found.

Likewise, a recent study showed that a species of fungus proliferated at this time whose specific habitat is decomposing wood. Taking this into account, it is possible to affirm then that the great extensions of trees and plants that were in the Pangea were devastated by this massive extinction event.

In animals

With regard to animals, they were the most affected by this "Great Death", since in general, approximately 90% of all species that populated the planet perished at that time.

Marine species were perhaps the most affected, since 96% of the species disappeared. Regarding terrestrial species, extinction affected 70% of the species, leaving only a few representatives.

Among those species that managed to survive this cataclysm, the first dinosaurs were found, which later came to dominate the Earth for the next 80 million years.

Another direct consequence in the animal kingdom is the total disappearance of trilobites. Importantly, the Permian-Triassic mass extinction was the only one that also affected insects.

Consequences

The Permian-Triassic extinction was such a devastating event that it took Earth an average of 10 million years to recover.

Regardless of the cause or causes that originated this phenomenon, the truth is that later, the Earth was not in habitable conditions. According to studies and fossil records, the planet became practically a hostile desert-like place, with practically no vegetation.

There are many consequences that this mass extinction entailed. These include:

Global warming

Yes, today global warming is a serious environmental problem, but the one that existed at that time was much more intense than the one that exists at this time. The atmosphere was full of greenhouse gases, many of which are much more powerful than they are today.

Due to this, the temperature on the planet was extremely high, which greatly prevented the development of life and survival of the species that had managed to save themselves.

Poor oxygen levels in the seas

As a result of the various environmental changes that occurred, oxygen levels decreased to very precarious levels, which caused the species that still existed there to be in danger of becoming extinct. However, thanks to the evolutionary process, many managed to adapt to these hostile conditions and survive.

Acid rain

Acid rain is not a phenomenon that made its appearance in the modern age, but has been around forever. The difference is that today it is caused by atmospheric pollution, for which humans are responsible.

Due to the unstable climatic conditions that existed at that time, many gases were released into the atmosphere, which reacted with the water from the clouds, causing the water that precipitated in the form of rain to be highly polluted and greatly affect the the living beings that still persisted on the planet.

References

1. Benton MJ (2005). When life nearly died: the greatest mass extinction of all time. London: Thames & Hudson.
2. Clarkson, MO et al. (2015) "Ocean acidification and the Permo-Triassic mass extinction". Science 34 (6231)
3. Erwin, D. (1994). The Permo - Triasic Extinction. Nature. 367 (6460). 231-235
4. Kaiho, et al., (2001) The Catastrophe at the End of the Permian Period by the Impact of a Bolide: Evidence for a Sulfur Escape from the Mantle. Geology, 29, 815.
5. Shen S.-Z. et al. (2011). "Calibrating the End-Permian Mass Extinction".
6. Wignall, P. and Hallam, A. (1992). Anoxia as a cause of the Permian / Triassic mass extinction: facies evidence from northern Italy and the western United States. Palaeo. 93 (1-2). 21-46