Jurassic period

Within the Mesozoic era there are 3 periods that separate different events that have marked a beginning and an end both at a geological and biological level. The first period is the Triassic and today we are going to focus on the second period of the Mesozoic. It is about the Jurassic. It is a division of the geological timescale that began approximately 199 million years ago and ended approximately 145 million years ago. As with most geologic eras, both the beginning and the end of the periods are not entirely accurate.

In this article we are going to tell you all the characteristics, geology, climate, flora and fauna of the Jurassic.

Key features

Dinosaurs

It is a period of time in which some important events have occurred globally and that is after the Triassic and before the Cretaceous. The name of Jurassic comes from the carbonate sedimentary formations that occurred in the European region of the Jura, located in the Alps. Hence the name is Jurassic. Throughout this period one of the main characteristics for which it stands out is the hegemony of the great dinosaurs (for which many films have been made) and the splitting of the super continent Pangea into the continents of Laurasia and Gondwana.

Australia broke off from the portion called Gondawana during the Upper Jurassic and early Cretaceous. In this same way, Laurasia was divided into what we know today as North America and Eurasia, giving rise to various new species of mammals as environmental conditions changed for all of them.

Jurassic geology

Jurassic period

This geological period is mainly divided into lower, middle and upper. These are the well-known epochs within a period. It has been given the names Lias, Dogger, and Malm. During the Jurassic the sea level experienced several minor changes but only during the interior. Already in the upper Jurassic it was possible to observe some faster oscillations in a matter of time that led to a rise in sea level causing the flooding of large areas in North America and Europe.

In this period we can point to two biogeographic provinces located in what we know today as Europe. One is known as Tethys to the south and another boreal to the north. All coral reefs had to be restricted for the most part in the province of Tethys. The transition that existed between the two provinces was located in what is now the Iberian Peninsula.

The geological record of the Jurassic period is quite good, especially in western Europe. And it is that in this part of the continent there were extensive marine sequences that indicate a time when much of the continent was submerged under tropical seas with little depth. Due to the fame that these submerged areas stand out, it is known as the World Heritage of the Jurassic Coast and the lagerstätten of Holzmaden and Solnhofen.

Jurassic climate

Jurassic vegetation

During this period, the plants that were accustomed to a warmer climate were the ones that spread almost all over the land. These plants were able to extend up to 60 degrees latitude. Both the flora that belonged to the southern Gondwana cleavage, to the north of Siberia included numerous groups of ferns that were able to withstand fairly strong frosts. Today, the modern relatives of these ferns are not able to model frost and low temperatures frequently.

All this of the existence of high temperatures caused that the landscapes of the Jurassic were richer in vegetation than those of the Triassic. Especially, there were a lot of abundant vegetation in the higher latitudes. Since it was quite hot and a humid climate allowed to extend to all the jungles, jungles and forests that formed a great amount of landscape is typical of the Jurassic films. This is how the forests also begin to spread throughout the earth's surface and families such as conifers similar to pines and araucarias stand out, accompanied by various types of ferns and palm trees. Surely all these landscapes full of post vegetation will recall some Jurassic movies.

Flora and fauna

jurassic landscape

During the Jurassic period, flora had quite a global relevance, especially at high latitudes. Not only were terrestrial forests full of conifers and ferns abundant, but ginkgoes and horsetails were also present. During this period, the plants that have inflorescences still do not appear. We recall that, up to now, the most widespread plants globally belong to the group of gymnosperms, that is, those that do not have flowers.

The differential distribution of the flora throughout the entire land area is a true reflection of the separation that existed between the equatorial and northern zones. The development of differentiated reindeer was caused by the existence of numerous marine barriers that existed between the north and south. These marine barriers were conditioned by a greater temperature gradient that went from the most part of the pole to the Equator. These thermal gradients were not as steep as they are today although there is no evidence of polar ice during the Jurassic. This means that the hypothesis that the temperatures were high and were the cause of the spread of this type of plants is further corroborated.

The flora that was far from the equator corresponded to the plants of temperate zones and all these Jurassic landscapes were called by the name of Cycadophyta. Ginkgo forests and two conifers overlooked the entire landscape. Modernity remains but true flowering plants were still absent. The same was true of hardwood trees.

As for the fauna, dinosaurs spread on a global scale in this period, being the animals that predominated on the planet during the rest of the period.

I hope that with this information you can learn more about the Jurassic.


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