Within the Paleozoic Era, we have several periods into which geological time is divided . The first division belongs to the Cambrian. This is a division of the geological timescale and the first of the six periods of the Paleozoic Era. It began approximately 541 million years ago and ended approximately 485 million years ago. The next period is the Ordovician.
In this article we are going to focus on all the features, geology, climate, flora and fauna of the Cambrian period.
Key features
This period of the Paleozoic era is particularly noteworthy due to its profound geological impact on the entire planet . The Cambrian period was once thought to span only 70 million years, but science has since revised this understanding thanks to information from the fossil record. The branch of geology that focuses on these transformations experienced by planet Earth since its formation is historical geology.
This entire period receives the name of the Cambrian from the name that comes from Cambria. This name is the Latinized form of Cymru which means Wales. Wales is today where the first geological remains belonging to this period were identified. Along this geological division there is a great explosion of life for the first time recorded in fossils. The first multicellular organisms can be distinguished which are more complex than sponges or jellyfish.
Among the most important creatures of this period were the green algae, which measured only a few millimeters in diameter, and the trilobites. These trilobites are a famous group of arthropods that were able to survive two mass extinctions. This surge of life is known as the Cambrian explosion and was one of the major events that marked the boundary between the Neoproterozoic and Cambrian periods. To learn more about this evolutionary dynamic, you can consult the article on Cambrian fauna and the different geological periods.
Cambrian period geology
During this period, it is thought that the continents resulted from the fragmentation of a large supercontinent that existed during the Neoproterozoic era and was called Pannotia. The largest fragment of the supercontinent is Gondwana, located in the south alongside three smaller continents called Laurentia, Siberia, and Baltica. These continents drifted northward due to plate tectonics , driven by convection currents in the Earth's mantle.
This is how continental drift began, eventually forming the positions we know today. Continental drift rates during the Cambrian period are estimated to have been abnormally high compared to previous periods. This indicates a high level of tectonic plate activity. Thanks to these continental movements, biodiversity increased globally, as diverse ecosystems with different characteristics were created. To delve deeper into these geological changes, it is interesting to review the article on the Proterozoic.
The Panthalassa Ocean covered most of the entire planet, while other smaller oceans such as the proto-Tethys and the Khanty Ocean were located between the waters of the smaller continents called Laurentia and Baltica.
Cambrian climate
The climate of the Cambrian Period is believed to have been significantly warmer than that of earlier periods. During this period, there was no polar glaciation. That is, none of the Earth's geographic poles were covered by ice. The Cambrian Period is further divided into three epochs: Early Cambrian, Middle Cambrian, and Late Cambrian. Let's briefly analyze the climate and geology of each epoch during this period.
- Lower Cambrian: During this time the Gondwana continent and other smaller land masses occupied all the equatorial zones. This has been known thanks to the records of the limestone deposits in the abundant seas and tropical epicontinental. At that time, the Cadomian orogeny is what led to periods of emergence of large land masses at the beginning of the Cambrian.
- Middle Cambrian: during this time there was a transgressive cycle that was interrupted by two regressive pulses.
- Upper Cambrian: Much of the Gondwana continent that occupied more equatorial positions, was moving towards colder latitudes. They were being replaced in positions since the smaller continental masses such as Laurentia, Siberia and Australia were occupying equatorial positions.
Life blast
As we mentioned earlier, this period is known as a division of time marked by an explosion of life more intense than any ever recorded. It is known as the Cambrian explosion. This explosion led to the emergence of incredible biodiversity on the planet, including many of the animal groups we know today, such as chordates, which belong to the vertebrate group and include humans. It is not known for certain how such a spark of biological explosion was possible. It is believed that it may have been the oxygen present in the atmosphere at that time, which, thanks to emissions from cyanobacteria and algae performing photosynthesis, reached the levels necessary for all organisms to develop their most complex structures, giving rise to different life forms.
Another aspect to consider is the environment, which became more hospitable as the climate warmed and sea levels rose. This created shallow marine habitats that were ideal for generating new life forms due to the abundance of nutrients. The relationship with other periods, such as the Ordovician , is also important for understanding the evolution of life in different eras and its connection to previous fauna.
However, it is thought that many scientists have exaggerated the magnitude of the Cambrian explosion due to the proliferation of animals with hard structures that fossilized more quickly and easily than their predecessors. Since fossil records of all these animals depend on their body structure, they cannot be fossilized in the same way. For example, quite a bit is known about brachiopods that lived in shells similar to clams and cockles, and other animals with articulated exoskeletons known today as arthropods.
I hope that with this information you can learn more about the Cambrian period.
